**1. Introduction**

One of the most urgent and essential needs of today is ensuring food security for the rapidly growing world population and, at the same time, ensuring long-term sustainable development in the reduction of food losses. Postharvest losses significantly increase food insecurity, reduce farmer's income and enhance inefficiency in the global food system. The essential elements of postharvest losses challenge include problem of multiple points of intervention, multiple technologies, complex value chain, and poorly developed food systems [1]. In accordance with projections by FAO, food production will need to grow by 70% to feed the world population, which will

reach over 10 billion by the year 2050. As efforts are being geared towards increased production, there must be corresponding efforts for an integrated and innovative approach to the global efforts to ensure sustainable food production, consumption and loss reduction [2]. One major way of strengthening food security is by reducing losses. Postharvest loss can be defined as degradation in both quantity and quality of food from harvest to consumption. Reduction in these losses would increase the amount of food available for human consumption and enhance global food security. Food losses occur due to poor infrastructure, logistics issues, lack of technology, lack of prompt access to markets, insufficient skills, and inadequate knowledge and management capacity of supply chain actors. Losses also occur at the production, postharvest and processing stages in the food supply chain [3, 4]. Food waste refers to food appropriate for human consumption being discarded along the food chain due to consumers' behaviour [5, 6]. Damage restricts the use of a product, whereas loss makes its use impossible. These losses occur because harvested agricultural produce consists of living tissues that respire and undergo physiological changes caused by conditions such as high temperature, low atmospheric humidity, physical injury, biotic contamination and enzyme actions. Food losses reduce the food available for human consumption and incur costs of waste management; loss of scarce resources used in crop production generates about 6–10 per cent of human-greenhouse gas emissions in the land where food wastes decompose anaerobically [1]. Pre-harvest refers to every activity embarked on by the producer in the production of crops before harvest, and this includes site selection, land preparations, appropriate planting date, optimum seed rate, recommended spacing, appropriate tools and equipment used, proper tillage activities and seedbed preparation, pests, disease and weed management, irrigation, mulching, staking and use of hormones. An adequate supply of potassium nutrition in tomato production enhances titratable acidity and fruit colour quality and reduces the incidence of the yellow shoulder [7, 8], while the inadequate application of potassium in aqua-phonic tomato production results in ripening disorders [9]. An increase in nitrogen supply to tomatoes grown in a controlled environment may reduce fruit quality by decreasing the sugar content of the fruits [10]. A high nitrogen supply of about 250 kg/ha can impair some important quality traits of tomato fruits, such as total soluble solids [11], glucose, fructose, and pH [12]. The addition of ammonium in tomato production results in improved fruit flavours [13]. The quality of tomato fruit is also affected by the amount of boron used. Lower amounts of boron supply reduce fruit firmness [14]. The compositional quality of harvested produce is affected by maturity stage; Howard [15] observed that total vitamin C content of red pepper was about 30% higher compared to green pepper. Tomato fruits harvested green at table ripeness contain less vitamin C than those harvested at the full ripe stage. Tomato fruits at the 'breaker' stage contained only 69% of their vitamin C concentration. Quality refers to the state of excellence of a produce, which may be either good or bad. It refers to a property or group of properties that make a produce acceptable or desired by a consumer. It is subjective and changes according to culture, customs, environment, social status and mindset. These parameters change from one food commodity to the other. Several attributes have been used to describe quality: size, shape, colour, consistency, flavour or organoleptic properties like texture, smell and tastes. Other properties that are used to measure qualities include appearance as presentation, nutritive value, dependability and wholesomeness. Higher quality will translate to higher prices and more consumers' satisfaction. Quality can be described based on produce usages, such as edible quality, dessert quality, shipping quality, table quality, nutritional quality, internal quality and appearance quality. The quality

