**3. The effects of management techniques on fruit quality**

In general, the most important quality factors for tropical fruit growers, production managers, processors, and packers are fruit juice content, soluble solids and acid concentrations, soluble solids-acid ratio, fruit size, and color, showing that these characteristics may change regarding fruit species.

Fruit qualities, when consumed, are decided largely before harvest and depend on the variety grown, crop management (fertilization, irrigation, etc.), environment [climate (excessive rainfall causes major problems with flowering, pests, diseases and fruit quality) and soil] and other preharvest factors. Specifically, fruit quality, depends on several factors including cultivar, rootstock, climate, soil, pests, irrigation and nutrition, although standardized foliar levels have not been established for some tropical fruit species yet, such as yellow passion fruit, coconut and papaya.

In this sense, some of other research works have been developed aiming to measure the contribution of each factor on fruit quality for several tropical fruits and, additionally, trying to reduce the use of synthetics for the production of fruits with less inorganic products and they have also have as their objective the production of adequate amounts of high-quality food, protecting resources and being both environmentally safe and profitable.

Since excessive irrigation and fertilization reduce fruit quality, supplying sufficient nutrition and using sound irrigation scheduling techniques should be a high-priority management practice for every tropical fruit grower. Each fruit species requires a properly designed, operated, and maintained water management system and a balanced nutrition program formulated to provide specific needs for maintenance, expected yield and fruit quality. Such information depends on scientific studies to make fruit production reach high incomes and to manage adequately environmental factor.

Accordingly, irrigation contributes to the efficiency of nutrient programs because fruit trees with sufficient water and nutrients grow stronger, tolerate pests and stresses in a better way, yield more consistently, and produce good quality of fruit.

Adversely, deficient or excessive irrigation or fertilization may result in poor fruit quality, considering that the most important management practices that influence fruit quality are irrigation and an adequate nutrient management, mainly in relation to nitrogen, phosphorus, potassium, and magnesium. In addition to that, some micronutrients like boron and copper, in deficient plants, can also affect fruit quality, as long as when any nutrient is severely deficient, fruit yield and fruit quality will be negatively affected.

Among many economically important tropical fruits, in this book chapter, yellow passion fruit (*Passiflora edulis* f. flavicarpa Deg), coconut (*Cocos nucifera* L.) and papaya (*Carica papaya*) are going to be focused.

Yellow passion fruit is one of the most potentially fruitful plants for tropical regions, where climatic and soil conditions are favorable for its cultivation. Yellow passion fruits produced in Brazil present good flavor, high nutritional value, pharmacological applications and they are especially consumed as juice, although being also very appreciated as cold drinks, yogurt, sauce, gelatin desserts, candy, ice cream, sherbet, cake icing, cake filling, meringue or chiffon pie, cold fruit soup, or cocktails.

Fruit quality of yellow passion fruit has been widely studied since it is affected by several agronomic treats during crop growth, such as fertilizing, mulching, biofertilizing, irrigation water quality in relation to salinity and soil water losses.

In general, the most important quality factors for tropical fruit growers, production managers, processors, and packers are fruit juice content, soluble solids and acid concentrations, soluble solids-acid ratio, fruit size, and color, showing that these

Fruit qualities, when consumed, are decided largely before harvest and depend on the variety grown, crop management (fertilization, irrigation, etc.), environment [climate (excessive rainfall causes major problems with flowering, pests, diseases and fruit quality) and soil] and other preharvest factors. Specifically, fruit quality, depends on several factors including cultivar, rootstock, climate, soil, pests, irrigation and nutrition, although standardized foliar levels have not been established for some tropical fruit species yet, such

In this sense, some of other research works have been developed aiming to measure the contribution of each factor on fruit quality for several tropical fruits and, additionally, trying to reduce the use of synthetics for the production of fruits with less inorganic products and they have also have as their objective the production of adequate amounts of high-quality

Since excessive irrigation and fertilization reduce fruit quality, supplying sufficient nutrition and using sound irrigation scheduling techniques should be a high-priority management practice for every tropical fruit grower. Each fruit species requires a properly designed, operated, and maintained water management system and a balanced nutrition program formulated to provide specific needs for maintenance, expected yield and fruit quality. Such information depends on scientific studies to make fruit production reach high incomes and

Accordingly, irrigation contributes to the efficiency of nutrient programs because fruit trees with sufficient water and nutrients grow stronger, tolerate pests and stresses in a better way,

