响应面试验优化青稞麸皮薏仁红曲霉发酵工艺

为优化青稞麸皮薏仁红曲霉发酵工艺,提高发酵产物中降脂活性物质的含量,以青稞麸皮和薏仁(质量比1∶1)为发酵底物,以紫色红曲霉菌(CICC.5046)为发酵菌种,以Monacolin K产量为评价指标,采用固态发酵工艺技术,在单因素试验的基础上,利用响应面优化设计,探究红曲霉固态发酵的最佳工艺条件,研究主要生理活性物质在发酵过程中的变化。结果表明,通过单因素试验筛选出发酵温度、接种量和装料量为影响Monacolin K产量的主要因素,响应面优化得出最佳工艺条件为发酵温度29℃、接种量8%、装料量40 g(250 m L烧杯为发酵容器)、初始含水量60%、发酵时间12 d,此时Monacolin K产量为110.556 mg/kg。在发酵过程中,可溶性多糖、总黄酮和β-葡聚糖含量减少,Monacolin K、色素和可溶性多酚含量增加,总体上降脂活性物质增加更多。

Optimization of Fermentation Process of A Mixture of Highland Barley Bran and Coix Seed by Monascus purpureus Using Response Surface Methodology

This study aimed to optimize the solid-state fermentation process of a mixture of highland barley bran and coix seed (1:1, m/m) by Monascus purpureus (CICC.5046) for improved production of Monacolin K as a hypolipidemic agent by the combined use of one-factor-at-a-time method and response surface methodology. The changes in the main substances with physiological activities were investigated during the fermentation process. The one-factor-at-a-time experiments selected fermentation temperature, inoculum size and filling quantity as the main factors that affect the production of Monacolin K, and these factors were optimized by response surface methodology to be 29 ℃, 8% and 40 g of substrates with 60% water added contained in a 250 mL beaker, respectively. After fermentation for 12 d under these conditions, the Monacolin K yield was 110.556 mg/kg. During the fermentation, Monacolin K, pigments and soluble polyphenols were significantly increased whereas soluble polysaccharides, total flavonoids and β-glucan were decreased significantly. In general, the substance with hypolipidemic activity was increased more significantly.