Nutritional and potential health benefits of konjac glucomannan, a promising polysaccharide of elephant foot yam, Amorphophallus konjac K. Koch: A review

Amorphophallus konjac (konjac) is one among the major vegetable (tuber) crops grown in Asian countries. In China and Japan, it has been used as food and a food additive for more than 1000 years. Over the last few decades, the purified konjac flour, commonly known as konjac glucomannan (KGM), a dietary fiber hydrocolloidal polysaccharide, has been introduced as a food additive as well as a dietary supplement in many Asian and European countries. The present article reviews the literature (up to January 2015) covering the development of various functional foods, food additives from KGM and their derivatives, Also, this review deals with global nutritional aspects and value added products of konjac corm. The bioprocessing techniques such as preparation, purification, and extraction of KGM from konjac flour and methods to improve quality of KGM are discussed.Abbreviations: 13C NMR: carbon-13, nuclear magnetic resonance spectroscopy; CHD: coronary heart disease; CKF: crude konjac flour; CVD: cardiovascular disease; DA: degree of acetylation; DMSO: dimethyl sulfoxide; DOB: degree of branching; EC: European Commission; EFSA: European Food Safety Authority; EFY: elephant foot yam; FCC: Food Chemical Codex; FDA: Food and Drug Administration; GM: glucomannan; KG: konjac gel; KGM: konjac glucomannan; KGMOS: KGM octenyl succinate; KM: konjac mannan; OSA: octenyl succinic anhydride; PKF: purified konjac flour; SEM: scanning electron microscopy; USDA: United States Department of Agriculture; WHO: World Health Organization; WVP: water vapor permeability