**Conventional and Organic Farming — Does Organic Farming Benefit Plant Composition, Phenolic Diversity and Antioxidant Properties?**

Alfredo Aires

[29] Schwartz, S.H. (1977), "Normative Influences on Altruism", Advances in Experimen‐

[30] Scialabba, N. (2000), "Factors Influencing Organic Agriculture Policies With A Focus On Developing Countries", IFOAM 2000 Scientific Conference, Switzerland.

[31] Sheperd, R., Magnusson, M., and Sjoden, P.O. (2005), "Determinants Of Consumer

[32] Sirieix, L., Pontier, S., and Schaer, B. (2004), "Orientations De La Confiance Et Choix Du Circuit De Distribution: Le Cas Des Produits Biologiques", Proceedings of the

[33] Soil Association (SA), 1999-2004, "Soil Association Organic Food and Farming Re‐

[34] Tarkiainen, A., and Sundqvist, S. (2005), "Subjective Norms, Attitudes And Inten‐ tions Of Finnish Consumers In Buying Organic Food", British Food Journal, Vol. 107

[35] Urala, N., and Lahteenmaki, L. (2003), "Reasons Behind Consumers' Functional Food

[36] Van Elzakker B., and Eyhorn F. (2010), "Developing Sustainable Value Chains With

[37] Weber, M. (1964), "Economy And Society", University of California Press. Retrieved from: https://docs.google.com/forms/d/16zP78RY0zQFemKdspwIz‐

[38] Wier, M., and Calverly, C. (2002), "Market Potential For Organic Foods In Europe",

[39] Wilkins, J.L., Bokaer-Smith, J., and Hilchey, D. (1996). "Local Foods And Local Agri‐ culture: Survey Of Attitudes Among Northeastern Consumers", Northeast Regional

[40] Willer, H., and Yussefi (2007), "The World Of Organic Agriculture", Online Report.

[41] Willer, H., and Kilcher, L. (2011), "The World of Organic Agriculture Statistics and

[42] Zanoli, R., and Naspetti, S. (2002), "Consumer Motivations in the Purchase of Organ‐ ic Food: A Means End Approach", British Food Journal, Vol. 104, 643-653.

Behaviour Related To Organic Foods", Ambio, Vol. 34 (4/5), 352-359.

10th FMA International Congress, St. Malo, France.

Choice", Nutrition and Food Science, Vol. 33 (4), 148-158.

Smallholders", The Organic Business Guide, Online Report.

CyEUIX24LHJc0ket\_uQMpnE/viewanalytics.

Emerging Trends 2011", IFOAM, Bonn, & FiBL.

British Food Journal, Vol. 104 (1), 45-62.

Food Guide Project. Cornell.

tal Social Psychology, (10), 221-279.

326 Organic Farming - A Promising Way of Food Production

port", SA, Bristol.

No. 11, pp. 808-22.

Additional information is available at the end of the chapter

http://dx.doi.org/10.5772/61367

### **Abstract**

The growing demanding from consumers for healthier foods, produced using environmentally friendly farming practices has resulted in the rapid expansion of organic farming. There are numerous studies about the importance of organic farming but the majority of the results are sometimes contradictory, inconsistent and show no clear link between organic farming practices and enhancement of the nutritional quality of plant-derived foods. As such, ongoing research into the effects of organic farming and cultivation practices in comparison with intensive farming, is very important. The objective of this chapter is to discuss the most recent data and variation in the responses of plants to farming regimes in order to better understand the relationship between agricultural practices and high levels of valuable compounds (glucosinolates, phenolics, minerals, vitamins, antioxidants), as well as low levels of undesirable components such as nitrates, nitrites and microorganisms.

**Keywords:** Organic farming, conventional faming, nutrient diversity, phytochemicals, quality, safety

### **1. Introduction**

Research studies continue to show that the desire of consumers to be able to purchase healthier fruits and vegetables, produced by a more sustainable and environmental friendly agricultural system, is increasing day-by-day. The majority of these studies attempt to show how safe and nutritious organic foods are for humans [1] and animals [2]. According to European regulations

© 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

[3] organic farming is defined as an overall system of farm management and food production that combines the best environmental practices, high levels of biodiversity, the preservation of natural resources, the application of high animal welfare standards and utilises production methods in line with the preference of consumers for products produced using natural substances and processes. The aim of an organic farming system is to provide to the consumer with fresh, tasty and natural food, while respecting natural systems and the environment. To achieve this, several principles and rules are followed in order to minimize human impact on the environment, while at the same time ensuring the agricultural system operates as naturally as possible [4]. Several different approaches are employed, but all of them are guided by strict rules [3] aimed at protecting the integrity of the environment, plants, animals and biodiversity.

A fundamental aim of organic farming is the provision of healthy, high quality plant and animal-derived foods. The concept of food quality can be defined in many different ways. Often, the quality of food is based on visual characters such as shape, size and colour, but can also be described as containing fewer pesticides, or more nutrients, or even containing specific functional properties due to elevated levels of phytochemicals [1, 5]. Thus, there is no one sole concept of quality. Nonetheless, countless studies of quality always refer to at least one or more of the following criteria: (i) food safety (absence of undesirable components like nitrites and pathogenic microorganisms); (ii) primary nutrients (minerals and vitamins, for example); (iii) secondary metabolites and phytochemicals that are closely associated with the beneficial health properties of plant and animal-derived foods; and (iv) observed health effects. How‐ ever, research studies using these criteria vary widely, with investigative topics ranging from the taste of the food to how the food in question benefits health. Despite this diversity, the link between organic products and their nutritional, functional, and biological values is far from being fully understood. Therefore, in this chapter, we discuss recent advances in organic farming, particularly its differences from conventional farming, highlighting the differences in vitamins, minerals, phytochemicals, antioxidant activity and sensorial properties.

### **2. Factors and constraints affecting crop and plant-derived food composition**

Growing crops in any part of the world is affected by many variables, including environmental, agronomical, social and economic factors, among others. These factors can affect not which particular type of agricultural system is employed, or which type of crop produced, but also and more importantly, the quality of the crop. Both conventional and organic farming systems are always heavily influenced by such factors. These factors can be grouped into 4 main types (Figure 1): a) socio-economic; b) pre-harvest; c) harvest; and d) post-harvest.

A recent study [6] showed that the choice between an organic or conventional farming system is primarily dependent on socio-economic factors, secondarily dependent on social aspects and then all of the remaining factors follow on. In fact, when farmers implement any produc‐ tion system or crop, their first question is: How profitable is it to produce? The answer will depend on the choices the farmer makes about what crops to grow, where to grow them, and

**Figure 1.** Constraint factors of any crop yield and production.

[3] organic farming is defined as an overall system of farm management and food production that combines the best environmental practices, high levels of biodiversity, the preservation of natural resources, the application of high animal welfare standards and utilises production methods in line with the preference of consumers for products produced using natural substances and processes. The aim of an organic farming system is to provide to the consumer with fresh, tasty and natural food, while respecting natural systems and the environment. To achieve this, several principles and rules are followed in order to minimize human impact on the environment, while at the same time ensuring the agricultural system operates as naturally as possible [4]. Several different approaches are employed, but all of them are guided by strict rules [3] aimed at protecting the integrity of the environment, plants, animals and biodiversity. A fundamental aim of organic farming is the provision of healthy, high quality plant and animal-derived foods. The concept of food quality can be defined in many different ways. Often, the quality of food is based on visual characters such as shape, size and colour, but can also be described as containing fewer pesticides, or more nutrients, or even containing specific functional properties due to elevated levels of phytochemicals [1, 5]. Thus, there is no one sole concept of quality. Nonetheless, countless studies of quality always refer to at least one or more of the following criteria: (i) food safety (absence of undesirable components like nitrites and pathogenic microorganisms); (ii) primary nutrients (minerals and vitamins, for example); (iii) secondary metabolites and phytochemicals that are closely associated with the beneficial health properties of plant and animal-derived foods; and (iv) observed health effects. How‐ ever, research studies using these criteria vary widely, with investigative topics ranging from the taste of the food to how the food in question benefits health. Despite this diversity, the link between organic products and their nutritional, functional, and biological values is far from being fully understood. Therefore, in this chapter, we discuss recent advances in organic farming, particularly its differences from conventional farming, highlighting the differences

328 Organic Farming - A Promising Way of Food Production

in vitamins, minerals, phytochemicals, antioxidant activity and sensorial properties.

Growing crops in any part of the world is affected by many variables, including environmental, agronomical, social and economic factors, among others. These factors can affect not which particular type of agricultural system is employed, or which type of crop produced, but also and more importantly, the quality of the crop. Both conventional and organic farming systems are always heavily influenced by such factors. These factors can be grouped into 4 main types

A recent study [6] showed that the choice between an organic or conventional farming system is primarily dependent on socio-economic factors, secondarily dependent on social aspects and then all of the remaining factors follow on. In fact, when farmers implement any produc‐ tion system or crop, their first question is: How profitable is it to produce? The answer will depend on the choices the farmer makes about what crops to grow, where to grow them, and

**2. Factors and constraints affecting crop and plant-derived food**

(Figure 1): a) socio-economic; b) pre-harvest; c) harvest; and d) post-harvest.

**composition**

what technologies he uses. In addition, farmers tend to follow the system producing a higher financial income, lower financial risks, lower labour requirements, and if possible, the greatest pleasure [7]. The ability to obtain credit will also influence the choice of crops, farming systems and technologies [8]. The level of technical and scientific knowledge of production will also affect a farmer's propensity to choose a particular crop or production system [9, 10]. Moreover, the capital requirement for any crop development is always present, but can vary seasonally and is often far higher during harvesting than at other times during the production period. Any financial or labour constraint can negatively affect negatively the farmer´s productivity and, therefore, income [11].

Another social aspect of decision to farm organically or conventionally is public demand [12]. If a farmer wants to succeed, then there must be a demand for their products, to generate an income, otherwise the farmer will switch to another, more profitable crop, whether it is organic or not.

Production is also affected by pre-harvest factors. In general, these factors include all physical factors, such as genetics, geology, soil and climatic conditions and cultural practices [13, 14, 15]. In other words, after a specific crop has been chosen, its success will depend on the outcome of the complex interaction between numerous elements such as the biology of the plant, interaction between plant and soil, crop management techniques, mineral and organic nutrition, chemical or biochemical treatments, and the watering regime employed, among other factors. Climatic parameters such temperature, humidity, altitude, rainfall and wind, are all fundamental factors affecting the variation of plant and crop success [16, 17] and thus their nutritional quality as food. Temperatures can limit the growth of crops; water is a key factor in plant growth with different crops requiring water at different times; altitude primarily affects the average temperatures and consequently the type of farming; wind can have a destructive effect on crops physically, as well as increasing the dryness of soils, reducing moisture and increasing the potential for soil erosion. The soil type will influence crop cultivation because different crops prefer different soils, e.g., clay soils with their high levels of water retention are widely used to produce rice, as rice requires a lot of of water to grow successfully [18, 19], whilst sandy soils are more suited to roots, tubers and vegetables, due to their need for better drainage, which is a requirement for good development of their roots [20]. Thus, selecting the right crop for the given specific conditions is fundamental to increasing yield and quality.

