Lipid digestion characteristics of a novel milk formula with large phospholipid-coated lipid droplets named Nuturis® (NF), four current standard formulas (CF1-4), and freshly expressed human milk (HM) were evaluated using a dynamic model of infant gastrointestinal digestion. Lipolysis degree (LD), triacylglycerol (TAG) lipolysis products including diacylglycerols, monoacylglycerols, and free fatty acids were determined. Structural changes including particle size distribution and microstructure of milk digesta were analyzed and compared. The LD of NF and HM showed no significant difference at 120 min of both gastric (G120) and intestinal digestion (I120). Compared to CFs, the lipolysis of NF was slower during gastric digestion while it caught up during the intestinal phase in which most of the lipolysis occurred. Milk lipolysis products are highly related to the milks initial TAG composition. Regarding structural changes during digestion, NF is closer to HM than CFs. In the gastric phase, NF and HM had constant particle size (∼5 μm) with mostly intact lipid droplet structures, while CFs started with smaller particles but flocculated to larger droplet aggregates (8–10 μm). Once the chyme had moved into the intestinal phase, the emulsion of all milks coalesced into large aggregates. This study showed that lipid digestion and structural changes of milk emulsions during digestion are highly dependent on the characteristics of the lipid droplets. In contrast to current standard formulas with small lipid droplets, milk formula with large phospholipid-coated lipid droplets and HM showed similar LD at the end of gastrointestinal digestion and droplet aggregation behaviors during digestion.

中文翻译：

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大磷脂包覆脂滴配方奶粉体外消化过程中的结构变化和三酰甘油脂解产物：与母乳和市售标准配方奶粉的比较

使用婴儿胃肠道消化动态模型评估了名为 Nuturis® (NF) 的具有大磷脂涂层脂滴的新型配方奶粉、四种现行标准配方奶粉 (CF1-4) 和新鲜母乳 (HM) 的脂质消化特性。测定脂肪分解度（LD）、三酰甘油（TAG）脂肪分解产物，包括二酰甘油、单酰甘油和游离脂肪酸。分析和比较了奶糜的粒度分布和微观结构等结构变化。NF和HM的LD在胃消化(G120)和肠消化(I120)120分钟时没有显着差异。与 CF 相比，NF 的脂肪分解在胃消化过程中较慢，但在发生大部分脂肪分解的肠道阶段则赶上。牛奶脂肪分解产物与牛奶初始 TAG 成分高度相关。关于消化过程中的结构变化，NF 比 CF 更接近 HM。在胃相中，NF和HM具有恒定的粒径（~5μm），且脂滴结构基本完整，而CF最初具有较小的颗粒，但絮凝成较大的液滴聚集体（8-10μm）。一旦食糜进入肠相，所有乳汁的乳液就会聚结成大的聚集体。这项研究表明，消化过程中乳状液的脂质消化和结构变化高度依赖于脂滴的特性。与目前具有小脂滴的标准配方奶粉相比，具有大磷脂涂层脂滴和HM的配方奶粉在胃肠道消化结束时表现出相似的LD，并且在消化过程中表现出液滴聚集行为。