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.
Keywords: chemical quality; coconut neera; frozen storage; microbial population; sensory characteristics.
© 2021 The Society for Applied Microbiology.