Effect of different milling methods on chemical composition of whole wheat flour
In order to assess the effect of different types of milling methods on protein and lipid composition of whole wheat flour, two types of wheat varieties belonging to strong and weak wheat type were selected and milled in different mills such as plate, hammer, stone and roller mills. The temperatures generated during grinding of wheat in stone, plate, hammer and roller mills were 90, 85, 55 and 35 °C respectively. The studies on SDS-PAGE indicated degradation in proteins of whole wheat flour obtained from stone and plate mills, especially in the high molecular glutenin regions. Greater loss of total amino acids was also observed in the above milled flours when compared with that of hammer and roller milled samples. Free lipid content was lower in flours milled in stone and plate mills when compared with that of flours milled in other mills. Unsaturated fatty acid content, particularly linolenic acid, was lower in stone milled flour (1.3%) followed by plate mill (2.2%), hammer mill (2.8%) and roller flour mill (3.8%). The trends in the above values as influenced by different milling methods remained similar both in the weak and strong wheat types.