Anilda Guri

Effect of processing on physicochemical characteristics and bioefficacy of β-lactoglobulin-epigallocatechin-3-gallate complexes.

Varying amounts of epigallocatechin-3-gallate (EGCG) were encapsulated in β-lactoglobulin (β-Lg) nanoparticles, either native or processed, denoted as heated or desolvated protein. The stability, physical properties, and bioactivity of the β-Lg-EGCG complexes were tested. Native β-Lg-EGCG complexes showed comparable stability and binding efficacy (EGCG/β-Lg molar ratio of 1:1) to heated β-Lg nanoparticles (1% and 5% protein w/w). The sizes of heated and desolvated β-Lg nanoparticles were comparable, but the latter showed the highest binding affinity for EGCG. The presence of EGCG complexed with β-Lg did not affect the interfacial tension of the protein when tested at the soy oil-water interface but caused a decrease in dilational elasticity. All β-Lg complexes (native, heated, or desolvated) showed a decrease in cellular proliferation similar to that of free ECGC. In summary, protein-EGCG complexes did not alter the bioefficacy of EGCG and contributed to increased stability with storage, demonstrating the potential benefits of nanoencapsulation.

Bovine milk fat globule membrane affects virulence expression in Escherichia coli O157:H7

The aim of this study was to examine the effect of the bovine milk fat globule membrane (MFGM) on the virulence of Escherichia coli O157:H7. The MFGM was extracted from raw or heat-treated milk, resulting in 2 preparations differing in protein composition. Both heated and raw MFGM exerted an inhibitory effect on Shiga toxin gene expression by E. coli O157:H7 (ratios of -7.69 and -5.96, respectively). Interestingly, the effect was stronger with heated MFGM, with a larger decrease in expression of the virulence gene fliC (ratio of -9.43). The difference in effect observed between heated and raw MFGM could be explained by the difference in protein composition between the 2 preparations. These results show, for the first time, a specific effect of MFGM on expressionof Shiga toxin genes as well as genes involved in the motility of E. coli O157:H7. This may offer a new approach to mitigate the adverse health effects caused by E. coli O157:H7 infections.

The effect of milk fat globules on adherence and internalization of Salmonella Enteritidis to HT-29 cells

Milk fat globules were extracted from bovine and goat milk and incubated with HT-29 human adenocarcinoma cells to assess the attachment and internalization of Salmonella Enteritidis. Because the expression of bacterial adhesins is highly affected by the presence of antibiotic, the attachment was studied with and without antibiotic in the cell growth medium. Although no inhibitory effect of the fat globules was observed in the presence of the antibiotic, milk fat globules significantly inhibited the binding and internalization of Salmonella in medium free of antibiotic. The fat globules from both bovine and goat milk markedly reduced bacterial binding and invasion compared with controls, and the cells treated with goat milk-derived fat globules demonstrated greater protective properties than those derived from bovine milk. The effect of heat treatment on bovine fat globules was also investigated, and it was shown that the fat globules from heated milk had a higher degree of inhibition than those from unheated milk.

Mucus interactions with liposomes encapsulating bioactives: Interfacial tensiometry and cellular uptake on Caco-2 and cocultures of Caco-2/HT29-MTX

Structuring of delivery matrices in foods aquires careful designing for optimal delivery and subsiquent absorption of the beneficial compounds in the gut. There has been quite improvement in mimicking digestion and absorption in vitro but as of yet little is understood on mucus interference in nutrient absorption Therefore in this study interactions of human intestinal mucus with milk and soy phospholipids liposomes carring hydrophilic (epigallocatechin-3-gallate) or hydrophobic (β-carotene) bioactive molecules were investigated. Liposomes of about 100nm were obtained using microfluidization and their behaviour with the human intestinal mucus were evaluated using drop shape tensiometry. The chemistry of the liposomes (milk or soy) and the encapsulated bioactive structure can affect the viscoelastic behaviour of the complex itself. Empty or loaded liposomes were differently interacting with the mucus at the interface. Mucus-liposomes interactions were also studied using cell cultures, Caco-2 (without mucus) and cocultures Caco-2/HT29-MTX (mucus producing). The interaction of mucus layer with liposomes was at some extent aligned with rheological studies. This work demonstrated that delivery systems may interact with the mucosal surface of intestinal cells, and in vitro approaches allow for screening of such interactions. These highlights could help us in carefully designing the delivery systems and moreover choosing the right carrier and/or bioactive that does not jeopardize the optimal delivery of the bioactive structure.

Dairy Materials as Delivery Tools for Bioactive Components in Dairy Platforms

Abstract Milk is composed of a wide variety of molecules with nutritional and multiple biological functionalities. The two main examples of colloidal structures in milk with multiple functions are fat globules and protein assemblies, referred to as casein micelles. Both assemblies are examples of how nature has resolved the task of delivering nutrients. They are often studied as a model of how to create structures in foods with enhanced functionality during consumption and digestion. Proteins and lipid aggregates in milk encode bioactive structures that will become important once digested, and will serve protective roles in the gut, for example, by regulating the immune system, by serving as cell differentiation factors, or by showing symbiotic functions with beneficial microorganisms. The milk components can form supramolecular structures that can be employed for the delivery of additional health benefits. The current knowledge of such structures present in milk, their changes during processing and digestion, and their relationship to biological functions in the gastrointestinal tract are outlined in this chapter. Recent findings in this area have created a paradigm shift in how we process and design new dairy foods aimed at providing additional health benefits to consumers.

