Calcium oxalate levels, glucomannan levels, and antioxidative activities of different sized Amorphophallus oncophyllus particles and the maceration of Strobilanthes crispus

Abstract

Abstract Porang (Amorphophallus oncophyllus) is a type of tuber widely planted in Indonesia. It has a high glucomannan content, but its use is limited due to high calcium oxalate content. However, it has previously been shown that the maceration of porang with the ethanolic extract of Strobilanthes crispus (SC) can serve to reduce its calcium oxalate content. This study sought to determine the impact of sieving in combination with ethanolic extract of SC maceration on the calcium oxalate levels, glucomannan levels, and antioxidant activities of different sized particles of porang. The calcium oxalate levels were analyzed by the atomic absorption method, whereas the glucomannan levels were determined based on the yield of glucomannan derived from the ethanolic extraction process. The porang particles were then analyzed to assess their antioxidant activities using DPPH (1,1-diphenyl-2-picrylhydrazyl). The particles were grouped into six in different particle size and maceration: AX, AY, AN, BY, and BN. The results revealed that porang with a particle size of <40 mesh that was macerated with SC exhibited lower calcium oxalate levels and higher glucomannan levels than porang with a particle size of >40 mesh. The antioxidant activity of the porang decreased after maceration with the ethanolic extract of SC.