Studies On Extraction Of Monascus Pigments And Preparation And Detection Of Yellow Components

Monascus pigments are natural pigments fermentated by Monascus spp. They are mixture of kinds of red or yellow single pigment, which is nutritional and bioactive. Application of Monascus pigments to replace Nitrates in meat is concerned particularly. There are only a little varieties of Monascus pigments products for sale and use in our market, and chemical composition of these productions is not clear. Because of the lack of information on quality specifications and unstability of quality, there are potential safety problems in production which used Monascus pigments as additive, and our Monascus pigments productions were restricted to enter the international market.Firstly, the extraction of Monascus pigments with ultrasonic auxiliary was studied with Monascus rice powder as materials, the effects of ultrasonic parameters on the extraction of red components and color tone we discussed. Monascine and Ankaflavine were separated and prepared by preparative HPLC. After purity analysis and structure identification, prepared Monascine and Ankaflavine were used as standard reference, the method to detect Monascine and Ankaflavine in Monascus pigments by High-performance liquid chromatography at one time was developed. Some kinds of Monascus pigments productions of different color value which were produced by several company in our contry were detected.The conclusions of this research were as follows:1. Ultrasonic extraction technology has the higher extraction rate, rapid speed, gentle condition and others advantages. Distinct mechanical vibration and cavitation of ultrasonic strengthen extraction and contribute the higher extraction rate. 60% ethanol was used as extracting solvent of Monascus pigments, the effects of such factors as different ultrasonic frequency and power on extraction of different pigments components was studied. The results showed that effects of ultrasonic factors on the extraction of red components was in the following order: frequency > ultrasonic time > power > liquid-solid ratio. The order of ultrasonic factors that influence the color tone was as follows:liquid-solid ratio > frequency > ultrasonic time > power. Considering both the extraction of red components and the color tone, the optimal extraction parameters were as follows: dual-frequency (45kHz/28kHz) alternately each 3min, power 120W, liquid-solid ratio1.5:1(L/g), ultrasonic time 30min。2. Established a simultaneous preparative method of Monascine and Ankaflavine with preparative HPLC. The object components were separated and prepared with a C18 preparative column and a mobile phase of Meth-H2O (80:20,v/v), the detection wavelength is 233mm, flow rate is 5.0mL/min.The products were detected by analysis HPLC and quantitated normalization method, the purity was 96.761%,99.234%. By UV-Vis absorption spectrum and mass-mass chromatographic analysis, molecular weight and structure were determined,and the molecular of Monascine and Ankaflavine were confirmed. It's a simple and effective preparative method, and the pure products of Monascine and Ankaflavine can be used as reference substance .3. An efficient method for detecting both Monascine and Ankaflavine in Monascus pigments by High-performance liquid chromatography at one time was developed. Monascine and Ankaflavine were extracted from red rice with n- hexane, and then analyzed with the reference pure pigments which were separated and purified by ourself, under the following conditions: SHIM-PACK HRC-ODS C18 column, methanol/water (80:20,v/v), 1.0mL/min, 394nm.The line arrange of the method was 10~500 mg/mL,the standard curve linearity relation was fine. The linear equation of Monascine was Y=0.00015x+0.82365 , with correlation coefficient 0.99988; The linear equation of Ankaflavine was Y=0.00031x-0.45,with correlation coefficient 0.99987. The relative standard deviation was smaller than 4%, with a good reproducibility and stability.4. Some kinds of Monascus rice power and Monascus pigments of different color value which were produced by several company in China were detected. The results show that content of Monascine and Ankaflavine can reflect composition of Monascus pigments productions to some extent.