Food 2 Flashcards
Explain oxidation…
Fresh fruit and vegetables start to lose nutrients as soon as they are harvested. During long periods of storage, particularly when exposed to oxygen, green vegetables change colour from dark green to yellow, their texture changes from crisp to limp.
What vitamin particularly is lost to oxidation?
What are the 3 factors that speed up the process of oxidation?
What 2 vitamins are lost when exposed to light?
Vitamin C, in particular, is lost through oxidation.
Air, heat, and sunlight speed up the process of oxidation.
Vitamins A and B are lost when exposed to light.
Fats and oils can develop an unpleasant taste and smell during prolonged storage, what is this process known as?
Rancidity
How is rancidity caused?
Rancidity is caused by oxidation.
What type of fat can rancidity affect, name as many products that include it…
Rancidity can affect: hard fats such as; butter vegetable oils; nuts; and foods containing fat such as cakes and biscuits.
How do commercially prepared food prevent rancidity from happening?
Commercially prepared foods often have antioxidants added to prevent fats from becoming rancid and developing an unpleasant taste.
State water loss in fruit and vegetables…
Fruit and vegetables begin to lose moisture during storage and dry out, with a loss of the water soluble vitamins B and C.
State how enzymes speed up the ripening process of foods, give an example…
The action of enzymes can speed up ripening during storage which can change the nutrient content of foods. For example, enzymic action converts starch to sugar in bananas as they ripen. Enzymes can also cause browning in foods that are cut or bruised, for example apples.
Enzyme (lipases) state what they do to fats…
Enzyme (lipases) in fats can cause them to break down into fatty acids.
Definition of oxidation…
Oxidation is the exposure to air causing loss of vitamin C in fruits and vegetables.
Definition of rancidity…
Unpleasant flavours which develop in fats when they are exposed to oxygen.
Definition of enzymes…
Molecules in foods which cause ripening or change the structure.
Definition of oxidation…
Oxidation is the exposure to air causing loss of vitamin C in fruits and vegetables.
Definition of rancidity…
Unpleasant flavours which develop in fats when they are exposed to oxygen.
Definition of enzymes…
Molecules in foods which cause ripening or change the structure.
