Investigating the effect of yeast quality, lysis time and protein removal method on ß-glucan extraction efficiency of baker yeast

Beta-glucans is a β-D-glucose polysaccharide, which has many applications in the food and pharmaceutical industries. Beta glucans is mainly derived from various sources of bacteria, fungus, yeast and Cereal. Studies have shown that the properties of different forms of 1,3 and 1,6 and 1,4 beta-glucans are the same, Therefore, the production cost is the best criteria for selecting the appropriat e source of beta-glucanproduction. Yeast is the most economical source of beta-glucan. Depending on the required purity, β-glucan extraction from yeast is done under different stages and conditions. Generally, Extraction steps include cell wall disruption, cell wall removal, and extraction of β-glucan from isolated cell walls. The performance and efficiency of each stage can effect on the efficiency and consequently on the cost of production. In this research, the effect of two factors of yeast quality, lysis time and protein removal methods on the efficiency of thealkaline-acidic extraction process of β-glucan were investigated for the proper extraction of beta-glucan from the baker s yeast. To evaluate the quality of yeast, two types of industrial dry yeast and fresh yeast (without emulsifier) were used and it was found that by using fresh yeast purity of β-glucan increases from 39 to 43% respect to dry yeast, probably presence emulsifier in dry yeast has an inhibitory effect on the lysis of the cell, which was shown in the enduring research. To investigation effect of the cell lysis time, the times of 2 and 4hours were examined and it was cleared that by increasing of the cell lysis time, the purity of β-glucan increased from 43 to 51%, which was possibly due to better lysis of the cell. Also, Study cell lysis revealed that by increasing the cell lysis time, the cell wall disruption was completely performed. In order to reduce the protein content of the final sample, Proteinase K, Sodium Hydroxide, and increased of cell lysis time were used and the highest effect was obtained by increasing of the cell lysis time.

کلیدواژه ها:

Beta glucan ، Baker s yeast ، Alkaline lysis ، Protein ، Extraction