Comparative Analysis of Nutritional and Sensory Qualities in Commercially Fermented Yogurts

Thesis Abstract

In the global dairy industry, fermented yogurt remains a highly valued functional food, yet variations in its nutritional composition and sensory attributes across commercially available brands pose challenges for both consumers and producers in selecting products that meet health and preference standards. This study aims to conduct a comprehensive comparative analysis of the nutritional and sensory qualities of popularly marketed fermented yogurts, focusing on how manufacturing practices influence product quality. The specific objectives are to evaluate the proximate composition, probiotic content, and bioactive compounds in selected yogurt brands; to assess sensory attributes such as taste, texture, aroma, and appearance through consumer panel evaluations; and to identify correlations between nutritional parameters and sensory perceptions. The research adopts a cross-sectional, descriptive-comparative design grounded in positivist scientific paradigms, utilizing quantitative analytical techniques complemented by sensory evaluation methods. The population comprises fifteen commercially marketed fermented yogurt brands available in urban retail outlets within the country, selected through stratified random sampling from the top five brands based on market share. A sample size of 200 consumers, stratified by age and gender, participates in sensory evaluation panels, while laboratory analysis of yogurt samples is conducted using standardized methods. Nutritional profiling includes proximate analysis through AOAC (Association of Official Analytical Chemists) methods, quantification of probiotics via microbial plate counts, and measurement of bioactive compounds such as peptides and antioxidants using high-performance liquid chromatography (HPLC) and spectrophotometry. Data collection instruments include validated laboratory protocols, structured sensory questionnaires, and calibrated tasting panels, ensuring high validity and reliability established through intra- and inter-rater consistency checks. Data analysis involves descriptive statistics to summarize nutritional profiles and sensory scores, followed by inferential analyses such as one-way ANOVA to compare differences across brands, multiple regression analysis to determine relationships between nutritional parameters and sensory scores, and factor analysis to identify underlying attributes influencing consumer preferences. The study further adopts the Theory of Planned Behavior to interpret how consumer perceptions and behavioral intentions relate to product choices, and the Food Quality Improvement Model to understand manufacturing influences on product characteristics. Expected findings anticipate significant variations in nutritional content, with some brands exhibiting higher probiotic counts and antioxidant levels, and notable differences in sensory attributes such as texture and flavor profiles. It is hypothesized that nutrient-rich yogurts with higher probiotic concentrations will correlate positively with consumer preferences for taste and aroma. The results are expected to reveal that manufacturing practices, including fermentation duration and ingredient quality, substantially influence both nutritional and sensory quality, thus providing actionable insights into product formulation and processing. This study contributes to existing knowledge by systematically contrasting commercial yogurt brands, highlighting the critical manufacturing factors affecting quality, and elucidating how nutritional parameters relate to sensory perceptions. The findings will inform producers on optimizing fermentation processes and ingredient selection to enhance both health benefits and consumer acceptability. Furthermore, the research offers policy implications for food regulatory agencies to set standardized quality benchmarks. Conclusively, recommendations include adopting best manufacturing practices, regular quality assessments, and consumer-centric product development, with suggestions for future studies to explore longitudinal impacts of processing innovations on yogurt quality. This comprehensive analysis enhances the understanding of the complex interplay between nutritional content and sensory attributes in fermented yogurts, ultimately supporting evidence-based improvements in dairy processing and product marketing strategies.