The effect of microbial transglutaminase on the immunoreactive and sensory properties of fermented milk beverages

Summary Fermented beverages were produced through the milk fermentation (at 37 °C and 42 °C) by yoghurt bacteria Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus and simultaneous addition of microbial transglutaminase (m‐TG). The results proved that the addition of m‐TG enzyme and storage at 4 °C for 28 days caused a significant reduction in the immunoreactivity of caseins in yoghurt produced at 37 °C and did not decreased their sensory quality. The reaction between yoghurt proteins and antibodies towards α‐lactalbumin (α‐la) and β‐lactoglobulin (β‐lg) was not observed. The results of yoghurt produced at 42 °C were different, and the reduction of κ‐casein only and the lack of β‐lg immunoreactivity was noticed. Statistically significant attributes, which differentiated the sensory profiles of yoghurts, were descriptors of taste (yoghurty, creamy) and mouth‐feel (density, creaminess and smoothness). The quantitative descriptive analysis (QDA) results were confirmed by principal component analysis (PCA). Two components (PC1, PC2) explain 90.68% of the variation of the sensory qualities of the yoghurts.