PREPARATION AND QUALITY EVALUATION OF PEANUT MILK INCORPORATED YOGHURT

Abstract

The main objective of this study was to prepare yoghurt by using cow milk and different proportion of peanut milk with 2% starter culture of Lactobacillus acidophilus and Streptococcus thermophilus and evaluate the effects of peanut milk incorporation on yoghurt quality. Raw peanut of variety 'Jayanti' (Type-Spanish bunch) was collected from Sunsari district, Dharan and were soaked for 18 h and grinded with water (1:6 of kernel to water) to prepare peanut milk. Design expert® version 10 D-optimal design was employed for the formulating the recipe of yoghurt. The obtained seven formulations coded A (5%), B (10%), C (15%), D (20%), E (25%), F (30%) and G (0%) of peanut milk incorporated yoghurt were prepared in laboratory. The samples were subjected to sensory evaluation (color, taste, texture, aroma and overall acceptability) by quality scoring method for consumer acceptability and the sensory data were analyzed by two-way ANOVA (no blocking) using Genstat and means were compared using LSD at 5% level of significance. From sensory evaluation, formulation D (20%) peanut milk incorporated yoghurt was found to be significantly (p<0.05) superior in sensory quality. The total solids, fat, acidity, protein, total ash, moisture content, lactose content, antioxidant activity and pH of this formulation were found to be 19.63%, 3.45%, 0.66%, 3.72%, 0.97%, 80.7%, 2.92%, 74.46% and 4.2 respectively. The shelf life of this product was estimated in terms of acidity and total plate count and the shelf life was found to be 1 day at room temperature and 6 days under refrigeration (5°C). The total cost of the best peanut milk incorporated yoghurt per 100 ml was found to be NRs. 12.05 (as of 2020).