【作者】 王铁军；

【导师】 许赣荣；

【作者基本信息】 江南大学 ， 发酵工程， 2008， 硕士

【摘要】 含莫纳可林K(Monacolin K)的红曲产品具有明显的抑制胆固酵合成和降血脂的功效。目前市场上的降脂红曲产品类型主要是固态发酵方法生产的功能性红曲米粉,除了含有降脂功效的Monacolin K之外,还含有大量的残余淀粉,由于其水溶性差,无法直接添加到液态食品中使用,因此常用红曲粉胶囊作为保健品或药品的终端产品形式,这很大程度上限制了功能性红曲的使用范围。目前市场上对功能性红曲产品的需求不断增加。本课题以功能性红曲米为原料,制备水溶性功能红曲产品,并对这一产品中的主要功能性成分Monacolin K在液体中的稳定性和水溶性功能红曲的应用进行了研究。本文以红曲菌9908作为生产菌株,研究了其固态发酵工艺条件。通过单因素和正交实验确定最优发酵条件如下:培养基配方:基质装料量80 g/L(大米与小米比例7:3);100 g物料中,初始加水量70 mL,葡萄糖和玉米浆添加量分别为10 g和4 g;拌料水初始pH值3。发酵工艺条件:采用1 L三角瓶,接种量0.40 mL/g(以物料质量计)、温度为先30℃培养4 d后26℃培养、发酵时间20 d,所产功能性红曲米中Monacolin K含量可达5100 mg/kg,比优化前Monacolin K产量提高了一倍,且红曲米中未检测出桔霉素,达到工业化生产要求。为制备水溶性功能红曲产品,对功能性红曲米的浸提工艺进行了详细研究,确定了最优提取条件:60%乙醇总用量15 mL/g于60℃下分三次浸提红曲米,总浸提时间60 min,红曲米中Monacolin K提取率最高达90.6%。同时研究了多罐组逆流浸提工艺在提取红曲米Monacolin K中的应用,研究表明采用三罐组逆流浸提工艺,在相同工艺参数下与单罐三次提取相比,可节省1/3的提取时间,少用37.1%的加热水蒸汽用量,提取率提高了1.2%。研究了红曲Monacolin K在水溶液中的稳定性,实验发现红曲Monacolin K在水溶液中的热稳定性较好,100℃下处理60 min,其水溶液中Monacolin K损失5%左右,酸型Monacolin K所占比例基本无变化。酸性环境下,酸型Monacolin K易向内酯型转化,使水溶液中红曲Monacolin K的溶解度下降,同时对溶液中Monacolin K有破坏作用。pH值位于6.0~7.0时,溶液中的Monacolin K含量及类型较稳定。长时间的光照可促进水溶液中Monacolin K的降解。食盐、氨基酸、维生素C(Vc)均可降低红曲Monacolin K的溶解度,但对水溶液中酸型Monacolin K所占比例影响甚微。适当的蔗糖浓度可提高红曲Monacolin K在水溶液中的溶解度,但对Monacolin K结构转化无作用。使用水溶性功能红曲粉制备红曲饮料醋和红曲酒,实验结果表明红曲饮料醋热稳定性不好,100℃下加热30 min,溶液中Monacolin K损失率可达46.3%,酸型Monacolin K所占比例基本无变化。醋液酸度对醋液中Monacolin K的稳定性有影响,选用酸度50 g/L以下的饮料醋较好。长时间光照可促进溶液中Monacolin K的降解。红曲酒在长时间的存放和光照条件下,溶液中Monacolin K含量及酸型Monacolin K所占比例几乎无变化,稳定性较好。更多还原

【Abstract】 The functional red rice(FRR) containing Monacolin K could inhibit the synthesis of cholesterol and reduce blood lipid significantly. The FRR produced by the traditional solid state fermentation contains not noly Monacolin K, but a large amount of starch. FPR capsules are usually the end products of healthcare and medical drugs due to the fact that FRR can not be added into the liquid food with the poor solubility, thus the applications of FRR are limited.The demand for water-soluble FRR is increasing in the market currently.In this dissertation, the process of preparing water-soluble FRR products from FRR powder was developed. As Monacolin K is the main functional componant of water-soluble FRR products, the stability of Monacolin K in water and the application of this product were investigated in this study.Monascus sp. 9908 was used as the FRR-producing strain, and the fermentation conditons were investigated. The optimal process parameters by the one-variable-at-a-time experiment and orthogonal experiment are as the following: The culture medium was composed of: 80 g cereal in a 1L Erelenmeyer flask (the ratio of rice to millet is 7:3), add water 56 mL, and the pH of the water is 3.0. glucose of 0.10 g/g, corn steep of 0.04 g/g, The fermentation process: with an inoculumn to a 1 L Erlenmeyer flask of 0.40 mL/g, the culture was fermented at 30℃for 4 days and then was cultured at 26℃for 20 days more. The concent of Monacolin K in the FRR could reach 5000 mg/kg, increased by 2-folds compared to the previous result before optimization, and the requirement of industrilization was achieved. Moreover, no citrinin was detected in the produced FRR by the above optimized culture process.To prepare water soluble FRR, the extraction technique of FRR was studied in detail and the optimal extraction process was obtained. FRR powder was extracted at 60℃for total time of 60 min with ethanol (60%) for three times, in a total ratio of 15 mL/g. The recovery rate of Monacolin K could reach as high as 90.6%. Meanwhile, multi-reactor countercurrent extraction technique in Monacolin K extraction was also performed. The results showed that with three reactor countercurrent extraction technique, the extraction time was reduced by 1/3, the steam amount was reduced by 37.1%, and the recovery rate was increased by 1.2%, compared with the single reactor technique (extractioned by three times),using same process parameters.The stability of Monacolin K in liquid-soluble functional red yeast rice was studied.The results showed that the thermal stability of Monacolin K in water-soluble FRR was very good.The concentration of Monacolin K in water just degraded by around 5% at 100℃for 60 min.The porportion of acid form Monacolin K in water is almost unchanged. Acid form Monacolin K was converted to lactom form Monacolin K in the acidic environment, and Monacolin K in water can be destructed so that the concentration of Monacolin K decreased also.The content and types of Monacolin K in water were comparatively stable when the pH range was 6.0~7.0. The Monacolin K in water is slightly destructed when exposure to light for a long-time. The solubility of Monacolin K in water can be degraded by Vitamin C, salt or amino acid, which had little influence on the ratio of acid form Monacolin K in water. The sucrose with a proper concentration could increase the solubility of Monacolin K, however, had no effect on the structure transformation of Monacolin K.The water soluble FRR was used to prepare functional vinegar beverages and monascus wine. The thermal stability of Monacolin K in vinegar beverages is poor. The concentration of MonacolinK in vinegar beverage decreased by 46.3% when heated at 100℃for 30 min. There were few changes of the ratio of acid form Monacolin K. Acidic environment had influences on the stability of Monacolin K in vinegar beverages, and a better stability in vinegar beverages was observed with its acidity lower than 50 g/L. The Monacolin K in vinegar beverages could be degraded by illumination for a long-time. With a long-time of storage and illumination, the concentration of Monacolin K and the ratio of acid form Monacolin K were almost unchanged, and the stability was better.更多还原