Effects of esterified tapioca starch on the physical and thermal properties of Japanese white salted noodles prepared partly by residual heat

The objective of this study was to evaluate the effects of esterified tapioca starch on the physical and thermal properties of Japanese white salted noodles prepared by residual heat to reduce the use of heat sources for energy saving. Dried noodles prepared with wheat flour and with wheat flour partly mixed with esterified tapioca starch were used. Reducing the boiling time of noodles and using residual heat to continue cooking standing noodles reduced electrical energy consumption by 32%. The physical properties and gelatinization characteristics of the food were then assessed. The koshi of standing noodles differed from that of boiling noodles because water temperature decreased in standing noodles. However, noodles that had been boiled for 3 min followed by standing for 6 min were as soft as those boiled for 10 min. The addition of esterified tapioca starch partly caused gelatinization and softening of the noodles, even while standing, because the amylopectin content of dried noodles mixed with esterified tapioca starch increased, and the structure was sparse. Noodles boiled for 3 min and kept standing for 6 min were more elastic (or springier) than those boiled for 10 min, but had the same hardness. The addition of esterified tapioca starch was partly responsible for maintaining or raising the physical and thermal properties of noodles prepared by residual heat compared with boiling, and the physical properties of the noodles could be changed by adjusting the standing time. Therefore, the addition of esterified tapioca starch is partly effective for optimizing energy savings.