Effect of Thermal and Alternate Thermal Processing on Bottle Gourd (L agenaria siceraria ) Juice

Abstract

Bottle gourd juice (BGJ), a rich source of nutrients can support the growth of microbes that cause spoilage. Processing methods used to reduce number of microbes have adverse affects on nutritional quality of BGJ. The purpose of this research work was to examine the microbial safety and quality changes during conventional and alternate thermal methods without addition of additives. Different physico-chemical, functional and microbial parameters were studied for conventional and alternate thermal treatments. BGJ was subjected to conventional pasteurization at 63C, 75C, 88C for 30, 10 and 1 min, respectively, and sterilization at 121C for 5, 6 and 7 min. Similarly, the BGJ was treated with alternate thermal method i.e. Ohmic heating ranging from 60C to 90C for 0–105 s with varying voltage (100–220 V). Maximum retention of ascorbic acid, total phenolics, total carotenoids and total antioxidant activity was observed after ohmic heating. Practical Application Bottle gourd (BG) is a vegetable extensively grown in India. Besides large scale production, consumption is limited to fresh use as vegetable or in the form of blended juice preparation. Negligible percentage of BG is used for juice extraction because of its quality and safety issues. The present study was undertaken with an aim to check the effect of different processing methods on microbial safety and nutritional quality of BGJ.