The aim of this study was to isolate and identify angiotensin I-converting enzyme (ACE) inhibitory peptides from sesame protein through simulated gastrointestinal digestion in vitro, and to explore the underlying mechanisms by molecular docking. The sesame protein was enzymatically hydrolyzed by pepsin, trypsin, and α-chymotrypsin. The degree of hydrolysis (DH) and peptide yield increased with the increase of digest time. Moreover, ACE inhibitory activity was enhanced after digestion. The sesame protein digestive solution (SPDS) was purified by ultrafiltration through different molecular weight cut-off (MWCO) membranes and SPDS-VII (< 3 kDa) had the strongest ACE inhibition. SPDS-VII was further purified by NGC Quest™ 10 Plus Chromatography System and finally 11 peptides were identified by Nano UHPLC-ESI-MS/MS (nano ultra-high performance liquid chromatography-electrospray ionization mass spectrometry/mass spectrometry) from peak 4. The peptide GHIITVAR from 11S globulin displayed the strongest ACE inhibitory activity (IC50 = 3.60 ± 0.10 μM). Furthermore, the docking analysis revealed that the ACE inhibition of GHIITVAR was mainly attributed to forming very strong hydrogen bonds with the active sites of ACE. These results identify sesame protein as a rich source of ACE inhibitory peptides and further indicate that GHIITVAR has the potential for development of new functional foods.

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To prepare and identify ACE-inhibitory peptides originated from sesame seed protein, peptides with strong ACE-inhibitory activities were obtained via the optimization of protease and hydrolysis conditions, and these peptides were purified and identified by membrane separation, gel filtration, and liquid chromatography-mass spectrometry. Results showed that the dual-enzyme comprised alcalase and trypsin with the enzyme activity ratio of 3:7 was suitable to produce ACE-inhibitory peptides. The highest ACE-inhibitory activity of 98.10 ± 0.26% was obtained at the following parameters, pH 8.35, E/S ratio of 6,145 U/g, and hydrolysis time of 4.4 hr.ISGAQPSLR and VVISAPSK ranked the first and second ACE-inhibitory activity among 15 identified ACE-inhibitory peptides. Both peptides influenced ACE via binding with the S1 pocket, S2 pocket, and Zn 2+ ion. ISGAQPSLR even impacted the S1′ pocket. ISGAQPSLR and VVISAPSK acted as a competitive and noncompetitive inhibitor, respectively. ACE-inhibitory peptides derivated from sesame seed protein have potential applications in functional food. Practical applicationsAlthough sesame seed protein is proven as the precursor of ACE-inhibitory peptide, preparing ACE-inhibitory peptide from sesame seed protein is still suffering from insufficient information on hydrolysis condition and the peptide sequence. Therefore, the performance of the typical protease on preparing ACE-inhibitory peptide from sesame seed protein has been evaluated, the effect of the amino acid composition of sesame seed protein and cleavage specificity of protease on the generation of ACEinhibitory peptide has been investigated, hydrolysis conditions have been optimized, the peptide sequence has been identified to illuminate the effect of sesame seed protein fraction on the formation of ACE-inhibitory peptide and discuss the structural characteristics. ACE-inhibitory peptides originating from sesame seed protein could apply in functional food. It is promising for dual-enzyme hydrolysis to utilize in preparation of high-value bioactive peptides.

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In this paper, we designed and synthesized composites of CoAl‐layered double hydroxide on reduced graphene oxide (CoAl‐LDH@rGO/NF) via a facile approach. The Co‐Al layered double hydroxide (CoAl‐LDH) nanosheets were grown onto the skeleton of reduced graphene oxide on Ni foam (rGO/NF). The as‐synthesized CoAl‐LDH@rGO/NF composites exhibited a superior electrochemical behavior, attributed to the coupling effect of homogeneous CoAl‐LDH nanosheets and high conductivity of rGO. In addition, the different morphologies of the CoAl‐LDH@rGO/NF composites can be controlled by adjusting the amount of NH4F. The optimum electrochemical performance of the CoAl‐LDH@rGO/NF hybrid electrode was obtained when the amount of NH4F was 6 mmol. The largest specific capacitance of 1671.4 F g−1 (1 A g−1) and the ultra‐high cycling performance with 97 % retention of the original value were achieved even after 5000 charge‐discharge cycles. A remarkable energy density value of 41.3 Wh kg−1 at a power density of 408.9 W kg−1 was achieved in the asymmetric supercapacitor (ASC) using CoAl‐LDH@rGO‐6/NF and activated carbon (AC) for positive and negative materials. Furthermore, the ASC retained 100 % of its original energy density value even after 5000 cycles. In addition, a design method for preparing high performance electrode materials with ideal morphology is proposed in this paper, which might be helpful to the future study of morphology and electrochemical properties.

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