Enzymatic Clarification and Preservation of Aloe vera Juice by Ohmic Heating

Abstract

Aims: The aim of this study was to optimize clarification process of the Aloe vera juice followed by its preservation by ohmic heating as no systematic study has been conducted on these aspects. Study Design: The enzymatic clarification method was used for clarification of Aloe vera juice by using the enzyme pectinase. The enzyme concentration, incubation temperature and time were optimized for clarification of juice. The Aloe vera juice was treated at different Time (min) gradients, current, initial temperature and after temperature at particular current gradient and the ohmic heated juice was then stored in sterilized bottles for further analysis. Place and Duration of Study: Experiments were done in Department of Food Science and Technology, Shivaji University, Kolhapur, M.S. (India) and completed within 12 months. Methodology: The optimal conditions for the enzymatic treatment of Aloe vera juice were investigated in order to minimize the turbidity of the juice and maximize the TSS of the juice. The clarified Aloe vera juice was then treated with ohmic heating at different time and current combinations and stored for 60 days to study the physic-chemical and microbial parameters of stored juice. Results: The recommended enzymatic treatment conditions were: enzyme concentration 1% incubation time 6 h and incubation temperature 45ºC and the TSS, acidity and Turbidity under these conditions were 3.5ºBx, 0.30% and 206.66 NTU respectively. During storage, increased in TSS value from 2.1 to 2.6ºBx, acidity from 0.21 to 0.33% were recorded in ohmic treated juice samples. A very high TPC (102x105 CFU/ml) and yeast and mold count (68x105 CFU/ml) was recorded in untreated sample at 30 days of storage whereas the juice samples treated with ohmic heating at different time and current gradients were observed to be within the limit of standard requirement of microbial quality even up to 60 days of storage. Conclusion: Enzymatic treatments can reduce the turbidity in Aloe vera juice. Ohmic treatment at different time and current gradients can preserve the clarified juice with respect to its microbial quality for more than 60 days.