Abstract：
Ageing leads to changes in the functionality of the digestive tract but the effect of age on digestion and absorption of nutrients remains unclear. The objective of this study was to investigate in vitro the digestion of two high-protein dairy products similar to cream cheese (24 % w/w proteins, 20 % w/w lipids) with opposite casein to whey protein ratios, 80:20 (WP-20), and 20:80 (WP-80). The new static digestion model adapted to the general older adult population (≥65 y.) proposed by INFOGEST was used, as well as the standard version of the protocol. Kinetics of proteolysis and lipolysis were compared between both models for each product, in the gastric and intestinal phases of digestion. In both cream cheeses, the degree of protein hydrolysis (DH-P) was significantly lower for older adults than for young adults at the end of the gastric phase (-19 % for WP-20, and -44 % for WP-80), and at the end of the intestinal phase (-16 % for WP-20, and -20 % for WP-80). The degree of lipid hydrolysis (DH-L) was also significantly lower for older adults than for young adults at the end of the digestion for WP-20 (-30 %), but interestingly it was not the case for WP-80 (similar DH-L were measured). Free fatty acids were also released faster from WP-80 than from WP-20 in both digestion conditions: after 5 min of intestinal digestion DH-L was already ≈32 % for WP-80 against 14 % for WP-20. This was attributed to the opposite casein to whey protein ratios, leading to the formation of different gel structures resulting in different patterns of deconstruction in the gastrointestinal tract. This study highlights the fact that it is essential to carefully consider the composition, structure, and digestibility of foods to develop products adapted to the specific needs of the older adult population.
摘要：
衰老导致消化道功能的变化，但年龄对营养物质消化和吸收的影响尚不清楚。本研究的目的是研究两种类似于奶油干酪的高蛋白乳制品的体外消化（24％w/w蛋白质，20％w/w脂质），酪蛋白与乳清蛋白的比例相反，80:20(WP-20),和20:80（WP-80）。使用了INFOGEST提出的适用于一般老年人群(≥65岁)的新静态消化模型，以及协议的标准版本。在每种产品的两种模型之间比较了蛋白水解和脂解的动力学，在消化的胃和肠阶段。在这两种奶油奶酪中，在胃期结束时，老年人的蛋白质水解程度（DH-P）显着低于年轻人（WP-20为-19％，WP-80为-44％），并且在肠期结束时（WP-20为-16％，WP-80为-20％）。在WP-20消化结束时，老年人的脂质水解程度（DH-L）也显着低于年轻人（-30％），但有趣的是，WP-80的情况并非如此（测量了类似的DH-L）。在两种消化条件下，WP-80释放的游离脂肪酸也比WP-20释放的更快：肠道消化5分钟后，WP-80的DH-L已经≈32％，而WP-20的DH-L为14％。这归因于酪蛋白与乳清蛋白的比例相反，导致形成不同的凝胶结构，从而导致胃肠道中不同的解构模式。这项研究强调了一个事实，即仔细考虑成分是至关重要的，结构,和食物的消化率，以开发适合老年人群特定需求的产品。
