Gabriel Davidov-Pardo

Nutraceutical delivery systems: Resveratrol encapsulation in grape seed oil nanoemulsions formed by spontaneous emulsification

The aim of this work was to fabricate nanoemulsions-based delivery systems to encapsulate resveratrol. Nanoemulsions were formed using spontaneous emulsification method: 10% oil phase (grape seed oil plus orange oil) and 10% surfactant (Tween 80) were titrated into 80% aqueous phase. An optimum orange oil-to-grape seed oil ratio of 1:1(w/w) formed small droplets (d ≈ 100 nm) with good stability to droplet growth. The maximum amount of resveratrol that could be dissolved in the oil phase was 120 ± 10 μg/ml. The effect of droplet size on the chemical stability of encapsulated resveratrol was examined by preparing systems with different mean droplet diameters of 220 ± 2; 99 ± 3; and 45 ± 0.4 nm. Encapsulation of resveratrol improved its chemical stability after exposure to UV-light: 88% retention in nanoemulsions compared to 50% in dimethylsulphoxide (DMSO). This study showed that resveratrol could be encapsulated within low-energy nanoemulsion-based delivery systems and protected against degradation.

Fluorescence quenching study of resveratrol binding to zein and gliadin: towards a more rational approach to resveratrol encapsulation using water-insoluble proteins

Several health benefits have been ascribed to consumption of resveratrol, a polyphenol that can be extracted from grape skins. However, its use as a nutraceutical ingredient is compromised by its low water solubility, chemical stability, and bioavailability. Encapsulation of resveratrol in protein nanoparticles can be used to overcome these issues. Fluorescence quenching experiments were used to study the interaction of resveratrol with gliadin and zein. Resveratrol interacted with both proteins, but the binding constant was higher for zein than for gliadin at 35 °C. Furthermore, binding between resveratrol and gliadin increased at higher temperatures, which was not observed for zein. Analysis of the thermodynamic parameters suggested that resveratrol-gliadin binding mainly occurs through hydrophobic interactions while the binding with zein is predominantly mediated through hydrogen bonds. These results help rationalise ingredient selection and production of protein nanoparticles and microparticles for encapsulation, protection and release of resveratrol and potentially other bioactive compounds.

Improving Resveratrol Bioaccessibility Using Biopolymer Nanoparticles and Complexes: Impact of Protein–Carbohydrate Maillard Conjugation

The impact of encapsulating resveratrol in biopolymer nanoparticles or biopolymer complexes on its physicochemical stability and bioaccessibility was determined. The biopolymer nanoparticles consisted of a zein core surrounded by a caseinate or caseinate-dextran shell. The biopolymer complexes consisted of resveratrol bound to caseinate or caseinate-dextran. The caseinate-dextran conjugates were formed using the Maillard reaction. Both the biopolymer nanoparticles and complexes protected trans-resveratrol from isomerization when exposed to UV light, with the nanoparticles being more effective. Nanoparticles coated by caseinate-dextran were more stable to aggregation under simulated gastrointestinal conditions than those coated by caseinate, presumably due to greater steric repulsion. The bioaccessibility of resveratrol was enhanced when it was encapsulated in both biopolymer nanoparticles and biopolymer complexes. These results have important implications for the development of effective delivery systems for incorporating lipophilic nutraceuticals into functional foods and beverages.

Lutein-enriched emulsion-based delivery systems: Influence of pH and temperature on physical and chemical stability

Lutein may be utilized in foods as a natural pigment or nutraceutical ingredient to improve eye health. Nevertheless, its use is limited by its poor water-solubility and chemical instability. We evaluated the effect of storage temperature and pH on the physical and chemical stability of lutein-enriched emulsions prepared using caseinate. The emulsions (initial droplet diameter=232 nm) remained physically stable at all incubation temperatures (5-70 °C); however the chemical degradation of lutein increased with increasing temperature (activation energy=38 kJ/mol). Solution pH had a major impact on the physical stability of the emulsions, causing droplet aggregation at pH 4 and 5. Conversely, the chemical stability of lutein was largely independent of the pH, with only a slight decrease in degradation at pH 8. This work provides important information for the rational design of emulsion-based delivery systems for a lipophilic natural dye and nutraceutical.

