Minimal Processing of Fruit and Vegetables

Minimal processing of fruit and vegetables

Summary   Part C

The part C mainly experimented the effect of ascorbic acid on storage of fruit juice. The experiment used two different sample of apple juice which included apple juice without ascorbic acid (AJ) and apple juice with ascorbic acid (0.6g/L apple juice) added (AJAA). Those two sample was measured the Vitamin C content using titration of ascorbic acid and titration of total Vitamin C content. The result indicated that homocysteine oxidises dehydroascorbic acid which has similar vitamin activity to ascorbic acid. Using different instrument to measure the refraction and PH of samples. In addition, different reagents were added to juice samples, which were examined the volume of sediment, the presence of microbial spoilage, the PH of samples and sensory analysis.

Milk

Result   Part A

Part A – Coagulation by Rennin

Table 1: Objective assessment of the effect of temperature and PH on the coagulation of milk by rennin

From Table 1 above, it was statement evidently that different temperature and PH had wide effects on the coagulation of milk by rennin. In 5℃, normal skim milk(PH6.44) and skim milk (PH6.3) did not coagulate through long time. In addition, normal skim milk (PH6.44) did not get coagulation, however, the skim milk (PH6.3) occur coagulation quickly when temperature was 30℃.When temperature is over 41℃, whatever skim milk can quickly was coagulated.

Discussion Part D

In this experiment, the enzyme rennin was used. Rennin is a coagulating enzyme in the synthesized by chief cells in the stomach glands of calves. Its role in digestion is to curdle or coagulate milk in the stomach. Rennin, well known also as Chymosin which is a proteolytic enzyme that is secreted by the cells lining the stomach. Its role in digestion is to curdle or coagulate milk in the stomach, a process of considerable importance in the very young animal. If milk were not coagulated, it would rapidly flow through the stomach and miss the opportunity for initial digestion of its proteins. Rennin efficiently converts liquid milk to a semisolid like cottage cheese allowing it to be retained for longer periods in the stomach. Chymosin is secreted as an inactive proenzyme and is activated on exposure to acid. It is also similar to pepsin in the sense because it is most active in acidic environments, i.e. at a very low PH.