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Modification of physicochemical properties of native tapioca starch, especially pasting properties and swelling power were performed to expand the application of tapioca starch in industry. This study aimed to investigate the effect of native starch modification on the pasting properties and swelling power. Process modification was done by chemical process using Sodium Trimetaphosphate (STMP), Sodium Tripolyphosphate (STPP), acetic acid, and lactic acid, while biological modification was done by using fermentation of Lactic Acid Bacteria (LAB). The brabender test showed that native tapioca starch suspension (6% w/w) had the highest maximum viscosity of 857 BU with a setback viscosity of 224 BU. While the lowest maximum viscosity was modified starch product using STMP as the crosslinking agent, which was 10 BU with a setback viscosity of 10 BU. Modification by STMP had a characteristic that was resistant to heating, as evidenced by the profile of a viscosity value that is stable when heated, held constant, and lowered again, still had a relatively constant viscosity value, which was 10 BU. The swelling power test showed that the modification using lactic acid had the highest swelling power of 12 g pasta/g sample, while the lowest swelling power had resulted from modification using STMP with the value of 3 g pasta/g sample. Swelling power indicated the ability of starch to swell in water. The higher the swelling power, the higher the starch's ability to expand in water. [ABSTRACT FROM AUTHOR]

Sorghum [Sorghum bicolor (L.) Moench] grain is prospectively used as an alternative foodstuff to substitute wheat which is progressively imported to Indonesia more than 11 million tons per year. A common problem faced in the utilization of sorghum grains domestically is the lack of equipment for the polishing process before the grains are ready to be used as foodstuff. Polishing is necessary to remove the tannin content contained in the pericarp layer and tightly fused with the endosperm. The tannin content causes a bitter and astringent taste that is not liked by consumers. Tannin can also reduce protein digestibility and cause constipation. This study purposed to design and modify the rice polishing machine into a sorghum grain polishing machine that can operate continuously and has a high capacity with good quality polished sorghum grains. An appropriate polishing machine is needed on a small scale that is user-friendly for the villager processor. The modification of the common rice polishing machine was conducted to fulfill the need. The rice polishing cylinder is made of cast iron and is equipped with two air distribution grooves along the cylinder which can blow the rice bran. Modifications are made by dividing the polishing cylinder into three parts. The centerpiece, cast iron was replaced by a grindstone that grooved along and around the cylinder for air distribution as well as ground pericarp transporter. The improved polisher machine could treat the sorghum grains continuously with polishing capacity of 100-120 kg/hour, and an average yield of 85 %. [ABSTRACT FROM AUTHOR]