The incorporation of spore-forming probiotics into thermally processed foods represents a promising strategy to expand functional food availability. In this study, probiotic snacks were formulated from oat and rice-bean matrices as delivery vehicles for Heyndrickxia coagulans (formerly Bacillus coagulans) BC4 spores. The effects of baking and microwave processing, packaging, and storage conditions on spore viability and functionality were evaluated. While oven baking (180 °C) preserved viability in both matrices under mild conditions (survival > 90%), dielectric heating induced significant viability loss depending on the matrix. The starch-based rice-bean matrix, characterized by higher post-processing water activity (Aw), suffered a thermal runaway effect, resulting in significant spore inactivation (viability decreased to 6.08 log colony forming units/g (CFU/g); 1.5 min). Conversely, the oat matrix acted as a thermo-physical stabilizer, maintaining high viability (9.41 log CFU/g; 1.5 min) by limiting dielectric energy absorption via its fiber-lipid composition. Oxidative stress and premature germination likely contributed to the viability loss observed in atmospheric packaging during the 30-day storage. The oat matrix mitigated this effect through a dual-protective mode: active radical scavenging (validated by superior ferric reducing ability of plasma (FRAP) values) and passive water binding. Simulated digestion data align with the functional preservation observed, resulting in increased survival for oat-based formulations. Overall, the results demonstrate the feasibility of developing oat and rice-bean snacks enriched with H. coagulans spores and highlight the critical role of matrix and processing conditions in preserving probiotic viability.
Bento et al. (Fri,) studied this question.