Improvement of sago starch extraction process using various pretreatment techniques and their pretreatment combination

Abstract

Sago starch extracted from the pith of sago palm using a traditional method has a low extraction yield. In this study, an effective extraction method for sago starch production with high extraction yield and acceptable starch quality was investigated using various pretreatment techniques, that is, ultrasonic, microwave, and enzymatic pretreatments, as well as combined pretreatment methods. The sago pith slurry was pretreated before subjecting to the normal process of sago starch extraction. The extracted sago starch was analyzed for extraction yield and physicochemical properties. Sago pith had high starch content of 82.0% (db). The highest extraction yields obtained using ultrasonic, microwave, enzymatic, and combined ultrasonic–enzymatic pretreatment methods were 71.5, 63.7, 71.4, and 72.5%, respectively, while the control method (without pretreatment) provided 61.0% extraction yield. The peak viscosity and color L* value of all extracted sago starches met the requirements of edible sago starch. Concerning the effective pretreatment method in terms of reduced time and energy consumption, while providing high extraction yield and acceptable starch quality, the ultrasonic pretreatment was recommended. The highest yielding ultrasonic pretreatment conditions were found to be 10% w/w sago pith slurry, 160 W power input, and 7 min pretreatment time.