Journal of Bioscience and Biotechnology Discovery

Significance of yeasts in food technology as well as in human nutrition, as alternative sources of protein to cover the demands in a world of low agricultural production and rapidly increasing population, makes the production of food grade yeasts important. The comparative study on the growth rate and physicochemical properties of yeast was carried out using corn and wheat flour substrates. 50 g of wheat and corn flour each was weighed into a calibrated culture plastic rubber. 120 ml of distilled water was added with 5 ml of lemon juice. The sample was stirred and kept under room temperature at 26°C. The growth of the yeast were observed every three days for two weeks and recorded in millimetre. Yeast (Saccharomyces cerevisiae) culture grown using corn flour gave a mean growth of 12.18±0.38 for the first week and 15.24±1.21 for the second week. On the other hand, the growth of yeast produced from wheat flour gave 8.29±0.35 and 10.46±1.23 for first and second week respectively. The result also showed that yeast produced from corn flour grew rapidly than the wheat flour. The acid value of  yeast produced from  corn  flour was 17.95 mgKOH/g, saponification value of 9.5 mgKOH/g, ester value of  164.37 mgKOH/g, iodine value  of  87.63 gI₂/100g, peroxide value  of 16.0 mEq/kg, free fatty-acid of 9.02%, refractive index of 1.50, specific gravity of 0.902, density of 5 g/cm³ and pH of 5, while yeast produced from wheat flour  had an acid value of 14.3 mgKOH/g, saponification value of 5.3 mgKOH/g, ester value of  152.1 mgKOH/g, iodine value  of  66.0 gI₂/100g, peroxide value  of 10.1 mEq/kg, free fatty-acid of 5.2%, refractive index of 0.6, specific gravity of 0.561, density of 3.2 g/cm³ and pH of 5. The result showed that the physico-chemical properties of yeast produced from corn flour were higher than that produced from wheat flour with p value of 0.001.