Foxtail millet prolamin as an effective encapsulant deliver curcumin by fabricating caseinate stabilized composite nanoparticles

Caseinate-coated zein nanoparticles as potential delivery vehicles for guavinoside B from guava: Molecular interactions and encapsulation properties

Guavinoside B (GUB) is a characteristic constituent from guava with strong antioxidant activity; however, its low water solubility limits its utilization. Herein, we investigated the interaction between GUB and zein, a prolamin with self-assembling property, using multiple spectroscopic methods and fabricated GUB-zein-NaCas nanoparticles (GUB-Z-N NPs) via the antisolvent coprecipitation approach. GUB caused fluorescence quenching to zein via the static quenching mechanism. Fourier-transform infrared spectroscopy and computational analysis revealed that GUB bound to zein via van der Waals interaction, hydrogen bond, and hydrophobic forces. The GUB-Z-N NPs were in the nanometric size range (< 200 nm) and exhibited promising encapsulation efficiency and redispersibility after freeze-drying. These particles remained stable for up to 31 days at 4 °C and great resistance to salt and pH variation, and displayed superior antioxidant activity to native GUB. The current study highlights the potential of zein-based nanoparticles as delivery vehicles for GUB in the food industry.

Alkali-assisted extraction, characterization and encapsulation functionality of enzymatic hydrolysis-resistant prolamin from distilled spirit spent grain

Curcumin is a natural lipophilic polyphenol that exhibits significant various biological properties such as antioxidant and anti-inflammatory properties following oral administration. However, its uses have shown limitations concerning aqueous solubility, bioavailability and biodegradability that could be improved by prolamin-based nanoparticle. In this study, curcumin was encapsulated into prolamin from sorghum (SOP) and wheat (WHP) and distilled spirit spent grain (DSSGP), which was obtained after microbial proteolysis of the former two cereal grains. All the three prolamins showed clear variation of protein profiles and microstructure as confirmed by electrophoresis analysis, disulfide bond determination and Fourier-transform infrared spectroscopy (FTIR). For curcumin-loaded nanospheres (NPs) fabrication, three prolamin-based NPs shared features of spherical shape, uniform particle size, and smooth surface. The average size ranged from 122 to 193 nm depending on the prolamin variety and curcumin loading. In the experiments in vitro, curcumin showed significantly improved UV/thermal stability. Furthermore, DSSGP was more resistant to enzymatic digestion in vitro, hence achieving the controlled release of curcumin in gastrointestinal tract. Collectively, the results indicated the improved bioavailability and biodegradability of curcumin encapsulated by DSSGP, which would be an innovative potential encapsulant for effective protection and targeted delivery of hydrophobic compounds.

A prediction method of interaction based on Bilinear Attention Networks for designing polyphenol-protein complexes delivery systems

Polyphenol-protein complexes delivery systems are gaining attention for their potential health benefits and food industry development. However, creating an ideal delivery system requires extensive wet-lab experimentation. To address this, we collected 525 ligand-protein interaction data pairs and established an interaction prediction model using Bilinear Attention Networks. We utilized 10-fold cross validation to address potential overfitting issues in the model, resulting in showed higher average AUROC (0.8443), AUPRC (0.7872), and F1 (0.8164). The optimal threshold (0.3739) was selected for the model to be used for subsequent analysis. Based on the model prediction results and optimal threshold, by verifying experimental analysis, the interaction of paeonol with the following proteins was obtained, including bovine serum albumin (lgKa = 6.2759), bovine β-lactoglobulin (lgKa = 6.7479), egg ovalbumin (lgKa = 5.1806), zein (lgKa = 6.0122), bovine α-lactalbumin (lgKa = 3.9170), bovine lactoferrin (lgKa = 4.5380), the first four proteins are consistent with the predicted results of the model, with lgKa >5. The established model can accurately and rapidly predict the interaction of polyphenol-protein complexes. This study is the first to combine open ligand-protein interaction experiments with Deep Learning algorithms in the food industry, greatly improving research efficiency and providing a novel perspective for future complex delivery system construction.

Co-encapsulation of curcumin and anthocyanins in bovine serum album-fucoidan nanocomplex with a two-step pH-driven method

BACKGROUND

Curcumin (CUR) and anthocyanins (ACN) are recommended due to their bioactivities. However, their nutritional values and health benefits are limited by their low oral bioavailability. The incorporation of bioactive substances into polysaccharide-protein composite nanoparticles is an effective way to enhance their bioavailability. Accordingly, this study explored the fabrication of bovine serum albumin (BSA)-fucoidan (FUC) hybrid nanoparticles using a two-step pH-driven method for the delivery of CUR and ACN.

