Solid-substrate fermentation of Colocasia esculenta tubers for improvement of its acceptability [Bangladesh]

• Published in: Bangladesh journal of microbiology Vol. 11; no. 2
• Main Authors: Hussain, M, Chowdhury, B, Saha, K.C, Rashid, H, Reza, M
• Format: Journal Article
• Language: English
• Published: 01.12.1994
• Subjects: BANGLADESH; CALIDAD; COLOCASIA ESCULENTA; FERMENTACION; FERMENTATION; PROTEINAS; PROTEINE; QUALITE; TUBERCULE; TUBERCULO
• ISSN: 1011-9981

The peeled, boiled, mashed and autoclaved tubers of Colocasia esculenta were fermented as solid-substrate for a period of 86 h in large aluminium saucepans by a mixed culture commercially known as Indonesia ragi Tape' which consists mainly of Amylomyces rouxii (a mould) and Endomycopsis burtonii (a yeast). The fermented product appeared creamy-white having somewhat sweet-sour taste due to the production of lactic acid and ethanol. The pH, total acidity, protein, starch, free sugar, ethyl alcohol and lactic acid content of the fermented product was determined every 24 h. The acridity of fresh, autoclaved and fermented tubers were estimated and compared. The effect of solid-substrate fermentation on acridity showed that acridity was eliminated in edible aroids by fermentation. The pH changed from 6.16 to 4.08. Ethanol production increased to 3.58 g/100 g and lactic acid production rose to 0.40 g per 100 g of fresh fermented material. The protein in dry fermented product was enhanced from 8.66% to 21.22% and starch decreased from 61.1% to 6.03%. The free sugar content fluctuated rising to 44% followed by a decrease to a minimum value of 2.64%. Production of ethanol and lactic acid protected the fermented product from contamination.