Growth, proteolytic, and ACE-I activities of Lactobacillus delbrueckii ssp. bulgaricus and Streptococcus thermophilus and rheological properties of low-fat yogurt as influenced by the addition of Raftiline HP.
This study investigated the influence of incorporating Raftiline HP on the pH, growth, proteolytic, and angiotensin-I converting enzyme inhibitory activities and on spontaneous whey separation, firmness, and rheological properties of low-fat yogurts during storage for 28 d at 4 degrees C. Three types of yogurts were prepared from skim milk containing 0% (YI0, control), 2% (YI2), and 3% (YI3) Raftiline HP, respectively. The incorporation of Raftiline HP improved the growth of starter organisms, particularly that of Lactobacillus delbrueckii ssp. bulgaricus, resulting in shorter fermentation time. There was a significant improvement in total proteolysis, which was highest in yogurt containing 3% Raftiline HP. The ACE inhibitory activity was maximal in YI3 compared to YI2 and YI0. Incorporation of Raftiline HP did not affect whey separation and firmness of the low-fat yogurts. All these products were more fluid like with distinct pseudoplastic properties and lesser ability to resist deformation upon applied shear.
Ramchandran
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Faculty of Health, Engineering and Science, Victoria Univ, Werribee Campus, PO Box 14428, Melbourne, Vic 8001, Australia.
Shah
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D019342:Acetic Acid / Q000032:analysis; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000378:metabolism*; D015169:Colony Count, Microbial; D019358:Fat Substitutes / Q000737:chemistry*; D005285:Fermentation; D005516:Food Microbiology; D006863:Hydrogen-Ion Concentration; D007444:Inulin / Q000737:chemistry; D019344:Lactic Acid / Q000032:analysis; D048668:Lactobacillus delbrueckii / Q000254:growth & development* / Q000378:metabolism; D008894:Milk Proteins / Q000032:analysis; D012212:Rheology; D048249:Streptococcus thermophilus / Q000254:growth & development* / Q000378:metabolism; D015014:Yogurt / Q000032:analysis* / Q000382:microbiology
D000806:Angiotensin-Converting Enzyme Inhibitors; D019358:Fat Substitutes; D008894:Milk Proteins; D019344:Lactic Acid; D007444:Inulin; D019342:Acetic Acid