Formulation and Evaluation of Black Rice Milk Incorporated Yoghurt

Abstract

This study was conducted to formulate and evaluate a guava-flavoured non-dairy yoghurt using black rice milk and coconut milk as the primary ingredients. Black rice milk and coconut milk were combined in different proportions, with selected treatments prepared either with or without agar-agar as a stabilising agent. Coconut milk yoghurt was used as the starter culture for fermentation. The developed samples were evaluated for sensory quality, and treatments T5 and T6 were selected for guava pulp incorporation and designated as T5(A) and T6(A). The selected formulations were analysed for physicochemical properties, texture profile, proximate composition, mineral content, microbial quality and product cost. The pH values of the selected yoghurt samples ranged from 3.69 to 3.72, while titratable acidity ranged from 0.70 to 0.71%, indicating successful fermentation. The formulation containing agar-agar, T6(A), showed higher viscosity, firmness and consistency than the formulation without agar-agar. Sensory evaluation showed that T6(A) received the highest overall acceptability score of 8.24 ± 0.66. Nutritional analysis indicated the presence of protein, fat, carbohydrate, dietary fibre, calcium, iron and phenolic compounds. Microbiological evaluation showed the absence of yeast, mould and coliform organisms during refrigerated storage. The findings suggest that black rice milk and coconut milk can be used to prepare an acceptable guava-flavoured, plant-based fermented yoghurt, although further standardisation and validation are required before broader application.