New Mathematical Model for Interpreting pH-Stat Digestion Profiles: Impact of Lipid Droplet Characteristics on in Vitro Digestibility
New Mathematical Model for Interpreting pH-Stat Digestion Profiles: Impact of Lipid Droplet Characteristics on in Vitro Digestibility
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DOI：
10.1021/jf101325m
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发表时间：
2010-07-14
影响因子：
6.1
通讯作者：
McClements, David Julian
中科院分区：
文献类型：
--
作者：
Li, Yan;McClements, David Julian
pH-stat方法通常用于表征脂质在模拟小肠条件下的体外消化率。该方法测量随时间从三酰基甘油释放的游离脂肪酸（FFA）的分数。已经开发了一种新的数学模型来表征由pH-stat方法生成的FFA与时间曲线，该模型可用于量化理化参数对脂质消化速率（k）和程度（phi（max））的影响。在该模型中，k是单位表面积每单位时间产生的FFA的量，而phi（max）是释放的可消化的FFA的最大分数。该模型用于量化脂滴特性（尺寸、浓度、组成和乳化剂类型）对乳化脂质消化的影响。脂质消化速率（k）随脂质含量降低（从2.5至0.5重量%）、液滴直径增加（从d = 200-15000 nm）和脂肪酸分子量降低（MCT与玉米油）而增加。玉米油的脂质消化程度（phi（max））也显著低于MCT。脂质消化的速率和程度并不强烈依赖于初始乳化剂类型：β-乳球蛋白，吐温20，卵磷脂，或溶血卵磷脂。这些结果被解释在消化过程中的脂滴表面的反应物，产物，催化剂和辅因子，例如，三酰甘油，乳化剂，FFA，脂肪酶，和胆汁盐的浓度的差异。该模型提供了一个有用的手段，量化的影响，具体参数的脂质消化使用的pH值统计方法。
The pH-stat method is commonly used to characterize the in vitro digestibility of lipids under simulated small intestine conditions. This method measures the fraction of free fatty acids (FFA) released from triacylglycerols over time. A new mathematical model has been developed to characterize the FFA versus time profiles generated by the pH-stat method, which can be used to quantify the influence of physicochemical parameters on the rate (k) and extent (phi(max)) of lipid digestion. In this model, k is the amount of FFA produced per unit time per unit surface area, whereas phi(max) is the maximum fraction of digestible FFAs released. This model is used to quantify the influence of lipid droplet characteristics (size, concentration, composition, and emulsifier type) on the digestion of emulsified lipids. The rate (k) of lipid digestion increased with decreasing lipid content (from 2.5 to 0.5 wt %), increasing droplet diameter (from d = 200-15000 nm), and decreasing fatty acid molecular weight (MCT versus corn oil). The extent (phi(max)) of lipid digestion was also considerably less for corn oil than for MCT. The rate and extent of lipid digestion did not depend strongly on initial emulsifier type: beta-lactoglobulin, Tween 20, lecithin, or lyso-lecithin. These results are interpreted in terms of differences in the concentrations of reactants, products, catalysts and cofactors at the lipid droplet surfaces during digestion, for example, triacylglycerols, emulsifiers, FFA, lipase, and bile salts. This model provides a useful means of quantifying the influence of specific parameters on lipid digestion using the pH-stat method.