In vitro screening of mare's milk antimicrobial effect and antiproliverative activity.

The aims of this study were to examine the effect of mares milk on virulence gene expression of Salmonella Typhimurium and observe its potential activity on proliferation of adenocarcinoma Caco-2 cells. Different supernatants of mares milk, raw or heat-treated at 65°C for 15 s or 30 min, were studied. The changes in hilA gene expression of Salmonella Typhimurium in presence of mares milk supernatants were assessed using a reporter luminescent strain. A significant decrease in hilA gene expression was observed with all tested supernatants. Virulence gene expression was then assessed using qPCR on a wild-type strain of Salmonella Typhimurium. A significant decrease of hilA and ssrB2 gene expression was observed with raw milk supernatants but not with heat-treated supernatants. The same supernatants were administered to Caco-2 cells to measure their proliferation rate. A significant reduction of proliferative effect was observed only with raw milk supernatants. This study reports that raw mares milk was able to modulate virulence gene expression of Salmonella Typhimurium and exerts antiproliferative effects on Caco-2 cells. These results may offer new approaches for promoting gastrointestinal health.

Nanocapsule formation by caseins

Global issues with increased incidence of common diseases have raised the demand for healthier diet and functional food products in the market that can possibly ameliorate or prevent the prevalence of diseases. Encapsulation technologies are proved to be a safe way to deliver and maintain the functionality of the biologically active components. With this in mind, food scientists are striving to identify and utilize natural agents, which would serve as potential carriers of bioactive compounds in food products. The structural organization and complexity of milk proteins especially caseins, as the main protein fraction in milk, offers more than a simple functional agent in dairy technology. Caseins possess a great potential in complex formation and encapsulation of biologically active species. In this chapter recent investigations being carried out to encapsulate bioactive agents, either food grade or pharmaceutical via caseins are highlighted; an overview of casein structural organization, and the underlying physicochemical characteristics that facilitates their usage as nanocarriers are discussed; an introduction of recent methods employed for encapsulation of bioactives via casein complexation are explained along with the relevant challenges and future insights.

In vitro uptake and immune functionality of digested Rosemary extract delivered through food grade vehicles

The digestion, absorption, uptake and bioavailability of a rosemary supercritical fluid extract encapsulated in oil in water emulsion were studied. Two emulsions with opposite surface charge were prepared, containing 7% canola oil, and either 2% lactoferrin or whey protein isolate. When absorption and uptake of carnosic acid and carnosol were followed on Caco-2 cell monolayers, there were no differences with protein type. However, when co-cultures of HT-29 MTX were employed, the presence of mucus caused a higher retention of carnosic acid in the apical layer for lactoferrin emulsions. The immune activity of the bioavailable fractions collected from cell absorption experiments was tested ex vivo on murine splenocytes. Although transport through the intestinal barrier models was low, the bioavailable fractions showed a significant effect on splenocytes proliferation. These results demonstrated the potential of using rosemary supercritical extract through protein stabilized oil in water emulsions, as a food with immunomodulatory functionality.

Lactococcus lactis subsp. cremoris strain JFR1 attenuates Salmonella adhesion to human intestinal cells in vitro

Lactococcus lactis subsp. cremoris JFR1 has been studied in reduced fat cheese due to its ability to produce exopolysaccharides (EPS) in situ, contributing to improved textural and organoleptic properties. In this study, the effect of strain JFR1 on virulence gene expression and attachment of Salmonella to HT-29 human colon carcinoma cells was investigated. Overnight cultures of L. lactis subsp. cremoris JFR1 containing EPS, grown in M17 media with 0.5% glucose supplementation, decreased attachment as well as down regulated virulence gene expression in Salmonella enterica subsp. enterica when tested on HT-29 cells. However, EPS isolated from milk fermented with L. lactis subsp. cremoris JFR1 did not affect Salmonella virulence gene expression or attachment to HT-29 cells. These results suggest that EPS does not contribute to the attachment of Salmonella to human intestinal cells. However, the possibility that the isolation process may have affected the structural features of EPS cannot be ruled out.

Delivery of Curcumin Using Skim Milk or Oil in Water Emulsions: Effect of the Matrices on Cellular Uptake

To enhance the curcumin delivery in a variety of food grade matrices namely spray dried ethanolic curcumin in fresh skim milk (Spray dried Cu-SM), a fresh mixture of ethanolic curcumin and skim milk (Fresh Cu-SM) a powder mixture of curcumin and skim milk powder (Powder Cu-SMP) and oil in water emulsion (Emulsion) were studied. The cellular uptake of curcumin from the respective matrices was studied on Caco-2 cell monolayers. Spray dried Cu-SM showed higher encapsulation efficiency compared to a corresponding Powder Cu-SMP and an oil-in-water emulsion (40% oil) bearing curcumin. Furthermore, ethanolic administration of curcumin in spray dried form enhanced the cellular uptake of curcumin considerably higher than non-ethanolic samples (approx. 4 times). Overall, milk protein based vectors were found to perform better than emulsion samples. These findings highlighted the fact that curcumin uptake may be tailored by fine tuning of curcumin delivery vehicles which highlights possible application of powders as functional foods.