Whey Protein Peptides Have Dual Functions: Bioactivity and Emulsifiers in Oil-In-Water Nanoemulsion

Development of low-allergenicity algal oil microcapsules with high encapsulation efficiency using extensively hydrolyzed whey protein

Algal oil is rich in docosahexaenoic acid, which is beneficial for infant development, but its susceptibility to oxidation necessitates microencapsulation. This study investigated the effects of incorporating varying ratios of octenyl succinic anhydride-modified starch (OSA-MS) into a base wall system comprising extensively hydrolyzed whey protein (eWPH) and maltodextrin (MD) to produce algal oil microcapsules with reduced allergenicity and high nutritional value, replacing whey protein isolate (WPI). The residual antigenicity of α-lactalbumin and β-lactoglobulin in eWPH was 3.60 % and 3.88 %, respectively. The addition of OSA-MS significantly enhanced emulsion stability in the eWPH/MD system for algal oil encapsulation. The highest microencapsulation efficiency (98.35 %) was achieved with 21 % OSA-MS, showing no significant difference from that of WPI/MD-based microcapsules. Furthermore, microcapsules prepared with eWPH/MD/OSA-MS (21 %) exhibited smooth surfaces, good dispersibility, and high solubility (91.79 %). These microcapsules also demonstrated superior oxidative stability after 18 days of storage at 60 °C compared to those with other OSA-MS ratios. Overall, incorporating OSA-MS into the eWPH/MD wall system achieved encapsulation performance comparable to WPI/MD, thereby broadening the application potential of eWPH in microencapsulation.

Oral barriers to food-derived active peptides and nano-delivery strategies

Food-derived bioactive peptides are a class of peptides from natural protein. It may have biological effects on the human body and play a significant role in protecting human physiological health and regulating physiological metabolism, such as lowering blood pressure, lowering cholesterol, antioxidant, antibacterial, regulating immune activity, and so on. However, most of the natural food-derived functional peptides need to overcome a variety of barriers in the body to enter the blood circulation system and target to specific tissues to generate physiological activity. During this process, the bioavailability of the functional peptides will be reduced. The nano-delivery system can offer the feasibility to overcome these obstacles and improve the stability and bioavailability of food-derived active peptides by nanoencapsulation. This work summarizes the application of food-derived bioactive peptides and the obstacles during the delivery pathway in vivo. Moreover, the different nano-delivery systems used for bioactive peptides and their application were summarized, which could provide ideas for oral delivery of food-derived bioactive peptides.

Preparation of sanguinarine/glabridin loaded antifungal double-layer nanoemulsion edible coating using arabic gum/WPI for forest frog's oviduct oil preservation

Forest frog's oviduct oil (FFOO) is highly susceptible to microbial spoilage during storage, which causes serious safety concerns and economic losses. However, little information is available regarding the preservation of it up to now. The aim of this research is to understand the dominant microbial community of FFOO spoilage, and based on this, develop a kind of edible nanoemulsion coating for preserving FFOO. Microbial metagenomic analysis indicated that the Aspergillus genus increased significantly during storage. In the present study, gum arabic and whey protein isolate were chosen as the coating matrix, the natural compounds sanguinarine and glabridin were selected as antimicrobial agents to prepare double-layer nanoemulsion edible coating. When the ratio of sanguinarine and glabridin in the nanoemulsion was 1:3, it exhibited strongest storage stability and antifungal activity. The mycelial inhibition rate of 1:3 nanoemulsion against dominant microbial community (Aspergillus niger and Aspergillus glaucus) reached 88.89 ± 1.37 % and 89.68 ± 1.37 %, respectively. The experimental results indicated that the edible nanoemulsion coating not only had outstanding antifungal activity, but also had excellent fresh-keeping effect on FFOO. This nanoemulsion coating could be a promising and potential candidate for food preservation.

