Changchun University of Chinese Medicine, Changchun, Jilin, China.
Center for Food Evaluation, State Administration for Market Regulation, Beijing, China.
Food Funct. 2023 Oct 30;14(21):9872-9891. doi: 10.1039/d3fo02988c.
We investigated the structural properties, foaming capacity and foaming stability, antioxidant activity, and amino acid composition of Kudzu protein (KP) and Kudzu protein hydrolysate (KPH). The peptide sequence of KPH was analyzed using ultra performance liquid chromatography/tandem mass spectrometry (UPLC-MS/MS), and the binding ability of the peptide sequence to Keap1 was predicted through molecular docking simulations. The electrophoresis and molecular weight distribution analysis results showed that the molecular weight of KPH was significantly lower than that of KP, with a mean molecular weight of approximately 2000-5000 Da. The structures and properties were characterized using Fourier transform infrared spectroscopy, relative fluorescence, and circular dichroism. The results showed that KP exposed a large number of hydrophobic groups after enzymatic hydrolysis, and its structure changed from α-helical to random coils. KPH has a higher foaming capacity (200%) and foaming stability (97.5%) than KP, which may be related to the change in structure. These results indicate that moderate hydrolysis can improve the functional properties of KP, providing a new opportunity for its application as a food ingredient. The antioxidant assay results showed that KP and KPH had a good hydroxyl radical, superoxide anion, 1,1-diphenyl-2-picrylhydrazyl (DPPH), and 2,2'-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) scavenging capacity and a high reducing capacity. KPH exerted better antioxidant effects than KP. The scavenging rates for DPPH, ABTS, hydroxyl radicals, and superoxide anions were 89.31%, 93.14%, 85.74%, and 58.29%, respectively, and its reducing capacity was 2.191, which may be related to the increase in amino acids with antioxidant activity after enzymolysis. , KP and KPH could significantly repair HO-induced oxidative damage in HepG2 cells, reduce the apoptosis rate, activate the Nrf2-Keap1 signaling pathway, reduce the accumulation of reactive oxygen species and malondialdehyde after oxidative damage, increase the activities of superoxide dismutase and glutathione (GSH) peroxidase, and increase the content of GSH and the total antioxidant capacity. Twenty-one peptide components were identified in KPH using UPLC-MS/MS, and the binding ability of 21 peptide components to Keap1 was analyzed through molecular docking technology. The results showed that all 21 peptides in KPH had good antioxidant activity, and real-time quantitative PCR (qRT-PCR) analysis was conducted to further explain the high antioxidant activity of KPH at the genetic level. These results show that KP and KPH are suitable for preparing antioxidant foods and related health foods to prevent oxidation-related diseases. KPH has more beneficial effects than KP.
我们研究了葛根蛋白（KP）和葛根蛋白水解物（KPH）的结构特性、起泡能力和起泡稳定性、抗氧化活性以及氨基酸组成。使用超高效液相色谱/串联质谱法（UPLC-MS/MS）分析 KPH 的肽序列，并通过分子对接模拟预测肽序列与 Keap1 的结合能力。电泳和分子量分布分析结果表明，KPH 的分子量明显低于 KP，平均分子量约为 2000-5000Da。使用傅里叶变换红外光谱、相对荧光和圆二色性对结构和性质进行了表征。结果表明，KP 经酶解后暴露了大量疏水性基团，其结构从α-螺旋变为无规卷曲。KPH 的起泡能力（200%）和起泡稳定性（97.5%）均高于 KP，这可能与结构变化有关。这些结果表明，适度水解可以提高 KP 的功能特性，为其作为食品成分的应用提供了新的机会。抗氧化测定结果表明，KP 和 KPH 对羟基自由基、超氧阴离子、1,1-二苯基-2-苦基肼（DPPH）和 2,2'-联氮-双-3-乙基苯并噻唑啉-6-磺酸（ABTS）具有良好的清除能力和较高的还原能力。KPH 比 KP 表现出更好的抗氧化效果。DPPH、ABTS、羟基自由基和超氧阴离子的清除率分别为 89.31%、93.14%、85.74%和 58.29%，还原能力为 2.191，这可能与酶解后抗氧化活性氨基酸的增加有关。KP 和 KPH 可显著修复 HO 诱导的 HepG2 细胞氧化损伤，降低细胞凋亡率，激活 Nrf2-Keap1 信号通路，减少氧化损伤后活性氧和丙二醛的积累，增加超氧化物歧化酶和谷胱甘肽（GSH）过氧化物酶的活性，增加 GSH 和总抗氧化能力的含量。使用 UPLC-MS/MS 在 KPH 中鉴定出 21 种肽成分，并通过分子对接技术分析 21 种肽成分与 Keap1 的结合能力。结果表明，KPH 中的所有 21 种肽都具有良好的抗氧化活性，实时定量 PCR（qRT-PCR）分析进一步从遗传水平上解释了 KPH 具有高抗氧化活性的原因。这些结果表明，KP 和 KPH 适合制备抗氧化食品和相关保健品，以预防与氧化相关的疾病。KPH 比 KP 具有更有益的效果。
