Influence of Fortification with Inulin and Hi-maize on Acidity and Viability of Starter Culture in Probiotic Yoghurt
Abstract
In this study, the effect of fortification with inulin
and resistant starch (Hi-maize) on yoghurt starter and probiotic bacteria
survival, as well as acidity properties of set-type probiotic yoghurt
containing Lactobacillus acidophilus
were investigated. Milk was fortified with inulin or Hi-maize at 2% and 4%
ratios whereas control group had no supplement. Samples fortified with Hi-maize
had higher lactic acid value than those fortified with same ratio of inulin.
Lactic acid percentages increased significantly in all probiotic yoghurts at
the end of storage in comparison to the first day (p<0.05). The highest
viable counts of Streptococcus
thermophilus were
enumerated in the sample fortified with 2% Hi-maize during 14 days of storage.
The control sample had as high viable counts of Lactobacillus bulgaricus as the sample fortified with 4% Hi-maize,
except first day of the storage. The highest viability of L. acidophilus was detected in control and the sample fortified
with 4% Hi-maize on 7th and 14th day whereas the highest
value was reported for the control sample at the end of the storage. L.acidophilus populations ranged from
6.30 to 7.95 log cfu/g in probiotic yoghurts during 21 days of refrigerated
storage. Therefore, all experimental yoghurts presented probiotic viability
above the minimum recommended level of 6 log cfu/g suggested for beneficial
health effects.
Keywords
References
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