酱油渣中副干酪乳杆菌的分离鉴定及抗氧化特性研究

利用传统微生物培养法从酱油渣中分离得到10株副干酪乳杆菌,其中8株为Lactobacillus paracasei subsp.paracasei,称为HT31、HT51、HT90、HT111、HT125、HT159、HT253和HT256;2株为Lactobacillus paracasei subsp.tolerans,称为HT155和HT158。通过形态学观察、生理生化特征试验及16SrRNA基因序列分析方法对其进行鉴定,并研究其对人工胃肠液耐受能力、疏水能力及抗氧化能力。模拟胃肠液耐受试验结果表明:耐受胃液3h后,菌株HT31、HT111、HT155菌株存活率分别为(86.33±1.24)%,(31.37±0.50)%,(57.43±1.56)%;在模拟肠液中培养8h后,菌株HT31、HT111、HT155菌株存活率分别为(60.22±0.16)%,(62.18±0.70)%,(52.84±0.00)%。疏水性试验结果表明:菌株HT31、HT111、HT155疏水率分别为(18.52±0.76)%,(26.51±0.66)%,(25.41±0.58)%。抗氧化试验结果表明:菌株HT31细胞悬浮液DPPH清除率为(26.25±0.01)%,其无细胞提取物DPPH清除率为(16.03±0.03)%;菌株HT31细胞悬浮液羟基自由基清除率为(42.88±0.21)%,其无细胞提取物羟基自由基清除率为(27.74±0.01)%,表明菌株HT31具有较好的模拟胃肠液耐受能力、疏水能力及抗氧化能力。

Isolation, identification and antioxidant properties of Lactobacillus paracasei from soy sauce residue

Lactobacillus paracasei were isolated from soy sauce residue by traditional microbial culture method, and identified by morphological observation, physiological and biochemical characteristics test, and 16S rRNA gene sequence analysis. Their tolerance to artificial gastrointestinal juice, hydrophobic capacity, and antioxidant capacity were also studied. Ten strains of Lactobacillus paracasei were isolated from soy sauce residue, of which eight were L. paracasei subsp. paracasei, named HT31, HT51, HT90, HT111, HT125, HT159, HT253, and HT256; two of them were L. paracasei subsp. tolerans, named HT155 and HT158. The results of simulated gastrointestinal fluid tolerance test showed that the viability of strains HT31, HT111 and HT155 reached (86.33 ±1.24)%, (31.37±0.50)%, (57.43±1.56)%. After 8 hours of culture in simulated gastrointestinal fluid, the viability of strains HT31, HT111 and HT155 reached (60.22±0.16)%, (62.18±0.70)%, and (52.84±0.56)%, respectively. The results of hydrophobicity test showed that the hydrophobicity of strains HT31, HT111 and HT155 reached (18.52±0.76)%, (26.51±0.66)%, and (25.41±0.58)%. The results of antioxidant test showed that the DPPH scavenging rate of cell suspension of strain HT31 was (26.25±0.01)%, and its DPPH scavenging rate of cell-free extract was (16.03±0.03)%. The hydroxyl radical scavenging rate of cell-free extract of strain HT31 was (42.88±0.21)%, and its hydroxyl radical scavenging rate of cell-free extract was (27.74±0.01)%. The result showed that strain HT31 had good capacity of tolerance to simulated gastrointestinal juice, hydrophobic and antioxidant.