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Abstract：
This research aimed to determine the biofunctional properties of wheat flour (WF) protein fractions and modifications to the antioxidant, anti-α-amylase and anti-angiotensin-I converting enzyme (ACE) activities induced by the action of digestive endopeptidases in vitro. A molecular characterization of the most abundant protein fractions, i.e., albumins, glutelins-1, glutelins-2 and prolamins, showed that low- and high-MW polypeptides rich in cysteine, glutamic acid and leucine were present in albumins and glutelins, whereas low-MW subunits with a high proportion of polar amino acids prevailed in prolamins. Prolamins exhibited the second-highest water holding capacity (54%) after WF (84%), while albumins provided superior foam stability (76%). Prolamins, glutenins-1 and globulins demonstrated the highest antioxidant activity (up to 95%, 68% and 59%, respectively) both before and after hydrolysis with pepsin (P-H) or trypsin-chymotrypsin (TC-H). Prolamins, globulins and WF strongly inhibited α-amylase (>90%) before and after TC-H, and before P-H (55-71%). Moreover, P-H significantly increased α-amylase inhibition by albumins from 53 to 74%. The fractions with strong ACE inhibitory activity (70-89%) included prolamins and globulins after TC-H or P-H, as well as globulins before TC-H and WF before P-H. This novel evidence indicates that WF protein fractions and their peptide-enriched P and TC hydrolysates are excellent sources of multifunctional bioactives with antioxidant, antihyperglycemic and antihypertensive potential.
摘要：
本研究旨在确定小麦粉（WF）蛋白质组分的生物功能特性和对抗氧化剂的修饰，消化内肽酶作用诱导的抗α-淀粉酶和抗血管紧张素I转换酶（ACE）活性。最丰富的蛋白质部分的分子表征，即，白蛋白,谷蛋白-1，谷蛋白-2和醇溶蛋白，表明富含半胱氨酸的低分子量和高分子量多肽，谷氨酸和亮氨酸存在于白蛋白和谷蛋白中，而在醇溶蛋白中普遍存在极性氨基酸比例较高的低MW亚基。醇溶蛋白的持水能力（54％）仅次于WF（84％），而白蛋白提供优异的泡沫稳定性（76％）。醇溶蛋白,谷蛋白-1和球蛋白表现出最高的抗氧化活性（高达95％，68%和59%，分别）在用胃蛋白酶（P-H）或胰蛋白酶-胰凝乳蛋白酶（TC-H）水解之前和之后。醇溶蛋白,球蛋白和WF在TC-H之前和之后强烈抑制α-淀粉酶（>90％），和P-H之前（55-71％）。此外，P-H显着将白蛋白对α-淀粉酶的抑制作用从53％提高到74％。具有强ACE抑制活性（70-89％）的级分包括TC-H或P-H后的醇溶蛋白和球蛋白，以及TC-H之前的球蛋白和P-H之前的WF。这一新的证据表明，WF蛋白级分及其富含肽的P和TC水解产物是具有抗氧化剂的多功能生物活性物质的极好来源，抗高血糖和抗高血压的潜力。