Another set of factors are relate to the harvest period. It is widely accepted that stage of maturity at harvest can have a critical influence on the nutritional content of the crop. Zaro et al. [21], observed marked changes in the level of bioactive compounds present (anthocyanins, carotenoids, ascorbic acid, phenolics) and in antioxidant activity of purple eggplants at the fruiting stage. They found a decrease of such compounds and beneficial properties when plants were harvested at earlier stages (I and II). The same tendency was recently observed [22] in carrots, where a relatively high amount of falcarindiol, an important antioxidant compound, was present during very early harvest (i.e. 103 to 104 days after sowing) compared with a later harvest (i.e. 117 to 118 days after sowing). The same trend was also recently noted [23] for anthocyanin content in blueberries when harvested earlier, but not when harvested at full maturity. Thus, correct choice of harvesting time is crucial in preserving the quality of fresh produce during storage. This way, it is possible to provide the consumer with high quality fresh food products.

After harvesting, several factors (identified here as post-harvest factors) can interfere with the quality of fruit and vegetables. Among them are temperature regime of storage, relative humidity of storage, type of atmosphere used if any, and packaging [24, 25]. Temperature management during shelf-life is one of the most important means of preserving the quality of fresh roots, fruits and vegetables. After harvest, any delay in cooling, or choosing the wrong temperature regime, can result in losses in nutritional quality, flavour, taste and saleability. Tano et al. [26], found that the quality of mushrooms, tomatoes and cabbages stored under a fluctuating temperature regime was severely affected by extensive browning, loss of firmness, increased weight loss, increased level of ethanol in plant tissues, and fungal infections due to physiological damage and excessive condensation, when compared with products stored at a constant temperature. Similar observations were recently made [27] for mandarins, when low storage temperatures (2, 5 and 8 ºC) resulted in a loss of orange peel colour, volatile com‐ pounds, and flavour. Thus, storage temperature is a fundamental factor affecting nutrients, colour and flavour [27]. In addition, particular attention should be paid post-harvest proce‐ dures such as cleaning, bruising, trimming and cutting, which may also affects the quality of products if they are conducted in inappropriate conditions or improperly performed [28]. Thus, the quality and stability of plant-derived food products will be strongly dependent on the interaction of several different factors and, therefore, an understanding of the physiological and biochemical process in plants and foods during the period of shelf-life, is crucial to maximising their nutritional quality and bioactive composition, and thereby their properties beneficial to health.

### **3. Conventional versus organic**

all fundamental factors affecting the variation of plant and crop success [16, 17] and thus their nutritional quality as food. Temperatures can limit the growth of crops; water is a key factor in plant growth with different crops requiring water at different times; altitude primarily affects the average temperatures and consequently the type of farming; wind can have a destructive effect on crops physically, as well as increasing the dryness of soils, reducing moisture and increasing the potential for soil erosion. The soil type will influence crop cultivation because different crops prefer different soils, e.g., clay soils with their high levels of water retention are widely used to produce rice, as rice requires a lot of of water to grow successfully [18, 19], whilst sandy soils are more suited to roots, tubers and vegetables, due to their need for better drainage, which is a requirement for good development of their roots [20]. Thus, selecting the right crop for the given specific conditions is fundamental to increasing

Another set of factors are relate to the harvest period. It is widely accepted that stage of maturity at harvest can have a critical influence on the nutritional content of the crop. Zaro et al. [21], observed marked changes in the level of bioactive compounds present (anthocyanins, carotenoids, ascorbic acid, phenolics) and in antioxidant activity of purple eggplants at the fruiting stage. They found a decrease of such compounds and beneficial properties when plants were harvested at earlier stages (I and II). The same tendency was recently observed [22] in carrots, where a relatively high amount of falcarindiol, an important antioxidant compound, was present during very early harvest (i.e. 103 to 104 days after sowing) compared with a later harvest (i.e. 117 to 118 days after sowing). The same trend was also recently noted [23] for anthocyanin content in blueberries when harvested earlier, but not when harvested at full maturity. Thus, correct choice of harvesting time is crucial in preserving the quality of fresh produce during storage. This way, it is possible to provide the consumer with high quality

After harvesting, several factors (identified here as post-harvest factors) can interfere with the quality of fruit and vegetables. Among them are temperature regime of storage, relative humidity of storage, type of atmosphere used if any, and packaging [24, 25]. Temperature management during shelf-life is one of the most important means of preserving the quality of fresh roots, fruits and vegetables. After harvest, any delay in cooling, or choosing the wrong temperature regime, can result in losses in nutritional quality, flavour, taste and saleability. Tano et al. [26], found that the quality of mushrooms, tomatoes and cabbages stored under a fluctuating temperature regime was severely affected by extensive browning, loss of firmness, increased weight loss, increased level of ethanol in plant tissues, and fungal infections due to physiological damage and excessive condensation, when compared with products stored at a constant temperature. Similar observations were recently made [27] for mandarins, when low storage temperatures (2, 5 and 8 ºC) resulted in a loss of orange peel colour, volatile com‐ pounds, and flavour. Thus, storage temperature is a fundamental factor affecting nutrients, colour and flavour [27]. In addition, particular attention should be paid post-harvest proce‐ dures such as cleaning, bruising, trimming and cutting, which may also affects the quality of products if they are conducted in inappropriate conditions or improperly performed [28]. Thus, the quality and stability of plant-derived food products will be strongly dependent on

yield and quality.

330 Organic Farming - A Promising Way of Food Production

fresh food products.

Organic farming has increased in popularity in recent decades due to the public's perception that health problems may arise from the consumption of plant-derived foods produced under intensive farming practices. This growing concern lead to a considerable number of studies into the effect of organic production on nutrients (mineral, vitamins) and phytochemicals such as polyphenols, antioxidant vitamins (A, C, E), glucosinolates, carotenoids and isoflavones, among others. Although a large number of studies about the differences between plants produced under conventional and organic farming systems is now available, most of the studies present contradictory facts, inconsistent results and the differences are often reported as negligible. Consequently, it is important to study the variation in nutritional quality and safety of plant-derived food produced under both organic and conventional farming methods. In the following paragraphs we discuss recent findings about the effect of the two different agricultural systems on the variation in nutrients and phytochemicals in plant-derived food, focusing on the major differences already discovered.

### **3.1. Variations in vitamin, mineral, amino-acid and nitrate content**

The nutritional value of food is essentially a function of its vitamin and mineral content, particularly those related to important beneficial functions in animals and humans [29]. Essential minerals required in the human diet include, among others, phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), iron (Fe), sulphur (S), boron (B), chromium (Cr), cobalt (Co), copper (Cu), iodine (I), manganese (Mn), molybdenum (Mo), selenium (Se), tin (Sn), and zinc (Zn) [30, 31] and the essential vitamins include mainly A, B (all vitamins of the B complex), C, E and K [30]. Compared with conventional farming, organic production relies on sustainable management practices, which include crop rotations, cover cropping, nutrient recycling, integrated pest management, and use of organic fertilisation [32], among other practices. All these practices, according to the majority of consumers have indeed had a positive impact on food quality, enhancing the levels of beneficial minerals and vitamins [33]. However, from a scientific point of view, the question of whether organic plant-derived foods are more nutritious than conventional ones remains.

Conventional farming usually relies on massive doses of readily soluble forms of mineral fertilisers (mainly in N, P, K form), whilst organic farming relies on the incorporation of organic material into the soil, normally through the use of animal manure as fertiliser [34]. Composted manure is the most commonly used fertiliser in organic farming [35] and thus the general consumer perception is that organic foods are better because they are produced using natural and safe agronomical inputs [33], and thus they are more nutritious.

Throughout the past 15 years, several comparative studies have demonstrated significant differences in the content of vitamins, minerals and free amino-acids (Table 1). However, several authors claim that no major or significant differences are found in mineral and vitamin content in fruits and vegetables produced under organic or conventional farming systems, and several others report that for some specific nutrients, conventionally grown plant-derived foods usually contain higher average levels (Table 1).


**Table 1.** Differences in the content of nutrients in organic and conventional fruit and vegetables

Some research studies have claimed that organic amendments can have a positive effect on the content of antioxidant vitamins such as vitamin C [47], but others claims that the effect is negative [42], whilst others still, claim no significant difference [43, 45, 55]. Thus, there is a discrepancy in the results, and external factors such as crop variety, crop location, climate and growing conditions [56] can all exert an effect. Moreover, it is unlikely that mineral fertilisers or manure alone can affect the nutritional content of fruits and vegetables. Nonetheless, the majority of authors seems to agree that an organic production system is friendlier than an intensive or conventional farming system and the choice of organic system as an alternative to conventional practice can be justified by its lower environmental impact [57].

Throughout the past 15 years, several comparative studies have demonstrated significant differences in the content of vitamins, minerals and free amino-acids (Table 1). However, several authors claim that no major or significant differences are found in mineral and vitamin content in fruits and vegetables produced under organic or conventional farming systems, and several others report that for some specific nutrients, conventionally grown plant-derived

**Products tested Nutrients analysed Key-results Reference**

cabbage Iron, Mg, and P **Higher** in **organics** [36]

Wheat Minerals (N, K, Mg, Ca, S, Fe,) **Similar** in **both** [38] Red potatoes Minerals (K, Mg, P, S and Cu) **Higher** in **organics** [39] Wheat Essential Amino acids **Lower** in **organics** [40] Wheat Minerals (P, K, Ca, Zn, Mo, Co) **Similar** in **both** [40] Kiwi fruits Minerals (N, P, K, S, B, Ca, Mg) **Higher** in **organics** [41] Tomato Vitamin C **Lower** in **organics** [42] Broccoli Vitamin C **Similar** in **both** [43] Spinach Nitrate **Lower** in **organics** [44] Strawberry Vitamin C **Similar** content [45]

Acerola Vitamin C and carotenoids **Higher** in **organics** [47] Strawberries Vitamin C and carotenoids **Similar** in **both** [47]

Potatoes Essential amino acids **Higher** in **organics** [49] Strawberries Ascorbic acid **Higher** in **organics** [50] Cauliflower Soluble solids, nitrates, P and K **Similar** in **both** [51] Green pepper Weight, firmness, thickness, N and P **Lower** in **organics** [52] Tomatoes Vitamin C **Higher** in **organics** [53]

Nitrates **Lower** in **organics** [46]

**Higher** in **organics**, but only when higher organic fertiliser levels were applied

**Higher** in **organics** [54]

[48]

lettuce, spinach Vitamin C, β-carotene and riboflavin **Higher** in **organics** [37]

foods usually contain higher average levels (Table 1).

Cauliflower Vitamin C

Apple Aromatic volatiles, organic acids and

**Table 1.** Differences in the content of nutrients in organic and conventional fruit and vegetables

sugars

Lettuce, spinach, carrots, potato and

332 Organic Farming - A Promising Way of Food Production

Chinese mustard, Chinese kale,

Broadbean, bean, lettuce, pepper, watermelon.

