Glycosylated α-lactalbumin-based nanocomplex for curcumin: Physicochemical stability and DPPH-scavenging activity

Food Protein-Based Nanodelivery Systems for Hydrophobic and Poorly Soluble Compounds

The hydrophobicity of bioactive molecules poses a considerable problem in the pharmaceutical and the food industry. Using food-based protein nanocarriers is one promising way to deliver hydrophobic molecules. These types of protein possess many functional properties such as surface activity, water-binding capacity, emulsification, foaming, gelation, and antioxidant activity, as well as their incorporation in the food industry as ingredients. Besides, they express low toxicity, are less expensive compared to synthetic polymers, and are biodegradable. This review aims to give a brief overview of the recent studies done using food proteins as colloidal delivery systems for hydrophobic and poorly soluble compounds.

Characteristics and antioxidant activity of Maillard reaction products from α-lactalbumin and 2'-fucosyllactose

The characteristics and antioxidant activity of Maillard reaction products (MRPs) from 2'-fucosyllactose (2'-FL), a human milk oligosaccharide, and α-lactalbumin (α-LA) were investigated. MRPs were prepared by reacting 2'-FL with α-LA at 60 °C and 79% relative humidity for up to 72 h. The absorbance and fluorescence intensity of heated α-LA-2'-FL increased as the heating time increased, while the free amino group content decreased, confirming that 2'-FL reacted with α-LA and produced various MRPs at different incubation stages. Conjugates of 2'-FL and α-LA and aggregation of α-LA were observed by SDS-PAGE. The secondary structure of α-LA did not change significantly after reacting with 2'-FL. In terms of antioxidant activity, the 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity and reducing power of α-LA-2'-FL increased significantly when compared with the protein only sample (p < 0.05). The findings provide a foundation for the characterization and functional analysis of MRPs in dairy products.

α-Lactalbumin and chitosan core–shell nanoparticles: resveratrol loading, protection, and antioxidant activity

Resveratrol (RES)-loaded protein–polysaccharide nanoparticles were fabricated through simple electrostatic interactions with oppositely charged α-lactalbumin (ALA) and chitosan (CHI) with a mass ratio of 5 : 1 without the addition of NaCl at pH 6.5.

Delivery of synergistic polyphenol combinations using biopolymer-based systems: Advances in physicochemical properties, stability and bioavailability

When consumed at sufficiently high levels, polyphenols may provide health benefits, which is linked to their antidiabetic, antiinflamatory, antimicrobial, antioxidant, antitumor, and hypolipidemic properties. Moreover, certain polyphenol combinations exhibit synergistic effects when delivered together - the combined polyphenols have a higher biological activity than the sum of the individual ones. However, the commercial application of polyphenols as nutraceuticals is currently limited because of their poor solubility characteristics; instability when exposed to light, heat, and alkaline conditions; and, low and inconsistent oral bioavailability. Colloidal delivery systems are being developed to overcome these challenges. In this article, we review the design, fabrication, and utilization of food-grade biopolymer-based delivery systems for the encapsulation of one or more polyphenols. In particular, we focus on the creation of delivery systems constructed from edible proteins and polysaccharides. The optimization of biopolymer-based delivery systems may lead to the development of innovative polyphenol-enriched functional foods that can improve human health and wellbeing.

Protein-polysaccharide nanohybrids: Hybridization techniques and drug delivery applications

Complex nanosystems fabricated by hybridization of different types of materials such as lipids, proteins, or polysaccharides are usually superior to simple ones in terms of features and applications. Proteins and polysaccharides hold great potential for development of nanocarriers for drug delivery purposes based on their unique biocompatibility, biodegradability, ease of functionalization, improved biodistribution and minimal toxicity profiles. Protein-polysaccharide nanohybrids have gained a lot of attention in the past few years particularly for drug delivery applications. In this review, different hybridization techniques utilized in the fabrication of such nanohybrids including electrostatic complexation, Maillard conjugation, chemical coupling and electrospinning were thoroughly reviewed. Moreover, various formulation factors affecting the characteristics of the formed nanohybrids were discussed. We also reviewed in depth the outcomes of such hybridization ranging from stability enhancement, to toxicity reduction, improved biocompatibility, and drug release modulation. We also gave an insight on their limitations and what hinders their clinical translation and market introduction.

