常见高蛋白运动补充剂中蛋白质体外水解评价

In Vitro Evaluation of Protein Hydrolysis of High-protein Sport Supplements

摘要:

运动营养除了强调多元化营养素的补充，也逐渐重视营养补充的时序性。蛋白补充剂是运动营养的重要来源，目前市面上相关产品多为蛋白粉，也有部分液体饮品，这些产品中蛋白质的消化水解情况尚未见报道。该文从蛋白质类型和剂型角度，挑选五种高蛋白运动补充剂及三种高蛋白食品，采用体外消化模型评价其胃肠道消化行为和蛋白质水解度。结果表明：蛋白粉产品冲泡后粒径较液体饮品大，且易分层。所有产品都具有pH值敏感性，但对胃部pH值降低的缓冲能力存在差异，酪蛋白含量较高的液体饮品pH值降低较慢。所有产品在胃部易形成聚集体，液体饮品黏弹性快速增加进而下降或趋于平缓，蛋白粉产品流变性相对稳定。在胃消化30 min后，其中一款液体饮品的蛋白质水解度最高（约29%），为三款粉剂产品的1.5、1.4、1.4倍；胃肠消化结束后各产品蛋白质水解度在60%~80%，高于鸡肉、牛肉等食品。结论：蛋白质类型和剂型会影响高蛋白运动补充剂的蛋白质水解，液体剂型以及浓缩牛奶蛋白可能更有利于蛋白质水解。该研究结果可为精准设计开发高蛋白运动补充剂提供数据支撑。

Abstract:

Sports nutrition emphasizes not only the diversity of nutrients, but also their timing intake. Protein supplements are important sources for the requirements of sports nutrition. Currently, the leading products on the market are mainly protein powders, although some liquid beverages are available. However, no previous studies have reported their gastrointestinal digestive behavior and protein hydrolysis profiles. In this paper, five commercially available high-protein sport supplements and three high-protein foods were selected based on protein type and formulations. Their gastrointestinal digestive behavior and protein hydrolysis were evaluated using an in vitro digestion model. The results showed that the water dispersion of powder products had large particle size and were apt to form sediments. All products were sensitive to pH, but they showed different buffering capacity against pH reduction during the in vitro gastric digestion. Products with higher casein content showed a slower pH reduction. All samples tended to form aggregates in the simulating stomach environment. During gastric digestion, the viscoelasticity of the liquid products increased rapidly and decreased or reached a plateau, while the rheological properties of powder products remained constant. One of the liquid products had the highest protein hydrolysis degree (approximately 29%) after 30 min of mimicked gastric digestion, which was 1.5, 1.4, and 1.4 times higher than that of the selected powder products. At the end of gastrointestinal digestion, the protein hydrolysis of each product was in the range of 60%~80%. The hydrolysis degree of proteins in these sports supplements was higher than that in chicken and beef. In conclusion, protein types and product formulations affect the hydrolysis of high-protein sport supplements. The application of liquid formulation and concentrated milk protein might be more favorable for protein absorption than powders. The results in this study may provide data support for the precise design and development of high-protein sport supplements.