Another important issue related to the nutritional quality and safety of organic food is nitrate content, particularly in fresh vegetables. Nitrates are a natural consequence of the mechanism by which plants absorb the element nitrogen, in the form of NO3-, from fertilisers or organic material [58]. Although nitrate is an important component of plants, it has the potential to accumulate in tissues, particularly in green leafy vegetables [59] and thus, nitrate from fertilizers could accumulate in vegetables on a large scale. The danger of this, lies in the fact that nitrates can be reduced to nitrites, which can react with amines and amides to produce "N-nitroso" compounds, responsible for gastric cancer [60]. In order to maximize the health benefits from eating vegetables, measures should be taken to reduce levels of nitrates and nitrites [59]. This is particularly true in organic farming due to the large quantities of manure used as natural fertiliser, which is sometimes reported as having the potential to elevate levels of nitrates and nitrites up to, or above, maximum residue levels (MRLs), which is dangerous. However, some studies report that manure fertilisers have no significant effect on nitrate levels because organic products should always contain fewer nitrates than their counterparts produced by conventional methods, due to their lower concentration of nitrogen-based fertilisers [61, 62]. Furthermore, several other authors have reported that nitrate content is more closely related to genotype, soil conditions, growth conditions (i.e., nitrate uptake, nitrate reductase activity, and growth rate), storage and transport conditions, than to mineral or organic amendments [63]. More recently [64] it was shown that that nitrate accumulation in vegetables is more closely related to the quality of water and water accumulation in vegetable tissues. Thus, the results available until now from various different studies are sometimes contradictory and doubts still remain. Nonetheless, based on the fact that organic farming enhances specific nutrients and is less aggressive to the environment, it is more beneficial than conventional farming, which is seen as more aggressive to the environment, fauna and flora, and ultimately, to animals and humans.

### **3.2. Influence on bioactive compounds and functional properties of foods**

### *3.2.1. Glucosinolates, phenolics, carotenoids and pigments*

Recent scientific advances in plant-derived foods studies have mainly focused on the potential health effects of phytochemicals in plant foods. Phytochemicals, also known as bioactive compounds, are naturally occurring substances in plants, functioning mainly as secondary metabolites [65]. Their distribution in plants is considered to be the result of the natural adaptation of plants to environmental stress, pathogen infection, insects and other pests [66]. According Harbone [66], phytochemicals can be divided into different classes: phenolics (e.g. phenolic acids, flavonoids, anthocyanin), terpenoids (e.g., carotenoids, xanthophylls and other pigments), alkaloids (e.g., indole compounds), and sulphur-containing compounds (e.g., glucosinolates). Table 2 gives a brief summary of phytochemicals commonly found in fruits and vegetables, and the potential health benefits associated with them. To date, studies have shown that phytochemicals can have a protective effect on human health (Table 2 and Table 3), including mopping-up free radicals, reduction of oxidative stress, inhibition of cell prolif‐ eration, induction of cell differentiation, inhibition of oncogene expression, suppression of gene expression in carcinogenic processes, modulation of detoxification enzymes, stimulation of the immune system, regulation of hormone metabolism, and antibacterial and antiviral effects [67]. Strong associations have been also found between disease risk reduction and consumption of foods with a high content of glucosinolates (anti-cancer), tocopherols (cardi‐ ovascular), phenolics and carotenoids (eye-health) [68].


Conventional and Organic Farming — Does Organic Farming Benefit Plant Composition, Phenolic... http://dx.doi.org/10.5772/61367 335


**Table 2.** Examples of some important phytochemicals commonly found in foods


• inhibition of signal transduction pathways

adaptation of plants to environmental stress, pathogen infection, insects and other pests [66]. According Harbone [66], phytochemicals can be divided into different classes: phenolics (e.g. phenolic acids, flavonoids, anthocyanin), terpenoids (e.g., carotenoids, xanthophylls and other pigments), alkaloids (e.g., indole compounds), and sulphur-containing compounds (e.g., glucosinolates). Table 2 gives a brief summary of phytochemicals commonly found in fruits and vegetables, and the potential health benefits associated with them. To date, studies have shown that phytochemicals can have a protective effect on human health (Table 2 and Table 3), including mopping-up free radicals, reduction of oxidative stress, inhibition of cell prolif‐ eration, induction of cell differentiation, inhibition of oncogene expression, suppression of gene expression in carcinogenic processes, modulation of detoxification enzymes, stimulation of the immune system, regulation of hormone metabolism, and antibacterial and antiviral effects [67]. Strong associations have been also found between disease risk reduction and consumption of foods with a high content of glucosinolates (anti-cancer), tocopherols (cardi‐

**Class Example literature**

Tea, kiwi fruit, strawberries,

apples, cranberries, beans

cocoa, black-eyed peas

Flavones Apigenin Chamomile, celery, parsley Lowers high blood pressure,

strawberries

chickpeas other legumes

seeds, pumpkin seeds

and peanuts

**Example of food sources Proposed health benefits found in**

pineapple, coffee Antioxidant and anti-inflammatory

Antioxidant, anti-inflammatory, enzyme inhibitor and immune modulation

Antioxidant, anti-hypertensive, antiinflammatory, anti-proliferative, antithrombogenic, and lipid lowering effects

antioxidant and anti-inflammatory

Improvement of vision, and neuroprotective effects

Reduction in blood pressure, antioxidant activity

Improves glucose control, prevents pre-cancerous cellular changes, decreases the incidence of several chronic diseases

Antioxidant, anti-inflammatory, protects the body against nitric oxide, keeps the blood vessels optimally dilated

ovascular), phenolics and carotenoids (eye-health) [68].

acid,

Flavonols Quercetin Red and yellow onions, tea, wine,

Flavanols Catechins Chocolate, tea, grapes, wine, apples,

Anthocyanins Cyanindin Blackberry, blueberries, red wine,

Isoflavones Genistein Soy, alfalfa sprouts, red clover,

Lignans Secoisolariciresinol Linseed, sunflower seeds, sesame

Stilbenes Resveratrol Grape skins and seeds, wine, nuts

**Phytochemicals**

334 Organic Farming - A Promising Way of Food Production

Phenolic acids Gallic acid, caffeic



**Table 3.** Proposed health protective mechanisms of dietary phytochemicals1

Glucosinolates are sulphur-containing compounds mainly present in the Cruciferae family. When consumed, they are hydrolysed via myrosinase (EC 3.2.1.147, thioglucoside glucohy‐ drolase) into isothiocyanates (ITCs) and other derivative products [69], that up-regulate genes associated with carcinogen detoxification cellular mechanisms [70]. Clinical studies have shown that the products of glucosinolate hydrolysis can reduce the incidence of certain forms of cancer [71].

Other compounds such as carotenoids lutein, β-carotene and tocopherols in addition to their role as vitamins, are also powerful antioxidants [72]. Tocopherols and carotenoids have been associated with the decrease of certain forms of cancer [73] and with a reduction in risk of cardiovascular diseases [74], whilst lutein protects against the development of cataracts and age-related macular degeneration [75], even if according Trumbo and Ellwood [76] there is no credible scientific evidence to support a health claim that lutein or zeaxanthin intake can reduce the risk of age-related macular degeneration or cataracts.

Phenolic compounds are a large group of secondary metabolites, categorised according to their chemical structure, into different classes, with phenolic acids, flavonoids, stilbenes and lignans being the most relevant ones [77]. They all have in common the presence of labile hydrogen able to neutralise or mop-up free radicals, and as such they are recognised as powerful antioxidants. Fruits and vegetables are the richest potential sources of these substances [78].

As mentioned above, the diversity of the chemical composition of plants, and thus by extension of phytochemicals is determined by a number of factors, including genotype, ontogeny, growth conditions, management practices and the environment. Thus, it might be expected that differences caused by organic vs. conventional growing practices may cause associated differences in phytochemical levels and diversity. Increasing organic food consumption is partially as a result of consumer perception that organic foods are healthier, but do organic foods actually contain more phytochemicals than conventional foods? Are the levels of phytochemicals in organic production relevant? Is the diversity of phytochemicals in foods affected by agronomical practices?

Table 4 summarises some of the results from different studies conducted over the last 15 years into the difference in phytochemical content in fruits and vegetables produced under organic and conventional farming practices. This is not an exhaustive list, but unsurprisingly several different conclusions are drawn. Recent studies [79, 80, 53] have indicated that organic produce contains higher concentrations of certain phytochemicals associated with health, than those produced under conventional farming systems. In addition, some studies [81, 82] reinforce this idea, stating that the abiotic and biotic stress induced by organic farming practices seems to overcome the variability among samples and consequently, the use of organic practices may be a means of increasing the levels of phytochemicals. However, according a recent observation [83] there is little evidence for any differences in the health benefits of organic and conventional produce. The differences often found may in fact be due to cultivar genotype influence and climatic variation rather than agricultural practices. The same observations was made by Oh et al. [84] and Lv et al. [85].

• enzyme induction and enhancing

336 Organic Farming - A Promising Way of Food Production

Adapted from Liu and Finley [67].

**Table 3.** Proposed health protective mechanisms of dietary phytochemicals1

the risk of age-related macular degeneration or cataracts.

affected by agronomical practices?

Glucosinolates are sulphur-containing compounds mainly present in the Cruciferae family. When consumed, they are hydrolysed via myrosinase (EC 3.2.1.147, thioglucoside glucohy‐ drolase) into isothiocyanates (ITCs) and other derivative products [69], that up-regulate genes associated with carcinogen detoxification cellular mechanisms [70]. Clinical studies have shown that the products of glucosinolate hydrolysis can reduce the incidence of certain forms

Other compounds such as carotenoids lutein, β-carotene and tocopherols in addition to their role as vitamins, are also powerful antioxidants [72]. Tocopherols and carotenoids have been associated with the decrease of certain forms of cancer [73] and with a reduction in risk of cardiovascular diseases [74], whilst lutein protects against the development of cataracts and age-related macular degeneration [75], even if according Trumbo and Ellwood [76] there is no credible scientific evidence to support a health claim that lutein or zeaxanthin intake can reduce

Phenolic compounds are a large group of secondary metabolites, categorised according to their chemical structure, into different classes, with phenolic acids, flavonoids, stilbenes and lignans being the most relevant ones [77]. They all have in common the presence of labile hydrogen able to neutralise or mop-up free radicals, and as such they are recognised as powerful antioxidants. Fruits and vegetables are the richest potential sources of these substances [78].

As mentioned above, the diversity of the chemical composition of plants, and thus by extension of phytochemicals is determined by a number of factors, including genotype, ontogeny, growth conditions, management practices and the environment. Thus, it might be expected that differences caused by organic vs. conventional growing practices may cause associated differences in phytochemical levels and diversity. Increasing organic food consumption is partially as a result of consumer perception that organic foods are healthier, but do organic foods actually contain more phytochemicals than conventional foods? Are the levels of phytochemicals in organic production relevant? Is the diversity of phytochemicals in foods

Table 4 summarises some of the results from different studies conducted over the last 15 years into the difference in phytochemical content in fruits and vegetables produced under organic and conventional farming practices. This is not an exhaustive list, but unsurprisingly several different conclusions are drawn. Recent studies [79, 80, 53] have indicated that organic produce contains higher concentrations of certain phytochemicals associated with health, than those produced under conventional farming systems. In addition, some studies [81, 82] reinforce this idea, stating that the abiotic and biotic stress induced by organic farming practices seems to overcome the variability among samples and consequently, the use of organic practices may

detoxification

of cancer [71].

1


**Table 4.** Summary of studies comparing phytochemical contents in fruits and vegetables from organic and conventional production

These authors stated that the most important factor affecting the phytochemical composition of plants is the interaction between genotype, environment and agronomical practices. Therefore, it is crucial to select the optimal environment conditions, genotype and best agronomical practices, in order to maximise the levels of a components beneficial to health.