Fabrication of Resveratrol-Loaded Whey Protein-Dextran Colloidal Complex for the Stabilization and Delivery of β-Carotene Emulsions

The effects of resveratrol (RES)-loaded whey protein isolate (WPI)-dextran nanocomplex on the physicochemical stability of β-carotene (BC) emulsions were evaluated. WPI-dextran was prepared by Maillard-based glycation and confirmed with gel electrophoresis and OPA assay. WPI-RES and WPI-dextran-RES nanoparticles were prepared with a simple nanocomplexation protocol. Fluorescence spectra indicated that hydrophobic interaction was the main driving force for the WPI-dextran-RES nanocomplex. Spherical and uniformly dispersed structures as well as nanoscale Z-average size (<100 nm) were confirmed for WPI-RES and WPI-dextran-RES nanocomplex with DLS and TEM. The Z-average diameter of emulsions with WPI-dextran conjugate was remarkably lower than that with WPI. Environmental stress (ionic strength, heat, and pH) and storage stability were pronouncedly improved. The chemical stability of BC with WPI-dextran-RES and WPI-RES was also remarkably enhanced when exposed to UV light and thermal treatment. The advantages of the WPI-dextran-RES colloidal complex may provide a better alternative to effectively protect and deliver hydrophobic nutraceuticals.

Improved stability, epithelial permeability and cellular antioxidant activity of β-carotene via encapsulation by self-assembled α-lactalbumin micelles

The low aqueous solubility, stability and bioavailability of hydrophobic bioactive compounds, such as β-carotene (β-c), greatly hinder their application in foods. Nanocarriers could overcome this problem by facilitating the delivery of the functional ingredients. We prepared lactalbumin (α-lac) micelles by partial enzymatic hydrolysis in aqueous solution. β-c can be incorporated into the cores of these micelles via hydrophobic interactions. The aqueous solubility and stability under 60 °C heating or UV light irradiation of encapsulated β-c improved significantly compared with free β-c. Moreover, it had an increased cellular uptake (3 times) and transmembrane permeability (13 times) in a Caco-2 cell monolayer model. It suggested that α-lac micelle-encapsulated β-c had an enhanced cellular absorption and transport efficiency. Encapsulated β-c also exhibited an enhanced cellular anti-oxidant activity (CAA) compared with free β-c. This work demonstrates that α-lac micelles showed a great potential for delivery of hydrophobic bioactive compounds in foods.

Physicochemical stability and antioxidant activity of soy protein/pectin/tea polyphenol ternary nanoparticles obtained by photocatalysis

The ternary nanoparticles were fabricated by soy protein, pectin and tea polyphenol through photocatalysis. The particulate characteristics, including particle size, polydispersity index, and zeta potential were monitored for ternary nanoparticles formed under different photocatalysis time. Photocatalysis was favorable to form ternary nanoparticles with moderate particle size (310-370 nm), uniform distribution, spherical shape, and improved antioxidant activity. It was found that the fluorescence intensity of soy protein decreased with the increase in photocatalysis time in the ternary nanoparticles. Far-UV circular dichroism results indicated that increasing photocatalysis time could alter the secondary structure of soy protein with an increase in the proportion of β-sheet and β-turn structure at the cost of unordered coil and α-helix structure. According to FT-IR results, photocatalysis time could also modulate the conjugation between pectin and soy protein. In addition, photocatalysis could increase the binding affinities among the components, leading to better environmental stability of the ternary nanoparticles. The ternary nanoparticles in this study could be used as a good alternative to understand and consequently improve the physicochemical stability in food, pharmaceutical, and cosmetic matrices.

