Food-grade Delivery Systems Research Articles

Development of oral food-grade delivery systems: Current knowledge and future challenges

In recent years there has been an increasing interest in the development of new and efficient oral food delivery systems as tools to prevent disease and promote human health and well-being. Such vehicles are sought to protect bioactive ingredients added to food while controlling and targeting their release as they pass through the human gastrointestinal tract (GIT). This review aims to summarize the key concepts of food delivery systems, their characterization and evaluation. Particularly, evaluation of their performance within the human GIT is discussed. To this end an overview of several in vivo and in vitro methods currently applied for the study of such systems is given. Although considered to be still in its infancy, this promising field of research is likely to infiltrate into real products through rational design. In order for such efforts to materialize into real products some challenges still need to be met and are discussed herein. Overall, it seems that adopting a comprehensive pharmacological approach and relevant cutting edge tools are likely to facilitate innovations and help elucidate and perhaps tailor delivery systems' behavior in the human GIT.

Curdlan Complexes As a Potential food-grade Delivery System: Genistein Case Study

Complexes of curdlan and genistein were prepared using four different methods. The total amount of genistein in curdlan-genistein complexes prepared at 40 degrees C (system I) was significantly higher (2.3 mg/100 mg dry matter) than that in other systems studied: curdlan-genistein complexes prepared at 60 degrees C (system II; 1.8 mg/100 mg dry matter); curdlan-genistein gel complexes (system III; 1.0 mg/100 mg dry matter); and curdlan-genistein dimethyl sulfoxide complexes (system IV; 1.8 mg/100 mg dry matter). x-ray diffraction results indicate that complexation of curdlan with genistein changes the crystalline nature of the pure components. Particle size analysis, atomic force microscopy and scanning electron microscopy imaging of curdlan-genistein complexes showed strong difference in particle size, surface and distribution in comparison with pure curdlan, confirming our assumption of a molecular interaction between curdlan and genistein and the formation of a new structure, which was revealed at the nanoscale level. All the curdlan-genistein complexes showed prolonged genistein release of up to 72 h, enhanced upon enzymatic digestion of curdlan by lyticase, thus opening the possibility of release regulation by the incorporation of lyticase in the delivery system. It is therefore suggested that the complexes could be used as a delivery system for the protection and slow release of genistein in the digestive tract.

Modulation of physicochemical properties of lipid droplets using β-lactoglobulin and/or lactoferrin interfacial coatings

There is considerable interest in the development of food-grade delivery systems to encapsulate, protect and release bioactive lipids. In this study, emulsion-based delivery systems were prepared consisting of lipid droplets covered by β-lactoglobulin (BLG) and/or lactoferrin (LF) coatings. BLG and LF are globular proteins with relatively low (pI∼5) and high (pI∼8) isoelectric points, respectively. Mixed systems were prepared by adding LF to BLG-stabilized corn oil-in-water emulsions (BLG/LF-coated droplets) or by adding BLG to LF-stabilized corn oil-in-water emulsions (LF/BLG-coated droplets) at pH 7, where there is an electrostatic attraction between the proteins. The influence of pH (3–7), ionic strength (0–60mM CaCl2 or 0–200mM NaCl, pH 7), and thermal treatment (21–90°C, pH 7, 20min) on the physical stability of the resulting emulsions was examined. Emulsions with good stability to pH, salt, and thermal processing could be created using mixed interfacial coatings. In addition, we found that the lipids in these emulsions could still be digested using an in vitro digestion model to simulate small intestine conditions. This work may lead to the formation of emulsion-based delivery systems with improved physicochemical and functional performance.

Emulsion-Based Delivery Systems for Tributyrin, a Potential Colon Cancer Preventative Agent

Tributyrin, a short-chain triglyceride oil used as a food additive, has been reported to be a potential preventive agent against colon cancer. The purpose of this study was to develop tributyrin delivery systems based on food-grade oil-in-water emulsions that could potentially be incorporated into foods. Emulsions containing only tributyrin as the lipid phase were highly unstable to droplet growth due to Ostwald ripening (OR) because of the relatively high water solubility of this low molecular weight triacylglycerol. The stability of the emulsions to OR could be greatly improved by incorporating >or=15-25% corn oil (a food-grade oil with a low water solubility) into the lipid phase. In addition, the tendency for droplet sedimentation to occur was reduced because the density contrast between the lipid and water phases was reduced in the mixed tributyrin/corn oil systems. The potential anticarcinogenic ability of the tributyrin emulsions was demonstrated using a cell culture model. Treatments with emulsions containing tributyrin significantly inhibited the viability of HT29 colon carcinoma cells. These results have important implications for the development and testing of nutraceuticals encapsulated in food-grade delivery systems as anticancer agents.