Adversely, deficient or excessive irrigation or fertilization may result in poor fruit quality, considering that the most important management practices that influence fruit quality are irrigation and an adequate nutrient management, mainly in relation to nitrogen, phosphorus, potassium, and magnesium. In addition to that, some micronutrients like boron and copper, in deficient plants, can also affect fruit quality, as long as when any

Among many economically important tropical fruits, in this book chapter, yellow passion fruit (*Passiflora edulis* f. flavicarpa Deg), coconut (*Cocos nucifera* L.) and papaya (*Carica* 

Yellow passion fruit is one of the most potentially fruitful plants for tropical regions, where climatic and soil conditions are favorable for its cultivation. Yellow passion fruits produced in Brazil present good flavor, high nutritional value, pharmacological applications and they are especially consumed as juice, although being also very appreciated as cold drinks, yogurt, sauce, gelatin desserts, candy, ice cream, sherbet, cake icing, cake filling, meringue

Fruit quality of yellow passion fruit has been widely studied since it is affected by several agronomic treats during crop growth, such as fertilizing, mulching, biofertilizing, irrigation

nutrient is severely deficient, fruit yield and fruit quality will be negatively affected.

food, protecting resources and being both environmentally safe and profitable.

**3. The effects of management techniques on fruit quality** 

characteristics may change regarding fruit species.

as yellow passion fruit, coconut and papaya.

to manage adequately environmental factor.

*papaya*) are going to be focused.

or chiffon pie, cold fruit soup, or cocktails.

water quality in relation to salinity and soil water losses.

yield more consistently, and produce good quality of fruit.

In a study about potassium fertilizing of yellow passion fruit, Campos et al. (2007) registered weightier and sweeter fruits in plants submitted to larger amounts of potassium, agreeing with Marschner (2005), who informs us about potassium influence on increasing soluble solids of fruits.

The effect of mulching is also confirmed because it reduces soil water loses for atmosphere trough evaporation and, consequently, soil moisture becomes higher on root zone making it possible a better nutrient solubility and availability for plants. Campos et al. (2007) verified increase in fruit soluble solids (ºbrix) from plants grown with soil mulching, with a quantitative difference of 0.2 ºbrix; additionally, Freire et al. (2010) found that soil mulch promoted enhancement on fruit weight, fruit firmness, pulp percentage, pulp pH and ascorbic acid, important variables for fruit industry, specially for yellow passion fruit which is at most consumed in processed forms.

Another important theme on yellow passion fruit quality is the use of saline water for growth and production of this tropical fruit. In tropical regions, where water availability is restricted to low quality in relation to salt contents but climatic and soil conditions are adequate for yellow passion fruit growth, researchers have tried to find alternative managements to make its cultivation viable. North-Eastern Brazil is one of these regions, in which, nowadays, there is an important production of yellow passion fruit, in many cases, under irrigation with saline water.

Costa et al. (2001) characterized yellow passion fruit from plants irrigated with different saline levels and concluded that water salinity higher than 3.0 dS m-1 does not affect the external and internal quality of fruits. In the same study, it was reported that fruit quality related to pulp percentage, soluble solids, titratable acidity and vitamin C contents were similar to standardized values for plants irrigated with good quality water. These successful results were possible because, as forthis study, planting pits without coating (R0) and with side coatings (R1; R2; R3; R4; respectively one, two, three and four lateral sides) were used, so plating pits with coating, promoted a better water use and, consequently, better fruits. Accordingly, Cavalcante et al. (2005) found a positive correlation between pit coating and number of fruits and fruit weight, under irrigation with saline water, i.e., coated pits increased fruit production under irrigation with saline water with results compatible to fruit production by plants irrigated with good quality water. Cavalcante et al. (2003) associated soil mulch with saline water levels for yellow passion fruit production and identified that increasing salinity of irrigation water has no effect on fruit quality when soil mulch also was used, it was also noticed that soluble solids (ºbrix), titratable acidity and pulp pH produced under irrigation with saline water and soil mulching are compatible to low demanding markets.

Yellow passion fruit is also positively affected by organic fertilizers, such as biofertilizers, which are obtained by anaerobic fermentation and could be simple [water + fresh bovine manure] at a ratio of [1:1] (in volume) or enriched [water + fresh bovine manure + a protein mix + nutrient sources], as can be seen in figure 4, adapted from Cavalcante et al. (2011c).

