Novel antioxidant peptides identified from coix seed by molecular docking, quantum chemical calculations and invitro study in HepG2 cells.

The aim of the study was to identify potent antioxidant peptides sourced from coix seed, analyze the structure-activity relationship through molecular docking and quantum chemical calculation. Molecular docking results showed that among thirteen peptides selected in silico, eight had favourable binding interaction with the Keap1-Kelch domain (2FLU). Promising peptides with significant binding scores were further evaluated using quantum calculation. It was shown that peptide FFDR exhibited exceptional stability, with a high energy gap of 5.24 eV and low Highest Occupied Molecular Orbitals (HOMO) and Lowest Unoccupied Molecular Orbitals (LUMO) values. Furthermore, FFDR displayed the capacity to enhance the expression of Nrf2-Keap1 antioxidant genes (CAT, SOD, GSH-Px) and improved cellular redox balance by increasing reduced glutathione (GSH) while reducing oxidized glutathione (GSSG) and malonaldehyde (MDA) levels. These findings highlight the potential of coix seed peptides in developing novel, effective and stable antioxidant-based functional foods.

Highly stable, antihypertensive, and antioxidative peptide production from Apostichopus japonicus by integrated enzymatic membrane reactor and nanofilter-purification mechanism.

Enzymatic hydrolysis-offline and membrane separation (EH-offline MS), enzymatic membrane reactor (EMR) (various operational modes), and conjoined nanofilter-purification (desalination) were used to produce highly stable antihypertensive and antioxidative peptides from ultrasonic-slurry viscosity reduced sea cucumber (A. japonicus) protein. The adoption of the optimum batch parameters by EMR-gradient diafiltration feeding (GDF), water feeding, and substrate feeding ensured a significant (p < 0.05) enhancement in protein conversion degree (PCD) by 60.39, 46.69, and 23.33%, respectively, over the conventional EH-offline MS. Also, the antihypertensive activity (ACE-inhibitory potency) of the peptides produced was in the order EMR-GDF > substrate feeding > water feeding > batch process > EH-offline MS. The EMR-GDF and nanofilter-purification produced highly digestible peptides with ACE-inhibition activities of 79.44% and 77.57% for gastric and gastrointestinal digests, respectively. Peptides with molecular weights of 1000-500 Da and 500 Da significantly contributed to the antihypertensive potency of desalinated peptides. In vitro simulated peptides showed a significant increase in the hydroxyl radical scavenging activity for gastric (77.27%) and gastrointestinal (85.32%) digests. The antioxidative stability of the produced peptides was least affected by high-temperature storage. The high arginine (Arg) and hydrophobic amino acid (HAA) content of the peptides resulted in their improved digestibility. Therefore, conjoined EMR-GDF and nanofilter-purification in the production of highly stable desalinated bioactive peptides for industrial applications could be a viable alternative.

Antihypertensive and Immunomodulatory Effects of Defatted Corn Germ Hydrolysates: An in vivo Study.

This study investigated the antihypertensive and immunomodulatory effects of defatted corn germ hydrolysates (DCGHs) in vivo and their potential regulatory mechanisms. The systolic blood pressure (SBP) of spontaneously hypertensive rats (SHRs) was significantly reduced (10.30%) by the long-term intragastric administration of DCGHs (high doses). Also, there was drastic inhibition of angiotensin-I-converting enzyme (ACE) activity in the lung, kidney, and heart tissues by 24.53, 22.28, and 12.93%, respectively. It could regulate the blood pressure by adjusting the balance between endothelium-derived vasoconstrictor factors and endothelium-derived relaxing factors. Meanwhile, DCGHs enhanced the phagocytosis of mononuclear macrophages, cellular immunity, and humoral immunity of ICR mice by increasing the phagocytic index of mononuclear macrophages (23.71%), ear swelling degree (44.82%), and antibody levels (52.32%). Moreover, it stimulated the release of immunoactive substances (e.g., lysozyme, interferon-γ, immunoglobulin G, and complement 3). Consequently, DCGHs could suitably be used in the formulation of novel functional foods with antihypertensive and immunomodulatory properties.

Effect of multi-frequency countercurrent ultrasound treatment on extraction optimization, functional and structural properties of protein isolates from Walnut (Juglans regia L.) meal.

This study evaluated the effects of ultrasound treatment on walnut meal protein (WMP) extraction and techno-functional properties. The Box-Behnken Design (BBD) was adopted for the optimization of the traditional and ultrasound-assisted extraction (UAE) processes. Standard protocols were used to assay the techno-functional characteristics. The extraction models' statistical results exhibited adequacy with the least desirability index of 95.8%. The UAE enhanced the WMP extraction yield, purity, and chemical score by 30.15%, 16.27%, and 9.74%, respectively, while reducing the extraction time by 25% over the control. The emulsion and foam stabilities and bulk density increased by 34.5%, 39.8%, and 6.1%, respectively, over the control. The α-helix decreased while ß-sheet, ß-turns and random coil secondary structure components increased significantly (p < .05) by 95.76%, 101.3%, 105.1%, and 85.7% correspondingly. The dual-frequency combination (20/40 kHz/kHz) was the best frequency mode. WMP could serve as a functional additive in manufactured foods as texture and flavor enhancer. PRACTICAL APPLICATIONS: Walnut meal protein (WMP) has a well-balanced amino acid profile and its economic use could be practically increased as a food ingredient by ultrasound-assisted extraction. By this technique, WMP could be employed for the development of enhanced food ingredients rather than being discarded as animal feed. This study showed a positive effect of ultrasonic-assisted alkaline pretreatment on WMP extraction, functionality and structure characteristics. In addition to process improvement, ultrasound is energy efficient and environmentally friendly. Therefore, the applicability of this technique to improve the functionality of plant proteins from industrial by-products to be included in food products is promising.