Preparation and physicochemical properties of Cyperus esculentus starch from its tubers using ultrasound-assisted alkali method

Abstract

Cyperus esculentus tubers are rich in starch, oil, protein, dietary fiber, and other nutrients. Ultrasonic treatment can reduce the combination of starch, protein, and dietary fiber in C. esculentus tubers during extraction of C. esculentus starch, thereby improving the extraction yield and shortening of the extraction time. In this study, the extraction yield of C. esculentus starch was 92.2% using ultrasound-assisted alkali method. The microstructure analysis showed that the granule characteristics of C. esculentus starch and other starches were similar. X-ray diffraction analysis showed that C. esculentus starch possessed an A-type crystal structure. The onset temperature of gelatinization endotherm and peak temperature of gelatinization of C. esculentus starch were only lower than those of sweet potato starch, and higher than other starches, which is 67.9 °C. The content of resistance starch (RS) (11.0%) in C. esculentus starch was the highest among the six starches. As an underutilized resource, C. esculentus is a new crop with high quality, high yield, and high comprehensive utilization value. Its aerial parts can be used as feed, green manure, and its underground parts can be edible and oily. C. esculentus starch can be a valuable source to develop into new functional food.