Effect of exopolysaccharides on the proteolytic and angiotensin-I converting enzyme-inhibitory activities and textural and rheological properties of low-fat yogurt during refrigerated storage

J Dairy Sci. 2009 Mar;92(3):895-906. doi: 10.3168/jds.2008-1796.

Abstract

The aim of this study was to examine the influence of using exopolysaccharide (EPS) producing strain of Streptococcus thermophilus on the viability of yogurt starters, their proteolytic and angiotensin-I converting enzyme-inhibitory activities, and on the textural and rheological properties of the low-fat yogurt during storage at 4 degrees C for 28 d. The use of an EPS-producing strain of S. thermophilus did not have influence on pH, lactic acid content, or the angiotensin-I converting enzyme-inhibition activity of low-fat yogurt. However, EPS showed a protective effect on the survival of Lactobacillus delbrueckii ssp. bulgaricus. Presence of EPS reduced the firmness, spontaneous whey separation, yield stress, and hysteresis loop area but not the consistency and flow behavior index of low-fat yogurt.

MeSH terms

  • Enzyme Inhibitors / metabolism
  • Fats
  • Food Handling*
  • Hydrogen-Ion Concentration
  • Lactic Acid / analysis
  • Lactobacillus delbrueckii / physiology
  • Peptide Hydrolases / metabolism*
  • Peptidyl-Dipeptidase A / metabolism
  • Polysaccharides, Bacterial / analysis
  • Polysaccharides, Bacterial / metabolism*
  • Refrigeration*
  • Rheology
  • Sensation*
  • Streptococcus thermophilus / enzymology*
  • Streptococcus thermophilus / physiology
  • Yogurt / analysis
  • Yogurt / microbiology
  • Yogurt / standards*

Substances

  • Enzyme Inhibitors
  • Fats
  • Polysaccharides, Bacterial
  • exopolysaccharide, Streptococcus
  • Lactic Acid
  • Peptide Hydrolases
  • Peptidyl-Dipeptidase A