以麦麸为基质的红曲霉的固态发酵及抗氧化活性研究

发布时间：2018-01-30 10:26

  本文关键词： 红曲霉 麦麸培养基 发酵工艺 抗氧化性　出处：《浙江工业大学》2015年硕士论文　论文类型：学位论文

【摘要】：红曲是以大米为原料经红曲霉(Monascus)发酵而成的一种红色米曲,论文以麦麸为基质进行红曲霉的发酵,一方面是扩大了红曲霉发酵基质的种类,另外一方面更重要的是麦麸自身的特点对于红曲霉发酵的影响。麦麸本身含有丰富的活性物质,如p-葡聚糖,是公认的降血脂物质,和红曲霉发酵出来的洛伐他汀功能相同,所以二者在一起具有协同降脂的效果。同时麦麸还富含多酚,具有很强的抗氧化作用,以麦麸为基质发酵红曲霉,得到的最终发酵产物的抗氧化活性也能得到增强。实验首先筛选出抗氧化活性较佳的红曲霉菌株,从来自山东、丽水、江苏、福建四个地方出厂的红曲米中分离单个红曲霉菌株,经固态发酵后,利用DPPH和ABTS方法测定各发酵产物的抗氧化活性,并结合生物量筛选最优菌株,筛选得到的菌株Y221,其ABTS清除率为90.44%,DPPH抑制率为为89.51%,生物量为0.077mg/mL,并对这支菌株进行鉴定,确定其为紫色红曲霉菌株。然后对筛选出来的菌株Y221通过改变培养基成分、发酵温度,考察发酵产物的抗氧化性能,最终确定培养基成分为：菌液量10%,含水量50%,2%蛋白胨,2%冰醋酸,培养温度30℃；在此培养条件下,对菌株Y221各方面的抗氧化性进行考察,结果为：浓度为5mg/mL的发酵产物提取液400μL,其Trolox当量为2.62mmol/L,Fe3+还原能力在700 nm吸光值为0.313；HPLC法测定发酵产物中阿魏酸含量为44.7 mg/g；总酚含量为450μg/mL。发酵前后游离型酚酸含量从106 μg/mL升高到：208μg/mL。最后,在此培养条件下,分别用麦麸和大米进行发酵,不同浓度麦麸发酵产物明显高于大米发酵产物的抗氧化性活力。筛选出来的红曲霉菌株抗氧化活性表现良好,发酵产物的液相结果表明其中阿魏酸含量丰富,无论是定性还是定量上,麦麸作为红曲霉发酵的基质,有利于产物抗氧化活性的提高,而且抗氧化活性优于利用大米等其他基质发酵,是红曲霉固态发酵的更好选择。
[Abstract]:Monascus is a kind of red rice koji fermented from rice by Monascus. The fermentation of Monascus was based on wheat bran. On the one hand, it expanded the variety of fermentation substrate of Monascus. On the other hand, more important is the effect of the characteristics of wheat bran on the fermentation of Monascus. Wheat bran itself is rich in active substances, such as p-dextran, which is recognized as a lipid lowering substance. The function of lovastatin fermented by Monascus is the same, so the two have synergistic effect of reducing lipid. Meanwhile, wheat bran is rich in polyphenols and has strong antioxidant effect, and fermented Monascus on the basis of wheat bran. The antioxidation activity of the final fermentation product can also be enhanced. Firstly, Monascus strains with better antioxidant activity were selected from Shandong, Lishui and Jiangsu. A single Monascus strain was isolated from four local Monascus rice plants in Fujian Province. After solid state fermentation, the antioxidant activity of each fermentation product was determined by DPPH and ABTS methods, and the optimum strain was screened by combining with biomass. The ABTS clearance rate of strain Y221 was 90.44 and the inhibition rate of DPPH was 89.51, the biomass was 0.077 mg / mL, and the strain was identified. The strain Y221 was determined to be Monascus purplicus. The antioxidant activity of the fermentation product was investigated by changing the composition of culture medium and fermentation temperature. The composition of the culture medium was determined as follows: the amount of liquid was 10, the water content was 50% peptone and 2% acetic acid, and the culture temperature was 30 鈩，

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