Impact of different processing techniques (chemical, heating and sonication) on physicochemical and microbial characterization of kinnow-whey based beverage

Abstract

Whey beverages that have been added with fruits pulp have always been remained the priority demand of food consumers, but loss of nutritional contents and microbial safety of such beverages is always matter of concern of food producers. To overcome these issues food experts are always in try to find out the processing and preservation techniques for safety of these beverages. In present study kinnow-whey beverage was prepared by addition of kinnow concentrate and acidic whey, at optimum concentrations. Effect of different processing techniques on the physicochemical properties, microbial inactivation, and sensory characteristics of beverage were investigated during 90 days of storage. The outcomes of pasteurization were compared with non-thermal techniques, such as use of preservatives and sonication (20 kHz frequency, 70% amplitude and 5, 10 and 15 min). pH values of all the treatments were reduced, whereas titratable acidity was increased significantly, during storage. There was a significant increase in the brix, viscosity and total solids, with the increase in the storage period. Highest values obtained for brix, viscosity and total solids were T3 (14.32°), T3 (15.13 cP), and T3 (15.13 mg/L) after 90 days storage, respectively. Total plate count (TPC) and yeast and mold count were increased during prolong storage in all treatments. Results showed that the maximum TPC was noted in T0 (2.9 × 104 cfu/ml) at 90 days, while minimum TPC was observed in T5 (0.8 × 104 cfu/ml) at start of study. Similarly, maximum yeast and mold count were noted in T1 (3.2 × 104 cfu/ml) at 90 days whereas, minimum yeast and mold count was observed in T5 (0.1 × 104 cfu/ml) at start of study. Overall acceptability of beverage was highest in 15 min sonicated treatments. It was concluded that the beverages processed with sonication (15 min) demonstrated better stability and sensory attributes compared to other techniques.