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