In order to accurately evaluate the differences between organic and conventional farming systems, all the factors affecting quality of produce must be controlled, which is a major limitation of some studies through their poor experimental design. So, an accurate evaluation of all these aspects should be made over a substantial period of time (more than one year at least) in order to assess the eventual changes related to the year, seasonal effect, genotype or agronomical practices employed. A multi-year sampling study to evaluate farming systems with the necessary consistency to draw valid conclusions, is a minimum requirement [103].

### *3.2.2. Antioxidant activity*

Closely linked to phytochemical content is the variation in antioxidants. Antioxidants, by definition, are any substance that reduce or inhibit oxidation or other reactions caused by oxygen and peroxides and free radicals, and which protect the body from the deleterious effects of free radicals [104]. Well-known antioxidants includes enzymes, vitamins (C and E), carotenes, polyphenols and others capable of counteracting the damaging effects of oxidation. They are important, because to date, epidemiological studies have shown their preventive effect against several infectious processes such as cancer, and neurodegenerative and cardio‐ vascular diseases [105, 106, 62, 81]. As with primary nutrients and phytochemicals, the effect of organic farming practices on the antioxidant properties of plant-derived foods is contro‐ versial. It is common to find an association between organic farming practices and an increase in antioxidant content, and the converse is also true (Table 5).

Wang [81] found that organic practices result in an increase antioxidant activity in blueberries (measured by the ORAC) due to the increase of phenolic acids and anthocyanin content when compared with a conventional system, whilst Garuso and Nardini [107], didn´t find any substantial difference in antioxidant activity in wines produced under organic and conven‐ tional farming practices. Similar observations were made by Unal et al. [108] for Brassicacea vegetables. They didn't detect any significant difference in antioxidant activity in brassicas produced under organic and conventional practices. However, Stracke et al. [97], when comparing the organic and conventional cultivation of apples over three years, observed that organic apples presented on average 15% higher antioxidant content, as determined by FRAP, TEAC and ORAC than conventionally produced fruits, but these authors also observed that inter-annual climatic variations were more critical to the antioxidant capacity than the type of farming. Despite these inconsistencies, the majority of authors seem to agree that the type of farming system may affect the phytochemical composition and thus by extension the amount of antioxidant activity. Since organic farming does not provide as much nitrogen as conven‐ tional fertilizers [56], as well as causing more stress to the plants (Straus et al., 2012)[109] than conventional farming, it has the potential to influence the synthesis of antioxidants, increasing their levels and thus increasing antioxidant activity, as recently reported [110]. Therefore, at least theoretically, it can be concluded that organic farming has a tendency to produce foods with more nutritional value, based on their enhanced antioxidant content and activity.


These authors stated that the most important factor affecting the phytochemical composition of plants is the interaction between genotype, environment and agronomical practices. Therefore, it is crucial to select the optimal environment conditions, genotype and best agronomical practices, in order to maximise the levels of a components beneficial to health. In order to accurately evaluate the differences between organic and conventional farming systems, all the factors affecting quality of produce must be controlled, which is a major limitation of some studies through their poor experimental design. So, an accurate evaluation of all these aspects should be made over a substantial period of time (more than one year at least) in order to assess the eventual changes related to the year, seasonal effect, genotype or agronomical practices employed. A multi-year sampling study to evaluate farming systems with the necessary consistency to draw valid conclusions, is a minimum requirement [103].

Closely linked to phytochemical content is the variation in antioxidants. Antioxidants, by definition, are any substance that reduce or inhibit oxidation or other reactions caused by oxygen and peroxides and free radicals, and which protect the body from the deleterious effects of free radicals [104]. Well-known antioxidants includes enzymes, vitamins (C and E), carotenes, polyphenols and others capable of counteracting the damaging effects of oxidation. They are important, because to date, epidemiological studies have shown their preventive effect against several infectious processes such as cancer, and neurodegenerative and cardio‐ vascular diseases [105, 106, 62, 81]. As with primary nutrients and phytochemicals, the effect of organic farming practices on the antioxidant properties of plant-derived foods is contro‐ versial. It is common to find an association between organic farming practices and an increase

Wang [81] found that organic practices result in an increase antioxidant activity in blueberries (measured by the ORAC) due to the increase of phenolic acids and anthocyanin content when compared with a conventional system, whilst Garuso and Nardini [107], didn´t find any substantial difference in antioxidant activity in wines produced under organic and conven‐ tional farming practices. Similar observations were made by Unal et al. [108] for Brassicacea vegetables. They didn't detect any significant difference in antioxidant activity in brassicas produced under organic and conventional practices. However, Stracke et al. [97], when comparing the organic and conventional cultivation of apples over three years, observed that organic apples presented on average 15% higher antioxidant content, as determined by FRAP, TEAC and ORAC than conventionally produced fruits, but these authors also observed that inter-annual climatic variations were more critical to the antioxidant capacity than the type of farming. Despite these inconsistencies, the majority of authors seem to agree that the type of farming system may affect the phytochemical composition and thus by extension the amount of antioxidant activity. Since organic farming does not provide as much nitrogen as conven‐ tional fertilizers [56], as well as causing more stress to the plants (Straus et al., 2012)[109] than conventional farming, it has the potential to influence the synthesis of antioxidants, increasing their levels and thus increasing antioxidant activity, as recently reported [110]. Therefore, at least theoretically, it can be concluded that organic farming has a tendency to produce foods with more nutritional value, based on their enhanced antioxidant content and activity.

in antioxidant content, and the converse is also true (Table 5).

*3.2.2. Antioxidant activity*

338 Organic Farming - A Promising Way of Food Production

**Table 5.** Some examples of studies comparing antioxidant activity of fruits and vegetables produced under organic and conventional farming practices

### **3.3. Consumers' sensory expectations and preferences related to variability of antioxidant activity and phytochemical content of organic foods**

There is common belief that organic food is healthier and safer than conventional food. According to the vast amount of literature already published, some of which is reported in this chapter, organic food is free of chemical residues, contain fewer nitrates and more antioxidants. In respect of product quality, surveys in the last 10 years [118, 119, 120, 121, 122, 123] indicate that consumers consider organic foods to be more beneficial for human health than their conventional counterparts, even if those studies often assume a lack of knowledge on behalf of the consumers of the aims and production practices of organic farming. Moreover, con‐ sumers often buy organic foods based on an emotional view, such as a desire to preserve traditional products and processes [124]. According to a survey conducted in Turkey in 2012 [120] consumers indicated 4 main reasons to buy organic foods: they are healthier, they have higher quality, the price is normally acceptable, and the food is microbiologically safe. As Monk et al. reported in 2012 [125], for the majority of consumers, the idea of enhanced nutrition, being free from chemicals, and a better taste, are the major advantages of organic foods. Consumers often think that organic food is better because it tastes better, but apart from physical and sensorial qualities, the understanding of nutritional quality by consumers seems to be a question of the ability to find credible information [118], which they often can't. A recent survey [126] showed that 78% of consumers when questioned about the quality of labelling information, responded that they didn't believe that all food labelled 'organic' was, in fact, organic, and neither did they totally believe in their healthier effects. Often, consumers purchased organic food due to personal morals or beliefs such as: 'I feel obliged to buy organic food to protect my health' and 'I feel obliged to buy organic food to protect the health of my family' [126]. The same authors observed that consumers repeatedly reported that they experience difficulty in getting more knowledge about a product's properties, certification bodies, and labels etc... Nonetheless, nowadays consumers tend to be more conscious and more aware about the positive effects of organic foods on health and the environment [127], and as a result are buying more organic foods.

### **4. Conclusions**

Since the 1980s, organic farming has been increasing due to growing demand from consumers for high quality foods, with lower pesticide residues, less synthetic fertilisers and produced using environmentally friendly practices. Presumably, animal and plant derived foods have fewer chemical residues and veterinary drugs in them when compared with conventional ones. The growing perception from consumers that organic foods are healthier and safer, has to the rapid growth of this type of production seen over the last 20 years. Although the beneficial properties of these foods for human health have not been unequivocally proven, the accumu‐ lation of nutritional metabolites in organic cultivation has been well documented. Recent studies have shown that organic foods are, from a nutritional point of view, at least similar to conventional ones, if not slightly better. Also, recent epidemiological studies advocate that under organic farming practices, plants can accumulate nutrients and phytochemicals, enhancing their biological value and thus increasing the nutritional quality of foods. Moreover, the growing evidence of lower pesticide exposure to consumers of organic foods, is one of the main reasons for converting to organic farming. Although more and more well-documented studies are still required to improve our understanding of which factors contribute to differ‐ ences between organic and conventional farming practices, the most recent findings provide evidence-based knowledge that organic farming is a sustainable way of producing healthier and safer plant-derived foods.

### **Acknowledgements**

The author acknowledges the financial support provided by the Portuguese Foundation for Science and Technology (FCT) (Alfredo Aires-SFRH/BPD/65029/2009) under the project UID/ AGR/04033/2013.

### **Author details**

Alfredo Aires

Address all correspondence to: alfredoa@utad.pt

Centre for the Research and Technology of Agro-Environment and Biological Sciences (CITAB), Universidade de Trás-os-Montes e Alto Douro, UTAD, Quinta de Prados, Portugal

### **References**

experience difficulty in getting more knowledge about a product's properties, certification bodies, and labels etc... Nonetheless, nowadays consumers tend to be more conscious and more aware about the positive effects of organic foods on health and the environment [127], and as

Since the 1980s, organic farming has been increasing due to growing demand from consumers for high quality foods, with lower pesticide residues, less synthetic fertilisers and produced using environmentally friendly practices. Presumably, animal and plant derived foods have fewer chemical residues and veterinary drugs in them when compared with conventional ones. The growing perception from consumers that organic foods are healthier and safer, has to the rapid growth of this type of production seen over the last 20 years. Although the beneficial properties of these foods for human health have not been unequivocally proven, the accumu‐ lation of nutritional metabolites in organic cultivation has been well documented. Recent studies have shown that organic foods are, from a nutritional point of view, at least similar to conventional ones, if not slightly better. Also, recent epidemiological studies advocate that under organic farming practices, plants can accumulate nutrients and phytochemicals, enhancing their biological value and thus increasing the nutritional quality of foods. Moreover, the growing evidence of lower pesticide exposure to consumers of organic foods, is one of the main reasons for converting to organic farming. Although more and more well-documented studies are still required to improve our understanding of which factors contribute to differ‐ ences between organic and conventional farming practices, the most recent findings provide evidence-based knowledge that organic farming is a sustainable way of producing healthier

The author acknowledges the financial support provided by the Portuguese Foundation for Science and Technology (FCT) (Alfredo Aires-SFRH/BPD/65029/2009) under the project UID/

Centre for the Research and Technology of Agro-Environment and Biological Sciences (CITAB), Universidade de Trás-os-Montes e Alto Douro, UTAD, Quinta de Prados, Portugal

a result are buying more organic foods.

340 Organic Farming - A Promising Way of Food Production

**4. Conclusions**

and safer plant-derived foods.

**Acknowledgements**

AGR/04033/2013.

