Abstract

In order to improve the permeability of yeast cell membrane, pulsed electric fields (PEF) was applied in extracting protein from beer waste brewing yeasts (BWBY). Through investigation of three independent variables, including electric field strength (10 to 50 kV/cm), pulse numbers (2 to 16 μs), and liquid-solid ratio (20:1 to 60:1), the optimal extraction parameters for protein were obtained by one-factor-at-a-time (OFAT) experiment and quadratic regression orthogonal design. The results showed that the extraction yield of protein could reach 2.788 ± 0.014% when electric fields intensity was chosen by 10 kV/cm, pulse number was 8, and liquid-solid ratio was of 40:1. Meanwhile, PEF method was a novel and promising method to extract protein from waste beer yeast which will benefit food and agriculture industry. The article mainly focuses on the extraction of dissoluble protein from waste beer yeasts by PEF. PEF could be considered as a highly efficient and energy saving technique to extract bio-component from raw materials.

Key words: Pulsed electric field (PEF), beer waste brewing yeast (BWBY), protein, regression model.