WET-MILLING FACTORS OF SORGHUM AND RELATIONSHIP TO GRAIN QUALITY

Relationships of grain sorghum quality factors (proximate composition and physical properties) to laboratory wet-milling attributes (fractio n yields, protein content of fractions and recovery values) of 24 grai n sorghum commercial hybrids were determined. Initial water absorption rate was positively correlated with both starch and gluten recoveries (r>0.45), thus showing the greatest significance among all quality fa ctors. The need to understand fully protein matrix breakdown relative to obtaining optimum separation of components was indicated. Positive correlations of residual protein in search with density and percent ab raded (r>0.45) were observed. Laboratory wet-milling attributes also w ere correlated among themselves. The highest positive correlations wer e observed among yield and recovery of starch and gluten (r>0.6). Thes e four parameters had strong negative correlations with fiber/germ yie ld (r<-0.6). Principal component factor analysis identified five facto rs (named as matrix-breakdown effect, solids-leaching effect, protein- dispersion effect, protein content of gluten effect, and washing-solid s effect) that explained 91% of the total variation among wet-milling attributes. (C) 1998 Academic Press Limited.