Document Type

Article

Rights

This item is available under a Creative Commons License for non-commercial use only

Disciplines

Microbiology, Bioprocessing technologies, Fermentation, Food and beverages, Agricultural biotechnology and food biotechnology

Publication Details

Industrial Crops and Products

Abstract

Utilization of brewers’ spent grain (BSG), for the development of a fermented liquid product rich in value-added phenolic compounds was investigated. Changes in and liberation of phenolic compounds and antioxidant activity during fermentation of BSG was studied. The effect of various particle size (PS), solid liquid (SL) ratio, fermentation time and rotation speed was optimized using response surface methodology (RSM) for the purpose of improving bacterial growth and the enhancement in the release of polyphenolic compounds. Contour maps generated using the response surface equation showed that the experimental variables significantly affected the response. A production of 10.4 log cfu/ml, 2.95 g/l lactic acid accompanied by a release of 268.6 mg Gallic Acid Equivalent (GAE)/ml of phenolic compounds, 135 mg Quercetin equivalent (QE)/ml of flavonoid compounds, 33.7 mg TE/ml ferric reducing antioxidant power (FRAP) and 75.1% radical scavenging activity (RSA) was obtained with the optimized factors of 19 h fermentation time, 0.25 SL ratio, 85 rpm and 440 μm PS. Shelf life was monitored over a period of 30 days and the product was shelf stable in terms of bioactive components for 15 days. The cell numbers, total phenol content and acidity (in terms of lactic acid) were maintained till 15 days storage period and a reduction was observed only after that.

DOI

10.1016/j.indcrop.2012.11.015

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