Effect of frozen storage on the inhibition of microbial population, chemical and sensory characteristics of coconut neera

Abstract

Aim In this study, the effect of frozen storage on the inhibition of microbial population in coconut neera for shelf life extension was analysed. Methods and Results The aliquots of fresh neera were frozen at −6 and −20°C. The microbial reduction and chemical qualities were analysed during storage days, and were compared with the control. The highest reduction in microbes was obtained at −20°C for lactic acid bacteria, yeast and total viable count. Moreover, the fluorescence cell staining and cell density analysis exhibited a decline at −20°C, however it showed higher at −6°C. At the end of 28 days, neera exhibited a pH of 5·37, total soluble solid of 14·0 °Brix and total acidity of 0·82 mg l−1 at −20°C. Besides, color, viscosity, total protein and ethanol showed a less difference with control and better sensory attribute up to 21 days at −20°C. Conclusions Frozen storage at −20°C resulted in a better inhibition of lactic acid bacteria, which preserves neera from the metabolic conversion. The physicochemical qualities of neera were preserved for a longer period when stored at −20°C than at atmospheric storage. Significance and Impact of the study Frozen storage reduced microbial population and preserves the chemical properties with acceptable sensory attributes and increases the shelf life of coconut neera, making it fit for consumption.