Protein characteristics and peroxidase activities of different Indian wheat varieties and their relationship to chapati-making quality

Different wheat varieties grown at a single geographical location were evaluated for protein quantity and quality, rheological properties, and activities of peroxidase as well as polyphenol oxidase. The protein content in these varieties ranged from 11.6 to 14.6%, farinograph water absorption ranged from 70 to 76%, and the damaged starch content varied from 12.3 to 16.3%. The total protein content of whole wheat flours significantly correlated to stiffness (R/E values) of the dough (r=0.73, p<0.05); however, it did not influence any of the quality parameters of chapati. However, the protein quality parameter, Glu-1 score, which reflects the high molecular weight (HMW) glutenin subunit composition, correlated significantly to the cutting force, which indicates the texture of chapati (r=0.78, p<0.05). The quantity of low molecular weight protein fraction having molecular weight of 20 kDa showed significant correlation to over all quality scores of chapati (r=0.78, p<0.05). The color of chapatis was significantly correlated to color of dough (r=0.76, p<0.05), which became darker on resting. Peroxidase activity greatly influenced the color of chapatis (r=0.81, p<0.05).