Comparative Analysis of Glucomannan Properties from Wet and Dry-Extractions of Porang (Amorphophallus muelleri Blume) and Commercial Konjac Glucomannan

Porang tubers (Amorphophallus muelleri Blume) are known as konjac in Indonesian prominent glucomannan sources. The research objective is to compare the dry and wet extraction methods. Two extraction methods (dry and wet) were carried out. First, porang flour was obtained from a centrifugal grinder and purified twice with 70 % ethanol solution for 2 h, respectively. Next, the sample was milled with ethanol solution and precipitated twice with 70 % ethanol solution. The 2 samples were compared to a konjac commercial glucomannan for physicochemical and molecular properties. The study revealed that the physical characteristics of glucomannan extracted through the wet method significantly differed from those obtained via dry extraction and the commercially available Konjac glucomannan. Specifically, the glucomannan from dry extraction demonstrated poorer physical qualities compared to its wet-extracted counterpart, and even more so when compared to commercial Konjac. The wet-extracted porang glucomannan’s viscosity (33,000 cPs) and whiteness level (70.04) were markedly different from the commercial Konjac, which had a viscosity of 39,000 cPs and a whiteness level of 83.17. In contrast, the dry extraction method yielded lower values, with a viscosity of 22,000 cPs and a whiteness level of 63.43. While FTIR, XRD and DSC analyses produced similar results across the board, the thermal properties of the wet-extracted porang glucomannan displayed a higher resistance to decomposition compared to the other 2 samples. HIGHLIGHTS Reliable and economical technique production of glucomannan Glucomannan obtained through wet extraction methods is of higher quality compared to that obtained via dry extraction. The molecular characteristics of konjac glucomannan and glucomannan extracted from wet porang are remarkably similar. Konjac glucomannan and glucomannan from wet porang exhibit comparable solubility profiles. The viscosity levels of glucomannan derived from wet porang align with the food industry’s standards. GRAPHICAL ABSTRACT