Walnut protein isolate was hydrolyzed using alcalase® to obtain angiotensin‐I‐converting enzyme (ACE) inhibitory (ACEI) peptides. The components with high ACEI activity were successfully purified from walnut protein isolate hydrolysates (WPIH) by ultrafiltration and G‐25 gel chromatography. The 1520 peptides were identified by high‐performance liquid chromatography–tandem mass spectrometry (HPLC‐MS/MS). Then the screening model of ACEI peptides was established by in silico approach. It was found that four ACEI active peptides (PPKP, YPQY, YLPP, and PKPP) were obtained with IC50 values ranging from 506 to 89 μmol/L, among which PPKP had the highest ACEI activity (IC50 = 89 ± 1 μmol/L). The four peptides mentioned above were novel, non‐toxic, and resistant to gastrointestinal digestion. The molecular docking studies showed that the ACEI effect of ACEI peptide was mainly due to the interaction with residues of Gln281 and His353 in the ACE active pockets. In vivo availability of ACEI peptides showed that the probability of PPKP binding to ACE was 37.9% in the human body. Our studies suggest that the ACEI peptides derived from the WPIH can be considered functional foods that can prevent hypertension. Practical applications Hypertension is a significant risk factor for cardiovascular and cerebrovascular disease, the leading cause of death worldwide. This study used a cost‐effective method to isolate and identify potential ACEI peptides from the walnut meal. Since the walnut meal is often discarded in the processing of walnut products and thus pollutes the environment, the preparation of walnut meal into ACEI peptides can reduce the impact of hypertension on people and reduce environmental pollution. The experimental results show that walnut ACEI peptides are a safe and healthy nutritional product.

This study encapsulated walnut angiotensin‐converting enzyme (ACE) inhibitory peptides within nanoliposomes and then modified them with chitosan. The resulting effect of the nanoliposome loading and chitosan coating on physicochemical characteristics, stability, bioactivity, chemical structure, and morphology of the encapsulated peptides was assessed. The resulting particle size and polymer dispersity index revealed that the chitosan‐coated nanoliposomes loaded with walnut ACE inhibitory peptides (WAIP) (CL‐P) exhibited higher physical stability compared with the nanoliposomes loaded with WAIP (L‐P). The encapsulation efficiency (EE) of CL‐P increased from 73.32% to 76.13% after chitosan modification, and the EE of L‐P and CL‐P could be maintained by storage at 4°C. In addition, the antioxidant activity and ACE inhibitory activity of the peptides were effectively protected by L‐P and CL‐P during storage. Fourier transform infrared spectroscopy showed that the nanoliposomes were bound in ionic form with both the peptides and chitosan. Transmission electron micrographs indicated the presence of vesicle‐like carriers with a reservoir‐type structure. This study highlights the potential of nanoliposomes and their modification with chitosan to increase the stability and bioactivity retention of ACE inhibitory peptides. Practical Application Chitosan‐coated nanoliposomes loaded with walnut ACE inhibitory peptides were prepared in this study. Chitosan coating increased nanoliposomes’ encapsulation efficiency and provided higher physical stability. In addition, the bioactivity of the walnut ACE peptides was effectively protected during storage. This study was relevant for improving the storage and transportation used for nanoliposome systems applied in the food and health product industry.