During the last years, biofertilizers have emerged as an important component of the integrated nutrient supply system and they have been tested on yellow passion fruit production and nutrition through environmentally better nutrient supplies. It is possible to find in the scientific literature some research work that has studied biofertilizers effects on fruit quality of yellow passion fruit, including the ones under irrigation with saline water. According to Cavalcante et al. (2011a), fruit quality and nutritional status of yellow passion fruit are affected by biofertilizer doses applied; fruit length, width, pulp percentage, skin diameter, mass,

Physical and Chemical Characteristics of Tropical and Non-Conventional Fruits 11

biofertilized in the work cited above presented the minimum titratable acidity required by juice industry, which is 2.5% (Anonymous, 1999). Dias et al. (2011) also concluded that higher biofertilizing frequency stimulates pulp percentage, titratable acidity, vitamin C contents and juice electrical conductivity. Enriched biofertilizer affected yellow passion fruit mass, promoting production of fruits with average mass compatible to the fresh fruit market

Coconut is another tropical fruit which is influenced by management techniques. According to Ferreira Neto et al. (2007), the mean weight of fruit is not influenced by the application of N and K through fertigation, but increasing N has decreased water volume and °Brix and increased pH, while increasing K dose has decreased salinity and increased ºbrix of coconut water. On another paper, Silva et al. (2006) verified that coconut water volume is affected by nitrogen and potassium, since the maximum coconut water volume observed (417.75 mL) was found when 818 g of nitrogen plant-1year-1 and 1487 g of potassium plant-1year-1 were tested. Nitrogen and potassium levels also demonstrated a linear effect on the soluble solids content of coconut water, on which nitrogen had a negative and potassium a positive effect. A negative linear effect was observed between nitrogen concentration and electrical conductivity of coconut water, while it was observed that potassium levels showed a quadratic effect on this same parameter. Coconut water quality is directly and mainly affected by coconut plant genotype, maturation, plant nutrition, irrigation and climatic conditions, thus it is important monitoring all fruit growth and maturation circle to obtain fruits with high amounts of water, what is very important for coconut water industry. As for papaya fruit processing it is necessary good quality fruits, produced under low costs, as suggested by Mesquita et al. (2007), who have evaluated the fruit quality and yield of papaya fertilized with bovine biofertilizers. The results of their study, except for fruit firmness, registered positive effects of the biofertilizers on 'Baixinho de Santa Amália'

papaya cultivar in relation to yield, physical and chemical fruit quality.

**4. Physical and chemical characteristics of non-conventional fruits** 

The higher and increasing demand, during the last decades, for exotic fruits has offered greater variety in the production market, the same way expanded marketing opportunities have been of fruit producers' interest, especially in Brazil where climatic and soil conditions are favorable for the production of non-conventional fruits. Equally, scientific information that characterizes these species in relation to quality and maturation of fruits is important to the development of this industry. In this sense, the determination of physical and chemical fruit characteristics constitutes an important reference for studies about the maturation and quality of fruits, with the ultimate aim of determining consumer acceptance requirements. Additionally, nowadays, fruit consumers are becoming increasingly aware of health and nutritional aspects of their food, demonstrating a tendency of avoiding synthetic products, such as additives, in their food, since they are obtaining therapeutic effects and nutrition from natural resources. This way, non-conventional fruits could satisfy these demands because they are also produced, in most cases, without agronomic techniques, as mentioned chemical fertilizing and pesticides, especially in Brazil where the Agriculture Ministry regulates the pesticides, dividing them into two groups: the ones which have been scientifically tested and proved their efficiency and, the ones which have not been through this process concerning non-conventional fruits. On the other hand, many of these fruits are highly perishable and difficult to store in their fresh form, some of them are not acceptable

(Rodrigues et al., 2009).

soluble solids and titratable acidity were improved with biofertilizer application, independently of type; simple biofertilizer promotes optimum supplies of potassium, calcium and sulphur, while enriched one promotes optimum supplies of nitrogen, phosphorus, potassium and calcium; and bovine biofertilizer is an important key to the production of yellow passion fruit with less use of chemical fertilizers, maintaining fruit quality.

Fig. 4. Preparation system of both biofertilizers (simple - A; enriched - B) by anaerobic fermentation.

