Development and assessment of a probiotic-enriched functional bread formulation

Thesis Abstract

The rising demand for functional foods with health-promoting properties has prompted significant interest in incorporating probiotics into various alimentary matrices, yet the development of probiotic-enriched bread formulations that retain viability, sensory acceptability, and functional efficacy remains underexplored. This study aims to develop and assess a novel probiotic-enriched bread formulation, with specific objectives to optimize probiotic strain viability during dough fermentation and baking processes, evaluate the physicochemical and sensory attributes of the final product, and determine the in vitro probiotic functionality and gastrointestinal survivability of the formulated bread. To achieve these aims, a mixed-method research design was employed, integrating quantitative formulation experiments with qualitative sensory evaluations. The study population comprised bread consumers and tested probiotic strains, specifically Lactobacillus rhamnosus GG and Bifidobacterium lactis BB-12, selected based on previous empirical evidence of probiotic efficacy and technological feasibility. A 12-factor optimization experiment utilized Response Surface Methodology (RSM) to identify optimal probiotic inoculation levels, fermentation conditions, and baking parameters that maximize probiotic viability, which was assessed through plate count analysis using selective MRS agar after random sampling of bread slices. Physicochemical parameters, including pH, moisture content, and water activity, were monitored throughout processing, while sensory evaluation employed a 9-point Hedonic scale with 100 untrained panelists to assess appearance, aroma, taste, texture, and overall acceptability. The probiotic functional efficacy was examined through in vitro gastrointestinal simulation, employing a standardized batch culture method to evaluate probiotic survivability under simulated gastric and intestinal conditions, and adherence potential was analyzed via fluorescence microscopy after exposure to human epithelial cell lines. Data were analyzed using ANOVA to identify significant differences among formulations, and regression analysis delineated relationships between process variables and probiotic viability. Theoretical underpinning was guided by the Health Belief Model and the Biopsychosocial Model, framing consumer acceptance and health benefits as interconnected determinants influencing probiotic bread adoption. It is anticipated that optimized formulations will maintain probiotic viability above 10^7 CFU per gram after baking and during storage, with sensory scores exceeding 7 on the Hedonic scale, indicating high consumer acceptability. The in vitro assessments are expected to demonstrate substantial probiotic survival (greater than 80%) through simulated gastrointestinal transit, confirming functional viability. This research contributes novel insight into the technological feasibility of producing probiotic bread with preserved probiotic function and consumer acceptability, filling existing gaps in the literature concerning processing parameters and sensory integration of probiotics in baked goods. It advances the theoretical understanding of probiotic integration in cereal-based foods, integrating food science, microbiology, and consumer behavior perspectives. The study concludes that with optimal process adjustments, probiotic bread can serve as an effective functional food intervention to enhance gastrointestinal health and general wellbeing. Recommendations include scaling up production, conducting clinical trials to confirm health benefits, and exploring preservation strategies to extend shelf life. Further research is suggested to evaluate long-term storage stability, bioavailability of probiotics post-consumption, and consumer perception across diverse demographic groups.