Spent brewer’s yeast is source of solid waste in large quantity and difficult to treatment in brewery [1] . However, it is a source of protein, vitamins (especially B vitamins) and minerals that used as a raw material source for the production of Yeast extract or hydrolysates. Yeast hydrolysates contain plenty of amino acids (about 16 amino acids) [2] so that they are used widely in food and medicine with many purposes, i.e., to increase the nutritional value.
There are three main methods for the hydrolysis of protein in spent brewer’s yeast: Hydrolyzing by acid, by alkaline and by enzymatic method [3]. In this study, we used enzymes for yeast hydrolysis.
The effect of yeast cell wall on degree of hydrolysis is high because it is very thick (about 25 nm) [2, 4] and difficult to be disrupted. According to Anna Bzducha-Wróbel [6], yeast cells could be disrupted by mechanical or physical methods. Mechanical methods are often used as a ball mill and agitation (during hydrolysis). Ball mill brings to highly effective in cell disruption but the application in industrial scale is restricted [7] whereas agitator is widely used in industrial production [2]. On the other hand, yeast cells are also disrupted by physical methods such as autoclaving, sonication and by biochemical way as autolysis. Cells disruption by sonication gave high efficiency [6, 7], the cell wall was mostly intact when disruption was carried out by autoclaving [9] or autolyzing [7, 9]. Read more…-Spent brewer’s yeast is source of solid waste in large quantity and difficult to treatment in brewery [1] . However, it is a source of protein, vitamins (especially B vitamins) and minerals that used as a raw material source for the production of Yeast extract or hydrolysates. Yeast hydrolysates contain plenty of amino acids (about 16 amino acids) [2] so that they are used widely in food and medicine with many purposes, i.e., to increase the nutritional value.
There are three main methods for the hydrolysis of protein in spent brewer’s yeast: Hydrolyzing by acid, by alkaline and by enzymatic method [3]. In this study, we used enzymes for yeast hydrolysis.
The effect of yeast cell wall on degree of hydrolysis is high because it is very thick (about 25 nm) [2, 4] and difficult to be disrupted. According to Anna Bzducha-Wróbel [6], yeast cells could be disrupted by mechanical or physical methods. Mechanical methods are often used as a ball mill and agitation (during hydrolysis). Ball mill brings to highly effective in cell disruption but the application in industrial scale is restricted [7] whereas agitator is widely used in industrial production [2]. On the other hand, yeast cells are also disrupted by physical methods such as autoclaving, sonication and by biochemical way as autolysis. Cells disruption by sonication gave high efficiency [6, 7], the cell wall was mostly intact when disruption was carried out by autoclaving [9] or autolyzing [7, 9]. Read more…
