SELECTION OF AN OSMOTOLERANT YEAST FOR WO RCESTERSHIRE SAUCE PRODUCTION

Worcestershire sauce production might include a fermentation step. The raw materials have high osmotic pressure, so we set out to select an osmotolerant yeast strain suitable for Worcestershire sauce production . Three commonly used yeasts were evaluated: Saccharomyces cerevisiae OC-2, a wine yeast; Kluyveromyces fragilis IFO 0288, widely used for f ermentation of kefir grains;and Zygosaccharomyces rouxii IFO 0493, a s oy sauce yeast. In the range of, total sugar concentrations of 28.1-47 .8% (the mixture contained sucrose, glucose, and fructose), cell numbe rs and ethanol production decreased as the sugar concentration rose, e specially with K.fragilis. The relationship between the total sugar co ncentration and ethanol production by each yeast was expressed as foll ows: S.cerevisiae OC-2 (n=8, r=0.999) P=-1.54x10(-4)xS(3)+1.72x10(-2)x S(2)-0.649XS+8.91 K.fragilis IFO 0288(n=8, r=0.995) P=(-3.57x10(-2)xS) +1.74 Z.rouxii IFO 0493 (n=8, r=0.987) P=-1.15x10(-3)xS(2)+9.38x10(-2) xS-1.36 where P is the ethanol production and S is the total sugar con centration. Under the usual conditions for Worcestershire sauce produc tion, with 39% total sugars, S.cerevisiae OC-2 had the greatest osmoto lerance of the three yeasts, with higher ethanol productivity and sati sfactory production of aromatic components than the other yeasts. We s elected S.cerevisiae OC-2 for trial in the proposed new step in Worces tershire sauce production.