Development and assessment of a sustainable probiotic yogurt fermentation process

Thesis Abstract

The increasing global demand for functional foods with probiotic benefits underscores the necessity for sustainable and efficient dairy fermentation processes, particularly in the production of probiotic yogurt, which presents challenges related to microbial stability, environmental impact, and process optimization. This study aims to develop and evaluate a sustainable probiotic yogurt fermentation method that enhances probiotic viability, reduces resource consumption, and maintains product quality. The specific objectives include optimizing fermentation conditions using environmentally friendly substrates, assessing microbial stability throughout shelf life, and evaluating consumer acceptability and physicochemical properties of the final product. The research adopts a mixed-methods approach anchored in an experimental design combined with sensory and microbiological analyses. A population comprising commercially available probiotic strains, Lactobacillus acidophilus and Bifidobacterium bifidum, within a sample of 20 distinct starter cultures, was utilized to identify the most resilient and viable strains for sustainable fermentation. The experimental phase involved developing fermentation protocols using renewable substrates such as agro-industrial by-products, including rice husk hydrolysates and fruit peels, combined with controlled fermentation parameters—temperature, pH, and fermentation duration—optimized via Response Surface Methodology (RSM). Data collection instruments integrated microbiological enumeration techniques including plate counts, molecular identification via PCR and sequencing, physicochemical assessments through pH and titratable acidity measurements, and spectroscopic analysis to monitor biochemical changes. Data were analyzed through statistical methods such as Analysis of Variance (ANOVA) to determine significant differences across treatment groups and regression analysis within RSM models to optimize fermentation parameters. Microbial viability and stability over a 28-day refrigerated shelf life were evaluated using repeated measures ANOVA, while consumer acceptability was examined via hedonic testing with a sample of 150 panelists utilizing structured questionnaires. The microbial community composition was characterized using metagenomic sequencing techniques, providing insights into microbial interactions and stability. Additionally, a sustainability assessment employed life cycle analysis (LCA) metrics to compare resource inputs and environmental impacts of the developed process versus conventional methods. The anticipated findings include identification of optimal fermentation conditions utilizing eco-friendly substrates that sustain probiotic microbial populations above the therapeutic threshold of 10^6 CFU/mL throughout shelf life, with improved physicochemical stability and sensory acceptance comparable to or exceeding traditional yogurt. The study expects to demonstrate that employing agro-industrial by-products can significantly decrease water, energy, and carbon footprints of yogurt fermentation. It is also projected that the microbial community analysis will reveal enhanced stability and resilience of probiotic strains under optimized conditions, contributing to increased product consistency. This research notably contributes to the body of knowledge by presenting a scalable, eco-conscious fermentation process that marries food technology innovation with sustainability principles, while ensuring probiotic efficacy and consumer satisfaction. The findings are expected to inform industry practices, encouraging adoption of renewable substrates and integrated microbial management strategies, thus advancing sustainable dairy fermentation technologies globally. The study concludes with recommendations for implementing environmentally sustainable practices in probiotic yogurt manufacturing, proposing further research on large-scale application and diversification of renewable substrates. It emphasizes the potential for policy development aimed at reducing the industry’s environmental footprint while delivering high-quality probiotic products that meet consumer health and sustainability expectations.