Determination of damaged starch content of flours of Indian wheats.

Damaged starch (DS) contents of 63 samples of flour from 39 varieties of Indian wheats were analysed by 4 different methods: the enzymatic methods of (i) Farrand [Cereal Chem. (1964) 41: 98], (ii) Stewart [Milling (1966) 146: 491] and (iii) the AACC [Cereal Sci. Today (1969) 14: 320] and the colorimetric method of (iv) Williams and Fegol [FSTA (1969) 1 9M635]. DS contents, correlation coeff., regression equations and residual variance ratios in prediction of DS by one method from another are tabulated. The following values were obtained by the 4 methods (% DS mean, range, SD, coeff. of variation): (i) 14.2, 3.5-33.2, 7.41, 52.3; (ii) 8.1, 2.3-12.9, 2.57, 31.7; (iii) 9.2, 3.0-16.9, 2.57, 27.9; (iv) (expressed as absorbance (OD) at 555 nm) 1.05, 0.11-2.38, 0.46, 43.8. Significant positive correlations were obtained between the values by the 4 methods (r = 0.81-0.96). From the ratios of residual variance in prediction of DS, the enzymatic methods appeared more reliable than the colorimetric procedure.