Inhibition of Acid Production in Gel Type Yogurt by the Lactoperoxidase System

호상 요구르트 제조시 LP System에 의한 산생성 억제에 관한 연구

  • Published : 1996.08.30

Abstract

This study was carried out to investigate the effect of the lactoperoxidase (LP) system on the acid production of gel type yogurt. The LP system was activated by adding freshly prepared solutions of 1 ppm (v/w) lactoperoxidase and three different concentrations (0.125 mM, 0.25 mM, 0.5 mM) in equimolar ratios of KSCN and $(H_{2}O_{2}$, In 0.25 mM treated samples for the 4 hr fermentation resulted in titratable acidity of $0.4{\%}$, pH of 5.06, lactic acid bacterial count of $3.0{\times}10^{8}\;CFU/ml and acetaldehyde concentration of 10.2 ppm, whereas the untreated samples were 1.0%, 4.54, $4.7{\times}10^{9}\;CFU/ml and 18.0 ppm, respectively. The residual amount of KSCN in 0.25 mM treated samples was determined during the experiments, which decreased to 4.4 ppm. There was no detectable $(H_{2}O_{2}$ for 6 hr fermentation. However, residual KSCN and $(H_{2}O_{2}$ concentrations in 0.5mM treated samples were 5.7 and 8.4 ppm, respectively. These results have indicated that the optimum concentration of $(H_{2}O_{2}$ and KSCN to activate the LP system was 0.25 mM each.

Keywords

LP system;antibacterial effect;gel type yogurt