Optimization of extraction parameters for trehalose from beer waste brewing yeast treated by high-intensity pulsed electric fields (PEF)

Abstract

High-intensity pulsed electric fields (PEF) was applied to treat beer waste brewing yeasts (BWBY) to improve the permeability of yeast cell membrane in order to extract trehalose. Several independent variables such as pH (3 to 7), electric field strength (0 to 50 kV/cm), pulse numbers (0 to 10) and liquidsolid ratio (20: 1 to 60: 1) were investigated. The optimal parameters were obtained by one-factor-at-atime (OFAT) experiment and quadratic regression orthogonal design. The results showed that under the conditions of electric fields intensity of 19.97 kV/cm, pulse number of 6, and liquid-solid ratio of 30:1, the extraction rate of trehalose could reach 2.635%. In addition, the extraction efficiency of trehalose treated by PEF was compared with other two trehalose extraction methods, example microwave and ultrasound, and the efficiency of PEF was found to be 103.15 μg/s; it was 15.96 times higher than microwave and 34.08 times higher than ultrasound. This demonstrated that the PEF could be regarded as a promising technique for bio-material extraction.

Key words: High-intensity pulsed electric field (PEF), Beer waste brewing yeast (BWBY), Trehalose, Regression model.