A COMPARATIVE STUDY OF THERMAL, MICROWAVE & ULTRASOUND PROCESS ON BIOACTIVE COMPOUNDS AND ANTIOXIDANT CAPACITY OF PINEAPPLE JUICE

Abstract

Thermal processing is considered one of the oldest techniques for preservation. Hence it possesses many limitations and causes degradation of bioactive compounds which inspire the researchers to develop other techniques to overcome the flaws and defect of thermal processing. These issues have served as a driver for the development of novel preservation technologies like microwave and ultrasonication. The actual aim of this study is to portray a comparative discussion on different preservative techniques of pineapple fruit juices which has been carried out based on empirical knowledge. To carry out this discussion, three preservative techniques; Thermal, Microwave, Ultrasonication have been applied on pineapple fruit juice and their impact on physicochemical properties, antioxidant capacity, bioactive compounds have been investigated for 21 days maintaining 7 days interval pattern. Though bioactive compounds are non-nutrient plant compounds, they possess many attributes which has substantial positive effect on health and disease prevention. So their stability after processing is crucial and need proper preservative method. Among the three techniques, it has been revealed that microwave and ultrasonication processes are more beneficial than thermal treatment in terms of retention of bioactive compounds and stability of antioxidant capacity. Better retention of total antioxidant 1.997 mg TE/100g, 1.594 mg TE/100g has been found for microwave and ultrasonication respectively. Similar effect has been recorded for flavonoid content. Drastic degradation has been found in terms of phenolic content 0.307mg GAE/100 for thermal sample which is 2 times less than rest of the treatments. In light of this, sonication and microwave pasteurisation may be utilized as a valuable option in place of thermal pasteurisation depending on the needs of the sample