Effect of pretreatment of fresh Amorphophallus paeoniifolius on physicochemical properties of starch

Fresh roots of Amorphophallus paeoniifolius were separately pretreated with sodium hexametaphosphate (SHMP), potassium metabisulphite (KMS), sodium chloride (NaCl), and ammonium hydroxide (NH4OH) within a range of 1-5% (w/v) concentration and glyceryl monostearate (GMS) at 0.025-0.125% concentration. The quality of starch extracted from pretreated roots was compared with that obtained from fresh roots by direct aqueous extraction. The starch samples prepared from chemically pretreated roots showed characteristic changes in properties of water soluble amylose content. swelling and solubility and alpha-amylase susceptibility. X-ray diffraction of starch samples from chemically pretreated roots although resembled that of control, there was noticeable shift with respect to their 'd' spacing and I-o/I-max values.