人乳中乳糖和总碳水化合物检测时寡糖的影响及方法比较。
The Influence of Oligosaccharides when Measuring Lactose and Total Carbohydrates in Human Milk and Comparison of Methods.
机构信息
Department of Nutrition, University of North Carolina Greensboro, Greensboro, NC, United States.
Department of Pediatrics, University of California, San Diego, La Jolla, CA, United States; Mother-Milk-Infant Center of Research Excellence, University of California, San Diego, La Jolla, CA, United States.
出版信息
J Nutr. 2023 Jul;153(7):2117-2124. doi: 10.1016/j.tjnut.2023.05.004. Epub 2023 May 5.
BACKGROUND
Understanding how human milk impacts growth requires valid analytical methods for quantifying the composition. Lactose, the most abundant constituent in human milk and a predominant source of energy, is often assessed using methods borrowed from the bovine dairy industry. However, the carbohydrate matrices of bovine and human milk are quite different, especially as they relate to human milk oligosaccharides (HMOs), each with a terminal lactose unit that may influence analytical methods.
OBJECTIVES
Our goals were to determine the extent to which HMOs influence common analytical methods for measuring carbohydrates in human milk and to compare common methods for measuring lactose.
METHODS
Two sets of experiments were performed. In the first set, native and HMO-spiked human milk samples (n = 16 each) were assessed and compared using 4 methods: AOAC 2006.06 (based on the Megazyme enzymatic assay), BioVision enzymatic assay, ultraperformance LC with MS, and infrared analysis. In the second set, human milk samples (n = 20) were assessed using 2 methods approved for measuring lactose in bovine milk: AOAC 984.22 that uses high-performance LC and refractive index detection and AOAC 2006.06 prepared using both volume and weighted dilutions.
RESULTS
Native and HMO-spiked samples were not significantly different in lactose using AOAC 2006.06 and ultraperformance LC with MS but were significantly different using BioVision (mean difference = 0.2 g/dL; 95% CI: 0.1, 0.4; P = 0.005). Total carbohydrate measurements assessed using infrared were also higher after HMO spiking (mean difference = 0.4 g/dL; 95% CI: 0.3, 0.6; P < 0.001). Only AOAC methods 984.22 and 2006.06 for measuring lactose were very highly correlated (r > 0.90, P < 0.001).
CONCLUSIONS
AOAC methods 984.22 and 2006.06 are comparable for measuring lactose in human milk and are not influenced by HMOs. HMOs influence other enzymatic methods as well as infrared analysis, which leads to an overestimate of energy values. J Nutr 2023;x:xx.
背景
了解人乳如何影响生长需要有效的分析方法来定量其成分。乳糖是人乳中最丰富的成分，也是主要的能量来源，通常使用从牛乳制品行业借用的方法进行评估。然而，牛乳制品和人乳的碳水化合物基质有很大的不同，尤其是与人乳低聚糖（HMOs）有关，每个 HMOs 都有一个末端乳糖单元，可能会影响分析方法。
目的
我们的目标是确定 HMOs 对人乳中碳水化合物常用分析方法的影响程度，并比较测量乳糖的常用方法。
方法
进行了两组实验。在第一组实验中，使用 4 种方法评估并比较了天然和 HMO 加标人乳样品（每组 16 个样本）：AOAC 2006.06（基于 Megazyme 酶法）、BioVision 酶法、超高效液相色谱-质谱联用（UPLC-MS）和红外分析。在第二组实验中，使用 2 种方法评估了 20 个人乳样本，这 2 种方法均被批准用于测量牛乳制品中的乳糖：使用高效液相色谱-折射指数检测的 AOAC 984.22 法和使用体积和重量稀释法的 AOAC 2006.06 法。
结果
使用 AOAC 2006.06 和 UPLC-MS 时，天然和 HMO 加标样品的乳糖含量无显著差异，但使用 BioVision 时则有显著差异（平均差异=0.2 g/dL；95%CI：0.1，0.4；P=0.005）。HMO 加标后，使用红外法评估的总碳水化合物含量也更高（平均差异=0.4 g/dL；95%CI：0.3，0.6；P<0.001）。仅用于测量乳糖的 AOAC 方法 984.22 和 2006.06 高度相关（r>0.90，P<0.001）。
结论
AOAC 方法 984.22 和 2006.06 可用于测量人乳中的乳糖，且不受 HMOs 的影响。HMOs 还会影响其他酶法以及红外分析，导致能量值的高估。
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