Effect of harvest timing and length of storage time on glucomannan content in porang tubers

Abstract

Amorphophallus muelleri Blume synonym of A. oncophyllus (porang) is one of the species of porang that grows in Indonesia, especially in East Java. It has a high economic value because the tubers contain glucomannan. Earlier work reported that harvest timing and length of storage affected secondary metabolite containing on plants. The study objective was to determine the glucomannan content of porang at 1, 2 months before dormant, at dormant and length of storage time (1 and 2 months after dormant) at room temperature. Glucomannan was isolated from fresh tubers to easier removal of the impurities and obtain the high purity of glucomannan. The highest obtained glucomannan was determined its functional groups using Fourier Transform Infrared (FTIR). The highest glucomannan content was derived in tubers taken at dormant compared to before and after dormant. FTIR spectra confirmed the presence of functional groups that compose the glucomannan compound.