PDF(Pubmed)
Abstract：
It is poorly understood how the physical state of emulsified triacylglycerol (TAG) alters colloidal behavior in the gastrointestinal tract to modulate lipid digestion and absorption. We, therefore, aimed to investigate the individual and combined effects on fatty acid (FA) bioaccessibility using the dynamic TIM-1 in vitro digestion model and integrate the results with those from a human clinical study. Four 20% oil-in-water emulsions with overlapping particle size distributions contained either partially crystalline solid (palm stearin) or liquid (palm olein) lipid droplets at 37°C and either the colloidally acid-stable Tween 80 (2.2%) or acid-unstable Span 60 (2.5%) emulsifier. Experimental meals were fed to the TIM-1, and jejunal and ileal dialysates were analyzed over 6 h to measure free FA concentration. Cumulative FA bioaccessibility was significantly higher for the liquid stable emulsion compared to all others (p < 0.05), which did not differ (p > 0.05). Emulsified TAG physical state was associated with differences in overall bioaccessibility (higher for liquid state TAG) in the colloidally stable emulsions, but this difference was blunted in droplets susceptible to acidic flocculation. In contrast, human postprandial TAG concentrations did not differ significantly between the emulsions. The discrepancy may relate to differences in in vivo gastric emptying (GE) as evidenced by ultrasonography. When the in vivo differences in GE were accounted for in follow-up TIM-1 experiments, the findings aligned more closely. Cumulative FA bioaccessibility for the liquid stable emulsion no longer differed significantly from the other emulsions, and SU\'s bioaccessibility was the lowest, consistent with the in vivo observations. This work highlights the potential for TAG physical state and colloidal stability to interactively alter behavior in the gastrointestinal tract with implications for FA absorption, and the importance of establishing and improving in vitro-in vivo correlations in food-nutrition research.
摘要：
对乳化三酰甘油（TAG）的物理状态如何改变胃肠道中的胶体行为以调节脂质消化和吸收的了解甚少。我们,因此,旨在使用动态TIM-1体外消化模型研究对脂肪酸（FA）生物可及性的个体和组合影响，并将结果与人类临床研究的结果相结合。四种具有重叠粒度分布的20％水包油乳液在37°C下包含部分结晶的固体（棕榈硬脂精）或液体（棕榈油精）脂滴，以及胶体酸稳定的吐温80（2.2％）或酸不稳定的Span60（2.5％）乳化剂。将实验餐喂入TIM-1，并在6小时内分析空肠和回肠透析液以测量游离FA浓度。与所有其他相比，液体稳定乳液的累积FA生物可及性显着较高（p<0.05），没有差异(p>0.05)。乳化的TAG物理状态与胶体稳定的乳液中整体生物可及性的差异有关（对于液态TAG更高），但是这种差异在易于酸性絮凝的液滴中被钝化。相比之下,人类餐后TAG浓度在两种乳剂之间没有显著差异.如超声检查所证明的，差异可能与体内胃排空（GE）的差异有关。当在后续的TIM-1实验中考虑到GE的体内差异时，调查结果更加一致。液体稳定乳液的累积FA生物可及性不再与其他乳液显著不同，SU的生物可获得性最低，与体内观察结果一致。这项工作强调了TAG物理状态和胶体稳定性在胃肠道中相互作用地改变行为的潜力，对FA吸收有影响。以及在食品营养研究中建立和改善体外-体内相关性的重要性。