Food-Grade Protein-Based Nanoparticles and Microparticles for Bioactive Delivery: Fabrication, Characterization, and Utilization

Proteins can be used to fabricate nanoparticles and microparticles suitable for use as delivery systems for bioactive compounds in pharmaceutical, food, cosmetic, and other products. Food proteins originate from various animal or vegetal sources and exhibit a wide diversity of molecular and physicochemical characteristics, e.g., molecular weight, conformation, flexibility, polarity, charge, isoelectric point, solubility, and interactions. As a result, protein particles can be assembled using numerous different preparation methods, from one or more types of protein or from a combination of a protein and another type of biopolymer (usually a polysaccharide). The final characteristics of the particles produced are determined by the proteins and/or polysaccharides used, as well as the fabrication techniques employed. This chapter provides an overview of the functional properties of food proteins that can be used to assemble nanoparticles and microparticles, the fabrication techniques available to create those particles, the factors that influence their stability, and their potential applications within the food industry.

Effect of Maillard Conjugates on the Physical Stability of Zein Nanoparticles Prepared by Liquid Antisolvent Coprecipitation

Protein nanoparticles are often not very stable in a complex food matrix because they are primarily stabilized by electrostatic repulsion. In this study, we envisaged the stabilization of zein nanoparticles through Maillard conjugation reactions with polysaccharides of different molecular mass. Zein nanoparticles (0.5% w/v) containing resveratrol (0.025% w/v grape skin extract) were produced by liquid antisolvent precipitation and coated with Maillard conjugates (MC) of sodium caseinate and different molecular mass carbohydrates during particle production. Zein nanoparticles coated with conjugated polysaccharides of 2.8, 37, and 150 kDa had diameters of 198 ± 5, 176 ± 6, and 180 ± 3 nm, respectively. The encapsulation efficiency (∼83%) was not affected by conjugation, but the conjugates significantly improved particle stability against changes in pH (2.0-9.0), CaCl2 addition (up to 100 mM), and heat treatment (30-90 °C, 30 min). Zein nanoparticles coated by MC may therefore be suitable delivery systems for hydrophobic bioactive molecules in a wide range of commercial products.

Kinetics of thermal modifications in a grape seed extract.

The thermal modification kinetics of a commercial grape seed extract (GSE) was investigated. A GSE was exposed to 60, 90, and 120 °C for 5, 10, 15, 30, 45, and 60 min. The antioxidant activity (AA) and the absorbance at 420 nm (A(420)) were measured. (+)-Catechin, (-)-epicatechin, procyanidins B1 and B2, and gallic acid were identified and measured. After the thermal treatments, the AA did not show a significant difference (p > 0.05) and both procyanidins and gallic acid increased as well as A(420). (+)-Catechin and (-)-epicatechin decreased. To obtain the activation energy (E(a)) of the changes, a modified Weibull and a combined zero- and first-order model were compared, both followed by the Arrhenius equation. The Weibull model was more accurate. The E(a) values for browning and (+)-catechin, (-)-epicatechin, gallic acid, and procyanidins B1 and B2 were 170, 286, 42, 102, 249, and 95 kJ/mol, respectively. The results were valid at a confident level of 95%.

Microencapsulation of Grape Seed Extracts

Grape seed extracts (GSE) from vinification by-products are an abundant and inexpensive source of polyphenols. They can be used as functional ingredients in the food industry due to their beneficial effects on human health. GSE can also substitute for synthetic anti-oxidants in organic or all-natural products. Despite the beneficial effects of the GSE, its use in the food industry is limited because it has limited solubility in water, it is unstable at high temperatures, and its bioavailability is low. Microencapsulation can be employed to overcome these drawbacks and facilitate the incorporation of GSE in food products. Microcapsules of GSE have been made using a wide variety of methods and materials, and show improvements in one or more of the problems with using the extracts. The aim of this chapter is to summarize studies of the microencapsulation of GSE, as well as GSE’s composition and benefits.