Abstract
Some physico-chemical properties of starches of cassava, arrowroot and sago were compared with those of potato starch. The influence of washing water on physico-chemical properties of cassava starch was also examined. The amylose content of cassava starch was 17 .9-18.9%, of arrowroot starch 19.4% and of sago starch 21.7%. Cassava starch samples prepared using tap water or 0.5 M CaCl2 solution contained higher amount of Ca, arrowroot starch contained higher amount of K and sago starch contained higher amount of Na than other starches . However, when demineralized water was used for the preparation of cassava starch, Ca content was low, and thus it was found that the amount of cation in the washing water influenced the cation content of the prepared starch samples. The distribution of particle size showed that the peak was located at around 10.1-20.2 pm for cassava starch, 16.0-25.4 pm for sago starch, 20.2-32.0μm for arrowroot and 32.0-64.0 μm for potato starch. The X-ray diffraction pattern of cassava starch was regarded as C type close to A type, arrowroot and sago starches as C type close to B type. The swelling power of cassava starches prepared using various washing water was largerin the following order: demineralized water tap water>0.5 M CaCl2. Ca was found to have suppressive effect on the swelling power of starch. Both the viscosity-rising and gelatinization temperature as determined by the Amylograph and photopastegraph, respectively, of the tropical starch samples were slightly higher than those of potato starch. Cassava starch showed the least tendency of retrogradation.
