FrieslandCampina, Amersfoort, the Netherlands.
Food Quality & Design Group, Wageningen University & Research Centre, Wageningen, the Netherlands.
Crit Rev Food Sci Nutr. 2020;60(14):2422-2445. doi: 10.1080/10408398.2019.1646703. Epub 2019 Aug 22.
Dairy is one of the main sources for high quality protein in the human diet. Processing may, however, cause denaturation, aggregation, and chemical modifications of its amino acids, which may impact protein quality. This systematic review covers the effect of milk protein modifications as a result of heating, on protein digestion and its physiological impact. A total of 5363 records were retrieved through the Scopus database of which a total of 102 were included. Although the degree of modification highly depends on the exact processing conditions, heating of milk proteins can modify several amino acids. and animal studies demonstrate that glycation decreases protein digestibility, and hinders amino acid availability, especially for lysine. Other chemical modifications, including oxidation, racemization, dephosphorylation and cross-linking, are less well studied, but may also impact protein digestion, which may result in decreased amino acid bioavailability and functionality. On the other hand, protein denaturation does not affect overall digestibility, but can facilitate gastric hydrolysis, especially of β-lactoglobulin. Protein denaturation can also alter gastric emptying of the protein, consequently affecting digestive kinetics that can eventually result in different post-prandial plasma amino acid appearance. Apart from processing, the kinetics of protein digestion depend on the matrix in which the protein is heated. Altogether, protein modifications may be considered indicative for processing severity. Controlling dairy processing conditions can thus be a powerful way to preserve protein quality or to steer gastrointestinal digestion kinetics and subsequent release of amino acids. Related physiological consequences mainly point towards amino acid bioavailability and immunological consequences.
乳制品是人类饮食中高质量蛋白质的主要来源之一。然而，加工过程可能导致其氨基酸发生变性、聚集和化学修饰，从而影响蛋白质质量。本系统综述涵盖了加热导致的牛奶蛋白修饰对蛋白质消化及其生理影响的作用。通过 Scopus 数据库共检索到 5363 条记录，其中共有 102 条被纳入。尽管修饰程度高度取决于确切的加工条件，但加热牛奶蛋白可以修饰几种氨基酸。动物研究表明，糖化会降低蛋白质的消化率，并阻碍氨基酸的可用性，尤其是赖氨酸。其他化学修饰，包括氧化、外消旋化、去磷酸化和交联，研究较少，但也可能影响蛋白质消化，从而导致氨基酸生物利用度和功能降低。另一方面，蛋白质变性不会影响整体消化率，但可以促进胃水解，特别是β-乳球蛋白。蛋白质变性还可以改变蛋白质的胃排空，从而影响消化动力学，最终导致不同的餐后血浆氨基酸出现。除了加工之外，蛋白质消化的动力学还取决于蛋白质加热的基质。总的来说，蛋白质修饰可以被认为是加工严重程度的指标。因此，控制乳制品加工条件可以成为一种有力的方法来保持蛋白质质量，或控制胃肠道消化动力学和随后氨基酸的释放。相关的生理后果主要指向氨基酸的生物利用度和免疫后果。