**Author details**

Address all correspondence to: alfredoa@utad.pt

Alfredo Aires


[23] Eichholz I, Huyskens-Keil S, Rohn S. Chapter 21 - Blueberry Phenolic Compounds: Fruit Maturation, Ripening and Post-Harvest Effects. In: Preedy V, editor. Processing and Impact on Active Components in Food,http://dx.doi.org/10.1016/ B978-0-12-404699-3.00021-4. San Diego: Academic Press; 2015. p. 173-180.

[12] Smith EG, Jill Clapperton M, Blackshaw RE. Profitability and risk of organic produc‐ tion systems in the northern Great Plains. Renewable Agriculture and Food Systems.

[13] Tiwari U, Cummins E. Factors Influencing β-Glucan Levels and Molecular Weight in Cereal-Based Products. Cereal Chemistry Journal. 2009;86:290-301.10.1094/

[14] Søltoft M, Nielsen J, Holst Laursen K, Husted S, Halekoh U, Knuthsen P. Effects of Organic and Conventional Growth Systems on the Content of Flavonoids in Onions and Phenolic Acids in Carrots and Potatoes. Journal of Agricultural and Food Chem‐

[15] Tiwari U, Cummins E. Factors influencing levels of phytochemicals in selected fruit and vegetables during pre- and post-harvest food processing operations. Food Re‐ search International. 2013;50:497-506.http://dx.doi.org/10.1016/j.foodres.2011.09.007

[16] Krishnan P, Ramakrishnan B, Reddy KR, Reddy VR. Chapter three - High-Tempera‐ ture Effects on Rice Growth, Yield, and Grain Quality. In: Donald LS, editor. Advan‐

[17] Oloyede FM, Adebooye OC, Obuotor EM. Planting date and fertilizer affect antioxi‐ dants in pumpkin fruit. Scientia Horticulturae. 2014;168:46-50.http://dx.doi.org/

[18] Bhattacharyya R, Prakash V, Kundu S, Srivastva AK, Gupta HS. Soil aggregation and organic matter in a sandy clay loam soil of the Indian Himalayas under different till‐ age and crop regimes. Agriculture, Ecosystems & Environment.

[19] Mekuria W, Getnet K, Noble A, Hoanh CT, McCartney M, Langan S. Economic valu‐ ation of organic and clay-based soil amendments in small-scale agriculture in Lao PDR. Field Crops Research. 2013;149:379-389.http://dx.doi.org/10.1016/j.fcr.

[20] Zotarelli L, Scholberg JM, Dukes MD, Muñoz-Carpena R, Icerman J. Tomato yield, biomass accumulation, root distribution and irrigation water use efficiency on a san‐ dy soil, as affected by nitrogen rate and irrigation scheduling. Agricultural Water

[21] Zaro MJ, Keunchkarian S, Chaves AR, Vicente AR, Concellón A. Changes in bioac‐ tive compounds and response to postharvest storage conditions in purple eggplants as affected by fruit developmental stage. Postharvest Biology and Technology.

[22] Kjellenberg L, Johansson E, Gustavsson K-E, Olsson ME. Polyacetylenes in fresh and stored carrots (Daucus carota): relations to root morphology and sugar content. Jour‐

nal of the Science of Food and Agriculture. 2012;92:1748-1754.10.1002/jsfa.5541

Management. 2009;96:23-34.http://dx.doi.org/10.1016/j.agwat.2008.06.007

2014;96:110-117.http://dx.doi.org/10.1016/j.postharvbio.2014.05.012

ces in Agronomy. Volume 111: Academic Press; 2011. p. 87-206.

2009;132:126-134.http://dx.doi.org/10.1016/j.agee.2009.03.007

2004;19:152-158,

342 Organic Farming - A Promising Way of Food Production

CCHEM-86-3-0290

10.1016/j.scienta.2014.01.012

2013.05.026

istry. 2010;58:10323-10329.10.1021/jf101091c


http://ec.europa.eu/food/safety/docs/labelling\_nutrition-special\_groups\_food-chil‐ dren-scf\_reports\_38\_en.pdf


[45] Kahu K, Jänes H, Luik A, Klaas L. Yield and fruit quality of organically cultivated blackcurrant cultivars. Acta Agriculturae Scandinavica, Section B — Soil & Plant Sci‐ ence. 2008;59:63-69.10.1080/09064710701865139

http://ec.europa.eu/food/safety/docs/labelling\_nutrition-special\_groups\_food-chil‐

[35] Moral R, Paredes C, Bustamante MA, Marhuenda-Egea F, Bernal MP. Utilisation of manure composts by high-value crops: Safety and environmental challenges. Biore‐ source Technology. 2009;100:5454-5460.http://dx.doi.org/10.1016/j.biortech.

[36] Worthington V. Nutritional Quality of Organic Versus Conventional Fruits, Vegeta‐ bles, and Grains. The Journal of Alternative and Complementary Medicine.

[37] Ismail A FChnompmmnap. Determination of vitamin C, β-carotene and riboflavin contents in five green vegetables organically and conventionally grown.. Malaysian Journal of Nutrition. 2003;9:31-39, http://nutriweb.org.my/publications/mjn009\_1/

[38] Ryan MH, Derrick JW, Dann PR. Grain mineral concentrations and yield of wheat grown under organic and conventional management. Journal of the Science of Food

[39] Wszelaki AL, Delwiche JF, Walker SD, Liggett RE, Scheerens JC, Kleinhenz MD. Sen‐ sory quality and mineral and glycoalkaloid concentrations in organically and con‐ ventionally grown redskin potatoes (Solanum tuberosum). Journal of the Science of

[40] Mäder P, Hahn D, Dubois D, Gunst L, Alföldi T, Bergmann H, et al. Wheat quality in organic and conventional farming: results of a 21 year field experiment. Journal of

[41] Amodio ML, Colelli G, Hasey JK, Kader AA. A comparative study of composition and postharvest performance of organically and conventionally grown kiwifruits. Journal of the Science of Food and Agriculture. 2007;87:1228-1236.10.1002/jsfa.2820

[42] Rossi F, Godani F, Bertuzzi T, Trevisan M, Ferrari F, Gatti S. Health-promoting sub‐ stances and heavy metal content in tomatoes grown with different farming techni‐ ques. European Journal of Nutrition. 2008;47:266-272.10.1007/s00394-008-0721-z [43] Wunderlich SM, Feldman C, Kane S, Hazhin T. Nutritional quality of organic, con‐ ventional, and seasonally grown broccoli using vitamin C as a marker. International Journal of Food Sciences and Nutrition. 2008;59:34-45.10.1080/09637480701453637 [44] Citak S, Sonmez S. Effects of conventional and organic fertilization on spinach (Spi‐ nacea oleracea L.) growth, yield, vitamin C and nitrate concentration during two suc‐ cessive seasons. Scientia Horticulturae. 2010;126:415-420.http://dx.doi.org/10.1016/

the Science of Food and Agriculture. 2007;87:1826-1835.10.1002/jsfa.2866

dren-scf\_reports\_38\_en.pdf

344 Organic Farming - A Promising Way of Food Production

2001;7:161-173.10.1089/107555301750164244

and Agriculture. 2004;84:207-216.10.1002/jsfa.1634

Food and Agriculture. 2005;85:720-726.10.1002/jsfa.2051

2008.12.007

mjn9n1\_art4.pdf

j.scienta.2010.08.010


[67] Liu RH, Finley J. Potential Cell Culture Models for Antioxidant Research. Journal of Agricultural and Food Chemistry. 2005;53:4311-4314.10.1021/jf058070i

[56] Dangour AD, Dodhia SK, Hayter A, Allen E, Lock K, Uauy R. Nutritional quality of organic foods: a systematic review. The American Journal of Clinical Nutrition.

[57] Conti S, Villari G, Faugno S, Melchionna G, Somma S, Caruso G. Effects of organic vs. conventional farming system on yield and quality of strawberry grown as an an‐ nual or biennial crop in southern Italy. Scientia Horticulturae. 2014;180:63-71.http://

[58] Gangolli SD, van den Brandt PA, Feron VJ, Janzowsky C, Koeman JH, Speijers GJA, et al. Nitrate, nitrite and N-nitroso compounds. European Journal of Pharmacology: Environmental Toxicology and Pharmacology. 1994;292:1-38.http://dx.doi.org/

[59] Correia M, Barroso Â, Barroso MF, Soares D, Oliveira MBPP, Delerue-Matos C. Con‐ tribution of different vegetable types to exogenous nitrate and nitrite exposure. Food

[60] Savino F, Maccario S, Guidi C, Castagno E, Farinasso D, Cresi F, et al. Methemoglobi‐ nemia Caused by the Ingestion of Courgette Soup Given in Order to Resolve Consti‐ pation in Two Formula-Fed Infants. Annals of Nutrition and Metabolism.

[61] Guadagnin SG, Rath S, Reyes FGR. Evaluation of the nitrate content in leaf vegeta‐ bles produced through different agricultural systems. Food Additives & Contami‐

[62] González-Gallego J, García-Mediavilla MV, Sánchez-Campos S, Tuñón MJ. Fruit pol‐ yphenols, immunity and inflammation. British Journal of Nutrition. 2010;104:S15-

[63] Burns IG, Zhang K, Turner MK, Meacham M, Al-Redhiman K, Lynn J, et al. Screen‐ ing for genotype and environment effects on nitrate accumulation in 24 species of young lettuce. Journal of the Science of Food and Agriculture.

[64] Burns I, Durnford J, Lynn J, McClement S, Hand P, Pink D. The influence of genetic variation and nitrogen source on nitrate accumulation and iso-osmotic regulation by

[65] Björkman M, Klingen I, Birch ANE, Bones AM, Bruce TJA, Johansen TJ, et al. Phyto‐ chemicals of Brassicaceae in plant protection and human health – Influences of cli‐ mate, environment and agronomic practice. Phytochemistry. 2011;72:538-556.http://

[66] Harborne JB. Recent advances in chemical ecology. Natural Product Reports.

lettuce. Plant and Soil. 2012;352:321-339.10.1007/s11104-011-0999-0

Chemistry. 2010;120:960-966.http://dx.doi.org/10.1016/j.foodchem.2009.11.030

2006;50:368-371, http://www.karger.com/DOI/10.1159/000094301

nants. 2005;22:1203-1208.10.1080/02652030500239649

S27.doi:10.1017/S0007114510003910

2011;91:553-562.10.1002/jsfa.4220

dx.doi.org/10.1016/j.phytochem.2011.01.014

1989;6:85-109.10.1039/NP9890600085

2009;10.3945/ajcn.2009.28041.10.3945/ajcn.2009.28041

dx.doi.org/10.1016/j.scienta.2014.10.015

10.1016/0926-6917(94)90022-1

346 Organic Farming - A Promising Way of Food Production


Pear, Pyrus communis L.). Journal of Agricultural and Food Chemistry. 2002;50:5458-5462.10.1021/jf0202584

[89] Lombardi-Boccia G, Lucarini M, Lanzi S, Aguzzi A, Cappelloni M. Nutrients and An‐ tioxidant Molecules in Yellow Plums (Prunus domestica L.) from Conventional and Organic Productions: A Comparative Study. Journal of Agricultural and Food Chemistry. 2004;52:90-94.10.1021/jf0344690

[78] Kondratyuk TP, Pezzuto JM. Natural Product Polyphenols of Relevance to Human Health. Pharmaceutical Biology. 2004;42:46-63.doi:10.3109/13880200490893519 [79] Fernandes VC, Domingues VF, de Freitas V, Delerue-Matos C, Mateus N. Strawber‐ ries from integrated pest management and organic farming: Phenolic composition and antioxidant properties. Food Chemistry. 2012;134:1926-1931.http://dx.doi.org/

[80] Vicas S, Teusdea A, Carbunar M, Socaci S, Socaciu C. Glucosinolates Profile and An‐ tioxidant Capacity of Romanian Brassica Vegetables Obtained by Organic and Con‐ ventional Agricultural Practices. Plant Foods for Human Nutrition.

