Accelerated autolysis of brewer's yeast cells for production of yeast extract powder

Abstract

Accelerated autolysis of spent brewer’s yeast was studied by adding different accelerating agents and optimizing conditions such as temperature and pH. Protein re leased c ontent in the hydrolysate was determined by Lowry method while the total α- amino nitrogen c ontent by Nihydrin method, using leuc ine as a standard. Four accelerating agents such as chitosan, ethanol, ethyl acetate, and thiamine was proposed to inc rease the protein a nd α- a mino nitrogen produc tion from the autolys is of brewe r’s yeast c ells c onducted at pH of 5.0 and temperature of 500C for 24 h. As a result, ethyl acetate was chosen as the best agent whic h made high α-a mino nitrogen produc tion with reasonable c ost . The rate of its inc lusion was suggested at 1.5%. In addition, ac c elerated autolysis with ethyl ac etate was also optimize d for pH a nd te mperature c onditions to get the highest c ontent of protein a nd α- a mino nitrogen. The result of expe riment showed the acc elerated autolysis with 1. 5% ethyl ac etate at pH 6.0 and 500 C produc ed highest protein c ontent (55.31%) and α- a mino nitroge n (6. 65%). The yeast extract was spray-dried to make the yeast powder with 10.1% nitrogen content, and 63.2% protein content. Key word: α-amino nitrogen, accelerating autolysis, Brewer’s yeast, yeast extract.