Microwave Assisted Batch Sterilization of Apple Juice

Abstract

A study was carried out to determine the effect of microwave exposure time and power level on the destruction of E.coli and yeast in apple juice. The locally procured apple juice was subjected to microwave treatment of power level 180-900W for various time duration of 20-100s.The time and power level parameters of the microwave were optimized based on the inactivation of the microorganisms present in the juice. E.coli was found to be inactivated at 90s with 900W power. Yeast was completely inactivated at 60 s with 450W power level. The results of inactivation were modeled using GInafit software. Among the various models, Weibull model and Double Weibull model were found to be the best fit for E.coli and yeast, respectively. Nutrient content of the fresh and microwave treated juice were analyzed for total sugar, reducing sugar, total soluble solids and ascorbic acid content. It was inferred from the results that there was no nutrient loss in the post treated samples whereas, the ascorbic acid content decreased considerably.