[81] Wang SY, Millner P. Effect of Different Cultural Systems on Antioxidant Capacity, Phenolic Content, and Fruit Quality of Strawberries (Fragaria × aranassa Duch.). Journal of Agricultural and Food Chemistry. 2009;57:9651-9657.10.1021/jf9020575 [82] García-Mier L, Guevara-González R, Mondragón-Olguín V, del Rocío Verduzco-Cuellar B, Torres-Pacheco I. Agriculture and Bioactives: Achieving Both Crop Yield and Phytochemicals. International Journal of Molecular Sciences. 2013;14:4203, http://

[83] Smith-Spangler C, Brandeau ML, Hunter GE, Bavinger JC, Pearson M, Eschbach PJ, et al. Are Organic Foods Safer or Healthier Than Conventional Alternatives?A Sys‐ tematic Review. Annals of Internal Medicine.

[84] Oh M-M, Carey EE, Rajashekar CB. Environmental stresses induce health-promoting phytochemicals in lettuce. Plant Physiology and Biochemistry. 2009;47:578-583.http://

[85] Lv J, Lu Y, Niu Y, Whent M, Ramadan MF, Costa J, et al. Effect of genotype, environ‐ ment, and their interaction on phytochemical compositions and antioxidant proper‐ ties of soft winter wheat flour. Food Chemistry. 2013;138:454-462.http://dx.doi.org/

[86] Weibel FP TD, Haseli A, Graf U. Sensory and health related quality of organic ap‐ ples: a comparative field study over three years using conventional and holistic methods to assess fruit quality. 1th International Conference on Cultivation Techni‐ que and Phyotpathological Problems in Organic Fruit Growing; LVWO: Weinsberg,

[87] Ren H, Endo H, Hayashi T. Antioxidative and antimutagenic activities and polyphe‐ nol content of pesticide-free and organically cultivated green vegetables using watersoluble chitosan as a soil modifier and leaf surface spray. Journal of the Science of

[88] Carbonaro M, Mattera M, Nicoli S, Bergamo P, Cappelloni M. Modulation of Antioxi‐ dant Compounds in Organic vs Conventional Fruit (Peach, Prunus persica L., and

2012;157:348-366.10.7326/0003-4819-157-5-201209040-00007

10.1016/j.foodchem.2012.03.130

348 Organic Farming - A Promising Way of Food Production

2013;68:313-321.10.1007/s11130-013-0367-8

www.mdpi.com/1422-0067/14/2/4203

dx.doi.org/10.1016/j.plaphy.2009.02.008

Germany. 2004, 8 pp. http://orgprints.org/14536/

Food and Agriculture. 2001;81:1426-1432.10.1002/jsfa.955

10.1016/j.foodchem.2012.10.069


Plant-to-plant variation. Food Chemistry. 2010;121:406-411.http://dx.doi.org/10.1016/ j.foodchem.2009.12.055


[109] Straus S BF, Turinek M, Slatnar A, Rozman C, Bavec M. Nutritional value and eco‐ nomic feasibility of red beetroot (Beta vulgaris L. ssp. vulgaris Rote Kugel) from dif‐ ferent production systems. African Journal of Agricultural Research. 2012;7:5653– 5660, http://www.oxfordjournals.jurnalpedia.academicjournals.org/article/arti‐ cle1380984270\_Straus%20et%20al.pdf

Plant-to-plant variation. Food Chemistry. 2010;121:406-411.http://dx.doi.org/10.1016/

[99] Balisteiro DM, Rombaldi CV, Genovese MI. Protein, isoflavones, trypsin inhibitory and in vitro antioxidant capacities: Comparison among conventionally and organi‐ cally grown soybeans. Food Research International. 2013;51:8-14.http://dx.doi.org/

[100] Miranda Rossetto MR, Shiga TM, Vianello F, Pereira Lima GP. Analysis of total glu‐ cosinolates and chromatographically purified benzylglucosinolate in organic and conventional vegetables. LWT - Food Science and Technology. 2013;50:247-252.http://

[101] López A, Fenoll J, Hellín P, Flores P. Cultivation approach for comparing the nutri‐ tional quality of two pepper cultivars grown under different agricultural regimes. LWT - Food Science and Technology. 2014;58:299-305.http://dx.doi.org/10.1016/j.lwt.

[102] Valverde J, Reilly K, Villacreces S, Gaffney M, Grant J, Brunton N. Variation in bioac‐ tive content in broccoli (Brassica oleracea var. italica) grown under conventional and organic production systems. Journal of the Science of Food and Agriculture.

[103] Migliori C, Di Cesare LF, Lo Scalzo R, Campanelli G, Ferrari V. Effects of organic farming and genotype on alimentary and nutraceutical parameters in tomato fruits. Journal of the Science of Food and Agriculture. 2012;92:2833-2839.10.1002/jsfa.5602

[104] Del Rio D, Rodriguez-Mateos A, Spencer JPE, Tognolini M, Borges G, Crozier A. Di‐ etary (Poly)phenolics in Human Health: Structures, Bioavailability, and Evidence of Protective Effects Against Chronic Diseases. Antioxidants & Redox Signaling.

[105] Stan SD, Kar S, Stoner GD, Singh SV. Bioactive food components and cancer risk re‐ duction. Journal of Cellular Biochemistry. 2008;104:339-356.10.1002/jcb.21623

[106] Vincent HK, Bourguignon CM, Taylor AG. Relationship of the dietary phytochemical index to weight gain, oxidative stress and inflammation in overweight young adults. Journal of Human Nutrition and Dietetics. 2010;23:20-29.10.1111/j.1365-277X.

[107] Garaguso I, Nardini M. Polyphenols content, phenolics profile and antioxidant activ‐ ity of organic red wines produced without sulfur dioxide/sulfites addition in com‐ parison to conventional red wines. Food Chemistry. 2015;179:336-342.http://

[108] Unal K SD, Taher M. Polyphenol content and antioxidant capacity in organically and conventionally grown vegetables. Journal of Coastal Life Medicine. 2014;2:864-871,

j.foodchem.2009.12.055

350 Organic Farming - A Promising Way of Food Production

10.1016/j.foodres.2012.11.015

2014.02.048

2009.00987.x

dx.doi.org/10.1016/j.lwt.2012.05.022

2015;95:1163-1171.10.1002/jsfa.6804

2012;18:1818-1892.10.1089/ars.2012.4581

dx.doi.org/10.1016/j.foodchem.2015.01.144

http://www.jclmm.com/qk/201411/6.pdf


## **Quality and Nutrient Contents of Fruits Produced Under Organic Conditions**

Taleb Rateb Abu-Zahra

[119] Cerjak M, Mesić Ž, Kopić M, Kovačić D, Markovina J. What Motivates Consumers to Buy Organic Food: Comparison of Croatia, Bosnia Herzegovina, and Slovenia. Jour‐ nal of Food Products Marketing. 2010;16:278-292.10.1080/10454446.2010.484745 [120] Ozguven N. Organic Foods Motivations Factors for Consumers. Procedia - Social and Behavioral Sciences. 2012;62:661-665.http://dx.doi.org/10.1016/j.sbspro.2012.09.110

[121] Ballute AK BP. The perceptions of and motivations for purchase of organic and local foods. Journal of Contemporary Issues in Business Research. 2014;3:1-18, http://

[122] Henryks J PD. Investigating the context of purchase choices to further understanding of switching behaviour. Journal of Organic Systems. 2014;9:38-48, http://www.organ‐ ic-systems.org/journal/92/JOS\_Volume-9\_Number-2\_Nov-2014\_Henryks-&-Pear‐

[123] Stanton JV, Guion DT. Perceptions of "Organic" Food: A View Through Brand Theo‐ ry. Journal of International Food & Agribusiness Marketing.

[124] Cicia G DGT, Ramunno I, Tagliaferro C. Splitting Consumer's Willingness to Pay Premium Price for Organic Products over Purchase Motivations. 98th Seminar of the European Association of Agricultural Economics (EAAE) Marketing Dynamics with‐ in the Global Trading System: New Perspectives, Chania, Crete, Greece, June 29 - Ju‐ ly 2. 2006, http://www.researchgate.net/profile/Pietro\_Pulina/publication/

28685241\_The\_Motivational\_Profile\_of\_Organic\_Food\_Consumers\_a\_Sur‐

vey\_of\_SpecializedStores\_Customers\_in\_Italy/links/00b7d52dfdeef516f5000000.pdf

[125] Monk A M, B, Lobo A, Chen J, Bez N. Australian organic market report 2012. Bris‐ bane: Biological Farmers Association (BFA) Ltd. 2012, 100 pp. http:// austorganic.com/wp-content/uploads/2013/09/Organic-market-report-2012-web.pdf

[126] McCarthy B, Murphy L. Who s buying organic food and why?: Political consumer‐ ism, demographic characteristics and motivations of consumers in North Queens‐ land. Tourism & Management Studies. 2013;9:72-79, http://www.scielo.mec.pt/

[127] H I. Consumers' Attitude and Intention towards Organic Food Purchase: An Exten‐ sion of Theory of Planned Behaviour in Gender Perspective. International Journal of Management, Economics and Social Sciences. 2015;4:17 – 31, http://ssrn.com/

scielo.php?script=sci\_arttext&pid=S2182-84582013000100011&nrm=iso

jcibr.webs.com/Archives/Volume-2014/Issue-1-january/Article-V-3-

N-1-082013JCIBR0037.pdf

352 Organic Farming - A Promising Way of Food Production

2015;27:120-141.10.1080/08974438.2014.897667

son.pdf

abstract=2578399

Additional information is available at the end of the chapter

http://dx.doi.org/10.5772/61245

### **Abstract**

Organic farming is an agricultural practice that raises plants especially vegetables and fruits without the use of synthetic pesticides, herbicides, fertilizers, or plant growth regulators. All over the world, the interest for organic farming has increased recently. Different greenhouse experiments were carried out in the northern Jordan Valley, to compare the effect of four fermented organic matter doses (1.5, 3.0, 4.5, and 6.0 kg m-2), or different organic matter sources (cattle, poultry, and sheep manure in addition to 1:1:1 mixture of the three organic matter sources) with that of the conventional fertilizer and control treatments on different fruit quality parameters.

Results obtained showed that fruit titratable acidity (TA) percentage, size, moisture content, and ammonium and nitrate contents were higher in the conventionally produced fruits in comparison to the organically produced fruits. The organic treatments tended to produce fruits with higher anthocyanin, total soluble solids (TSS) percentage, dry matter content, ascorbic acid, total phenols, and crude fibre content in comparison to the control and conventionally produced fruits. In most cases, sheep manure source and 4.5 kg O.M m-2 treatment amount produced the best results.

