【作者】 吴会丽；

【导师】 张丽叶；

【作者基本信息】 北京化工大学 ， 生物化工， 2007， 硕士

【摘要】 啤酒糟是啤酒工业中的主要副产物，其产出率为投入生产原料的31％左右。目前，大多数厂家将其当饲料出售，有的甚至当废物排放，污染环境的同时也造成了资源的浪费。啤酒糟中含有大量的膳食纤维和蛋白质，是一种良好的膳食纤维源和蛋白质源。本文主要研究啤酒糟的深加工利用，确定了啤酒糟中蛋白质、水不溶性膳食纤维和水溶性膳食纤维的最佳提取工艺条件，并对绿色木霉固态发酵啤酒糟产纤维素酶进行了初步研究。对酶法提取啤酒糟中蛋白质进行了研究。确定了蛋白酶酶解啤酒糟提取蛋白质的最佳工艺条件，即温度60℃，pH 8.0，加酶量2mL／100g干啤酒糟，反应时间5h，液固比12：1。在此条件下，蛋白提取率达到63.6％。确定了丹粒酶酶解啤酒糟的最佳工艺条件，即温度55℃，pH 5.5，加酶量1.2g·100g干啤酒糟^-1，反应时间4h。丹粒酶和蛋白酶共同酶解啤酒糟后，蛋白质提取率较蛋白酶酶解啤酒糟时提高了7.4％。蛋白水解液中总蛋白含量为1106.4mg·（100mL）^-1，游离氨基酸含量为267.4mg·（100mL）^-1。通过纳滤膜对蛋白水解液进行了浓缩。蛋白酶酶解后的残渣经过筛分得到了水不溶性膳食纤维，水不溶性膳食纤维的得率为56.7％，持水性为6.83，溶胀性为6.0mL·g^-1，其中仍含有8％的蛋白质。对碱法和酶法提取啤酒糟的水溶性膳食纤维进行了研究。碱法提取啤酒糟中水溶性膳食纤维的最佳工艺条件，即提取温度70℃，NaOH浓度0.9％，提取时间80min，液固比17：1，在此条件下，SDF得率为13.37％。酶法提取啤酒糟中水溶性膳食纤维的最佳工艺条件，即温度55℃，加酶量10g／100g干啤酒糟，反应时间5h，pH值为5.5，液固比15：1，在此条件下SDF得率为4.71％。碱法提取SDF的得率要远大于酶法提取SDF的得率，但提取的SDF颜色较酶法的深。对用绿色木霉固体发酵啤酒糟产纤维素酶进行了初步研究。绿色木霉可以发酵啤酒糟产生纤维素酶，但酶活力比较低，有待于进一步研究。更多还原

【Abstract】 Brewer’s spent grain（BSG） is the main by-product of brewing industry.The ratio of BSG and raw materials is about 31%. Many factories sold it asanimal feed, but some factory pull it as waste which causing pollution to theenvironment and resource waste. BSG is rich in dietary fiber and protein. It isa high quality dietary fiber source and protein source. This paper mainly studyon the comprehensive utilization of BSG. The optimum conditions ofextracting protein, insoluble dietary fiber（IDF） and soluble dietary fiber（SDF）was studied and cellulase produced by Trichoderma viride with solidfermentation was preliminarily studied.The optimum conditions of extracting protein from BSG was studied. Theoptimum enzymatic conditions of protease: the enzyme load is 2mL/100gdried BSG; the temperature of hydrolysis is 60℃; the pH of hydrolysis is 8．0;the time of hydrolysis is 5 hour; the proportion of liquid and solid is 12:1．Atthe optimum conditions, the extraction rate of protein could reach 63．61%.The optimum enzymatic conditions of cellulose: the temperature of hydrolysisis 55℃; the pH of hydrolysis is 5．5; the enzyme load is 1．2g/100g dried BSG;the time of hydrolysis is 4 hour. The extraction rate of protein was increased by 7．4% with protease and cellulose hydrolysis compared with only proteasehydrolysis. The total protein content of hydrolysate is 1106．4mg·（100mL）^-1 .The content of free amino acid is 267．4mg·（100mL）^-1 . The hydrolysate couldbe concentrated by nanofiltration membranes. After protease hydrolysis, IDFcould be extracted from solid waste by screening. The yield rate of IDF is56．7%. The water-holding capacity is 6．83 and the swelling capacity is6．0mL·g^-1 ; but it also has 8% protein.The extraction of SDF from brewer’s spent grain by alkali and enzymewas also ,studied. The optimum conditions of extracting SDF from BSG byalkali: the temperature of extraction is 70℃; the concentration of NaOH is0．9%, the time of extraction is 80min; the proportion of liquid and solid is17:1．At the optimum conditions, the yield rate of SDF could reach 13．37%.The optimum conditions of extracting SDF from BSG by enzyme: thetemperature of hydrolysis is 55℃; the enzyme load is 10g/100g dried BSG;the time of hydrolysis is 5 hour; the pH of hydrolysis is 8．0; the proportion ofliquid and solid is 15:1．At the optimum conditions, the yield rate of SDFcould reach 4．71%. The yield of SDF extracted by alkali is higher than theyield of SDF extracted by enzyme; and the colour of SDF extracted by alkaliis deeper than the colour of SDF extracted by enzyme.Cellulase produced by Trichoderma viride with solid fermentation waspreliminarily studied. Trichoderma viride could ferment BSG and producecellulose during this process, but cellulose activity is low. The technology is suggested to further studied.更多还原