Functional and Bioactive Properties of Wheat Protein Fractions: Impact of Digestive Enzymes on Antioxidant, α-Amylase, and Angiotensin-Converting Enzyme Inhibition Potential

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.

Assessing the Potential of Old and Modern Serbian Wheat Genotypes: Yield Components and Nutritional Profiles in a Comprehensive Study

“…Duan et al [74] emphasized that leucine is usually one of the most abundant amino acids in high-quality protein foods. Additionally, leucine emerged as a predominant essential amino acid within the albumin, glutenin-1, and glutenin-2 protein fractions of wheat flour [75]. In the analyzed wheat genotypes, the average content of phenylalanine was determined to be 4.59 g 100 g −1 protein, which is in line with the results obtained by Siddiqi et al [33] and Khan et al [35].…”

Enemies or Allies? Hormetic and Apparent Non-Dose-Dependent Effects of Natural Bioactive Antioxidants in the Treatment of Inflammation

“…Different natural bioactive antioxidant compounds show beneficial effects for reducing oxidative stress [1][2][3][4][5][6][7][8]. Oxidative stress is generated by an imbalance between reactive oxygen species (ROS) and the body's antioxidant system that can trigger inflammatory processes, as well as various pathologies [9][10][11][12][13].…”