【作者】 张媛媛；

【导师】 付瑞燕； 汪洪波；

【作者基本信息】 安徽农业大学 ， 工程硕士（专业学位）， 2019， 硕士

【摘要】 红曲米是将红曲霉菌接种至蒸熟的米上进行生长发酵,从而产生并累积红曲色素,在我国已有一千多年的食用历史。红曲米发酵基质多为籼米,研究表明,发酵基质对于红曲霉的生长和代谢可能具有重要的影响。糯米与籼米相比,其营养成分和加工特性存在显著差异,因此以糯米为基质生产红曲米是一个值得探索的方向。目前,国内外在糯米红曲米方面的报道很少,因此,本研究拟对红曲霉发酵制备糯米红曲进行初步研究。主要研究结果如下:(1)通过单因素和正交实验得到市售籼米红曲米的活化条件为:蛋白胨0.1 g/L、pH 3、温度 30℃。(2)将9种市售籼米红曲米活化后分别制备糯米红曲米,以色价/桔霉素为指标,从中筛选得到最佳样品3#。从发酵样品中通过稀释涂布平板法分离纯化得到一株红曲霉菌株M1,结合形态学及碱基序列比对,鉴定为紫红曲霉(Monascus purpureus)。(3)通过单因素及响应面法对红曲霉菌M1单菌发酵制备糯米红曲的培养条件进行了优化。结果显示:初始pH为3.5、温度30℃、接种量13%条件下时发酵所制备的糯米红曲样品色价较高,桔霉素含量较低,比优化前的色价提高了 0.84倍,桔霉素含量降低了 0.24倍。与3#市售籼米红曲米样品相比,色价提高了 2.34倍,桔霉素含量降低了 0.19倍。(4)研究了糯米红曲色素的稳定性并与市售籼米红曲色素稳定性进行了对比。糯米红曲色素在避光条件下比市售籼米红曲色素更耐储存,糯米红曲米较市售籼米红曲米在酸性环境更稳定,但是籼米红曲色素对常见金属离子的稳定性要高于糯米红曲色素。更多还原

【Abstract】 Red fermented rice(RPR)is prepared by inoculation of Monascus on steamed rice to produce pigments.It has been used for more than a thousand years in China.The fermentation substrate of RFR is mostly long-shaped rice.Studies have shown that the fermentation substrate may have an important influence on the growth and metabolism of Monascus.There are significant differences in nutrient composition and processing characteristics between long-shaped rice and glutinous rice.Therefore,the fermentation of red fermented rice using glutinous rice as substrates(GRFR)is a direction that deserves more research.However,to date,there have been few reports on GRFR at home and abroad.Therefore,this study intended to conduct a preliminary study on the preparation of GRFR by Monascus.The main results are as follows:(1)The optimal condition for activating the commercially available RFR samples by single factor and orthogonal experiment was as follows:peptone 0.1 g/L,pH 3,and temperature 30℃.(2)GRFR samples were prepared using nine activated RFR samples respectively,from which the best one was selected based on the ration of pigment and citrinin.A Monascus strain M1 was isolated and purified from the sample by the dilution-plate method,Then strain MI was identified as Monascus purpureus according its characteristics of morphology and 18 S rDNA sequence.(3)The single-factor and response surface method were used to optimize the culture condition of the preparation of GRFR by strain M1.The results showed that the optimized condition was as follows:initial pH 3.5,temperature 30℃,inoculum amount 13%.With optimized parameters,the content of pigment was increased by 0.84 times and citrinin content was reduced by 0.24 times.Compared with commercial available RPR sample 3#,the content of pigment and citrinin of the GRFR sample prepared under the condition were increased by 2.34 times and reduced by 0.19 times,respectively.(4)The stability of GRFR was studied and compared with RPR stability.The pigment of GRFR was more shelf-stable in dark conditions than that of RFR.GRFR was more suitable to be used in acidic food than RFR.However,the pigment of GRFR was more stable to common metal ions than that of RFR.更多还原