Department of Food Science, University of Massachusetts Amherst, Amherst, MA 01003, USA.
Food Funct. 2020 Nov 18;11(11):9936-9946. doi: 10.1039/d0fo01505a.
The oil droplets in commercial emulsified foods have dimensions that vary widely, from hundreds of nanometers to tens of micrometers. Previously, the size of the droplets in oil-in-water emulsions has been shown to impact their gastrointestinal behavior, which may influence their physiological effects. In this study, we analyzed the impact of oil droplet diameter (0.16, 1.1 and 8.2 μm) on lipid digestion and nutraceutical bioaccessibility using a widely used standardized gastrointestinal tract model: the INFOGEST method. The emulsions used consisted of corn oil droplets stabilized using a food-grade non-ionic surfactant (Tween 20), and the droplet size was controlled by preparing them with a microfluidizer (small), sonicator (medium), or high-shear blender (large). The surfactant-coated oil droplets were relatively resistant to size changes in the mouth and stomach, due to the strong surface activity and steric stabilization mechanism of the non-ionic surfactant used. As expected, the kinetics of lipid digestion were enhanced for smaller droplets because of their greater specific surface area. The degree of lipid digestion fell from 117% to 78% (p < 0.001) as the initial droplet diameter was raised from 0.16 to 8.2 μm. In addition, there was a reduction in β-carotene bioaccessibility from 83 to 15% (p < 0.001) with increasing droplet diameter. This result was ascribed to several effects: (i) some carotenoids were trapped inside the undigested oil phase; (ii) fewer mixed micelles were produced to internalize the carotenoids; and, (iii) a fraction of the carotenoids crystallized and sedimented. Our results underline the critical importance of considering droplet size when developing emulsified foods loaded with carotenoids. The results obtained by the INFOGEST method are consistent with those found using other in vitro methods in earlier studies.
商业乳化食品中的油滴尺寸差异很大，从数百纳米到数十微米不等。以前已经表明，水包油乳液中的液滴大小会影响它们的胃肠道行为，从而可能影响它们的生理效应。在这项研究中，我们使用广泛使用的标准化胃肠道模型：INFOGEST 方法，分析了油滴直径（0.16、1.1 和 8.2 μm）对脂质消化和营养生物利用度的影响。所使用的乳液由玉米油滴组成，使用食品级非离子表面活性剂（吐温 20）稳定，通过使用微流体处理器（小）、超声处理器（中）或高剪切搅拌器（大）制备乳液来控制液滴尺寸。由于使用的非离子表面活性剂具有很强的表面活性和空间稳定机制，因此包被油滴在口腔和胃中相对不易发生尺寸变化。由于较小的油滴具有更大的比表面积，因此脂质消化动力学得到增强，这是可以预期的。随着初始油滴直径从 0.16 增加到 8.2 μm，脂质消化的程度从 117%下降到 78%（p <0.001）。此外，随着油滴直径的增加，β-胡萝卜素的生物利用度从 83%下降到 15%（p <0.001）。这一结果归因于以下几个因素：（i）一些类胡萝卜素被困在未消化的油相中；（ii）生成的混合胶束较少，无法内化类胡萝卜素；（iii）一部分类胡萝卜素结晶并沉淀。我们的结果强调了在开发含有类胡萝卜素的乳化食品时考虑液滴尺寸的重要性。INFOGEST 方法获得的结果与早期其他体外方法的结果一致。
