Drying process affects vitamin in food

The vitamin content of a food is, in general, reduced by drying. This is especially true for those vitamins (e.g. vitamin A and ascorbic acid) that are easily destroyed by heat in the presence of air, through oxidation.

The drying temperature has been shown to have no influence on vitamins B1, B2, B6 and niacin, whereas vitamin A losses increase with increasing drying temperatures. β-carotene which may be applied as the source of the vitamin A is shown to be far more stable than the straight vitamin.

Drying methods affect vitamin C content as well. It can be stated that the higher the drying temperature and air velocity, the greater the degradation of vitamin C durign drying.

However the application of a drying process with low temperatures for a short period of time can result in relatively high ascorbic acid retention, avoiding its sensitivity to heating processes. The sulfuring of fruit previous to drying also aids in reducing the amount of ascorbic acid destroyed during drying.
Drying process affects vitamin in food

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Vitamin C in citrus fruit

Citrus fruits such as lemons, sweet orange, mandarin or tangerine contain vitamin C which prevents the deficiency disease scurvy.

Citrus fruits and juices are excellent sources of vitamin C containing more than the minimum daily requirements of 60 mg of vitamin C in 240 ml of juice.

There is considerable variation in the vitamin C content of juices of different citrus fruits. Grape fruit, tangerine and lemon generally contain between 20 and 50 mg.100 mL juice.

Vitamin C is an important antioxidant, which increase the protective antioxidant layer, glutathione concentration around the cells. Vitamin C also critical for production of collagen. Greater acidity or sour taste is a clear indicator for greater amount of vitamin C existence in citrus fruits.

Freshly squeezed juice usually has the highest vitamin C content, followed by juice made from frozen concentrate.

Unopened canned and bottled juices are next best: stored at room temperature, they retain more than 75 percent of their vitamin C for a year or longer.
Vitamin C in citrus fruit

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