Effect of Chemical Modification on Starch of Some Legume Flours

Abstract

Chemical modification of the starch of gourd seed, white melon, yellow melon, bennissed and bulma cottonseed were carried out. Infra-red spectrophotometer was run to confirm the products obtained after chemical modification. Hypochlorite oxidation and acetylation of the starch samples were studied for pasting stability using Brabender amylograph, freeze – thaw stability, starch paste clarity and water binding capacity. The results obtained for modified starch were compared with the native starch. The paste clarities of the oxidized starch were better than the acetylated and unmodified starches. The acetylated and unmodified starches allowed 90% transmittance at 650nm. Acetylation, markedly decreased the tendency for syneresis and improved the freeze thaw stability. This may be due to bulky acetyl groups which caused stearic hindrance. Modification had influenced the stability of the starch studied. The oxidized starch has better stability than those of the corresponding acetylated and unmodified starch.