β-glucans obtained from beer spent yeasts as functional food grade additive: Focus on biological activity

Nowadays, there is an increasing interest in the search for new healthy compounds obtained from by-products of the food industry, because of the concomitant trend towards reutilization and by-products exploitation, both hallmarks of the circular economy. One of these by-products are the brewers spent yeasts (BSY), generated by the brewing industry. BSY, if not properly inactivated and disposed-off, represents an environmental problem. One of the uses given to it is as a feed for livestock. However, certain components of yeast cell walls (in particular, β-glucans) have great potential to be used as Biological Response Modifiers (BRM) for humans. In recent years the interest on these compounds has grown-up, as the research on its potential application as food additives capable of conferring a benefit on consumer's health. Prebiotic, immunomodulatory and antitumoral activities are particularly of great interest. Since β-glucans possess several physiological functions and considering that BSY cell walls are rich in β-glucans, the food industry could generate additional revenue by isolating β-glucans from SBY as a high-value product. The possibility of producing value-added products such as β-glucans from this by-product could benefit beer manufacturers and, in addition, minimize the environmental impacts from these industries. This review summarizes the potential application of BSY by-product by the purification of cell wall components (β-glucans) for application as functional additive, focused on their biological effect on the intestinal context. • BSY are a rich source of β-glucans. • β glucans are promising biomolecules to be used as healthy food additives. • β glucans prebiotic effect could be related to other benefic effects described. • Extraction of β-glucans from BSY contributes to sustainability of brewing industry.