Effect of addition of different dairy ingredients on the quality of yogurt

Research Hypothesis: Yogurt flavor depends on both starter cultures and dairy base composition. Different ingredients alter flavor precursors (amino acids, fatty acids), directing microbial metabolism to produce distinct key flavor compounds and sensory profiles.

Data & Methods: Flavor differences were characterized using sensory evaluation, E-nose, GC×GC-O-MS (for OAVs and concentrations of 19 key odorants), and HPLC (for amino and organic acids). Correlation analyses linked chemical and sensory data.

Key Findings: Whey protein (WP) yogurt performed best, with the highest levels of key volatiles (e.g., acetoin, diacetyl), organic acids, and sweet amino acids (alanine, lysine), resulting in superior creamy/fresh aroma and balanced taste. Core flavor drivers were acetoin (OAV=76), acetic acid (OAV=181), diacetyl (OAV=30), and 2-nonanone (OAV=52). Milky aroma correlated with acetoin, fresh with styrene, and fishy odor with hexanoic/butyric acids.

Interpretation & Application: High OAV compounds drive sensory perception. For optimal flavor, use whey protein. To correct fishy off-notes, trace and reduce precursors like caproic/butyric acid by adjusting ingredients or process.