Physicochemical Properties of Sago Starch Fractionated by Butanol

Amylose is one of the sago starch constituents which plays an important role in the processes of gelatinization, retrogradation, and the pasting process of starch texture. By separating amylose from amylopectin through a fractionation process, high-content amylose can be obtained. In this study, the process of fractionating sago starch is carried out using hot water and the addition of n-butanol dropwise with certain time variations (1, 2, 3, 4, and 5 h). The precipitate formed, which is the fractionated sago starch, is separated from the n-butanol fraction using centrifugation. The physicochemical properties of fractionated sago starch are characterized in terms of chemical change using Fourier transform infrared (FTIR), molecular weight using gel permeation chromatography (GPC), particle size, morphology, amylose content, crystallinity, water-solubility, swelling power, moisture, ash content, thermal stability using differential scanning calorimetry (DSC), crystallinity using X-ray diffraction (XRD), and morphology using field emission scanning electron microscopy (FESEM). The results show that the fractionation process using n-butanol increases the particle size, amylose content, and thermal stability compared to the native sago. The crystallinity, water solubility, and swelling power of the fractionated-sago starches are decreased. The highest amylose content and gelatinization temperature properties are achieved by the addition of n-butanol for 4 h.