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

Abstract

Eight Indian wheat varieties grown at a single geographical location were evaluated for protein quantity and quality, rheological properties, activities of peroxidase and polyphenol oxidase (catechol oxidase), and their influence on chapatti quality. Protein contents ranged from 11.6 to 14.6%, farinograph water absorption ranged from 70 to 76% and damaged starch content varied from 12.3 to 16.3%. The total protein content of whole wheat flours significantly correlated with stiffness (R/E values) of the dough (r = 0.73, P < 0.05), but did not influence any of the quality parameters of chapattis. However, the protein quality parameter, Glu-1 score, which reflects high mol. wt. glutenin subunit composition, correlated significantly to the cutting force, which provides information about the texture of chapattis (r = 0.78, P < 0.05). The quantity of low mol. wt. protein with a mol. wt. of 20 kDa correlated significantly with overall quality scores for chapattis (r = 0.78, P< 0.05). The colour of chapattis was significantly correlated to the colour of dough (r =0.76, P < 0.05), which became darker on resting. Peroxidase activity greatly influenced the colour of chapattis (r =0.81, P < 0.05).