Fruit of watermelon

Watermelon, Citrullus lanatus is a frost tender, vining annual crop with sweet-tasting fruit that is often consumed as a cool desert.

The composition of watermelon per 100 g edible portion (50-70% of the mature fruit) is: water 91.5 g, energy 134 kJ (32 kcal), protein 0.6 g, fat 0.4 g, carbohydrate 7.2 g, Ca 8 mg, P 9 mg, Fe 0.17 mg, thiamine 0.08 mg, riboflavin 0.02 mg, niacin 0.2 mg, folate 2 mg, ascorbic acid 9.6 mg.

Watermelon is served fresh as slices, as chunks, as juice, pickled rind, gale candy, and as edible seeds (harvested from confectionary type cultivars).

It is no longer just a summer fruit and is becoming an everyday fruit like apples, bananas and oranges.

Worldwide the yield of watermelon averages about 25 t/ha, varying from 5-60 t/ha, depending on cultivar and cultural practices.

Watermelon varieties are separated by seeded and seedless, types, then by rind color, shape, size and flesh color. There are at least 1000 named watermelon varieties, some of these originating 50-80 years ago still planted.
Fruit of watermelon

Chemical composition of fruit

Fruit as a dessert item, is the mature ovaries of plants with their seeds. The edible portion of most fruit is the fleshy part of the pericarp or vessel surrounding the seeds.

The quality attributes and evaluation methods of fruits could be grouped into three categories: physical, chemical and physiological on the basis of analytical process and principle involved.

Fruits normally contain between 10% and 25% carbohydrates, less than 1% of protein and less than 0.5% of fat.

Compositions of fruit not only vary for a given kind in according to botanical variety, cultivation practices and weather but also to the changes with degree of maturity prior to harvest.

Carbohydrates, sugars, and starches are broken down into CO2, water and energy during catabolism.

Natural sugar such as fructose, glucose, and sucrose are the major contributors to the sweetness of fruits, whereas the tart flavor component is partially due to organic acids located in the cell sap.

Fruits like banana, plantain, date raisin, breadfruit, and jackfruit are the major sources of carbohydrates.

Proteins and amino acids are contained in dried apricot and fig. Meanwhile citrus fruit like oranges, grapefruit and lemons are high in citric acid.

Acidity varies with maturity of the plant usually decreasing as the fruit ripening.

Fruits are also known as an important sources of minerals and certain vitamins, such as vitamins A and C. It is well known that citrus are excellent sources of vitamin C.

Chemical composition of fruit

Nutrient composition in papaya

Analysis of the fruit gave moisture 89.6 %, proteins 0.5%, carbohydrate 9.5%m, ether extract 0.1%, mineral matter 0.4%, calcium 0.01%, phosphorus 0.01%, and iron 0.4 mg/100 gm.

The high content of water in the papaya almost as a melon (92%), This is why some call it the ‘tropical melon’.

The chemical composition of papaya fruit with respect to sugars, organic, amino acids, vitamins, and minerals change during ripening.

Most of its carbohydrates are formed from sugars: saccharose, glucose and fructose.

The fresh fruit pulp contains sucrose, invert sugar, a resinous substance, papain, malic acid and salts of tartaric and citric acids 1.2 per cent.

The dry matter which was 7% at 15 days after pollination, increased to 13% at harvest.

Both ripe and unripe papaya fruit is a rich source of pectins.

Papaya is a source of calcium, and an excellent source of vitamin A and C. The B vitamins are also present in small amounts.

Papaya’s fruit and seed have been shown to possess bactericidal activity against Staphylococcus aureus, Bacillus cereus, Escherichia coli, Pseudomonas aeruginosa and Shigella flexneri.

Nutrient composition in papaya

Postharvest Factors that Influencing Composition and Quality of Fruits

Postharvest Factors that Influencing Composition and Quality of Fruits
Environment
Environmental: temperature, relative humidity, atmospheric composition.

Temperature management is the most import tool for extension of shelf life and maintenance of the quality of fresh fruit.

Relative humidity influences water loss, decay development, incidence of some physiological disorders and uniformity of fruit ripening.

Optimal relative humidity for storage of fruits is 85 to 90%. Finally, atmospheric composition (O2, CO2, and C2H2 in particular) can greatly affect respiration rate and storage life.

Handling method
Postharvest handling systems involve the channels though which harvested fruit reaches the processing facility or consumer. Handling methods should be chosen such that they maintain fruit quality and avoid delays.

Time period between harvesting and consumption
Delays between harvesting and cooling or processing may result in direct losses (due to water loss and decay) and indirect losses (decrease in flavor and nutritional quality).
Postharvest Factors that Influencing Composition and Quality of Fruits

Preharvest Factors Influencing Composition and Quality of Fruits

Preharvest Factors Influencing Composition and Quality of Fruits
Genetic: selection of cultivar, rootstocks.
Cultivar and rootstock selection are important because there are often differences in raw fruit composition, postharvest-life potential, and response to processing.
In many cases fruit cultivars grown for fresh market sale are not optimal cultivars for processing.

Climatic: temperature, light, wind.
Climatic factors may have a strong influence on nutritional quality of fruits.
Light intensity significantly affects vitamin concentration and temperature influences transpiration rate, which will affect mineral uptake and metabolism.

Cultural practices: soil type, soil nutrient and water supply, pruning, thinning, pest control.
Fertilizer addition may significantly affect the mineral content of fruit, while other practice such as pruning and thinning may influence nutritional composition by changing fruit load and size.

Preharvest Factors Influencing Composition and Quality of Fruits