Poster: Emerging Technologies

Abs # 885: Efficiency of starch extraction from the tubers of Dioscorea alata through microbial softening technique.

Presenter:	Eyini, M. , eyini@eth.net
Authors	Eyini, M.  (A)   Rani, J.Joice  (A)
Affiliations:	(A): Thiagarajar College (Autonomous)

The efficiency of Dioscorea alata tubers as the non-conventional source of industrial starch was analyzed. Two yeast strains, tY1 and tY2 selected from toddy and two bacterial strains, cB1 and cB2 selected from curd were used in the microbial softening process and their fermentation characteristics were assessed by growing them in rich medium (pH 6.5). Among the bacterial and yeasts isolates, the fermentive efficiency of cB2 was found to be higher. The starch content of Dioscorea Spp varied between 65 –91% dry weight. The recovery of starch from the control uninoculated tubers ranged between 36.4% and 39.4% dry weight within a period of 96 h of spontaneous fermentation. Curd and curd-toddy mixture inoculated Dioscorea tuber yielded 38.7% and 41.3% dry weight starch within 24 h of incubation. The bacterial isolates were comparatively more efficient than the other isolates as they helped in the recovery of 60-74% starch within the same period. Dioscorea starch had a low paste stability (17 min), but its pasting temperature was 50-70oC .The clarity of 2% Dioscorea starch solution was 0.47. Microbial softening process using the bacterial isolate cB2 from curd coupled with the wet grinding method of starch extraction resulted in the maximum 66.5% increase in the extracted starch over the control.