ENHANCEMENT OF NUTRITIONAL AND FUNCTIONAL PROPERTIES OF RICE FLOUR BY MICROBIAL ENZYMES
Loading...
Date
2011
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
PAU Ludhiana
Abstract
Filamentous fungi have been widely used to produce hydrolytic enzymes for industrial applications. Amylase and glucoamylase were produced using Aspergillus oryzae under solid state fermentation. Different agricultural residues such as rice bran, wheat bran, rice bran: wheat bran (1:1) and rice bran: paddy husk (1:1) were used to produce amylase and glucoamylase. Rice bran yielded maximum amylase (2.72 IU) and glucoamylase (4.11 IU) activity among all other residues. Various cultural conditions were optimized and temperature of 30 °C, moisture content (80 %), pH 5.0, spore suspension (1 ml) of 1x107 spores/ml and incubation period of 5 days were found optimum for maximum production of enzymes. The enzymes obtained were partially purified using isopropanol and rice flour was treated with these hydrolysing enzymes. Enzymatic pretreatment conditions were optimized using Response Surface Methodology (RSM). Effect of different parameters such as slurry concentration, enzyme concentration, time and temperature was studied. Enriched rice flour was obtained by treating 7 % slurry with 1 ml of enzyme at 55 °C for 40 min. This enriched rice flour was analysed for its nutritional, functional, toxic residues and microbiological parameters. Protein content of the enzymatically treated rice flour increased from 8.03 % to 20.79 % (2.5 fold enhancement) and ash from 0.69 % to 1.40 %. Fat content of both, untreated and treated rice flours, differed insignificantly but crude fiber was hydrolysed from 2.50 to 0.42. Moisture content of the treated rice flour decreased from 12.40 % to 11.85 %. The digestibility coefficient of in vitro digestibility also increased from 644.63 to 1351.67 in treated rice flour. Microbiological count of treated rice flour decreased whereas contaminating organisms (coliforms and salmonella) and toxic residues (aflatoxins) were not detected.
Description
Keywords
null