Cavalcante et al. (2007b) reported that enriched biofertilizer inhibited the mean weight of fruits and yield of yellow passion fruit in relation to simple biofertilizer, and fruits produced under simple fertilizer use were compatible to the average standardized fruit weight of 200g quoted by Meletti et al. (2002). Despite, different results can be found: Rodrigues et al. (2008), adversely, concluded that yellow passion plants submitted to enriched biofertilizer produced adequate titratable acidity (citric acid) and low pulp percentage and vitamin C content, including that soluble solids (ºbrix) ranged from 12.9 to 13.9ºbrix, thus above the limit of 11ºbrix required by the industry (Anonymous, 1999).

Simple biofertilizer promoted enhancement on titratable acidity of yellow passion fruits (Dias et al., 2011), what is pretty much important for juice industry, since it reduces the addition of artificial acid components. Furthermore, all the yellow passion fruit plants

soluble solids and titratable acidity were improved with biofertilizer application, independently of type; simple biofertilizer promotes optimum supplies of potassium, calcium and sulphur, while enriched one promotes optimum supplies of nitrogen, phosphorus, potassium and calcium; and bovine biofertilizer is an important key to the production of

**Methane gas** 

**B**

**Water + Bovine manure + Protein mix + Nutrients** 

yellow passion fruit with less use of chemical fertilizers, maintaining fruit quality.

Fig. 4. Preparation system of both biofertilizers (simple - A; enriched - B) by anaerobic

limit of 11ºbrix required by the industry (Anonymous, 1999).

Cavalcante et al. (2007b) reported that enriched biofertilizer inhibited the mean weight of fruits and yield of yellow passion fruit in relation to simple biofertilizer, and fruits produced under simple fertilizer use were compatible to the average standardized fruit weight of 200g quoted by Meletti et al. (2002). Despite, different results can be found: Rodrigues et al. (2008), adversely, concluded that yellow passion plants submitted to enriched biofertilizer produced adequate titratable acidity (citric acid) and low pulp percentage and vitamin C content, including that soluble solids (ºbrix) ranged from 12.9 to 13.9ºbrix, thus above the

**Water + Bovine manure** 

**Water** 

**Methane gas** 

**A**

Simple biofertilizer promoted enhancement on titratable acidity of yellow passion fruits (Dias et al., 2011), what is pretty much important for juice industry, since it reduces the addition of artificial acid components. Furthermore, all the yellow passion fruit plants

fermentation.

biofertilized in the work cited above presented the minimum titratable acidity required by juice industry, which is 2.5% (Anonymous, 1999). Dias et al. (2011) also concluded that higher biofertilizing frequency stimulates pulp percentage, titratable acidity, vitamin C contents and juice electrical conductivity. Enriched biofertilizer affected yellow passion fruit mass, promoting production of fruits with average mass compatible to the fresh fruit market (Rodrigues et al., 2009).

Coconut is another tropical fruit which is influenced by management techniques. According to Ferreira Neto et al. (2007), the mean weight of fruit is not influenced by the application of N and K through fertigation, but increasing N has decreased water volume and °Brix and increased pH, while increasing K dose has decreased salinity and increased ºbrix of coconut water. On another paper, Silva et al. (2006) verified that coconut water volume is affected by nitrogen and potassium, since the maximum coconut water volume observed (417.75 mL) was found when 818 g of nitrogen plant-1year-1 and 1487 g of potassium plant-1year-1 were tested. Nitrogen and potassium levels also demonstrated a linear effect on the soluble solids content of coconut water, on which nitrogen had a negative and potassium a positive effect. A negative linear effect was observed between nitrogen concentration and electrical conductivity of coconut water, while it was observed that potassium levels showed a quadratic effect on this same parameter. Coconut water quality is directly and mainly affected by coconut plant genotype, maturation, plant nutrition, irrigation and climatic conditions, thus it is important monitoring all fruit growth and maturation circle to obtain fruits with high amounts of water, what is very important for coconut water industry.

As for papaya fruit processing it is necessary good quality fruits, produced under low costs, as suggested by Mesquita et al. (2007), who have evaluated the fruit quality and yield of papaya fertilized with bovine biofertilizers. The results of their study, except for fruit firmness, registered positive effects of the biofertilizers on 'Baixinho de Santa Amália' papaya cultivar in relation to yield, physical and chemical fruit quality.