RESULTS

Under a 1:1 weight ratio of BSA to FUC, the point of zero charge moved from pH ⁓ 4.7 for BSA to around 2.5 for FUC-coated BSA, and the formation of BSA-FUC nanocomplex was pH-dependent by showing the maximum CUR emission wavelength shifting from 546 nm (CUR-loaded BSA-FUC at pH 4.7) and 544 nm (CUR/ACN-loaded BSA-FUC nanoparticles at pH 4.7) to 540 nm (CUR-loaded BSA-FUC at pH 6.0) and 539 nm (CUR/ACN-loaded BSA-FUC nanoparticles at pH 6.0). Elevated concentrations of NaCl from 0 to 2.5 mol L-1 caused particle size increase from about 250 to about 800 nm, but showing no effect on the encapsulation efficiency of CUR. The CUR and ACN entrapped, respectively, in the inner and outer regions of the BSA-FUC nanocomplex were released at different rates. After incubation for 10 h, more than 80% of ACN was released, while less than 25% of CUR diffused into the receiving medium, which fitted well to Logistic and Weibull models.

CONCLUSION

In summary, the BSA-FUC nanocomposites produced by a two-step pH-driven method could be used for the co-delivery of hydrophilic and hydrophobic nutraceuticals. © 2023 Society of Chemical Industry.

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.

Oil palm kernel globulin antihypertensive peptides: isolation and characterization, ACE inhibition mechanisms, zinc-chelating activity, security and stability

Introduction: The oil palm kernel (OPK) expeller is the main byproduct of palm oil, but its utilization is limited. Methods: To obtain angiotensin-I-converting enzyme (ACE) inhibition peptides with Zn-chelating capacity, defatted oil palm kernel globulin hydrolysates (DOPKGH) were subjected to Sephadex G-15 gel electrophoresis, reverse-phase high liquid performance chromatography, and UPLC-ESI-MS/MS analysis. Results and discussion: Five representative oligopeptides, including Gln-Arg-Leu-Asp-Arg-Cys-Lys (QRLERCK), Leu-Leu-Leu-Gly-Val-Ala-Asn-Tyr-Arg (LLLGVANYR), Arg-Ala-Asp-Val-Phe-Asn-Pro-Arg (RADVFNPR), Arg-Val-Ile-Lys-Tyr-Asn-Gly-Gly-Gly-Ser-Gly (RVIKYNGGGSG), and Glu-Val-Pro-Gln-Ala-Tyr-Ile-Pro (EVPQAYIP), without potential toxicity and allergenicity, were identified in DOPKGH. Of these, only EVPQAYIP showed both ACE-inhibitory activity (IC50: 102.75 μmol/L) and Zn-chelating capacity (11.69 mg/g). Molecular docking and inhibition kinetics showed that EVPQAYIP was a competitive inhibitor of ACE because it could bind to Glu384, Lys511, and Gln281 (belonging to the central S1 and S2 pockets, respectively) of ACE. Moreover, EVPQAYIP affects zinc tetrahedral coordination in ACE by binding to Glu411; the amino and carboxyl groups of EVPQAYIP chelate with zinc ions. During gastrointestinal digestion, the ACE inhibitory activity of EVPQAYIP was relatively stable. Additionally, EVPQAYIP enhanced zinc stability in the intestine and exerted antihypertensive effects in spontaneous hypertensive rats. These results suggest the potential application of OPK peptides as ingredients in antihypertensive agents or zinc fortification.

Preparation and nutritional characterisation of protein concentrate prepared from foxtail millet (Setaria italica)

Plant-based protein sources as a sustainable alternative to animal sources are highly relevant for food and dietary supplements industries. Plant proteins are becoming popular as an eco-friendly source for meeting global protein requirements due to their importance in nutrition, management of metabolic diseases, biological activities, functionality in processed food products and their low carbon footprints. We applied biochemical protein extraction protocol and prepared protein concentrate from an underutilised cereal, foxtail millet, with plausible applications in foods and supplements. Herein efforts were utilised to obtain foxtail millet protein (FMP) concentrate by means of standardisation of processes of extraction cum isolation. The conditions including flour to solvent ratio, extraction-precipitation pH, dissolution time, etc. were optimised to significantly improve protein yield and recovery. The FMP concentrate prepared was also analysed for nutritional composition, bioactive compounds, amino acid content and digestion properties in comparison to packaged brown rice protein concentrate. The protein concentrate prepared was found to have high digestibility, rich in essential amino acids with good phenolic and flavonoid content, thereby making it a potential sensory and antioxidant additive for food/pharmaceutical applications.

