STUDY ON CHEMICAL PARAMETERS AND CYANOGENS CONTENT OF CASSAVA (Manihot esculenta Crantz) JAND DURING TRADITIONAL FERMENTATION.

Abstract

A study was conducted to know the effect of traditional Nepalese fermentation process of making jand on various chemical attributes including the most common group of toxins i.e. cyanogenic glycosides of cassava (Manihot esculenta Crantz) tubers. Cassava tubers were bought from the local market of Dharan. Proximate analysis of cassava tubers were carried out. Before the tubers were subjected to fermentation, they were thoroughly cleaned, cut into suitable sizes and cooked.. Inocolum of traditional starter i.e. murcha was sprinkled over the cooked tubers and were allowed to ferment in small plastic jars. Analysis of changes in different parameters i.e. pH, alcohol, TSS, reducing sugars, proteins and cyanogens were analysed in the regular interval of 3 days until the fermentation was complete. Alcohol content of the mash increased gradually from nil to 12.403 % m/v during initial 12 days of fermentation and finally reached upto 13.6 m/v in 21st day of fermentation. TSS of brew was found to be increasing initially where it reached 16.47ºBx in 9th day of fermentation and finally decreased to 7 upto the final 21st day of fermentation. Initially not traceable amount of reducing sugars in tubers reached upto 11.87 % in 6th day of fermentation and was recorded 0.57% in 12th day after which it wasn’t detected by Lane and Eynon method. Initial pH of cassava was found to be 6.11 which dropped to the final pH of 3.64% in final product. Final protein content of product was analysed to be 3.195% from the initial value of 1.84%. Initial cyanogens content of 75.124 mg HCN/kg fresh wt of cassava was reduced to 45.17 mg HCN/kg after boiling which was analysed to be just 6.911mg HCN/kg in final product which was below the marked permitable limit for cyanogens recommended by FAO. A sheer drop of 90.8% in cyanogens contents of cassava was seen during the overall process of jand preparation including both boiling and fermentation.