The present investigation was undertaken to use whey for the production of nutritious whey-soya milk dahi. Neutralized whey (pH 7.0 ± 0.2) was used to extract soya milk from cleaned, dried, dehulled and steamed soybean in soya milk extraction plant. Whey-soya milk was extracted having whey to soybean ratio of 5:1. It was further diluted with whey to get different whey to soybean ratios i.e. 9:1, 8:1, 7:1 and 6:1. To set dahi, skim milk powder was added to whey-soya milk so as to make the final total solid concentration of 16, 18 and 20 %. Dahi was prepared by inoculating different whey-soya milk ratios with vita brand of dahi. Results revealed that whey-soya milk having whey to soybean ratio of 5:1 and 20 % total solids was found to be most appropriate for preparation of dahi on the basis of time taken for firmly setting of dahi (5 h) and sensory evaluation scores (7.7 on 9 point hedonic scale). Whey-soya milk dahi was found to be at par with milk dahi (control) based on the sensory scores. Whey-soya milk dahi and milk dahi samples were stored at refrigeration temperature and evaluated for changes in physico-chemical (fat, protein, total sugar, total solids, pH, viscosity and syneresis) and sensory (color and appearance, flavor, consistency and overall acceptability) properties at an interval of 2 days up to 10 days. The results of the study revealed that whey-soya milk dahi could be stored up to 10 days with good sensory quality.
Keywords: Dahi; Milk; Physico-chemical parameters; Soybean; Syneresis; Whey.