Bioactive evaluation and application of different formulations of the natural colorant curcumin (E100) in a hydrophilic matrix (yogurt)

Curcumin (E100) is a natural colorant that, besides conferring color, has bioactivity, serving as an alternative to some artificial colorants. As a hydrophobic colorant, its modification/compatibilization with the aqueous medium is required to improve stability and enable its application in hydrophilic food matrices. Herein, different formulations of curcumin (curcumin powder: PC, water-dispersible curcumin: DC: and nanoencapsulated curcumin: NC) were evaluated as yogurt colorants. PC showed the strongest bioactivity in all assays (EC₅₀ values: 63 ± 2 to 7.9 ± 0.1 μg.mL^-1; GI₅₀ values: 48 ± 1 to 17 ± 1 μg.mL^-1 and MIC values: 0.0625 to 0.5 mg.mL^-1), which might indicate that DC and NC reduce the short-term accessibility to curcumin. The tested curcumin formulations produced yogurts with different appearance, specifically associated with their color parameters, besides presenting slight changes in nutritional composition and free sugars and fatty acids profiles. The water compatible formulations (DC and NC) showed advantages over hydrophobic (PC) having a wider industrial utilization.

Enhanced pH and thermal stability, solubility and antioxidant activity of resveratrol by nanocomplexation with α-lactalbumin

The health-promoting benefits of resveratrol (RES) have attracted significant attention.

Improved Chemical Stability and Antiproliferative Activities of Curcumin-Loaded Nanoparticles with a Chitosan Chlorogenic Acid Conjugate

A chitosan (CS)-chlorogenic acid (CA) conjugate was successfully prepared through free-radical-induced protocols with a substitution of CA on CS of 103.5 mg/g. ATR-FTIR and ¹H NMR results validated the covalent conjugation of CA onto CS. XRD results indicated the decrease of crystallinity after CA conjugation. DPPH-scavenging activity and reducing-power studies indicated that the CS-CA conjugate had stronger antioxidant activity than chitosan. The particle diameters of curcumin-loaded CS and CS-CA nanoparticles simultaneously formed by ionic gelling in the presence of tripolyphosphate (TPP) were less than 300 nm (243.6 and 256.5 nm, respectively), and zeta-potential values between 25 and 30 mV were obtained. TEM results showed that the nanoparticles were spherically shaped and homogeneously dispersed. Curcumin with the CS-CA conjugate showed better heat stability than with CA at both temperatures (25 and 95 °C) (p <0.05). Curcumin release was inhibited by the CS-CA conjugate. The total release amount of curcumin from CS and CS-CA-conjugate nanoparticles were 70.5 and 61.7%, respectively (p <0.05). A methyl thiazolyl tetrazolium (MTT) assay showed that the antiproliferative activity of curcumin in CS-CA nanoparticles was remarkably higher than that in CS nanoparticles because of the higher chemical stability. The results suggest that CS-CA-based nanoparticles are promising candidates for the encapsulation and controlled release of hydrophobic, bioactive compounds and can improve these compounds' chemical stabilities and anticancer activities.

Soy Soluble Polysaccharide as a Nanocarrier for Curcumin

The complexation between soy soluble polysaccharide (SSPS) and curcumin at pH 7.0 and 4.0, as well as some physicochemical characteristics of the resultant complexes, was investigated. The encapsulation efficiency and loading amount of curcumin in the complexes at pH 4.0 reached 67.3% and 4.49 μg/mg SSPS, respectively. Ethanol-induced denaturation and structural unfolding of the protein fraction in SSPS was essential for complex formation. The complexation with curcumin resulted in aggregation of SSPS and the subsequent formation of compacted nanoparticles with curcumin as the core. The complexation greatly improved the heat stability and in vitro bioaccessibility of curcumin. In general, the encapsulation efficiency, heat stability, and bioaccessibility of curcumin in the complexes at pH 4.0 were better than those at pH 7.0. The findings are of importance for the development of food grade nanovehicles for enhanced water solubility, stability, and bioaccessibility of hydrophobic bioactives.