Optimization and Characterization of Arrowroot Porous Starch Using Thermostable α-amylase by Response Surface Methodology

Abstract

Abstract Arrowroot is a local tuber from Indonesia with a high starch content and potential source as a porous starch (PS) material. However, the utilization of arrowroot starch as PS and optimization of PS production using the Central Composite Design (CCD) has not been explored. This study aims to optimize the incubation time (3, 6, and 9 h) and enzyme concentration (50, 100, and 150 U/g) of arrowroot PS production with thermostable α-amylase (AA) by response surface method using the CCD model. The starch suspension (25% w/v) was hydrolyzed with AA at sub-gelatinization temperature (60°C) and the effects of incubation time (3, 6, 8, 10, and 12 h) and enzyme concentration (50, 100, 150, 200, and 300 U/g) on functional characteristics of PS (Water (WAC) and Oil Absorption Capacity (OAC)) were determined to obtain near optimal value for further optimization in CCD. The result concludes and validate that the optimum condition of 5.24 h incubation time and 107.86 U/g AA concentration may achieve maximum WAC and OAC of 96.67% and 103,06%. The optimal PS also showed an improved AR (25.01%), high solubility (88.92%), and lower amylose content (36.56%) against non-modified starch. SEM result confirms porous structure. FTIR data shows increase in intensities and no alterations in functional groups. XRD data reports changes of crystalline type of CA to A, and a decrease in relative crystalline value. These data demonstrate that arrowroot can be used as an alternative economical local source in porous starch production for adsorbent application in various fields.