Lactoperoxidase Effects on Rheological Properties of Yogurt

A mixed culture (Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus) was inoculated into reconstituted skim milk and incubated. When 0.45 Unit/g or more of lactoperoxidase (LPO) was added, the yogurts had softer and smoother texture than untreated yogurt. The apparent viscosity of yogurt was also reduced by addition of LPO. The storage modulus (G') of the gel of LPO-treated yogurt decreased but the frequency-dependency remained unchanged. The amount of exopolysaccharide or degree of proteolysis in yogurt was not changed by addition of LPO.