Increasing Health Benefit of Wild Yam (Dioscorea hispida) Tuber by Red Mold (Angkak) Fermentation

Abstract

Detoxification of cyanogen is very important in cyanide containing tubers such as wild yam (Dioscorea hispida). Principally, cyanogen detoxification is by converting cyanogenic glycoside into acetone cyanohydrin and further converted into free HCN that is easily removed by heating or soaking. Conversion of cyanogenic glycoside into free HCN is catalyzed by beta glucosidase enzyme (linamarase) in linamarin deglycosilation and a- hydroxyinitril liase (HNL) in acetone cyanohydrin degradation into free HCN and acetone. Endogen linamarase is found in the tubers and exogenous linamarase might be from microbes. It is supposed that fermentation of wild yam by angkak will reduce cyanide level. Angkak or Red Mold Rice (RMR) is a product of rice fermentation using Monascus sp mainly M. purpureus. Beside red pigment, angkak fermentation also produces a variety of secondary metabolites such as lovastatin, mevinolin, and citrinin. Monacolin K (lovastatin) from Monascus purpureus is an inhibitor for HMG-CoA reductase in cholesterol biosynthesis. Monacolin K production is higher in Dioscorea substrate compared to rice. RMD (Red Mold Dioscorea) reveals higher anti-cholesterol activity and anti-hypertension than red mold rice. RMD also exhibits antioxidant, anti-diabetic, anti-obesity, and induces cancer sell apoptosis and does not reveal mutagenic and toxicity. In RMD, monascin and ankaflavin have a role in reducing cholesterol. It is expected that wild yam fermentation by angkak will reduce cyanide level and produce health beneficial secondary metabolites.

Thermal stability of natural pigments produced by Monascus purpureus in submerged fermentation

“…These pigments also include antioxidant, antimicrobial, and antifungal characteristics. Furthermore, Mps are used as nitrite or nitrate replacements of meats (Estiasih et al, 2020 ; Feng et al., 2012 ; Nateghi et al., 2020 ; Seong et al., 2017 ). The most important pigment produced by Monascus sp.…”

Valorization of Cassava By-Products: Cyanide Content and Quality Characteristics of Leaves and Peel

“…This is due to the ability of the enzyme to hydrolyze, break, and damage the cell wall [43]. Once the cell wall is damaged and cells are disrupted, this does not only promote the release of endogenous linamarase and trapped linamarin, but also accelerates the degradation of linamarin, as reported by Sornyotha et al [32] and Estiasih [18].…”

“…Acetone cyanohydrin is then spontaneously degraded to HCN and acetone by hydroxynitril lyase (HNL) [17]. Linamarin is usually located in the vacuole, while linamarase and HNL are localized in the cell wall [18]. Various processing methods such as drying [19][20][21], cooking [20,22,23], fermentation [2,10,19], enzyme and ultrasonic treatment [24], and membrane filtration or coagulation [25] have been well studied in relation to the removal of cyanide from cassava tissues of different varieties.…”