Research progress on the antioxidant biological activity of beer and strategy for applications

Beer is the most widely consumed fermented beverage in the world. Due to its antioxidation properties and other prebiotic effects related to non-alcoholic components, moderate drinking of beer is conducive to health. Antioxidants in beer, including phenolic compounds, melanoidins, selenium, vitamins B6, B12, E and C, etc., can effectively participate in the prevention of oxidative stress and prevent DNA damage, lipid peroxidation, and intermediate oxidative free radicals from attacking cellular components. In this review the importance of endogenous antioxidants in beer are described in order to improve the flavor stability and antioxidant activities (AOX) of beer. This study emphasizes the importance of brewing process controls to improve AOX, starting with optimization of the wort preparation and fermentation process to ensure the optimum technologies are used. The optimization of malting, mashing and fermentation processes can increase the contents of phenolic compounds, melanoidins, selenium and vitamins C and E and AOX of malt. Decoction mashing is more conducive to promoting the formation of phenolic compounds and melanoidins than infusion mashing. Rapid cooling following heat treatment and boiling can be used to increase the contents of melanoidins. The use of excellent yeast, an appropriate pitching rate, high gravity wort and low-temperature fermentation is more beneficial for the maintenance of high AOX in beer. It is effective to selectively add exogenous antioxidants rich in plant phenolic compounds or micronutrients to improve the AOX of beer.