Research On Antioxdation Of Malt

With the development of beer industry, people are not only chasing beer quality but meanwhile propose new demands for the taste and flavor, therefore, the breweries are increasingly concerned about the impact of brewing raw materials and upstream process on the finished beer flavor stability and development of new high-end beer. As main raw material of brewing, the endogenous antioxidant capacity of malt is directly related with beer quality and shelf life. Seeking high antioxidant capacity malt and malting conditions improved malt antioxidant activity from malt variety and malting process could fundamentally improve the malt endogenous antioxidant capacity and inhibit the generation of aging precursors, which could be the effective measures to improve beer flavor stability.This paper first studied Esterel, Prestige, Metcalfe as well as Inner Mongolia barley from four different varieties of barley, and its antioxidant index changes in malting process, such as oxidoreductase, total polyphenol content, TBA value and DPPH radical scavenging rate, etc.. The results showed that: change trends of the four varieties barley were basically the same in total polyphenol content, aging precursor and oxidoreductase enzyme activities during germination process, the value reached max at the end of germination. After high temperature drying, the TBA values and DPPH radical scavenging increased in different degrees. Among four varieties, Prestige had relatively high antioxidant capacity, while domestic Inner Mongolia barley had relatively low antioxidant capacity.As some factors such as temperature and moisture, would affect the synthesis and decomposition of oxidoreductase, total polyphenol and aging precursor in barley germination process, this paper examined changes of antioxidant capacity of malt from the same variety by changing steeping time, germination temperature, kilning temperature and time etc.. The results showed that all stages in the malting process had different impact on the malt antioxidant capacity. Barley would germinate under steeping process using steep4off8and at15℃constant temperature. The malt antioxidant capacity was relatively high when the drying process used45℃,3hâ†'1hâ†'55℃,3hâ†'1hâ†'65℃,3hâ†'1hâ†'70℃,3hâ†'1hâ†'88℃,3h. This paper also developed the relativity between physical and chemical indicators and antioxidant activity through5different varieties of Prestige, Sebastian, Schooner, Gairdner and inner Mongolia malt and20different malt samples. The results showed that there was a certain correlation between malt physical and chemical indicators and antioxidant activity. The malt POD enzyme activity and chroma were moderately correlated (γ=0.543). Malt total protein content were inversely correlated with the total polyphenol content and antioxidant activity (y=-0.521,γ=-0.677). The experiments also showed that there were certain correlations among malt antioxidant indicators, such as DPPH radical scavenging rate and the total polyphenol content (γ=0.921), highly significant positive correlation between TBA value and LOX enzyme activity (γ=0.737), inversely correlation between TBA value and DPPH radical scavenging rate (γ=-0.643).Through the development on malt antioxidant activity in this paper, it was showed that low-energy of oxidoreductase could inhibit the production and release of aging precursor, which increased the malt endogenous antioxidant capacity to a certain extent. This experiment laid the foundation for the high antioxidant capacity of malt production and R&D of new high-end beer, and provided guidance to enhance beer flavor stability and non-biological stability.