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VOL. 10, ISSUE 4 (2025)
Effect of sugar concentration on acidification profile (pH) of Streptococcus thermophilus cultures in skim milk
Authors
Dr. Amit Kumar Barman
Abstract
This study investigated the acidification
profiles of ten different Streptococcus thermophilus cultures (C1-C10)
in skim milk supplemented with varying sugar concentrations (0%, 5%, 10%, 15%,
20%, and 25%) over an 8-hour incubation period. The objective was to determine
the influence of sugar content and incubation time on the pH reduction
capability of these cultures. The pH of each culture was monitored at 0, 4, 6,
7, and 8 hours. Results indicated that for all cultures, pH decreased significantly
(p<0.05) with increasing incubation time across all sugar concentrations.
The initial pH, averaging between 6.00 and 6.31, dropped to final values
ranging from 4.77 to 5.49 after 8 hours. The effect of sugar concentration on
acidification was variable and dependent on the specific culture. Generally,
the addition of sugar up to 15% enhanced the rate of acidification compared to
the control (0% sugar). However, concentrations of 20% and 25% showed an
inhibitory effect on some cultures (e.g., C1, C4, C8), resulting in a higher
final pH compared to intermediate sugar levels.
Conversely, other cultures (e.g., C5, C6) demonstrated high tolerance and
effective acidification at these higher concentrations. Notably, significant
variations (p<0.05) were observed among the ten cultures, with C3 and C6
emerging as the most robust acidifiers, achieving a pH of approximately 4.78.
In contrast, cultures like C5 and C9 were slower acidifiers, maintaining a pH
above 5.0 throughout the incubation. These findings underscore the critical
importance of selecting specific S. thermophilus strains and optimizing
sugar levels to control fermentation rates and achieve desired final pH in
dairy products.
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Pages:8-12
How to cite this article:
Dr. Amit Kumar Barman "Effect of sugar concentration on acidification profile (pH) of <i>Streptococcus thermophilus </i>cultures in skim milk". International Journal of Food Science and Nutrition, Vol 10, Issue 4, 2025, Pages 8-12
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