Effects of cooking fruits and vegetables

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In their raw state most of fruits and vegetables are appetizing, retaining maximum texture, colour, flavour and content of vitamins such as ascorbic acid and those of the B- complex. Fruits are generally stewed or baked and vegetable are boiled, steamed, baked, grilled or stir-fried. The pressure cooker and the microwave oven are also useful for cooking fruits and vegetables.
The following are the effects of cooking on fruits and vegetables;
i. Pectin; Heat treatment of fruits and vegetables is a crucial method of preservation. When the pectic substances in cell walls decompose, softening of wall cells and subsequently separation may happen.
ii. Colour; Colour may be the most important factor influencing the attractiveness of the fruits and vegetables. There have been many studies to determine and obtain the optimum techniques to minimise the undesirable effects on quality of fruits and vegetables including colour.The changes that arise in green pigments of vegetables may be in connection with the properties of chlorophyll.The initial colour change can be identified when the green vegetable is dropped into boiling water resulted in brightening of the green colour that may be as a result of expulsion of air and collapse of the intercellular spaces.During cooking, the choloroplasts shrink and get clumped in the centre of coagulated protoplasm. In this stage the remaining chlorophyll in the chloroplasts is no longer protected by the plastid membranes from the acid-containing cell sap. As a result, the dull olive green pheophytins may be formed.The level of colour change is dependent on the acidity of the cooking medium, the pH of the vegetable, the chlorophyll content, and the time and temperature of cooking.
iii. Flavour; The volatile flavouring components are crucial including organic acids, aldehydes, alcohols and esters. Phenolic compounds – e.g. catechin and leucoanthocyanins are responsible for the astringent taste of some foods. Time and temperature of heating during preparation of juice extracts from e.g. red currant and red raspberry fruits can highly affect the tannin content of the juice. As tannin portion increases, the degree of bitterness and astringency will also increase.
iv. Some nutrients may be lost e.g. vitamin C.

Titany answered the question on April 25, 2022 at 13:07

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Effects of cooking fruits and vegetables

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