Trends in millet and pseudomillet proteins - Characterization, processing and food applications

Millets are small-seeded crops which have been well adopted globally owing to their high concentration of macro and micronutrients such as protein, dietary fibre, essential fatty acids, minerals and vitamins. Considering their climate resilience and potential role in nutritional and health security, the year 2023 has been declared as 'International Year of Millets' by the United Nations. Cereals being the major nutrient vehicle for a majority population, and proteins being the second most abundant nutrient in millets, these grains can be a suitable alternative for plant-based proteins. Therefore, this review was written with an aim to succinctly provide an overview of the available literature take on the characterization, processing and applications of millet-based proteins. This information would play an important role in realizing the research gap restricting the utilization of complete potential of millet proteins. This can be further used by researchers and food industries for understanding the scope of millet proteins as an ingredient for novel food product development.

Millet bran protein hydrolysates derived peptides-zinc chelate: Structural characterization, security prediction in silico, zinc transport capacity and stability against different food processing conditions

A novel peptide Ser-Asp-Asp-Val-Leu (SDDVL) of excellent zinc-chelating capacity (13.77 mg/g) was identified in millet bran protein hydrolysates. In silico prediction demonstrated that SDDVL had no potential toxicity. The results of structural characterization demonstrated that both amino group and carboxyl group of SDDVL were the primary zinc-chelating sites. Moreover, SDDVL-zinc chelate showed higher stability (p < 0.05) than ZnSO₄ and zinc gluconate under different processing conditions including most pasteurization conditions, heating at 100°C for 10-50 min, various pH values (8.0-10.0), treatment of glucose (4-8 g/100 g) or NaCl (1-4 g/100 g), and simulated gastrointestinal digestion. In addition, SDDVL-zinc chelate showed higher zinc transport capacity than ZnSO₄ and zinc gluconate in Caco-2 cells (p < 0.05). These results suggested that millet bran peptide had a positive effect on the gastrointestinal stability and bioavailability of Zn, and SDDVL-zinc chelate could be used as ingredient of zinc supplements. PRACTICAL APPLICATION: The current study provided a practical method to identify peptides of excellent zinc-chelating capacity from millet bran protein hydrolysates. This study demonstrated that in silico prediction assisted with suitable database was a fast, practical, and economic way to evaluate the security and to analysis the physicochemical properties of novel peptides. Moreover, it provided an efficient method to assess the stability of peptide-zinc chelate under different food processing conditions, which was the theoretical basis for utilization of peptide as ingredient of zinc fortifications.

Curcumin Hybrid Lipid Polymeric Nanoparticles: Antioxidant Activity, Immune Cellular Response, and Cytotoxicity Evaluation

Poor solubility and short biological half-life present a challenge that needs to be overcome in order to improve the recognized bioactivities of curcumin (CUR), the main phenolic compounds derived from the roots of Curcuma longa. However, drug delivery systems have proven to be an excellent strategy to improve and obtain greater bioavailability. Our previous studies on curcuminoid hybrid nanoparticles have shown promising results by significantly increasing the solubility of desmethoxycurcumin (DMC) and bisdemethoxycurcumin (BDM). In this contribution, we performed a detailed characterization of a CUR as well as in vitro and in vivo studies. The developed method produced CUR loaded nanoparticles with an average size of 49.46 ± 0.80. Moreover, the FT-IR analysis confirmed the encapsulation, and TEM images showed their spherical shape. The NP achieved an encapsulation efficiency greater than 99%. Further, the release studies found that the NPs obtained a significantly higher release than the pure compounds in water. In vivo delayed-type hypersensitivity (DTH) studies showed promising results by enhancing the immune activity response of CUR in NP compared to bulk CUR. Furthermore, we report a significant increase in antioxidant activity for CUR-NP in aqueous solution compared to free CUR. Finally, an important in vitro cytotoxic effect on gastric AGS and colon SW620 adenocarcinoma cell lines was found for CUR-NP while empty carrier nanoparticles are observed to exhibit low cytotoxicity, indicating the potential of these CUR-PLU NPs for further studies to assess their phytotherapeutic applications.

