Physicochemical Properties of Spicy Lactic Fermented Tigernut-milk Drink Monitored during Ambient and Refrigeration Temperature Storage

Abstract

The development of non-dairy fermented products is fast gaining acceptability due to its unique benefits. Several factors such as storage conditions, processing methods and constituent of such products usually affect its physicochemical properties. Tigernut-milk drink fermented by mixed culture of lactic acid bacteria (LAB) isolated from ‘ogi’ identified as Lactobacillus plantarum, L. acidophilus, L. brevis and Streptococcus thermophilus using API 50 CHL test kit was separately spiced with 3%, 5% ginger; 3%, 5% garlic. Each tigernut-milk drink was stored at ambient (28±2°C) and refrigeration (4±2°C) temperature for 12 weeks. Non-spiced lactic fermented tigernut-milk drink was the control. At 4 weeks interval, ethanol content, calorific value and total soluble solids (TSS) in the drink were monitored. During ambient and refrigeration temperature storage, there was increase in ethanol content of the spiced and non-spiced lactic fermented tigernut-milk drinks. Maximum ethanol content of spicy lactic fermented tigernut-milk drink stored at 4±2°C and 28±2°C was 0.73 g/L and 0.96 g/L, respectively. At both storage conditions, non-spiced lactic fermented tigernut-milk drink had the highest ethanol content 1.76 g/L. There was reduction in calorific value with few exceptions and continuous reduction in TSS which ranged between (245.08-134.41 Kcal) and (14.31-5.29 °B) in the spicy lactic fermented tigernut-milk drinks during storage at 28±2°C and 4±2°C, respectively. This study revealed that calorie content and total soluble solids in ginger and garlic spiced lactic fermented tigernut-milk drinks considerably reduced during the period of storage at ambient and refrigeration temperature with few exceptions while ethanol content of the drinks consistently increased.