Sensory and physico-chemical changes during storage of UHT-treated whey-based lassi

Abstract

Rennet whey-based sweetened lassi was prepared by fermenting whey-milk blends using a mesophilic dahi culture and added with stabilizers, sugar and flavour and heat processed by ultra-high temperature treatment. The optimized product contained 2.13% fat, 1.78% protein, 4.56% lactose, 0.21% ash and 19.24% total solids. Changes in selected physico-chemical and sensory parameters of the UHT-treated whey based lassi were evaluated during storage at 30^°C, 37^°C and 45^°C for a period of 60 days. Decrease in sensory score was faster in samples stored at elevated temperature (45^°C). Overall acceptability scores decreased from 87.3 to 81.5, 80.1 and 69.1 at 30^°C, 37^°C and 45^°C, respectively on a 100-point scale. Viscosity and pH of the product also decreased, while sediment, acidity and free fatty acids (FFA) values increased at elevated storage temperature. A strong negative correlation of -0.91 between flavour and FFA content of the product was established at 30°C storage.