Effect of arabinoxylan arabinofuranohydrolases of Jiangsu barley malt on the filterability

Arabinoxylan arabinofuranohydrolase (AXAH) is one of the key degrading enzymes of arabinoxylan. The activities of AXAH between Jiangsu barley malt (Dan'er and Gangpi) and imported barley malt (Metcalfe and Baudin) with different filterability were compared, the results found that AXAH average activities in Dan'er and Gangpi was only about 60% of that in Metcalfe and Baudin. In order to confirm effect of AXAH on the malt filterability, AXAH was isolated from Dan'er barley malt by ammonium sulfate precipitation, SP FF and Q FF ion exchange chromatography and Sephacryl S-100 HR gel filtration chromatography, and was then added into mash during the initial period of congress mash. The filtration rate of wort increased 34.2% when 6mU/g of AXAH was added, the viscosity decreased 5.5% but the turbidity increased 32.5%. These results showed that the added AXAH and its synergistic effect with others hydrolases promote the decrease of contents of polymeric arabinoxylans (PAX) , β-glucan and macromolecular nitrogen, but the increase of contents of AX and total nitrogen of wort.