Markussen Jacob Østergaard, Madsen Finn, Young Jette Feveile, Corredig Milena
Department of Food Science, CiFood Multidisciplinary Center, Aarhus University, 48 Agro Food Park, Aarhus N, 8200, Denmark.
IFF R&D Braband, DuPont Nutrition Biosciences ApS, Edwin Rahrs Vej 38, 8220, Brabrand, Denmark.
Curr Res Food Sci. 2021 Apr 6;4:250-261. doi: 10.1016/j.crfs.2021.03.012. eCollection 2021.
Hydrocolloids are often added as functional ingredients in foods, to better design the structure of the matrix and ensure food quality and optimal sensory properties. However, much less is known about their influence on the physical and chemical changes during gastric digestion. In this study, semi-continuous gastric digestion was applied on a model food system, prepared with milk protein concentrate (MPC) (3% w/v) and 1% alginate, pectin, guar gum, as well as a 1:1 mixture of alginate and pectin. The dynamics during simulated gastric digestion were observed by measuring particle size distributions, structuring at various length scales, as well as by evaluating differences in protein breakdown. Immediately after contact with the simulated gastric fluids, all samples showed extensive aggregation and formation of different structures. MPC control dispersions (no polysaccharide) and MPC containing alginate formed large inhomogeneous aggregates. The lack of structural homogeneity affected the simulated gastric emptying: there were marked differences in the type of aggregates present at various times of emptying depending on the hydrocolloid present in the mixture. MPC containing pectin or guar gum formed macroscopically homogeneous dispersion, with rather small protein aggregates showing a large population of particles between 60 and 100 μm of diameter, with marked differences in microstructure. Pectin created large coacervates, while guar microscopic phase separated systems. These dispersions showed a higher extent of protein digestion, due to the larger surface area created for enzyme activity compared to the macroscopically phase separated matrices. In all cases, there was a large undigested fraction at the end point of 140 min. SDS PAGE demonstrated differences in the casein peptides distribution depending on the type of polysaccharide present during simulated gastric emptying. This in spite of similarities in cumulative protein emptied. It was concluded that in this semi-continuous gastric digestion model, structuring with polysaccharides has a significant impact on gastric emptying and protein digestion kinetics.
水胶体常作为功能性成分添加到食品中，以更好地设计基质结构并确保食品质量和最佳感官特性。然而，关于它们在胃消化过程中对物理和化学变化的影响，人们了解得要少得多。在本研究中，对一种模型食品体系进行了半连续胃消化实验，该体系由浓缩乳清蛋白（MPC）（3% w/v）和1%的海藻酸盐、果胶、瓜尔豆胶以及海藻酸盐和果胶的1:1混合物制备而成。通过测量粒径分布、不同长度尺度下的结构形成以及评估蛋白质分解差异，观察了模拟胃消化过程中的动态变化。与模拟胃液接触后，所有样品均出现广泛聚集并形成不同结构。MPC对照分散液（无多糖）和含海藻酸盐的MPC形成了大的不均匀聚集体。结构均匀性的缺乏影响了模拟胃排空：根据混合物中存在的水胶体不同，在排空的不同时间存在的聚集体类型存在显著差异。含果胶或瓜尔豆胶的MPC形成了宏观上均匀的分散液，蛋白质聚集体相当小，大量颗粒直径在60至100μm之间，微观结构存在显著差异。果胶形成了大的凝聚层，而瓜尔豆胶形成了微观相分离体系。由于与宏观相分离基质相比，这些分散液为酶活性创造了更大的表面积，因此显示出更高程度的蛋白质消化。在所有情况下，140分钟结束时都有大量未消化部分。SDS-PAGE表明，在模拟胃排空过程中，酪蛋白肽的分布因存在的多糖类型而异。尽管累积排空的蛋白质相似。得出的结论是，在这个半连续胃消化模型中，多糖的结构化对胃排空和蛋白质消化动力学有显著影响。
