Castaneda Nuria, Lee Youngsoo
Department of Food Science and Human Nutrition, University of Illinois, Urbana-Champaign, Champaign, IL 61801, USA.
Gels. 2019 Mar 10;5(1):16. doi: 10.3390/gels5010016.
In this study, the effect of a composition (protein to fat (P/F) ratio) and a processing condition (homogenization pressure for emulsification of cheese milk) on the texture, microstructure, and bioaccessibility of vitamin D₃ of a model acid coagulated fresh cheese was evaluated. It was hypothesized that increasing P/F ratios (0.9, 1.3, 1.7, and 2) and homogenization pressures (17, 50, 75, and 150 MPa) will decrease the particle size of the cheese milk emulsion. The decreased emulsion particle size will result in a more rigid and elastic cheese matrix with smaller pore sizes, with an increased interfacial surface area of fat particles, which will then improve the bioaccessibility of vitamin D₃. The P/F ratio exhibited a positive impact on the texture in a large deformation analysis. On the other hand, the effect of the P/F ratio and homogenization pressure was not significant on rheological properties of the cheese using a small deformation by means of a frequency sweep test, nor the porosity determined by environmental scanning electron microscopy (ESEM). These results suggested that the modification of the microstructure of acid coagulated fresh cheeses required other variables than P/F ratio and homogenization pressure probably due to a compression step after curd formation. Interestingly, the bioaccessibility of vitamin D₃ measured by in vitro digestion was reduced as P/F ratio and homogenization pressure increased, which may indicate a reinforced protein⁻protein interaction that affected protein hydrolysis.
在本研究中，评估了一种成分（蛋白质与脂肪（P/F）比）和一种加工条件（用于奶酪乳乳化的均质压力）对模型酸凝新鲜奶酪的质地、微观结构和维生素D₃生物可及性的影响。研究假设，提高P/F比（0.9、1.3、1.7和2）和均质压力（17、50、75和150兆帕）将减小奶酪乳乳液的粒径。乳液粒径减小将导致奶酪基质更坚硬且更有弹性，孔径更小，脂肪颗粒的界面表面积增加，进而提高维生素D₃的生物可及性。在大变形分析中，P/F比对质地有积极影响。另一方面，通过频率扫描测试进行小变形时，P/F比和均质压力对奶酪的流变学性质没有显著影响，通过环境扫描电子显微镜（ESEM）测定的孔隙率也不受其显著影响。这些结果表明，酸凝新鲜奶酪微观结构的改变可能需要P/F比和均质压力以外的其他变量，这可能是由于凝乳形成后的压缩步骤所致。有趣的是，随着P/F比和均质压力的增加，通过体外消化测定的维生素D₃生物可及性降低，这可能表明蛋白质-蛋白质相互作用增强，从而影响了蛋白质水解。
