Norovirus elimination on the surface of fresh foods.

Fresh foods like fruits, vegetables and shellfish are potential sources for viral infections such as human norovirus (NoV). Chemical treatment like chlorination is a well-known process for food pathogens and virus elimination. However, with the increase of the consumer demand for less toxic treatment, the use of natural antimicrobials like essential oils from spice or plants, fruit extracts, and cold pasteurization treatments (fermentation, irradiation, ozonation and high pressure) could be considered. The aim of this review is to discuss these technologies and their efficacy to eliminate NoV on the surface of fresh food.

In vitro protein digestibility and physico-chemical properties of lactic acid bacteria fermented beverages enriched with plant proteins.

The objective of this study was to develop probiotic beverages, enriched with plant proteins, with high nutritional value. A rice-based beverage fermented with a specific probiotic formulation comprised Lactobacillus acidophilus CL1285, Lactobacillus casei LBC80R and Lactobacillus rhamnosus CLR2 has been enriched with a combination of pea and rice proteins (PR) or pea and hemp proteins (PH) at 13 and 11% total protein, respectively. These protein associations have been selected because their amino acid ratio was >1, as recommended by the FAO. The beverage enriched with protein significantly increased its viscosity by more than 10 times thanks to the enrichment, while the fermentation reduced it by 50% for PR and 20% for PH. In vitro protein digestibility results showed that the protein enrichment and the fermentation treatment significantly increased digestibility values of the beverages with value of 72.7% for fermented PR beverage and 61.4% for unenriched fermented control beverage (p ≤ 0.05). Peptide profiles of PR and PH enriched beverages indicated that the fermentation led to a reduced level of high molecular weight (HMW) peptides of about 60% and an increase of low molecular weight (LMW) peptides by over 50%. Therefore, both the fermentation and the enrichment in protein increased the nutritional value of the rice-based beverages. PRACTICAL APPLICATION: Good quality of probiotics formulation and high-protein products are in increasing demand and plant proteins as an alternative of animal protein are popular. This study has permit to develop rice-based commercial probiotic beverages enriched in a combination of pea and rice or pea and hemp proteins in order to obtain a complete protein in terms of amino acids composition. The lactic acid fermentation and the enrichment with a plant protein combination led to a better protein digestibility of beverage.

The synergistic effect of cell wall extracted from probiotic biomass containing Lactobacillus acidophilus CL1285, L. casei LBC80R, and L. rhamnosus CLR2 on the anticancer activity of cranberry juice-HPLC fractions.

Anticancer effects were evaluated on three HPLC fractions obtained from a concentrated cranberry juice and cell wall constituents extracted from a probiotic biomass containing Lactobacillus acidophilus CL1285, Lactobacillus casei LBC80R, and Lactobacillus rhamnosus CLR2. The samples were tested at increasing concentrations for the antiproliferative assay using HT-29 cells' line and for the quinone reductase (QR) assay using Hepa-1c1c7 murine hepatoma cells. Fraction 1 (F1) which is highly concentrated with phenolic acids inhibited the growth of the HT-29 cells' line with IC50 values of 14.80 µg Gallic acid equivalent (GAE)/ml. The fraction 3 (F3) which is highly concentrated in flavonols had potency as QR inducer. Furthermore, the results showed that all cranberry fractions combined with cell wall constituents extracted from the probiotic biomass were more effective in inhibiting the growth of HT-29 as compared to the cranberry fractions tested alone, indicating a possible synergy effect between these bio-functional compounds. PRACTICAL APPLICATIONS: This study strongly evidenced that cranberry juice fractions combined with cell wall constituents extracted from the probiotic biomass can be used as a potent preventive functional compound against colorectal cancer. Therefore, this research proposes a natural dietary compound to prevent mutagenesis and carcinogenesis of colorectal cancer. Furthermore, the industry can formulae products containing probiotic and phenolic compounds as colon cancer cell growth preventive and anticancer products.

Antimicrobial Properties of Encapsulated Antimicrobial Natural Plant Products for Ready-to-Eat Carrots.