**Keywords:** Nutrients, pigments, quality

### **1. Introduction**

### **1.1. Environmental Issues**

Environmental issues are capturing more and more of the world's attention; therefore, researchers and scientists are aiming at improving environmental quality through the

adoption of techniques and measures that have a reduced impact on the environment [1]. Conventional agriculture practices utilize high-yield crop cultivars, chemical fertilizers and pesticides, irrigation techniques, and mechanization that have a huge impact on our environ‐ ment [2]. Plants are subjected to attack by a large and diverse number of pathogens and pests; as a result, crop producers often use large amounts of agrochemicals in an attempt to improve and protect the fruit quality and plant vigor [3]. Ever since people have become aware that health is linked to health environment, the control and reduction of pollution have become the focus of worldwide concern [4]. Pollution is becoming a serious problem in agricultural regions; for example, various mineral fertilizers and agrochemicals lead to pollution and serious health problems in humans, hence alternative production techniques which employ biological or organic compounds for disease and pest control are needed [5]. In addition to the human health concern of elevated heavy metal concentrations in soil, they can cause harm to native ecosystem and accumulation in plant tissue can result in damage to wildlife [6]. Plant toxicity is the primary concern for elevated zinc concentration in soil, whereas the potential for risk to the herbivores is the primary concern with elevated cadmium concentration in soil, while human health concerns focus on lead concentration for which the most pertinent pathway is direct ingestion of soil [7].

### **1.2. Organic culture**

Organic farming, which essentially excludes the use of many inputs associated with modern farming, most notably synthetic pesticides and fertilizers, is becoming more and more popular worldwide [2, 8]. Consumer's awareness of the relationship between foods and health, together with environment concerns, has led to an increased demand for organical‐ ly produced foods. In general, the public perceives organic foods as being healthier and safer than those produced through conventional agricultural practices [9]. Consumers demand organic products because they believe they are more favorable and respectful to the environment and human health [10]. Organic foods have a nutritional and sensory advantage in comparison to their conventionally produced counterparts. Advocates for organic produce claim that it contains fewer harmful chemicals, is better for the environ‐ ment, and may be more nutritious [11].

### **2. Fruit nutrient contents**

### **2.1. Mineral contents**

Mineral contents of fruits were found to be higher in fruits produced under conventional systems in comparison to the fruits produced under organic systems [12]. For example, bell pepper fruits, which were produced under conventional systems, were characterized by a high content of minerals (Table 1). The highest contents of zinc and iron in bell pepper were obtained in the conventional treatment with significant differences between other treatments, while there were no significant differences among the organic matter treatments, which could be attributed to the high application of chemical fertilizers [13].


\*Means within each column having different letters are significantly different according to Least Significant Difference at 5% level.

**Table 1.** Effect of culture systems on contents of zinc and iron in bell pepper fruit

The contents of calcium, magnesium, sodium, potassium, and phosphorous in bell pepper fruit were significantly higher in those produced with conventional system than all those produced with organic matter systems (Table 2); even though the highest calcium content was obtained by the conventional treatment, there was no significant difference with the poultry manure, which could be due to the high use of limestone in the chicken food mixture [13].


\*Means within each column having different letters are significantly different according to Least Significant Difference at 5% level.

**Table 2.** Effect of culture systems on contents of calcium, magnesium, phosphorus, sodium, and potassium in bell pepper fruit

### **2.2. Ammonium and nitrate**

adoption of techniques and measures that have a reduced impact on the environment [1]. Conventional agriculture practices utilize high-yield crop cultivars, chemical fertilizers and pesticides, irrigation techniques, and mechanization that have a huge impact on our environ‐ ment [2]. Plants are subjected to attack by a large and diverse number of pathogens and pests; as a result, crop producers often use large amounts of agrochemicals in an attempt to improve and protect the fruit quality and plant vigor [3]. Ever since people have become aware that health is linked to health environment, the control and reduction of pollution have become the focus of worldwide concern [4]. Pollution is becoming a serious problem in agricultural regions; for example, various mineral fertilizers and agrochemicals lead to pollution and serious health problems in humans, hence alternative production techniques which employ biological or organic compounds for disease and pest control are needed [5]. In addition to the human health concern of elevated heavy metal concentrations in soil, they can cause harm to native ecosystem and accumulation in plant tissue can result in damage to wildlife [6]. Plant toxicity is the primary concern for elevated zinc concentration in soil, whereas the potential for risk to the herbivores is the primary concern with elevated cadmium concentration in soil, while human health concerns focus on lead concentration for which the most pertinent

Organic farming, which essentially excludes the use of many inputs associated with modern farming, most notably synthetic pesticides and fertilizers, is becoming more and more popular worldwide [2, 8]. Consumer's awareness of the relationship between foods and health, together with environment concerns, has led to an increased demand for organical‐ ly produced foods. In general, the public perceives organic foods as being healthier and safer than those produced through conventional agricultural practices [9]. Consumers demand organic products because they believe they are more favorable and respectful to the environment and human health [10]. Organic foods have a nutritional and sensory advantage in comparison to their conventionally produced counterparts. Advocates for organic produce claim that it contains fewer harmful chemicals, is better for the environ‐

Mineral contents of fruits were found to be higher in fruits produced under conventional systems in comparison to the fruits produced under organic systems [12]. For example, bell pepper fruits, which were produced under conventional systems, were characterized by a high content of minerals (Table 1). The highest contents of zinc and iron in bell pepper were obtained in the conventional treatment with significant differences between other treatments, while there were no significant differences among the organic matter treatments, which could be

pathway is direct ingestion of soil [7].

354 Organic Farming - A Promising Way of Food Production

ment, and may be more nutritious [11].

attributed to the high application of chemical fertilizers [13].

**2. Fruit nutrient contents**

**2.1. Mineral contents**

**1.2. Organic culture**

Vegetables represent the most important source of nitrogen for human nutrition, which is essential for growth. Therefore, its accumulation in plants is a natural phenomenon resulting from uptake of the nitrate ion that is found in excess amounts, and the intensive use of nitrogen fertilizer and manure causes nitrate contamination of the environment; therefore, vegetables can accumulate high levels of nitrogen and, when consumed, pose serious health concerns [13]. Ammonium and nitrate contents in conventionally grown strawberry fruits were 49.4 and 23.6 ppm, respectively, due to high use of inorganic nitrogen fertilizers, whereas it was found that ammonium content was 32.3 ppm and nitrate content was extremely low in organically produced fruits [10]. The nitrate content in bell pepper fruit was very low (<200 mgkg-1), for all different cultural systems (organic or inorganic), even though the minimum value of nitrate content for organically produced bell peppers and the maximum value for fertilized bell peppers were found below the safe limit [13].

### **3. Fruit quality**

### **3.1. Total soluble solids and titratable acidity**

All organically produced fruits had significantly higher total soluble solids (TSS) and lower titratable acidity (TA) in comparison to the conventionally produced fruits [5, 14]; for example, sensory attributes are important aspects of fruit quality, and the balance between sweetness and sourness are the most important determinants of overall quality of fruits [15]; for example, acceptance of the flavor quality of strawberry fruits is minimum 7% for TSS content, while the maximum is 0.8% for TA [16]. Organically grown strawberries had significantly higher TSS (7.1%) and lower TA content (0.93%) in comparison to the conventionally grown strawberries that had 6.6% TSS and 0.99% TA. On the other hand, addition of animal manure improved bell pepper fruit taste by increasing the percentage of TSS and the addition of animal manure decreased the percentage of TA in bell pepper fruit [10].

### **3.2. Total phenols**

Phenolic metabolites may suit human health and contribute to the prevention of chronic diseases such as cancer and cardiovascular diseases [17]. In addition, phenolic compounds play a vital role in plant defense mechanisms against insect, fungi, and animal herbivores [18]. Levels of phenolic compounds were higher in organically grown fruits than the levels in conventionally produced fruits, because the restricted use of herbicides, pesticides, insecti‐ cides, and chemical fertilizers was reported to accelerate synthesis of phenolic compounds in organically produced fruits [19].

### **3.3. Ascorbic acid (Vitamin C)**

Ascorbic acid content in fruits is cultivar dependent according to Leskinen et al. [20]; levels of ascorbic acid in organically produced fruits were consistently higher than the levels in the conventionally grown ones [8]. The highest fruit ascorbic acid content (50.5 mg 100 g-1 fruit fresh weight) was obtained by the organically treated berry fruits, whereas the conventional treatment gave the lowest ascorbic acid content (41.25 mg 100 g-1 g fruit fresh weight), according to Abu-Zahra et al. [10]. On the other hand, Cayuela et al. [14] did not find significant difference in the ascorbic acid content between organic and conventional grown strawberry fruits. Also manure type has an effect; the highest amount of vitamin C was obtained from the sheep manure–treated pepper fruits, while the lowest amount was obtained by the conven‐ tionally produced pepper fruits [10].

### **3.4. Crude fiber**

produced fruits [10]. The nitrate content in bell pepper fruit was very low (<200 mgkg-1), for all different cultural systems (organic or inorganic), even though the minimum value of nitrate content for organically produced bell peppers and the maximum value for fertilized bell

All organically produced fruits had significantly higher total soluble solids (TSS) and lower titratable acidity (TA) in comparison to the conventionally produced fruits [5, 14]; for example, sensory attributes are important aspects of fruit quality, and the balance between sweetness and sourness are the most important determinants of overall quality of fruits [15]; for example, acceptance of the flavor quality of strawberry fruits is minimum 7% for TSS content, while the maximum is 0.8% for TA [16]. Organically grown strawberries had significantly higher TSS (7.1%) and lower TA content (0.93%) in comparison to the conventionally grown strawberries that had 6.6% TSS and 0.99% TA. On the other hand, addition of animal manure improved bell pepper fruit taste by increasing the percentage of TSS and the addition of animal manure

Phenolic metabolites may suit human health and contribute to the prevention of chronic diseases such as cancer and cardiovascular diseases [17]. In addition, phenolic compounds play a vital role in plant defense mechanisms against insect, fungi, and animal herbivores [18]. Levels of phenolic compounds were higher in organically grown fruits than the levels in conventionally produced fruits, because the restricted use of herbicides, pesticides, insecti‐ cides, and chemical fertilizers was reported to accelerate synthesis of phenolic compounds in

Ascorbic acid content in fruits is cultivar dependent according to Leskinen et al. [20]; levels of ascorbic acid in organically produced fruits were consistently higher than the levels in the conventionally grown ones [8]. The highest fruit ascorbic acid content (50.5 mg 100 g-1 fruit fresh weight) was obtained by the organically treated berry fruits, whereas the conventional treatment gave the lowest ascorbic acid content (41.25 mg 100 g-1 g fruit fresh weight), according to Abu-Zahra et al. [10]. On the other hand, Cayuela et al. [14] did not find significant difference in the ascorbic acid content between organic and conventional grown strawberry fruits. Also manure type has an effect; the highest amount of vitamin C was obtained from the sheep manure–treated pepper fruits, while the lowest amount was obtained by the conven‐

peppers were found below the safe limit [13].

356 Organic Farming - A Promising Way of Food Production

**3.1. Total soluble solids and titratable acidity**

decreased the percentage of TA in bell pepper fruit [10].

**3. Fruit quality**

**3.2. Total phenols**

organically produced fruits [19].

**3.3. Ascorbic acid (Vitamin C)**

tionally produced pepper fruits [10].

