The beer brewing process involves malting, milling, mashing, boiling, cooling, and fermentation. Approximately 20 kg of byproducts are produced for every 100 liters of beer brewed, of which brewer’s spent grains (SG), spent hops (SP), and surplus yeasts (SY) account for approximately 85, 5, and 10%, respectively. SG is rich in cellulose, protein, essential amino acids, phenolics and mineral; SP is rich in nitrogen free extract, fiber and protein; SY is rich in proteins and saccharides; where both SP and SY also are rich in prenylflavonoids and hop bitter acids. Although several nutrients or functional components have been found in such beer brewing byproducts, most of these byproducts are used as animal feed and fertilizers since insufficient research has been devoted to the physiological activities for human. To date, only activities of antiobesity and antiproliferation of cancer cells were possessed by SY. Hence, further research is required to clarify the health potential and novel application of these byproducts for environmental protection and other economic activities.
Part of the book: Current Topics on Superfoods