The antimicrobial activity of natural antimicrobials (fruit extracts, essential oils and derivates), was assessed against six bacteria species (E. coli O157:H7, L. monocytogenes, S. Typhimurium, B. subtilis, E. faecium and S. aureus), two molds (A. flavus and P. chrysogenum) and a yeast (C. albicans) using disk diffusion method. Then, the antimicrobial compounds having high inhibitory capacity were evaluated for the determination of their minimum inhibitory, bactericidal and fungicidal concentration (MIC, MBC and MFC respectively). Total phenols and flavonoids content, radical scavenging activity and ferric reducing antioxidant power of selected compounds were also evaluated. Based on in vitro assays, five antimicrobial compounds were selected for their lowest effective concentration. Results showed that, most of these antimicrobial compounds had a high concentration of total phenols and flavonoids and a good anti-oxidant and anti-radical activity. In situ study showed that natural antimicrobials mix, applied on the carrot surface, reduced significantly the count of the initial mesophilic total flora (TMF), molds and yeasts and allowed an extension of the shelf-life of carrots by two days as compared to the control. However, the chemical treatment (mix of peroxyacetic acid and hydrogen peroxide) showed antifungal activity and a slight reduction of TMF.

Nanoliposomal carriers for improvement the bioavailability of high - valued phenolic compounds of pistachio green hull extract.

In present study, nanoliposomes were prepared by thin hydration method with different concentrations of phenolic compounds (500, 750 and 1000ppm) of pure extract and lecithin (1, 2 and 3%w/w) and characterized by considering the particle size, polydispersity index (PDI), zeta potential, encapsulation efficiency (EE) and morphology. The results showed that nanoliposome (90.39-103.78nm) had negative surface charge varied from -51.5±0.9 to -40.2±0.2mV with a narrow size distribution (PDI≈0.069-0.123). Nanoliposomes composed of 1% lecithin with 1000ppm of phenolic compounds had the highest EE (52.93%). The FTIR analysis indicated the formation of hydrogen bonds between the polar zone of phospholipid and the OH groups of phenolic compounds. Phenolic compounds also increased phase transition temperature (Tc) of nanoliposomes (2.01-7.24°C). Moreover, nanoliposomes had considerable stability during storage. Consequently, liposome is an efficient carrier for protection and improving PGHE biofunctional actives in foodstuffs.

World Market Development and Consumer Acceptance of Irradiation Technology.

Food irradiation is an efficient technology that can be used to ensure food safety by eliminating insects and pathogens to prolong the shelf life. The process could be applied to fresh or frozen products without affecting the nutritional value. Presently more than 60 countries have adopted the technology. However, the technology adaptation differs from one country to another and, in some cases, consumers' misunderstanding and lack of acceptance may hinder the technology adaptation process. This review summarizes the development of irradiation treatment worldwide and consumer attitudes towards the introduction of this technology. Also, the wholesomeness, beneficial effects, and regulation of irradiation are assessed.

Influence of lecithin-lipid composition on physico-chemical properties of nanoliposomes loaded with a hydrophobic molecule.

In this work, we studied the effect of nanoliposome composition based on phospholipids of docosahexaenoic acid (PL-DHA), salmon and soya lecithin, on physico-chemical characterization of vector. Cinnamic acid was encapsulated as a hydrophobic molecule in nanoliposomes made of three different lipid sources. The aim was to evaluate the influence of membrane lipid structure and composition on entrapment efficiency and membrane permeability of cinnamic acid. These properties are important for active molecule delivery. In addition, size, electrophoretic mobility, phase transition temperature, elasticity and membrane fluidity were measured before and after encapsulation. The results showed a correlation between the size of the nanoliposome and the entrapment. The entrapment efficiency of cinnamic acid was found to be the highest in liposomes prepared from salmon lecithin. The nanoliposomes composed of salmon lecithin presented higher capabilities as a carrier for cinnamic acid encapsulation. These vesicles also showed a high stability which in turn increases the membrane rigidity of nanoliposome as evaluated by their elastic properties, membrane fluidity and phase transition temperature.

Calcein release behavior from liposomal bilayer; influence of physicochemical/mechanical/structural properties of lipids.

The design of the drug delivery depends upon different parameters. One of the most noticeable factors in design of the drug delivery is drug-release profile which determines the site of action, the concentration of the drug at the time of administration, the period of time that the drug must remain at a therapeutic concentration. To get a better understanding of drug release, large unilamellar liposomes containing calcein were prepared using 1,2-dioleoyl-sn-glycero-3-phosphocholine, 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine and 1,2-palmitoyl-sn-glycero-3-phosphocholine, and a mixture of them; calcein was chosen as a model of hydrophilic drug. The calcein permeability across liposomal membrane (with different compositions) was evaluated on the basis of the first-order kinetic by spectrofluorometer. Also, the effects of liposome composition/fluidity as well as the incubation temperature/pH were investigated. Furthermore, we simulated the digestion condition in the gastrointestinal tract in humans, to mimic human gastro-duodenal digestion to monitor calcein release during the course of the digestion process. In vitro digestion model ''pH stat'' was used to systematically examine the influence of pH/enzyme on phospholipid liposomes digestion under simulated gastro-duodenal digestion. The results revealed that calcein permeates across liposomal membrane without membrane disruption. The release rate of calcein from the liposomes depends on the number and fluidity of bilayers and its mechanical/physical properties such as permeability, bending elasticity. Chemo-structural properties of drugs like as partition coefficient (Log P), H-bonding, polar surface area (PSA) are also determinative parameter in release behavior. Finally, stimulated emission depletion (STED) microscopy was used to study calcein translocation through liposomal bilayers.

