Production of skimmed yogurt enriched by rice resistant starch: physicochemical properties, microscopic structure and model prediction during storage

Resistant starch (RS) could be considered as a dietary fiber in yogurt, but its association with the shelf-life qualities is not clear. The characteristics and microstructure of low-glycemic yogurt (LGY) during fermentation and storage were investigated. During fermentation, principal component analysis combined with Mantel's test demonstrated that yogurt containing 0.6 % RS was best for storage. Over the 28-day storage, LGY maintained higher lactic acid bacteria count, with comparatively smaller reduction in microbial viability. LGY exhibited superior textural hardness (143.32 g) and elasticity (0.75). Microstructural analysis indicated that larger and looser pores appeared in both LGY and control over time, but the network cross-linking structure formed by RS with proteins resulted in less change in LGY. This structural reinforcement helped preserve the gel matrix and textural integrity. The kinetic model confirmed the storage stability of LGY. This provides a theoretical foundation for the stable LGY.