A casein phosphopeptide (CPP) fraction derived from tryptic hydrolysis of bovine casein was evaluated for antioxidant activity. Conjugations or mixtures of CPP with polysaccharide, galactomannan (Gal), or xyloglucan (Xyl) were prepared to evaluate potential enhancement of CPP antioxidant activity. The effect of calcium was also investigated. The CPP preparation alone was effective at scavenging hydroxyl radicals and sequestering Fe²⁺ to protect against Fenton reaction-induced deoxyribose oxidation in non-site-specific (up 63.3% inhibition) and site-specific (up 32.1% inhibition) binding assays, respectively. CPP also effectively quenched 2,2’-azinobis-3-ethylbenzothiazoline-6-sulfonic acid radicals (ABTS^•+) to an extent of 67.6% scavenging in an aqueous system. In a soybean lecithin liposome system, CPP exhibited effective protection against peroxyl radical-induced liposomal peroxidation (38.3% of control in terms of rate of propagation). Conjugating CPP with Gal or Xyl polysaccharides using Maillard reaction conditions significantly reduced activity in the Fenton reaction-deoxyribose assays, while exhibiting no effect on the antioxidant activity of native CPP in both the ABTS and liposome assays, respectively. These results represent comparative antioxidant capacity of the native CPP and associated conjugates in phases that varied in relative hydrophilic and hydrophobic character. We conclude that CPP has the potential to act as both a primary and secondary antioxidant by displaying transition metal ion sequestering activity and free radical quenching activity. Improvements in antioxidant activity of CPP by Maillard-type conjugation with Xyl or Gal were relatively small and model-specific.

中文翻译：

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酪蛋白磷酸肽 (CPP) 和美拉德型缀合产品的抗氧化特性。


对源自牛酪蛋白胰蛋白酶水解的酪蛋白磷酸肽 (CPP) 级分进行了抗氧化活性评估。制备 CPP 与多糖、半乳甘露聚糖 (Gal) 或木葡聚糖 (Xyl) 的缀合物或混合物，以评估 CPP 抗氧化活性的潜在增强作用。还研究了钙的作用。在非位点特异性（抑制高达 63.3%）和位点特异性（抑制高达 32.1%）结合测定中，单独的 CPP 制剂可有效清除羟基自由基并隔离 Fe ²⁺以防止芬顿反应诱导的脱氧核糖氧化。 CPP 还可以有效猝灭水性体系中的 2,2'-联氮双-3-乙基苯并噻唑啉-6-磺酸基 (ABTS ^•+ )，清除率达 67.6%。在大豆卵磷脂脂质体系统中，CPP 对过氧自由基诱导的脂质体过氧化表现出有效的保护作用（就增殖速率而言，为对照的 38.3%）。使用美拉德反应条件将 CPP 与 Gal 或 Xyl 多糖结合显着降低了 Fenton 反应-脱氧核糖测定中的活性，而在 ABTS 和脂质体测定中分别对天然 CPP 的抗氧化活性没有影响。这些结果代表了天然 CPP 和相关缀合物在相对亲水性和疏水性特征不同的相中的比较抗氧化能力。我们得出的结论是，CPP 通过表现出过渡金属离子螯合活性和自由基猝灭活性，具有作为主抗氧化剂和辅助抗氧化剂的潜力。通过与 Xyl 或 Gal 进行美拉德型缀合，CPP 的抗氧化活性的改善相对较小且具有模型特异性。