#### *Pre-Harvest and Postharvest Factors Affecting Quality and Shelf Life of Harvested Produce DOI: http://dx.doi.org/10.5772/intechopen.111649*

of harvested produce is a combination of characteristics, attributes and properties that give the produce value to humans for food. Quality standards are usually sets to essentially meet specification and demand of the consumer. Every change in food that causes it to lose its desired quality and eventually become unpalatable is called food spoilage or rot. Food spoilage is also a metabolic process that causes foods to be undesirable or unacceptable for human consumption due to changes in sensory characteristics [16]. Quality losses include those that affect the nutrient composition, acceptability, and edibility of a given product, while quantity losses refer to those that result in the loss of the amount of a product [3]. Reducing food losses requires an understanding of pre-harvest and postharvest factors resulting in loses, cultural background and economic level of the people involved. It is essential because all food losses occur at a particular socio-cultural environment. Reduction of postharvest food losses is critical in ensuring future global food security. The issue of food losses is of high importance in the efforts to combat hunger, raise income and improve food security in the world today. It is very important to know the pattern and scale of these losses across the world, especially in developing countries and identify their causes and possible solutions.

### **2. Quality attributes**

*Appearance:* This is the evaluation of quality by sense of sight, shape, wholesomeness and pattern. It includes quality traits such as:

*Shape:* The shape should not deviate from the typical accepted standard set for that produce. It must not have any damage or bruise, for example, cucumbers are supposed to be elongated in shape and also robust, not sickle or twisted in shape.

*Size:* The size of some harvested produce determines their market acceptability. Examples of such are plumb, robust banana finger, carrot, okra, plantain are more acceptable than a slim one; also in cauliflower, size and compactness of the head are quality parameters that determine market acceptability. Matured plants are harvested at about 15 cm in diameter, and protruding floral parts indicate over maturity.

*Colour:* Colour of harvested produce like fruits and vegetables is expressed through their various pigments and can be grouped into red: anthocyanin pigments, green: chlorophyll and yellow to orange: carotenoids. There are many factors that influence colour, such as genetic constitution, maturity, climate, environment, season, soil type, plant nutrition, plant density and postharvest treatment. Maturity is a very important factor in determining the colour of harvested produce. At early stages of development, colour is usually green and only attains its characteristic colour at full maturity. The chlorophyll colour is important in vegetables, and if this is lost, the vegetables are not acceptable. Examples of such green vegetables are celery, green bell peppers, chayote squash, cucumbers, collard greens, green beans, green onions, green peas, leeks, lettuce, mustard greens, endive, kale, kohlrabi, jalapenos, okra, snap peas, snow peas, Swiss chard, watercress and zucchini. It must show the true colour of the product in terms of lightness, transparency, turbidity, and glossy nature [17, 18].

*Wholesomeness:* This involves the sanitary factors of the product. It must be clean without impurities, extraneous matter, sediments or specks. Also, a product must be a whole product, not part of a whole.

*Pattern:* This also describes shape and size; it should follow the specific pattern peculiar to the product.

*Firmness:* For cauliflower, a firm and compact head of white to cream-white curds surrounded by a crown of well-trimmed, turgid green leaves are required quality indices with freedom from severe yellowing, defects due to handling and decay.

*Texture:* This is the hand and mouth feel, the assessment of quality by the sense of touch and taste. It also indicates coarseness or crispness, firmness, turgidity, density, viscosity, surface tension, juiciness or dryness, fibrousness or chewiness, softness, mildness or stickiness. The texture of tomato is majorly contributed by the insoluble solids derived from cell walls which determined the consistency, smoothness and juiciness of the fruit [24].

*Consistency:* This may also be considered by a sense of touch. This refers to visualisation, flow or spread proportion of the produce. Appearance and texture can be measured by a team of experts ranging in order of quality importance. It is, therefore, a very elusive factor to measure because it depends on individual judgement. This means of measurement is usually referred to as organoleptic test [19–22].

*Flavour:* This is the quality evaluation by the sense of taste or smell. It refers to terms such as odour, fragrance, acid, burnt or gutty; taste: sweet, sour, bitter, salty or bland, off-flavour, enzymatic reaction, physiological deterioration and chemical contamination, overcooked or stale. For example, apples should have a crunchy texture and a sweet flavour while pomegranates should have a juicy texture and a sweet-tart flavour while strawberries should have a juicy texture and a sweet flavour. Tomatoes are typically juicy and firm, but can range from soft and mushy to hard and crunchy feel. Cucumbers are typically crunchy and juicy; while carrots are typically crunchy and sweet. Beetroots are firm and sweet, and cabbage is crunchy and slightly bitter while lettuce is crisp and slightly bitter, and ginger and turmeric are fibrous and slightly spicy. Enzyme reactions also occur, resulting in desirable flavour. For example, hydroperoxide lyase catalyses the production of tomato flavours [23]. To enhance sales, these quality factors are essential for market acceptability and consumers' choice to buy or reject the product. Sometimes, initial sales occur based on appearance, but repeated purchases are driven by expected quality factors determined by flavour compounds and texture [24, 25].

