薏苡仁多菌发酵液的菌种优选及其抑制黑色素生成的作用研究

以薏苡仁作为发酵基质，确定利于提高发酵液体外活性的较优乳酸菌种，并分析优势乳酸菌种薏苡仁发酵液对斑马鱼胚体黑色素生成的抑制作用。通过比较分析乳酸乳球菌（Lactococcus lactis）、嗜热链球菌（Streptococcus thermophilus）和保加利亚乳杆菌（Lactobacillus bulgaricus）3种单一乳酸菌和三者复合乳酸菌的薏苡仁发酵液的还原糖、总酚、游离氨基酸、蛋白、总酸和乳酸含量等理化指标及体外羟自由基清除能力和酪氨酸酶活抑制率确定较优发酵菌种，采用高通量测序测定发酵过程中微生物菌群结构；利用斑马鱼模型研究发酵液对黑色素生成的抑制作用。研究结果表明,采用乳酸乳球菌、嗜热链球菌和保加利亚乳杆菌3种乳酸菌复合发酵比单一乳酸菌发酵更具优势。使用以上菌种复合发酵薏苡仁过程中，乳酸乳球菌和嗜热链球菌为发酵前期优势菌群，发酵中后期则以保加利亚乳杆菌为优势菌群。经复合乳酸菌发酵后，薏苡仁发酵液的羟自由基清除率和酪氨酸酶活抑制率分别提高了20.82%和87.26%；斑马鱼模型实验结果表明，薏苡仁发酵液可以显著减少斑马鱼体表黑色素分布，当使用含量为2.0%时，对黑色素生成抑制率达到59.45%。研究结果为利用薏苡仁多菌发酵液开发为具美白肌肤性能的功能性新原料提供了科学数据支撑，并希望进一步推进薏苡产业的升级。

Study on Strain Optimization of Coix Seed Multi Lactobacillus Fermentation Broth and its Inhibition on Melanin Production

With coix seed as the fermentation substrate， the better lactic acid bacteria that can improve the activity in vitro of the fermentation liquid were screened， and the inhibitory effect of the dominant lactic acid bacteria coix seed fermentation broth on the melanin production of fish embryos was explored and analyzed. By comparing and analyzing the chemical indexes such as reducing sugar， total phenol， free amino acid， protein， total acid， lactic acid content， and hydroxyl radical scavenging ability and tyrosinase activity inhibition rate of coix seed fermentation broth of three kinds of single lactic acid bacteria Lactococcus lactis， Streptococcus thermophilus and Lactobacillus bulgaricus and three kinds of compound lactic acid bacteria of fermented coix seed with single or mixd Lactobacillus， the better fermentation strains were determined. High throughput sequencing was used to explore the microbial community structure and succession. The inhibitory effect of fermentation broth on melanin production was studied by zebrafish model. It was screened and determined that the compound fermentation of Lactococcus lactis， Streptococcus thermophilus and Lactobacillus bulgaricus had more advantages than that of single Lactobacillus. Lactococcus lactis and Streptococcusthermophilus were the dominant bacteria in the early stage of fermentation， and Lactobacillus bulgaricus was the dominant bacteria in the middle and late stage of fermentation. After fermentation with compound Lactobacillus， the hydroxyl radical scavenging rate and tyrosinase activity inhibition rate of fermented coix seed increased by 20.82% and 87.26%， respectively. The results of zebrafish model experiment showed that fermented coix seed could significantly reduce the distribution of melanin on zebrafish surface and when the content was 2%， the inhibition rate of melanin production could reach 59.45%. The research results can provide scientific data for the development of coix seed multi Lactobacillus fermentation broth as a new functional raw material with skin whitening properties， and promote the progress of coix seed industry.