富含γ-氨基丁酸酸奶的制备及质构特性研究

Production and Texture Analysis of High γ-aminobutyric Acid-enriched Fermented Milk

本试验对单菌发酵、混菌发酵和添加不同底物浓度的L-谷氨酸钠对酸奶感官特性和质构特性的影响作用进行了研究,为开发富含γ-氨基丁酸的新型功能发酵乳制品提供依据。试验结果表明,当底物L-谷氨酸钠的添加浓度为75mmol/L,辅酶浓度为20μmol/L,植物乳杆菌NDC75017、德氏乳杆菌保加利亚亚种、嗜热链球菌3株菌混合(L.P∶L.b∶S.t=0.5∶0.5∶1.5)按2%的比例添加量,在43℃条件下发酵酸奶时,酸奶的感官特性和质构特性最好。此时酸奶的粘度为1 466.5±1.0p·s、保水力为71.7±3.2%、硬度为77.3±1.7g、凝聚性为48.1±1.2g、粘性指数为146.8±0.9p·s;用高效液相色谱法检测酸奶中GABA的含量高达46mg/100g。综合酸奶口感、质构特性及GABA含量等指标,最终选择添加底物L-谷氨酸钠的浓度为75mmol/L,植物乳杆菌NDC75017、德氏乳杆菌保加利亚亚种、嗜热链球菌3株菌作为酸奶发酵的混合发酵剂。

The aim of this study was to evaluate the texture, nutrition and sensory properties of yogurt which was fermentated by addition of different concentration of L-sodium glutamate （L-MSG） mixed-strain starter and L. plantarum NDC 75017 starter, in order to afford reference for producing fermented milk containing GABA. The results showed that when yogurt was fermented by 75mmol/L L-sodium glutamate （L-MSG）, 20μmol/L pyridoxal 5＇-phosphate （PLP）, 2% inoculation concentration, the ratios of Lb. plantarum, Lb. delbrueckii subsp, bulgaricus and Streptococcus thermophilus at O. 5：0. 5：1.5 and 43℃ incubation, the best texture and sensory properties could be obtained. The viscosity, water holding capacity, firmness, coherence and viscosity index were 1 466. 5 ± 1.0p·s, 71.7 ± 3.2% , 77. 3 ± 1.7g, 48. 1 ± 1.2g, 146. 8 ±0. 9p·s, respectively. The maximum GABA concentration in fermented milk was 46 mg/100g by HPLC. These results indicated that the best oppropriate concentration addition of L-sodium glutamate was 75mmol/L, Lb. plantarum NDC 75017, Lb. delbrueckii subsp, bulgaricus and Streptococcus thermophilus were selected as mixed-strain starter.