*Nutritional value:* This quality attribute is very important in ascertaining produce composition. It includes: total protein content, amino acid composition, mineral and vitamins, juice content, total soluble solids and vitamin C. Vitamin C content varies in fruits and vegetables from one to 150 mg/100 g [26]. In berry fruits, it ranges from 14 to 103 mg/100 g [27]. Rosehip, jujube, guava, kiwifruit, peppers, citrus fruit, spinach, broccoli and cabbage are rich in ascorbic acid. Tomato is about 93–95% water and 5–7% total solids. The lipids constituent in grapes is 0.1%, in bananas is 0.2% and in apple is 0.06%. Lipids content of 35 to 70% of dry mass is obtained in avocados, olives and nuts [28]. Fat-rich fruits and nuts include avocado, cauliflower, broccoli, carrots, hazelnuts, almond, walnut, Brazil nuts and chestnut [29]. Hazelnuts and almonds have flavonoid content of 18 and 15 mg/100 g, respectively [9]. Walnuts and Brazil nuts have phenolic acid content of 36 and 11 mg/100 g, respectively [10–14]. Good examples of fibre-rich foods are mango, orange, papaya, sweet lime, watermelon and apple [30]. Grains, fruits and vegetables are good sources of fibre. Fruits and vegetables provide 37% of the fibre in the diet and grains (36%) while legumes supplied 13% [31, 32]. Pro-vitamin A refers to precursors of vitamin A, obtained from fruits and vegetables such as carrot, pumpkin, peach and mango. Riboflavin is the central component of flavour proteins. It can be obtained from beans, beetroot, pepper and spinach. Niacin is derived from almonds, avocado and cape gooseberries. Vitamin B5 or pantothenic is obtained from meats, potatoes, oat cereals, tomato products and

*Pre-Harvest and Postharvest Factors Affecting Quality and Shelf Life of Harvested Produce DOI: http://dx.doi.org/10.5772/intechopen.111649*


**Table 1.**

*Food sources supplying vitamins, carotenoids and phenolic.*

whole grains. Sources of vitamin B6 include beans, cabbage, cauliflower, spinach, sweet potato, grape, avocado and banana. It occurs in peas, beans, nuts, broccoli, mushrooms, potatoes, strawberries and sweet potatoes. Folic acid is essential for reproduction and normal growth. It is present in strawberry, tomato, avocado, spinach, cabbage and other green vegetables [33, 34]. **Table 1** showed food sources supplying vitamins, carotenoids and phenolic.

### **2.1 Quality deterioration**

This is associated with advance spoilage; any change in food quality, when optimum quality is not obtained, is referred to as spoilage. The major causes of food deterioration in harvested crops are microorganisms, natural food enzymes, insects, rodents and parasites, heat and cold, moisture and dryness, air, for exmaple, O2, light and time.


not have occurred. These enzymatic reactions persist after maturation. Some of these enzymes may be more active in fruit crops such as pepper, tomatoes, plantain and banana to cause fruit deterioration. It is not in all cases that low temperature is required to preserve most tropical produce. The colder, the worse for some produce. For example, if the avocado is stored in a fridge, it turns black without ripening because the respiratory pattern is upset and other biological processes take place, leading to deterioration. Specific conditions for preservation must be selected in accordance with the unique spoilage pattern of individual harvested produce [35–37].


*Pre-Harvest and Postharvest Factors Affecting Quality and Shelf Life of Harvested Produce DOI: http://dx.doi.org/10.5772/intechopen.111649*


#### **Table 2.**

*Crops and their safe moisture content.*

but this is not often possible due to time. Microorganisms have plenty of time to act and cause deterioration. Time is needed to produce toxic substances, exposure of food to cold or heat takes time, and length of time affects deterioration. In some food industry, fermentation may be beneficial in producing the required flavour and aroma; this also takes time to develop. All deterioration takes time, and all processes leading to deterioration must be arrested on time [43, 44].
