Sensory and Chemical Characteristics of Soymilk Yogurt With Different Yogurt Cultures

Abstract

Analyses showed that acetaldehyde and diacetyl were predominant volatiles in soy yogurts. Acetone, ethanol, 2-heptanone, and methanol were also found. The amounts of hexanal found in yogurt samples were lower than the threshold values and did not contribute to distinctive beany flavor in soy yogurts. The STD culture produced higher concentrations of acetaldehyde and diacetyl than the STDAB and STDL cultures in both soy and dairy yogurts. Refrigerated storage at 4&deg;C for up to 60 days did not have major effect on the concentrations of most volatiles in soy yogurts. However, the acetaldehyde declined significantly in dairy yogurt samples after 10 days of storage (P < 0.05). That suggested better flavor stability in soy yogurts than dairy yogurts. Raffinose and stachyose were reduced in soy yogurt samples with STDAB and STDL cultures. Although acetaldehyde and lactic acid were present in higher concentrations in the dairy yogurts, the sensory study indicated that soy yogurts were rated higher in overall flavor, acetaldehyde and lactic acid flavors.