Recent advances in self-assembly behaviors of prolamins and their applications as functional delivery vehicles

Prolamins are a group of storage proteins (zeins, kafirins, hordeins, secalins, gliadins, glutenins, and avenins) found in the endosperm of cereal grains and characterized by high glutamine and proline content. With the high proportion of nonpolar amino acids (40-80%) and peculiar solubility (alcohol (60-90%), acetic acid, and alkaline solutions), prolamins exhibit tunable self-assembly behaviors. In recent years, research practices of utilizing prolamins as green building materials of functional delivery vehicles to improve the health benefits of bioactive compounds have surged due to their attractive advantages (e.g. sustainability, biocompatibility, fabrication potential, and cost-competitiveness). This article covers the recent advances in self-assembly behaviors leading to the fabrication of nanoparticles, fibers, and films in the bulk water phase, at the air-liquid interface, and under the electrostatic field. Different fabrication methods, including antisolvent precipitation, evaporation induced self-assembly, thermal treatment, pH-modulation, electrospinning, and solvent casting for assembling nanoarchitectures as functional delivery vehicles are highlighted. Emerging industrial applications by mapping patents, including encapsulation and delivery of bioactive compounds and probiotics, active packaging, Pickering emulsions, and as functional additives to develop safer, healthier, and sustainable food products are discussed. A future perspective concerning the fabrication of prolamins as advanced materials to promote their commercial food applications is proposed.

Chondroitin sulfate deposited on foxtail millet prolamin/caseinate nanoparticles to improve physicochemical properties and enhance cancer therapeutic effects

In this study, curcumin (Cur)-loaded chondroitin sulfate (CS)-sodium caseinate (NaCas)-stabilized foxtail millet prolamin (FP) composite nanoparticles (NPs) were fabricated via a one-pot process. FP is capable of self-assembly via liquid antisolvent precipitation under neutral and alkaline conditions (pH 7.0-11.0). Under this condition, the microstructures of hydrophobic FP cores, amphiphilic NaCas and hydrophilic CS shells were fabricated readily by a one-pot method. With an optimal FP/NaCas/CS weight ratio of 3 : 2 : 4, FP-NaCas-CS NPs shared globular microstructures at about 145 nm, and hydrophobic interactions, electrostatic forces, and hydrogen bonds were the main driving forces for the formation and maintenance of stable FP-NaCas-CS NPs. CS coating enhanced the pH stability but reduced the ionic strength stability. The formed NPs were stable over a wide pH range from 2.0 to 8.0 and elevated salt concentrations from 0 to 3 mol L^-1 NaCl. FP-NaCas-CS NPs exhibited a higher Cur encapsulation efficiency of 93.4% and re-dispersion capability after lyophilization. Moreover, CS coating promoted selective accumulation in CD44-overexpressing HepG2 cells, resulting in higher inhibition of tumor growth compared to free Cur and FP-NaCas NP-encapsulated Cur. As for comparison, encapsulated Cur exhibited reduced cytotoxicity on normal liver cells L-O2. This preclinical study suggests that FP-NaCas-CS NPs could be very beneficial in terms of encapsulating hydrophobic drugs, improving the effectiveness of cancer therapies and reducing side effects on normal tissues.

Co-assembly of foxtail millet prolamin-lecithin/alginate sodium in citric acid-potassium phosphate buffer for delivery of quercetin

Foxtail millet nanoparticles with smaller mean size at ∼130 nm and narrower polydispersity index at ∼0.05 were prepared in citric acid-potassium phosphate buffer (pH 8.0). Through lecithin (Lec)/sodium alginate (Alg) coating, a hydrophobic FP core, a Lec monolayer, and a hydrophilic Alg shell were formed spontaneously. Dissociation experiment revealed that electrostatic interaction and hydrogen bonding were main driving forces for the formation and maintenance of stable FP-Lec/Alg NPs. In addition, Lec/Alg coated NPs exerted an important role in sustaining the controlled release of the encapsulated quercetin under simulated gastrointestinal tract conditions. Cellular uptake test exhibited that FP-Lec-Alg NPs cold enter epithelial cells in a time-dependent manner, showing the maximum uptake efficiency were 22% and 24%, respectively, after 2 h of incubation. About 220 nm NPs can be recovered by adding 10% (w/v) sucrose. FP-Lec-Alg NPs were found to be promising delivery materials to deliver quercetin and improve its bioavailability.