14A-26 |
Manufacture of custard-style yogurt using probiotic strains of lactobacilli |
Y. J. CHO1, Y. Li, K. Adhikari3, R. B. Johnston, and A. Mustapha1. (1) Department of Food Science, University of Missouri, 256 William Stringer Wing, Eckles Hall, Columbia, MO 65211-5160, (2) Dept. of Food Science, Univ. of Missouri, Columbia, 256 Eckles Hall - Stringer Wing, Columbia, MO 65211 Health benefits from the consumption of probiotics is an area receiving great research attention currently. Probiotics can be incorporated as live cultures in fermented dairy foods, including yogurt, for transmission to humans. The principal objective of this study was to ferment yogurt with probiotic strains of lactobacilli and compare them with conventionally fermented yogurt with regards to microbial numbers and sensory attributes. The control yogurt was made with Streptococcus thermophilus (St) and Lactobacillus delbrueckii subsp. bulgaricus (Lb), while the experimental yogurts were manufactured with either Lactobacillus rhamnosus GG (Lr) or Lactobacillus paracasei (Lp) instead of Lb. Custard-style yogurts, flavored with either strawberry or vanilla flavors were produced. Viability of the cultures, pH and titratable acidity (TA) were determined over a refrigerated storage period of 30 days. A trained panel of judges performed descriptive analysis on the yogurt samples on d 0, 15 and 30 of the storage period. No reduction in the population of Lp (d 0: >8 log CFU/ml) was observed, while a reduction of approximately 6 log CFU/ml for both Lb and Lr (d 0: >8 log CFU/ml) was found. There was no change in the population of St (d 0: >8 log CFU/ml) throughout storage, irrespective of the lactobacilli cultures used. pH and TA of probiotic yogurts were more stable than those of traditional yogurt during the 30 days of refrigerated storage. Principal Component Analysis of the sensory data showed that the control yogurts were more acidic in taste compared to the probiotic yogurts. The texture of the yogurts over storage was characterized by an increase in smoothness, stickiness and thickness, with a decrease in whey separation and powdery aftertaste. This study demonstrated that probiotic strains can be used to manufacture yogurts of comparable characteristics to those of conventional yogurt.
Session 14A, Dairy Foods: General developments in dairy technology I
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