Optimization of Chemical Biochemical and Physical Treatments for Bakerûs Yeast Lysis for Yeast Extract Production

Abstract

The effects of chemical, biochemical and physical treatments on baker's yeast lysis were studied. The standard conditions for autolysis were pH 5.2, temperature 54°C and yeast concentration 13% dry wt. The optimum chemical treatment obtained by using 5% v/v ethanol and 5% w/v NaCl. The optimum biochemical and physical treatments were the use of 0.1%w/w of papain and 8,000 psi of homogenization respectively. The combination treatment of 5% ethanol and 5% NaCl exhibited highest protein content (61.90%).The physical treated sample obtained 42.45% of total carbohydrate yield and biochemical treated sample obtained 46.53% of autolysate. The chemical analysis of the samples showed the best result in the biochemical treated sample as (g/100g dry wt): 57.50 of total protein, 8.22 of amino-nitrogen, 24.27 of carbohydrate, 7.86 of nucleic acid and 10.72 of ash contents. This treatment showed the feasibility of producing yeast extract, yeast autolysate at pilot plant or industrial scale.