Nimalaratne Chamila, Bandara Nandika, Wu Jianping
Department of Agricultural, Food and Nutritional Science (AFNS), 4-10 Ag/For Centre, University of Alberta, Edmonton, Alberta, Canada.
Department of Agricultural, Food and Nutritional Science (AFNS), 4-10 Ag/For Centre, University of Alberta, Edmonton, Alberta, Canada.
Food Chem. 2015 Dec 1;188:467-72. doi: 10.1016/j.foodchem.2015.05.014. Epub 2015 May 6.
Egg white is considered as a rich source of high quality proteins with various bioactive peptide fractions. Enzymatic hydrolysis of proteins can be used to release bioactive fractions and different enzymes have different abilities in releasing such bioactive fractions depending on the enzyme's site of activity on a protein. In this study, several proteases were examined for their ability to release antioxidant peptides from hen egg white and protease P was selected based on the antioxidant activity and the digestion yield of the crude protein hydrolysate. A combination of several purification steps including ultrafiltration with low molecular weight cut-off membranes, cation exchange chromatography and reversed phase high performance liquid chromatography was used to purify 'protease P egg white hydrolysate'. Sixteen antioxidant peptides, which were derived from ovalbumin, ovotransferrin and cystatin were isolated from the most active fractions. Amino acid sequences of those peptides were determined using LC-MS/MS. Oxygen radical absorbance capacity (ORAC) values of selected short chain peptides were determined using synthetic peptides. Two peptides AEERYP and DEDTQAMP (Ala-Glu-Glu-Arg-Tyr-Pro and Asp-Glu-Asp-Thr-Gln-Ala-Met-Pro) showed the highest ORAC values. The results from this study indicate that egg white is rich in antioxidant peptides which can be used as a potential source for preparing bioactive ingredients using enzymatic hydrolysis followed by purification techniques.
蛋清被认为是富含各种生物活性肽组分的优质蛋白质来源。蛋白质的酶促水解可用于释放生物活性组分，并且不同的酶在释放此类生物活性组分方面具有不同的能力，这取决于酶在蛋白质上的活性位点。在本研究中，检测了几种蛋白酶从鸡蛋白中释放抗氧化肽的能力，并根据粗蛋白水解物的抗氧化活性和消化率选择了蛋白酶P。采用包括用低分子量截留膜超滤、阳离子交换色谱和反相高效液相色谱在内的多种纯化步骤组合来纯化“蛋白酶P蛋清水解物”。从活性最高的组分中分离出16种源自卵清蛋白、转铁蛋白和半胱氨酸蛋白酶抑制剂的抗氧化肽。使用LC-MS/MS测定这些肽的氨基酸序列。使用合成肽测定所选短链肽的氧自由基吸收能力（ORAC）值。两种肽AEERYP和DEDTQAMP（丙氨酸-谷氨酸-谷氨酸-精氨酸-酪氨酸-脯氨酸和天冬氨酸-谷氨酸-天冬氨酸-苏氨酸-谷氨酰胺-丙氨酸-甲硫氨酸-脯氨酸）显示出最高的ORAC值。本研究结果表明，蛋清富含抗氧化肽，可作为通过酶促水解随后采用纯化技术制备生物活性成分的潜在来源。
