ISOLATION AND COMPARATIVE ASSESSMENT OF DOUGH-FERMENTING POTENTIALS OF PURIFIED YEAST CELLS FROM LOCALLY TAPPED PALM WINE

Abstract

Yeasts from palm wine can become suitable substitutes to their counterparts imported in Nigeria. In this study, total of eight Elaeis guineensis and Raphia hookeri palm wine samples were collected from Enugu and Imo States, Southeastern Nigeria. Their physicochemical analysis, isolation, identification, and purification of yeast isolates in the samples were conducted. After immobilization, both free and immobilized yeasts were used to ferment the dough. The effects of isolates on organoleptic properties of resulting dough were analyzed. However, S. cerevisiae was the most predominant, other yeast species isolated were S. uvarum, S. carlbengesis, and Schizosaccharomyces pombe. There was no significant difference in flavour and taste of dough fermented by thirteen free and thirteen immobilized yeast isolates, as well as baker’s yeast, used. Dough fermented with immobilized S. carlbengesis isolated from E. guineensis palm wine from Orlu and baker’s yeast had the best appearances, while the best texture was recorded in dough fermented with immobilized S. carlbengesis isolated from E. guineensis, from Enugu. The dough hardness recorded with baker’s yeasts was not significantly different from those fermented by immobilized S. cerevisiae and S. carlbengesis (both from E. guineensis from Owerri) isolates, as well as free S. carlbengesis (E. guineensis from Enugu State) and S. cerevisiae (R. hookeri from Enugu State). Also, yeasts from E. guineensis performed better than those from R. hookeri, with immobilization, a great influence on the organoleptic properties of the resulting dough was observed. Consequently, some yeast isolated in locally tapped palm wine can be usefully applied in bread-making.