Whey Protein Sodium-Caseinate as a Deliverable Vector for EGCG: In Vitro Optimization of Its Bioaccessibility, Bioavailability, and Bioactivity Mode of Actions

Epigallocatechin gallate (EGCG), the principal catechin in green tea, exhibits diverse therapeutic properties. However, its clinical efficacy is hindered by poor stability and low bioavailability. This study investigated solid particle-in-oil-in-water (S/O/W) emulsions stabilized by whey protein isolate (WPI) and sodium caseinate (NaCas) as carriers to enhance the bioavailability and intestinal absorption of EGCG. Molecular docking revealed binding interactions between EGCG and these macromolecules. The WPI- and NaCas-stabilized emulsions exhibited high encapsulation efficiencies (>80%) and significantly enhanced the bioaccessibility of EGCG by 64% compared to free EGCG after simulated gastrointestinal digestion. Notably, the NaCas emulsion facilitated higher intestinal permeability of EGCG across Caco-2 monolayers, attributed to the strong intermolecular interactions between caseins and EGCG. Furthermore, the emulsions protected Caco-2 cells against oxidative stress by suppressing intracellular reactive oxygen species generation. These findings demonstrate the potential of WPI- and NaCas-stabilized emulsions as effective delivery systems to improve the bioavailability, stability, and bioactivity of polyphenols like EGCG, enabling their applications in functional foods and nutraceuticals.

Ultrasound-assisted fabrication and stability evaluation of okra seed protein stabilized nanoemulsion

The structure and functional properties of okra seed protein (OSP) were characterized, the ultrasonic homogenization process of OSP nano-emulsion was optimized by response surface methodology (RSM), and its stability was also evaluated in this study. The results suggested that OSP was a high-quality plant protein, rich in glutamic acid. The molecular weight of its main subunits distributed in the range of 10-55 kDa, and some subunits were connected by disulfide bonds. Although the water and oil holding capacities of OSP were inferior to those of soy protein isolate (SPI), its emulsifying ability was superior to that of SPI. And the OSP concentration, ultrasonic time and ultrasonic power had obvious effects on the droplet size of nanoemulsion. The optimum process of OSP emulsion was determined as follows: OSP concentration 2.4 %, ultrasonic power 600 W, ultrasonic time 340 s. Under these conditions, the median droplet size of the nanoemulsion was 192.03 ± 3.48 nm, close to the predicted value (191.195 nm). And the obtained nano-emulsion exhibited high stability to the changes of pH, temperature and ionic strength in the environment. Our results can provide reference for the application of OSP, and promote the development of plant protein-based nanoemulsions.

Preparation of Nanoemulsions with Low-Molecular-Weight Collagen Peptides from Sturgeon Fish Skin and Evaluation of Anti-Diabetic and Wound-Healing Effects in Mice

This study aims to isolate collagen peptides from waste sturgeon fish skin, and prepare nanoemulsions for studying their anti-diabetic and wound-healing effects in mice. Collagen peptides were extracted and purified by acetic acid with sonication, followed by two-stage hydrolysis with 0.1% pepsin and 5% flavourzyme, and ultrafiltration with 500 Da molecular weight (MW) cut-off dialysis membrane. Animal experiments were performed with collagen peptides obtained by pepsin hydrolysis (37 kDa) and pepsin plus flavourzyme hydrolysis (728 Da) as well as their nanoemulsions prepared at two different doses (100 and 300 mg/kg/day). The mean particle size of low-MW and low-dose nanoemulsion, low-MW and high-dose nanoemulsion, high-MW and low-dose nanoemulsion and high-MW and high-dose nanoemulsion was, respectively, 16.9, 15.3, 28.1 and 24.2 nm, the polydispersity index was 0.198, 0.215, 0.231 and 0.222 and zeta potential was -61.2, -63.0, -41.4 and -42.7 mV. These nanoemulsions were highly stable over a 90-day storage period (4 °C and 25 °C) and heating at 40-100 °C (0.5-2 h). Experiments in mice revealed that the low-MW and high-dose nanoemulsion was the most effective in decreasing fasting blood glucose (46.75%) and increasing wound-healing area (95.53%). Collectively, the sturgeon fish skin collagen peptide-based nanoemulsion is promising for development into a health food or wound-healing drug.