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豆渣曲制备工艺及其提取物抗氧化性研究
Study on the Preparation of Koji with Soybean Residues and Antioxidants Activity of Its Extract
【作者】 伍时彬；
【导师】 王淼；
【作者基本信息】 江南大学 ， 食品科学， 2010， 硕士
【摘要】 豆渣是大豆制品加工中的主要副产物,占全豆干重的15%～20%,并含有丰富的蛋白质等生理活性物质。米曲霉是生产酱油等发酵的重要微生物,且具有多种酶系。本文研究以豆渣为基质,制备豆渣曲,并利用豆渣曲中多种酶水解曲料,以获得具有抗氧化的活性提取物,为揭示酱油的抗氧化性奠定基础。研究得到的以下主要结论:1.优化了以豆渣和麸皮为基质的固态发酵条件:在30℃,麸皮豆渣比为1:9,培养时间为48h,接种量为0.15%,水分含量为50%水分,米曲霉在此条件下,生长较好,米曲霉蛋白酶活力达到3283U/g。同时考察了添加葡萄糖和硫酸铵可以提高豆渣曲的蛋白酶活力。2.利用豆渣曲自身酶系水解曲料可获得具有较强抗氧化的提取物,添加纤维素酶和果胶酶可以有效提高抗氧化生理活性物质溶出。直接提取:提取时间为3h,提取温度:40℃,固液比为1:20,在此条件下,测得豆渣曲蛋白质溶出率为69%。分子量大多小于1000,大部分为二肽、三肽及氨基酸。外加纤维素酶提取条件为:加酶量为0.3g/L,提取温度为40℃,固液比为1:25,提取时间为4h。在此条件下,测得豆渣曲蛋白质溶出率为77.3%;外加果胶酶提取抗氧化液最优条件:固液比为1:20,提取温度为45℃,提取时间为4h,加酶量为1g/L。提取液的抗氧化活性分别为:0.20ml提取液清除DPPH能力为67.5%,30μl提取液清除ABTS+能力为72.1%。3.外加纤维素酶和果胶酶,不同程度的提高曲料中小肽,多酚,多糖以及黄酮抗氧化物质溶出速率和溶出量,从而提高了提取液的抗氧化能力,其中果胶酶效果最好,制得提取液具有最高的抗氧化活性。当含有7.5mg/ml多肽,1.4mg/ml多糖,多酚含量为2.0 mg/ml,以及6.5μg/ml黄酮,具有清除ABTS+和DPPH·自由基的IC50分别是21.5μl和0.21ml,0.1ml的提取液就具有49.2%的羟基自由基清除能力,而邻苯三酚半数抑制率IC50为0.49ml,0.2ml其还原能力就很强,还原产物吸光值就达到0.723。
【Abstract】 Soybean residue, the main by-product of soy products, is not only accounting for 15%~20% in dried soybean, but also rich in protein and physiological active elements. Aspergillus oryzae is a universal strain in traditional fermented industry, which contain complexed enzymes. Using soybean residue as raw material, Koji was produced by fermentation of Aspergillus oryzae. The complex enzymes from aspergillus oryzae were used to hydrolyze Koji, anti-oxidant elements was obtained. In this paper, using soybean residue as a medium, Koji is obtained ,and then hydrolyze the koji to obtain the anti-oxidant elements. The results concluded from experiments were as follows.1. Optimized cultivation conditions for the production of enzyme by Aspergillus oryzae under solid-state fermentation were obtained. The results showed the optimum conditions as followed: at 30℃, wheat bran, bean dregs ratio 1:9, incubation time 48h, inoculum dosage 0.15%, moisture 50%. Under these conditions, the protease activity reached 3283U/g. In addition, Glucose and Ammonium Sulfate can increase the neutral protease activity of the Koji.2. By the Koji autolysis, the extract with antioxidants was obtained. When temperature is 40℃, the solid-liquid ratio is 1:20, the hydrolysis time is 3h, the dissolution rate of protein was 69%. Polypeptides are mostly less than 1000 MW. They were tri-peptides, dipeptides and amino acids. The cellulase and the pectinnase were used to improve the antioxidant components. the dissolution rate of protein was 77.3%, at the dosage of cellulase: 0.3g/L, temperature: 40℃, the solid-liquid ratio of 1:25 for 3h; 0.2ml of the extract can scavenge 49.2% DPPH·free radical, 30μl can scavenge 72.1 % ABTS+, at amount of pectinnase added 1g / L, solid-liquid ratio of Koji to water 1:20, temperature 40℃,for 4h.3. The added cellulase and pectinnase can increased the extract rate and content of antioxidant from the Koji, and the antioxidant activity of the extract improved. As pectinase was added, the antioxidant activities of extract are the best. The extract contained 7.5 mg/ml polypeptides, 1.4mg/ml polysaccharide, 2.0mg/ml polyphenol, 6.5μg/ml flavones,which has high antioxidant activities in different system, the IC50 were 21.5μl, 0.21ml and 0.49ml in ABTS+, DPPH·free radical and pyrogallic acid auto-oxidation system , respectively. 0.1ml of the extract can scavenged 49.2% OH·free radical, and the reduce power reach 0.732 with 0.2ml of the extract。