Designing and development of laboratory scale ohmic pasteurizer and its effect on ascorbic acid in Amla juice
Chinmay Joshi, Iranna Udachan
Amla is one of the popular fruits which is rich in fiber, carbohydrate, iron and considered as the one of the richest source of ascorbic acid (vitamin C). Pasteurization is the conventional method given to fruit juices for preservation which has drawbacks such as degradation of the nutritional compounds, overheating, loss of nutrients and sensory changes. Vitamin C being heat sensitive reduces drastically during pasteurization. Therefore, use of alternate non-thermal technologies for preservation is needed. Ohmic heating is a non-thermal processing technology which includes passage of alternating electric current through foods where heat is internally generated due to electrical resistance. A laboratory scale ohmic heating equipment was manufactured. Amla juice was pasteurized by laboratory scale ohmic pasteurizer in batch-wise manner. The results were compared with the juice pasteurized by conventional method. It has been found that there was more retention of vitamin C in amla juice pasteurized by ohmic heating as compared to that of by conventional pasteurization. Juice processed by both methods was found to have similar sensory quality. Therefore, application of non-thermal treatments results in preservation of essential nutrients in food.