Obando Mónica, Papastergiadis Antonios, Li Shanshan, De Meulenaer Bruno
NutriFOODchem Unit, Department of Food Safety and Food Quality (Partner in Food2Know), Faculty of Bioscience Engineering, Ghent University , Coupure Links 653, B-9000 Ghent, Belgium.
Agroindustrial Engineering, Department of Sanitation and Vegetable Production, Faculty of Agronomic Engineering, Universidad del Tolima , Santa Helena, 564 Ibagué, Colombia.
J Agric Food Chem. 2015 Nov 11;63(44):9820-30. doi: 10.1021/acs.jafc.5b03563. Epub 2015 Oct 29.
Enrichment of polyunsaturated fatty acids (PUFAs) is a growing trend in the food industry. However, PUFAs are known to be susceptible to lipid oxidation. It has been shown that oxidizing lipids react with proteins present in the food and that as a result polymeric protein complexes are produced. Therefore, the aim of this work was to investigate the impact of lipid and protein co-oxidation on protein digestibility. Casein and whey protein (6 mg/mL) based emulsions with 1% oil with different levels of PUFAs were subjected to respectively autoxidation and photo-oxidation. Upon autoxidation at 70 °C, protein digestibility of whey protein based emulsions containing fish oil decreased to 47.7 ± 0.8% after 48 h, whereas in the controls without oil 67.8 ± 0.7% was observed. Upon photo-oxidation at 4 °C during 30 days, mainly casein-based emulsions containing fish oil were affected: the digestibility amounted to 43.9 ± 1.2%, whereas in the control casein solutions without oil, 72.6 ± 0.2% of the proteins were digestible. Emulsions containing oils with high PUFA levels were more prone to lipid oxidation and thus upon progressive oxidation showed a higher impact on protein digestibility.
多不饱和脂肪酸（PUFAs）的富集是食品工业中一个不断发展的趋势。然而，已知PUFAs易受脂质氧化影响。研究表明，氧化的脂质会与食品中存在的蛋白质发生反应，从而产生聚合蛋白复合物。因此，这项工作的目的是研究脂质和蛋白质共氧化对蛋白质消化率的影响。以酪蛋白和乳清蛋白（6 mg/mL）为基础，分别制备含不同水平PUFAs的1%油相乳液，并使其分别进行自氧化和光氧化。在70℃自氧化48小时后，含鱼油的乳清蛋白乳液的蛋白质消化率降至47.7±0.8%，而不含油的对照乳液为67.8±0.7%。在4℃光氧化30天后，主要是含鱼油的酪蛋白基乳液受到影响：消化率为43.9±1.2%，而不含油的对照酪蛋白溶液中，72.6±0.2%的蛋白质可被消化。含有高PUFA水平油的乳液更容易发生脂质氧化，因此随着氧化程度的加深，对蛋白质消化率的影响更大。
