Profiles of Oligosaccharides Synthesized from Under-Explored Tuber Starches Using Aspergillus oryzae Amylase

Abstract

Oligosaccharides are beneficial compounds for human health that are widely used in the food, cosmetic, and pharmaceutical industries. Our knowledge on the synthesis of oligosaccharides from tropical plant sources using amylases of indigenous microorganisms are still limited. This study aims to determine the profiles of oligosaccharides synthesized from under-explored tuber starches by Aspergillus oryzae amylase. Submerged fermentation was applied to obtain the crude enzyme. Starches used as substrate in the enzymatic reaction were from four tubers, including Tacca leontopetaloides (L.) Kuntze, Canna indica L., Xanthosoma sagittifolium (L.) Schott, and Dahlia pinnata Cav. Thin layer chromatography (TLC) showed typical oligosaccharide patterns depending on the tuber source. High performance liquid chromatography (HPLC) confirmed the presence of three types of oligosaccharides, including maltotriose, maltotetraose, and maltoheptaose in the Tacca starch-enzyme reaction. Higher maltoheptaose was observed when the substrate was starch from Xanthosoma. The oligosaccharide proportion at about 93% of total detected saccharides was obtained in the enzymatic reaction of Xanthosoma starch.