米根霉发酵米糠工艺优化及其益生活性研究

为探究米根霉发酵米糠的最佳条件,本研究采用过热蒸汽对米糠作稳定化处理,以米根霉为菌种发酵稳定化米糠,以米糠可溶性膳食纤维(SDF)得率为指标,并对此条件下发酵米糠的体外益生活性进行评价。结果表明,过热蒸汽稳定米糠最佳条件为160℃、2 min,此条件下脂肪酶失活率为88.01%;甜香型米根霉发酵米糠的最佳条件为:以甜香型米根霉为发酵菌种,料液比1∶2.25、接种量0.7%、发酵温度35℃、发酵时间24 h,此条件下SDF得率为5.83%,比未发酵米糠提高了近一半;与未发酵米糠相比,经甜香型米根霉发酵后的米糠,可有效促进双歧杆菌(对数值6.85)和乳酸杆菌(对数值5.23)的增殖;总短链脂肪酸含量提高37.30%,肠道益生活性显著增强(P<0.05)。本研究结果为改善米糠功能特性提供了依据,对今后米糠在发酵方面的应用具有一定的指导意义。

Optimization of the Fermentation Process of Rice Bran With Rhizopus oryzae and Its Probiotic Activities

The explore the optimun condition for rice bran fermented with Rhizopus oryzae, rice bran was first stabilized by superheated steam, and then fermented with Rhizopus oryzae. The yield of soluble dietary fiber (SDF) was used as an indicator to explore the optimal conditions of Rhizopus oryzae fermenting rice bran. The optimum fermentation conditions for higher yield of SDF were obtained and the probiotic activities of rice bran affected by fermentation were determined. The results showed that the optimal superheated steam condition was at 160°C for 2 min, in which the rate of inactivation of lipase increased to 88.01%; Under this condition, the maximum yield of SDF can reach 5.83% after fermentation by sweet-flavored Rhizopus oryzae at 35°C for 24 h and inoculation quantity with a solid-to-solvent ratio of 1:2.25, which was improved by 48.72% compared with the unfermented rice bran. The rice bran fermented by sweet-flavored Rhizopus oryzae, which stimulated the proliferation of bifidobacteria (6.85 log copies·mL^-1) and lactobacillus (5.23 log copies·mL^-1) and the content of total short-chain fatty acids (SCFAs) increased by 37.30%, with higher probiotic activities in comparison with the unfermented rice bran(P<0.05). The results of this study can be used to improve the functional properties of rice bran using fermentation.