Development of probiotic fermented oat and ragi based food mixtures - nutritional evaluation and utilization
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Date
2008
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Publisher
CCSHAU
Abstract
The present investigation was conducted to study the development of probiotic
fermented oat and ragi based food mixtures-nutritional evaluation and utilization. Four
different food mixtures namely raw oat flour + whey powder + tomato pulp; (OWT)
germinated oat flour + whey powder + tomato pulp; (RWT) raw ragi flour + whey
powder + tomato pulp; germinated ragi flour + whey powder + tomato pulp were
developed. In these food mixtures, oat / ragi flour, whey powder and tomato pulp were
added in the ratio of 2:1:1(w/w). Each of these mixtures was mixed with water (1:5
w/v), autoclaved and fermented with 5 per cent L. acidophilus containing curd as
inoculum at 37C for 12 h. L. acidophilus count was found maximum in germinated +
autoclaved + fermented OWT and RWT food mixtures as compared to non-germinated
mixtures. The pH declined with a corresponding rise in titratable acidity in all the
probiotic fermented food mixtures. The maximum increase in titratable acidity was
noticed in germinated + autoclaved + fermented OWT and RWT food mixtures.
Autoclaving and fermentation did not bring any change in moisture, ash, fat whereas
crude protein and crude fibre contents were reduced non-significantly upon germination
and fermentation. Total soluble, reducing and non-reducing sugars increased
significantly when food mixtures were autoclaved but on germination and fermentation
with L acidophilus curd lowered down the level of total and non reducing sugars and
increase in reducing sugars. Starch content of all the food mixtures decreased as a result
of germination, autoclaving and fermentation. Autoclaving caused significant reduction
in total and insoluble dietary fiber whereas soluble fraction increased significantly.
When autoclaved food mixtures were subjected to fermentation for 12 h, it caused
reduction in all dietary fibre constituents. Germinated food mixtures contained lower
contents of all dietary fibre constituents as compared to non-germinated food mixtures.
Similar trend was also observed in case of total, soluble and insoluble -glucan
contents of all food mixtures. Total lysine contents of all food mixtures were found to
be decreased on autoclaving but germination and fermentation caused improvement in
total lysine. Protein fractions were affected by all processing treatments. Phytic acid,
polyphenols and amylase inhibitor activity significantly reduced after autoclaving and
fermentation. Germination also caused reduction in contents of all the antinutrients.
Simultaneously, a significant improvement in protein and starch digestibility (in vitro)
and availability (in vitro) of Ca, Fe + Zn was observed in autoclaved, fermented and
germinated food mixtures. Where as contents of total minerals were remained
unchanged on autoclaving and fermentation. Developed products namely buttermilk,
kadhi, papad and wadi were found to be organoleptically acceptable. Probiotic
buttermilk was more nutritious as compared to control buttermilk. Similarly, kadhi,
papad and wadi contained significantly higher contents of total lysine, protein and
starch digestibility and availability (in vitro) of calcium, iron and zinc and lower
amount of antinutrients as compared to control products and their respective food
mixtures.
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Keywords
Fermentation, Germinability, Proteins, Biological phenomena, Acidity, Millets, Vegetables, Enzymes, Flours, Starch