Spent Brewer's Yeast as a Source of Insoluble β-Glucans

Abstract

In the brewing process, the consumption of resources and the amount of waste generated are high and due to a lot of organic compounds in waste-water, the capacity of natural regeneration of the environment is exceeded. Residual yeast, the second by-product of brewing is considered to have an important chemical composition. An approach with nutritional potential refers to the extraction of bioactive compounds from the yeast cell wall, such as β-glucans. Concerning the potential food applications with better textural characteristics, spent brewer's yeast glucan has high emulsion stability and water-holding capacity fitting best as a fat replacer in different food matrices. Few studies demonstrate the importance and nutritional role of β-glucans from brewer's yeast, and even less for spent brewer's yeast, due to additional steps in the extraction process. This review focuses on describing the process of obtaining insoluble β-glucans (particulate) from spent brewer's yeast and provides an insight into how a by-product from brewing can be converted to potential food applications.

Keywords: Saccharomyces cerevisiae; bioactive polysaccharides; particulate β-glucans; spent brewer’s yeast.

Figure 1

Schematic representation of the yeast cell wall and distribution of β-glucans in Saccharomices cerevisiae (adapted from [42,59]).

Figure 2

Schematic representation of yeast β-glucans: (A) soluble β-glucans; (B) insoluble β-glucans (adapted from [103,104]).

Figure 3

Different cell lysis methods for obtaining β-glucans.

Figure 4

Protocols for obtaining β-glucans from spent brewer’s yeast.

Figure 5

Schematic representation of protein content during β-glucan extraction.