Development of Composite Pseudocereal-based Yogurt Enriched with Pea Protein Concentrate: Sensory Evaluation and Microbiological Storage Stability

Abstract

The increasing demand for plant-based dairy alternatives has stimulated the development of innovative fermented products using nutrient-dense raw materials. This study aimed to develop a composite pseudocereal-based yoghurt using amaranth, buckwheat, quinoa and other grains, such as ragi and oats, enriched with pea protein concentrate, and to evaluate its sensory properties. Four formulations, including the control, F1, F2 and F3, were prepared by varying the proportions of oats and ragi while maintaining constant levels of the other pseudocereals. The protein content of the formulations was standardised using pea protein concentrate before fermentation with yoghurt starter cultures containing Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus. Sensory evaluation was conducted using a 9-point hedonic scale with 30 untrained panellists to assess appearance, consistency, aroma, taste, flavour, texture and overall acceptability. Statistical analysis using a randomised block design (RBD) and analysis of variance (ANOVA) revealed significant differences (p < 0.05) among the formulations for all sensory attributes. Among the developed formulations, F3 exhibited the highest sensory scores for appearance (8.25 ± 0.099), consistency (8.10 ± 0.100), aroma (8.00 ± 0.103), taste (8.10 ± 0.143), flavour (8.05 ± 0.153), texture (8.25 ± 0.123) and overall acceptability (8.15 ± 0.082), with an acceptability index of 90.07 ± 0.72%, indicating superior consumer preference. Shelf-life studies conducted under refrigerated storage (4 ± 1°C) demonstrated a gradual increase in total bacterial count (TBC) and total mould count (TMC) during storage; however, microbial counts remained within the permissible limits specified by the Food Safety and Standards Authority of India (FSSAI) throughout the 20-day storage period for TBC and the 15-day storage period for TMC. The optimised formulation maintained desirable sensory quality and microbiological safety, confirming its suitability for refrigerated storage. The results indicate that plant-based yoghurt with functional and economic potential can be successfully developed by including pseudocereals, ragi, oats and pea protein concentrate. This study highlights the feasibility of utilising underused pseudocereals and plant proteins for the development of innovative fermented foods that cater to the increasing demand for sustainable and health-oriented dairy alternatives.