Quince Seed Mucilage Powder as a Natural Stabilizer for Probiotic Ayran: Effects on Microbiological, Physicochemical and Microstructural Properties

This study investigated the effects of quince seed mucilage powder (QSMP; 0.05, 0.10, 0.15, and 0.20%) on the microbiological, physicochemical, rheological, and microstructural properties of probiotic ayran fermented with a commercial starter culture and Lactiplantibacillus plantarum ACC66 during 14 days of refrigerated storage. QSMP completely prevented serum separation at all concentrations, whereas the control exhibited progressive whey separation throughout storage. This improvement was associated with the formation of a denser and more continuous protein network, as confirmed by scanning electron microscopy, rather than with increased apparent viscosity. QSMP also reduced post-acidification, moderated lactic acid accumulation, and enhanced the survival of L. plantarum ACC66, with the 0.15% treatment showing the highest viable counts. All samples complied with the microbiological criteria specified by the Turkish Food Codex throughout storage. Multivariate analyses further confirmed QSMP concentration as the primary factor influencing the physicochemical and microbiological characteristics of ayran. Overall, the results demonstrate that QSMP is an effective natural stabilizer for improving the physical stability of probiotic ayran while maintaining its microbiological quality, suggesting its potential application as a functional ingredient in industrial ayran production.