Fruit crude fiber content highly differs according to fruit dry weight [21], but it is found to be higher in organically produced fruits in comparison to conventionally produced fruits [10]; the high crude fiber content in the organically produced fruits could ensure better nutritional and health benefits related to fiber consumption [22]. The highest strawberry crude fibre fruit value (8.13%) was obtained by the 4.5 kg organic matter/m2 , which was significantly different from the conventional, and control treatments [13]. Although, crude fiber of bell pepper fruit was improved by the use of the cattle manure which produced the highest (2.96%) crude fiber content in comparison to the conventional system which produced the lowest content (2.8%) [23].

### **3.5. Fruit size**

Fruit size is highly affected by the farming systems; the conventional agriculture resulted in the biggest fruits, in comparison to organically produced fruits. The large fruit size in the conventional farming system may be due to the good availability of soil nutrients that produced vigorous plants with higher yield and larger fruits. But it was observed that the use of high amount of organic matter (6 kg O.M/m2 ) produced a large fruit size, which may be due to the good improvement of physical and chemical properties of the soil [10, 24].

### **3.6. Fruit fresh weight**

Fruit weight depends on cultivar and temperature rather than on the culture system (organic or conventional) [10]. Moreover, most researchers found only small and non-significant differences between organic and conventional systems in respect to fruit weight [20]. But in an experiment conducted on strawberry plants, they observed that the use of chemical fertilizers were found to produce the highest significant average fruit weight compared to fruits produced by using organic materials or without using any type of fertilizers [10, 25].

### **3.7. Fruit moisture content and dry weight**

Fruit moisture content showed an opposite trend to fruit dry matter content; organically produced fruits had more dry matter and lower water content in comparison to the conven‐ tionally produced ones. The decrease in fruit water content of the organically produced fruits was reflected on increasing fruit dry matter content in comparison to the conventionally produced fruits that produced the lowest fruit dry matter and highest water content [10]. For example, the highest strawberry moisture content (93.37%) was obtained by the conventional system which produced the lowest fruit dry matter content (6.63%), while strawberry fruits that are produced under organic systems, contains 92.61% moisture content and 7.39% of dry matter content [10].

### **3.8. Fruit pH**

The fruit taste is highly affected by the fruit pH; addition of organic materials was found to lower the strawberry fruit pH, especially by using sheep manure as a source of organic matter [24]. However, in an experiment conducted on pepper plant, results do not show any signifi‐ cant differences between all of the used organic and inorganic treatments on fruit pH [23].

### **4. Fruit pigments**

### **4.1. Chlorophyll**

Chlorophyll content of the leaves was increased by the use of organic matter applications; the highest increase was obtained by using the sheep manure as a source of organic matter, while the lowest amounts of leaf chlorophyll content were obtained by the use of chemical fertilizers [26].

A promotional effect of organic matter treatments on chlorophyll contents might be attributed to the fact that nitrogen is a constituent of chlorophyll molecule [3]; moreover, nitrogen is the main constituent of all amino acids in protein and lipids that act as a structural compound of the chloroplast. Contradictory data about the relationship between growth and chlorophyll content of leaves have been reported in which bio-fertilizers increased the content of photo‐ synthetic pigments [27].

### **4.2. Anthocyanin**

Organically grown fruits developed a significantly stronger color than conventionally grown ones [14]. The highest anthocyanin content of strawberry fruits (42.88 mg 100 g-1fruit fresh weight) was obtained by the 6 kg O.M/m2 treatment, while the least anthocyanin content was obtained by the control treatment (neither synthetic fertilizers nor organic materials). In spite of that, the anthocyanin content of the control treatment of strawberry plants remained within the ranges between 17.8 and 41.8 mg 100 g-1, and values lower or higher than that range should not be acceptable [10].

In another study conducted on red pepper fruits, the highest anthocyanin (38.5 mg 100 g-1) amount was obtained by the mixture of different organic matter treatment. And the least anthocyanic content was obtained by the conventional culture system, which proves that organic farming provides peppers with the highest intensities of red and yellow colors, while the conventional fruits were those with the lowest values of color intensity [23].

### **4.3. Lycopene**

It is recorded that fruit lycopene content was the highest in conventional agriculture, but without significant differences from the different organic matter sources. Also fruit lycopene was affected by the organic matter source, and the lowest lycopene content was obtained by the poultry manure source–treated pepper fruits, which means lycopene fruit content does not improve by the use of organic matter treatments in comparison to conventional agriculture that hastened fruit lycopene content [23].

### **5. Conclusions**

[24]. However, in an experiment conducted on pepper plant, results do not show any signifi‐ cant differences between all of the used organic and inorganic treatments on fruit pH [23].

Chlorophyll content of the leaves was increased by the use of organic matter applications; the highest increase was obtained by using the sheep manure as a source of organic matter, while the lowest amounts of leaf chlorophyll content were obtained by the use of chemical fertilizers

A promotional effect of organic matter treatments on chlorophyll contents might be attributed to the fact that nitrogen is a constituent of chlorophyll molecule [3]; moreover, nitrogen is the main constituent of all amino acids in protein and lipids that act as a structural compound of the chloroplast. Contradictory data about the relationship between growth and chlorophyll content of leaves have been reported in which bio-fertilizers increased the content of photo‐

Organically grown fruits developed a significantly stronger color than conventionally grown ones [14]. The highest anthocyanin content of strawberry fruits (42.88 mg 100 g-1fruit fresh weight) was obtained by the 6 kg O.M/m2 treatment, while the least anthocyanin content was obtained by the control treatment (neither synthetic fertilizers nor organic materials). In spite of that, the anthocyanin content of the control treatment of strawberry plants remained within the ranges between 17.8 and 41.8 mg 100 g-1, and values lower or higher than that range should

In another study conducted on red pepper fruits, the highest anthocyanin (38.5 mg 100 g-1) amount was obtained by the mixture of different organic matter treatment. And the least anthocyanic content was obtained by the conventional culture system, which proves that organic farming provides peppers with the highest intensities of red and yellow colors, while

It is recorded that fruit lycopene content was the highest in conventional agriculture, but without significant differences from the different organic matter sources. Also fruit lycopene was affected by the organic matter source, and the lowest lycopene content was obtained by the poultry manure source–treated pepper fruits, which means lycopene fruit content does not improve by the use of organic matter treatments in comparison to conventional agriculture

the conventional fruits were those with the lowest values of color intensity [23].

**4. Fruit pigments**

358 Organic Farming - A Promising Way of Food Production

synthetic pigments [27].

not be acceptable [10].

**4.3. Lycopene**

that hastened fruit lycopene content [23].

**4.2. Anthocyanin**

**4.1. Chlorophyll**

[26].

Fruit characteristics from plants cultivated in soil supplemented with animal manure were generally better than those from plants grown in soils only or supplemented with chemical fertilizers. In most cases of animal manure sources, sheep manure gave the best results. On the other hand, the use of chemical fertilizers was found to increase the fruit lycopene content and improve fruit size and yield by increasing the fruit weight. Organic foods contain fewer harmful chemicals, are better for the environment, and may be more nutritious.

### **Author details**

Taleb Rateb Abu-Zahra

Address all correspondence to: talebabu@yahoo.com

Department of Plant Production and Protection, Faculty of Agricultural Technology, Al-Balqa Applied University, As-Salt, Jordan

### **References**


[19] Hakkinen, S. H., and Torronen, A. R. 2000. Content of flavonols and selected phenol‐ ic acids in strawberries and *Vaccinium* species: Influence of cultivar, cultivation site and technique. Food Research International. 33: 517-524.

[7] Brown, S., Chaney, R., Hallfrisch, J., Rayan, J. A., and Berti, W. R. 2004. *In situ* soil treatments to reduce the phyto- and bioavailability of lead, zinc, and cadmium. Jour‐

[8] Asami, D. K., Hong, Y. J., Barrett, D. M., and Mitchell, A. E. 2003. Comparison of the total phenolic and ascorbic acid content of freeze-dried and air-dried marionberry, strawberry, and corn grown using conventional, organic, and sustainable agriculture

[9] Jolly, D. A. 1989. Organic foods-consumer attitudes and use. Food Technology.

[10] Abu-Zahra, T. R., Al-Ismail, K., and Shatat, F. 2007. Effect of organic and convention‐ al systems on fruit quality of strawberry (*Fragaria* X *Ananassa* Duch) grown under plastic house conditions in the Jordan Valley. Acta Horticulturae. 741: 159-172. [11] Mitchell, A. E., and Chassy, A. W. 2005. Antioxidants and the nutritional quality of organic agriculture. Retrieved from http://mitchell.ucdavis.edu/Is%20Organic

[12] Jadczak, D., Grzeszuczuk, M., and Kosecka, D. 2010. Quality characteristics and con‐ tent of mineral compounds in fruit of some cultivars of sweet pepper (*Capsicum an‐*

[13] Abu-Zahra, T. R., Ta'any, R. A., Tahboub, A. B., and Abu-Baker, S. M. 2013. Influence of agricultural practices on soil properties and fruit nutrient contents of bell pepper.

[14] Cayuela, J. A., Vidueira, J. M., Albi, M. A., and Gutierrez, F. 1997. Influence of the ecological cultivation of strawberries (*Fragaria X Ananassa* Cv. Chandler) on the qual‐ ity of the fruit and on their capacity for conservation. Journal of Agricultural and

[15] Shamaila, M., Baumann, T. E., Eaton, G. W., Powrie, W. D., and Skura, B. J. 1992. Quality attributes of strawberry cultivars grown in British Columbia. Journal of Food

[16] Kader, A. A. 1999. Fruit maturity, ripening, and quality relationships. Acta Horticul‐

[17] Torronen, R., and Maatta, K. 2002. Bioactive substances and health benefits of straw‐

[18] Cheng, G. W., and Breen, P. J. 1991. Activity of phenylalanine ammonia-lyase (PAL) and concentration of anthocyanins and phenolics in developing strawberry fruit.

Journal of American Society for Horticultural Science. 116: 865-869.

practices. Journal of Agricultural and Food Chemistry. 51: 1237-1241.

nal of Environmental Quality. 33: 522-531.

360 Organic Farming - A Promising Way of Food Production

43(11): 60.

%20Better.pdf (access 2006)

Food Chemistry. 45: 1736-1740.

berries. Acta Horticulturae. 567: 797-803.

Science. 57: 696-699.

turae. 485: 203-208.

*num* L.). The Elemental Journal. 15(3): 509-515.

Biosciences Biotechnology Research Asia. 10(2): 489-498.


### *Edited by Petr Konvalina*

Organic farming is a progressive method of farming and food production it does not mean going back to traditional (old) methods of farming. Many of the traditional farming methods used in the past are still useful today. Organic farming takes the best of these and combines them with modern scientific knowledge. Authors' task was to write a book where many different existing studies could be presented in a single volume, making it easy for the reader to compare methods, results and conclusions. As a result, studies from different countries have been compiled into one book. I believe that the opportunity to compare results and conclusions from different authors will create a new perspective in organic farming and food production. I hope that our book will help researchers and students from all over the world to attain new and interesting results in the field of organic farming and food production.

Photo by Bonnie McCann / iStock

Organic Farming - A Promising Way of Food Production

Organic Farming

A Promising Way of Food Production

*Edited by Petr Konvalina*