The Bio-fortification of Barley with Selenium

Abstract

Selenium is an essential micronutrient for human health and is reported to play a role in a number of physiological and metabolic processes. It has antioxidant, anti-cancer and anti-viral functions, and there is evidence suggesting that Se could reduce alcohol-induced liver damage and the risk of prostate cancer. In South Korea, 70 percent of soil consists of granite and basalt with very low contents of selenium, potentially leading to Se deficiencies in the population. A study was undertaken to biofortify barley. The biofortified barley was then malted and brewed to determine if Se is available in the final beer. Two means of biofortifying barley were undertaken. Firstly, the application of sodium selenate to barley in the field, and secondly, the addition of sodium selenate and sodium selenite to barley during the steeping and watering phases of the malting process. A concentration of up to 2.7ppm Se was achieved in barley from foliar application, and 8.4ppm Se was achieved in malt from additions during the germination phase of malting, around 25 to 80 times higher than un-biofortified barley. The bio-fortified barley was micro-malted and brewed through both laboratory and pilot-scale processes. A mass balance of this bio-accumulated Se was conducted throughout the various intermediary and by-products of the malting and brewing process. Beer from both brewing methods contained appreciable concentrations of Se. The laboratory brew from malt containing 2.2ppm Se contained 38ppb, while 20L and 500L pilot brews from malt with approximately 0.4ppm resulted in beer with a concentration of 17 and 15ppb, respectively. Typically, Australian beer contains around 3ppb (our unpublished data), while a survey of European beer found a mean Se level of just 1.4ppb, suggesting that beer made from Se-biofortified barley has elevated Se levels, and may be used to alleviate Se deficiency.