【作者】 刘军；

【导师】 顾国贤； 陆健；

【作者基本信息】 江南大学 ， 发酵工程， 2005， 硕士

【摘要】 本论文研究了不同品种国产啤酒大麦中的氧化还原酶系,包括过氧化物酶(Peroxidase,简称POD)、超氧化物歧化酶(Superoxide dismutase,简称SOD)和多酚氧化酶(Polyphenol oxidase,简称PPO),研究它们在制麦过程、糖化过程中的变化规律,并初步了解这些酶对啤酒酿造的影响,主要研究结果如下: 啤酒大麦中的POD、SOD和PPO主要受大麦品种影响:通过回归分析,POD、SOD、PPO与蛋白质含量的相关系数R~2值分别为0.1849、0.2096、0.07673,P值分别为0.4524、0.3766、0.8382,基本不受大麦蛋白质影响。 对制麦及贮藏过程中氧化还原酶系的研究结果表明:发芽结束时POD酶活增加了4～5倍,SOD酶活增加了4～7倍,PPO酶活增加了2～7倍;焙燥过程中酶活均会降低,焙燥结束时POD酶活残留24.4%,SOD和PPO均已完全失活;延长焙燥时间、升高焙燥温度可降低POD酶活36.4%、59.1%;贮藏过程中氧化还原酶的酶活会恢复,其恢复的速度受到贮藏温度和出炉水分影响,贮藏温度和出炉水分高,酶活恢复速度快。 氧化还原酶系对麦汁和啤酒质量影响的初步研究结果表明:POD会降低麦汁的质量,表现在麦汁的浊度、色度增高、TBA值升高、抗氧化力降低;通过在制麦过程中控制POD酶活的方法,可以使啤酒的TBA值降低了19.1%,抗氧化力增强了42.8%,从而进一步提高了我国啤酒大麦的酿造品质。更多还原

【Abstract】 The oxido-reductases which are peroxidase (Abbr. POD ), superoxide dismutase (Abbr. SOD ) and polyphenol oxidase (Abbr. PPO ) of different domestic barleys were studied in this paper. The alternation of these enzymes during malting and mashing were studied, also the primary study of the their effects on the wort and beer quality was done in this paper. The results can be concluded as following:The POD, SOD and PPO were affected significantly by the barley varieties but had little relationship with the barley protein content, which could be tested by the results of R~2 values and P values (R~2=0.1849, 0.2096, 0.07673;P=0.4524, 0.3766,0.8382).The study on these enzymes during malting and storage showed that: the POD activity increased 4-5 times by the end of germination, for the SOD was 4-7 times and for PPO was 2-7 times. The enzymes’ activity decreased during the phase of kilning, and the POD activity increased by 24.4% in the end of kilning, however, the SOD and PPO lost their activities. The POD activity decreased by 36.4% and 59.1% according to prolonging the kilning time and elevating the kilning temperature. The enzymes’ activity recovered by different percentage according to the time, water and temperature during storage. The results showed that the higher the storage temperature, the bigger recovery percentage reached.The primary study on the wort and beer showed that the POD decreased the wort quality by increasing the haze, colour and TBA value. By controlling the POD activity through malting which could significantly decrease the TBA value by 19.1% and increase the antioxidant potential by 42.8%. It was benefit to improve the domestic barleys’ brewing characteristics.更多还原