Akademik Veri Yönetim Sistemi
AUSTRALIAN JOURNAL OF DAIRY TECHNOLOGY, cilt.64, sa.2, ss.171-176, 2009 (SCI-Expanded)
This study was performed to investigate the effects of microbial transglutaminase treatment on yogurt quality during storage. Three yogurt samples were produced. The first was a control, the second was produced using milk treated with 0.2% transglutaminase inactivated for 1 minute at 80 degrees C after incubation for 2 hours at 40 degrees C, and the third was produced using milk treated by 0.2% transglutaminase but without incubation of the enzyme. All yogurt samples were stored at 4 +/- 1 degrees C and analysed for dry matter, fat, protein, acetaldehyde, titratable acidity, syneresis, viscosity, gel strength, pH, yogurt bacteria, total psychrotrophic aerobic micro-organisms, moulds and yeasts, and sensory properties on days 1, 3, 7, 10, 14 and 21 of storage. Treatment with 0.2% transglutaminase had a very significant effect on titratable acidity, gel strength, syneresis, counts of yeasts and moulds, and consistency-in-spoon (p<0.01). Significant effects on pH, appearance, mouthfeel and overall acceptability (p<0.05) were also demonstrated. Enzymatic inactivation affected the counts of yeasts and moulds, pH, syneresis, mouthfeel and overall acceptability in the MTGase-treated samples. In addition, storage time had a very significant effect on pH, titration acidity, syneresis, counts of Lactobacillus delbrueckeii subsp. bulgaricus, total psychrotrophic bacteria, yeasts and moulds (p<0.01), as well as significant effects on gel strength, counts of Streptococcus thermophilus and consistency-in-spoon (p<0.05). Aust. J. Dairy Technol. 64, 171-176