萨能山羊乳中低聚糖的靶向绝对定量研究

Targeted Absolute Quantification of Oligosaccharides in Saanen Goat Milk

摘要:

为探究萨能山羊乳特定低聚糖组成、含量及构成比例及其与荷斯坦牛乳的差异,采用超高效液相色谱-亲水作用色谱-三重四极杆质谱联用(UPLC-HILIC-QqQ MS/MS)技术,对萨能山羊乳和荷斯坦牛乳中23种目标低聚糖开展靶向绝对定量测定。该检测方法定量限低至10.0ng/mL,回收率为83.98%~111.44%,精密度良好,可满足乳源低聚糖精准定量检测的要求。研究发现,萨能山羊乳和荷斯坦牛乳中均检测出2′-岩藻糖基乳糖(2′-FL)、3′-岩藻糖基乳糖(3′-FL)、乳糖-N-新四糖(LNnT)、6′-半乳糖基乳糖(6′-GL)、4′-半乳糖基乳糖(4′-GL)、乳糖-N-己糖(LNH)、3′-唾液酸乳糖(3′-SL)和6′-唾液酸乳糖(6′-SL)这8种低聚糖。萨能山羊乳中8种低聚糖总质量浓度为(109.28±10.00) mg/L,显著高于荷斯坦牛乳(44.87±2.87) mg/L,为其2.44倍(P<0.05)。萨能山羊乳中中性与酸性低聚糖占比分别为(42.96±2.50)%、(57.04±1.57)%,荷斯坦牛乳中中性和酸性低聚糖占比分别为(32.44±4.37)%、(67.56±5.68)%。此外,萨能山羊乳中2′-FL、4′-GL、6′-GL、6′-SL、3′-SL 的质量浓度分别为荷斯坦牛乳的2.03、6.20、2.53、2.05、2.07倍(P<0.05)。研究结果表明,与荷斯坦牛乳相比,萨能山羊乳不仅低聚糖总量更高,且其中性低聚糖占比更高,展现出作为婴幼儿配方乳粉及其他功能性食品优质乳源的应用潜力。

Abstract:

To investigate the specific oligosaccharide composition, content, and proportional distribution in Saanen goat milk and to perform a comparative analysis with Holstein bovine milk, targeted absolute quantification of 23 target oligosaccharides was performed in Saanen goat milk and Holstein bovine milk using ultra-performance liquid chromatography-hydrophilic interaction chromatography-triple quadrupole mass spectrometry (UPLC-HILIC-QqQ MS). The method exhibited a limit of quantification as low as 10.0ng/mL, recoveries ranging from 83.98% to 111.44%, and satisfactory precision, meeting the requirements for accurate quantitative detection of milk oligosaccharides. Eight oligosaccharides were detected in both Saanen goat milk and Holstein bovine milk, including 2′-fucosyllactose (2′-FL), 3′-fucosyllactose (3′-FL), lacto-N-neotetraose (LNnT), 6′-galactosyllactose (6′-GL), 4′-galactosyllactose (4′-GL), lacto-N-hexaose (LNH), 3′-sialyllactose (3′-SL), and 6′-sialyllactose (6′-SL). The total content of these eight oligosaccharides in Saanen goat milk was (109.28±10.00)mg/L, which was significantly higher than that in Holstein bovine milk (44.87±2.87)mg/L, 2.44 times that of the latter value(P<0.05). The relative proportions of neutral and acidic oligosaccharides were (42.96±2.50)% and (57.04±1.57)% in Saanen goat milk, and (32.44±4.37)% and (67.56±5.68)% in Holstein bovine milk, respectively. Furthermore, the mass concentrations of 2′-FL, 4′-GL, 6′-GL, 6′-SL and 3′-SL in Saanen goat milk were 2.03,6.20,2.53,2.05 and 2.07 times those in Holstein bovine milk, respectively(P<0.05). The findings demonstrated that compared with Holstein bovine milk, Saanen goat milk not only had a higher total oligosaccharide content, but also a higher proportion of neutral oligosaccharides, highlighting its significant potential as a high-quality dairy source for infant formula and other functional food products.