Making And Brewing Process On The Influence Of Malt And Beer Oxidation Resistance

Effects of steeping degree, germination time and baking temperature on antioxidant activity of KA4B using a single factor experiment and three levels of three factors response analysis methods were investigated. The results showed that the degree of barley was44.4%in the steeping, germination time was112.2h, baking coke temperature was82℃, and the best reducing power of malt was2.558mmol Vc/L. Test the best conditions for reducing power as2.566±0.022mmol Vc/L, and that was consistent with the prediction.Effects of adding different concentrations of NaOH and GA during the stage of production on the malt antioxidant were studied. The results showed TBA value, polyphenol, reducing power and DPPH clearance rate of malt were0.182,94.26mg/mL,2.568mmolVc/L,70.68%when treated by0.2g/L NaOH, and were0.179,94.83mg/mL,2.638mmolVc/L,72.56%when treated by0.2mg/kg GA. TBA value was significantly correlated with malt protein, total nitrogen but was a significantly negative correlation with water extract, diastatic power. Malt reducing power was significantly positive correlation with extract, protein solving index, saccharifying power. But it was significantly negative correlated with protein, total nitrogen.Different metal ions with different concentrations were added during the stage of dipping barley. Effects of metal ions in the concentration range of0-100mg/kg on the malt antioxidant activity were different. K+、Mg2+、Zn2+、Ca2+had activation on antioxidant activity of malt within the concentration of100mg/kg. Cu2+decreased the antioxidant activity of malt within low concentration. Mg2+、Cu2+on the activity of PPO had activation in a certain degree, and Ca2+had a certain degree of inhibition. Zn2+in the concentration of0-20mg/kg had activation in a certain degree and inhibition when there were more than40mg/kg on the PPO activity. Mg2+and Ca2+on the activity of SOD had a significant role in activation, Cu2+significantly inhibited the activity of SOD in the80mg/kg concentration. K+、Mg2+、Zn2+、Cu2+had different degrees of activation on POD activity in malt. Low concentrations of Ca2+(20mg/kg) had a certain extent inhibition on the POD activity of malt. In the range of100mg/kg. Cu2+inhibited the CAT activity of the malt, and other ions had activation. The CAT enzyme activity of malt treated by K+were strongest,increased95.7%.The Plackett-Burman multifactorial design was employed to find saccharification initial pH value, protein rest temperature and saccharification temperature. Box-Behnken experimental design was further used to optimize the important three factors. The results showed that protein rest temperature was52℃, saccharification initial pH value was5.4and saccharification temperature was66℃, and the best reducing power of wort was2.362mmol Vc/L. Test the best conditions for reducing power as2.388±0.019mmol vc/L, and that was consistent with the prediction.By measuring the TBA under five different starting parameters, including yeast, wort concentration, the main fermentation temperature, fermentation time and the addition of ZnSO47H2O, we found the most appropriate fermentation of beer to the greatest degree of reduction aging, improving beer quality. TBA values during fermentation increased and then decreased, compared with other experimental conditions, wort concentration was9°P, inoculation was2×107/mL, the main fermentation temperature was9℃, Zn2+addition level was0.75mg/L which was the value of the best control of TBA. At this point the beer aging was lowest, helping extend the shelf life of beer, improving beer flavor stability.