Influence of lipid composition on physicochemical properties of nanoliposomes encapsulating natural dipeptide antioxidant l-carnosine.

Natural dipeptide antioxidants (l-carnosine) are recieving increasing attention because of their noticeable potential as biopreservatives in food recent technology. Encapsulation of antioxidants by nanoliposomes could represent an ameliorative approach to overcome the problems related to the direct application of these antioxidant peptides in food. In this study, nanoliposomes prepared from different lipids (DOPC, POPC and DPPC) by thin film hydration method, were assessed by considering their size, ζ-potential, phase transition temperature and fluidity. One important parameter of interest in this article was to compare the encapsulation efficacy of l-carnosine in three different nanoliposomes using a rapid and precise approach (1)H NMR without the need for physical separation of entrapped and non-entrapped l-carnosine. Furthermore, the morphology of small unilamellar nanoliposomes with different compositions on mica surface was investigated using Atomic Force Microscopy.

Elaboration and characterization of nanoliposome made of soya; rapeseed and salmon lecithins: application to cell culture.

Health benefits of unsaturated fatty acids have been demonstrated over the last decades. Nanotechnology provided new process to produce particles such as liposomes and nanoliposomes made of pure phospholipids. These techniques are already used in pharmaceutics to augment the bioavailability and the bioefficiency of drugs. The aim of this paper is to characterize and evaluate the potential of nanoliposomes made of three lecithins (soya, rapeseed and salmon) on cell culture in order to use them in the future as drug delivery systems for tissue engineering. We began to measure, with zetasizer, the radius size of liposomes particles which are 125.5, 136.7 and 130.3 nm respectively for rapeseed, soya and salmon lecithin. Simultaneously, solutions observed by TEM demonstrated the particles were made much of liposomes than droplet (emulsion). Finally, we found that the solutions of lecithins were enough stable over 5 days at 37 °C to be used in culture medium. We investigated the effect of soya, rapeseed and salmon lecithin liposome from 2mg/mL to 5.2 µg/mL on metabolic activity and cell proliferation on rat bone marrow stem cells (rBMSC) during 14 days. The results showed that the three lecithins (soya, rapeseed and salmon) improve cell proliferation at different concentration.

Optimization and characterization of liposome formulation by mixture design.

This study presents the application of the mixture design technique to develop an optimal liposome formulation by using the different lipids in type and percentage (DOPC, POPC and DPPC) in liposome composition. Ten lipid mixtures were generated by the simplex-centroid design technique and liposomes were prepared by the extrusion method. Liposomes were characterized with respect to size, phase transition temperature, ζ-potential, lamellarity, fluidity and efficiency in loading calcein. The results were then applied to estimate the coefficients of mixture design model and to find the optimal lipid composition with improved entrapment efficiency, size, transition temperature, fluidity and ζ-potential of liposomes. The response optimization of experiments was the liposome formulation with DOPC: 46%, POPC: 12% and DPPC: 42%. The optimal liposome formulation had an average diameter of 127.5 nm, a phase-transition temperature of 11.43 °C, a ζ-potential of -7.24 mV, fluidity (1/P)(TMA-DPH)((¬)) value of 2.87 and an encapsulation efficiency of 20.24%. The experimental results of characterization of optimal liposome formulation were in good agreement with those predicted by the mixture design technique.

Mechanism of bioactive transfer through liposomal bilayers.

Today, liposomes are one of the most effective carriers systems employed in biological, pharmaceutical, medical and nutritional research. In order to optimize a liposomal formulation for the encapsulation, delivery and release of the entrapped material, it is necessary to study material passage through the lipidic and aqueous phases of the lipid vesicle. Towards this end, this article aims to review the mechanisms of bioactive transfer between different layers of a liposome and it also discusses about the bioactive release mechanism. Several methods of detection and observation of bioactive transfer in liposomal systems are presented.