RELATIONSHIP OF DAMAGED STARCH WITH SOME PHYSICOCHEMICAL PARAMETERS IN ASSESSMENT OF WHEAT FLOUR QUALITY.

Abstract

The samples of 18 different semi hard flour from four different mills were analyzed for damaged starch (DS) and for various other physicochemical properties through Kernalyzer, solvent retention capacity (SRC) profile, Farinograph, Micro Visco-Amylo-Graph and Glutomatic to establish the correlations that may exist among them. It was found that water absorption and dough development time from Farinograph, beginning of gelatinization, peak, trough and final viscosities from Micro Visco-Amylo-Graph, sodium carbonate and lactic acid values from SRC tests, retained and passed gluten from Glutomatic while the protein from Kernalyzer were closely related to damaged starch as determined by enzymatic analysis using Megazyme kit. The particle size analysis showed that amount of large particle i.e. >160 micron is inversely proportional to percentage of damaged starch. Alkaline water retention capacity (AWRC) and sodium carbonate SRC values are directly related as the increase in damaged starch will also increase the water absorption/ holding capacity of flour. The overall exercise has revealed that lengthy enzymatic damaged starch analysis which requires skilled manpower as well, may be replaced by certain instrumental and simple SRC analysis especially for ommercial purposes where rapid tests are so much desired. An interesting correlation was found between the DS and the difference in water absorption measured from Farinograph and Glutomatic. It is clearly demonstrated that starch intact to gluten proteins is invisibly damaged during milling.