Nanoscalar Structures of Spray-Dried Zein Microcapsules and in Vitro Release Kinetics of the Encapsulated Lysozyme As Affected by Formulations

Sustained release of antimicrobials may be a viable solution to enhance the bioavailability during the shelf life of food products. In this work, spray-drying was used to encapsulate a model antimicrobial of lysozyme in corn zein. The effects of zein/lysozyme (20:1 to 4:1) and zein/thymol (1:0 to 4:1) ratios on the microstructures of microcapsules and in vitro release profiles of the encapsulated lysozyme were investigated. In all cases, less lysozyme was released at higher pH, resulting from stronger molecular attraction between zein and lysozyme. Nanoscalar matrix structures of microcapsules were correlated with release characteristics of the encapsulated lysozyme. At intermediate zein/lysozyme (10:1) and zein/thymol (50:1) ratios, microcapsules had a continuous matrix structure and showed sustained release (11.1-65.3%) of lysozyme at pH 6 over 49 days. This work may be developed into practical food grade delivery systems of antimicrobials.

Application of Supercritical Anti-Solvent Technologies for the Synthesis of Delivery Systems of Bioactive Food Components

To develop edible delivery systems suitable for food applications, regulations require that solvents and ingredients are either generally recognized as safe or listed by the Food and Drug Administration as processing aids. In this work, we studied a food grade polymer-corn zein, a category of alcohol-soluble proteins, as the carrier material for microencapsulating bioactives. Zein is insoluble in aqueous solutions; zein-based delivery systems may thus maintain the integrity in aqueous food products during processing and storage. Three alcohols, i.e., ethanol, methanol, and isopropanol, with an appropriate amount of water were used to dissolve zein. A supercritical anti-solvent process was applied to synthesize micro- and nanoparticles of zein for edible delivery systems of bioactive compounds. We studied critical variables during the particle formation: polymer concentration, CO2 flow rate, and co-solvent chemistry. Particles were produced only when mass transfer was fast enough that the co-solvent in the atomized droplets could be extracted by the reservoir CO2 and polymers could nucleate and grow into particles. Manipulation of the above variables enabled the production of micro- and nanoparticles, which can be used as bases for microencapsulating bioactives. Our results demonstrated promising applications of the supercritical anti-solvent technology to synthesize food grade delivery systems of bioactive food ingredients that can enhance the healthfulness, safety, and quality of food products.

A food-grade delivery system for Lactococcus lactis and evaluation of inducible gene expression.

The genetic improvement of Lactococcus lactis is a matter of biotechnological interest in the food industry and in the pharmaceutical and medical fields. However, to construct a food-grade delivery system, both the presence of antibiotic markers or plasmid sequences should be avoided and the maintenance and expression of the cloned gene should be guaranteed. The objective of this work was to produce crossover mutants of L. lactis with a reporter gene under the control of an inducible promoter in order to evaluate the level of gene expression. We utilized a nuclease gene of Staphylococcus aureus as a reporter gene, P(nisA) as the nisin-inducible promoter, a non-essential gene involved in histidine biosynthesis of L. lactis as the site for homologous recombination, and pRV300 as a suicide vector for the genomic integration in L. lactis NZ9000. Single- and double-crossover mutants were identified by genotype and phenotype. Relative to episomal transformants of L. lactis, the level of expression of the heterologous protein after nisin induction was similar in the crossover mutants, suggesting that a single copy of the heterologous gene can be used to produce the protein of interest.

Food-grade delivery system for controlled gene expression in Lactococcus lactis

Food-grade delivery system for controlled gene expression in <em>Lactococcus lactis</em>