Bioavailability of nutraceuticals: Role of the food matrix,processing conditions,the gastrointestinal tract,and nanodelivery systems

Nowadays, many consumers prefer foods with a high content of nutraceuticals that contribute to the prevention or healing of chronic diseases. Therefore, in recent years, more and more researchers have studied the bioefficiency, safety, and toxicity of nutraceutical‐enriched foods. The key stage of nutraceutical bioefficiency is oral bioavailability, which involves the following processes: the release of nutraceuticals from food matrices or nanocarriers in gastrointestinal fluids, the solubilization of nutraceuticals and their interaction with other components of gastrointestinal fluids, the absorption of nutraceuticals by the epithelial layer, and the chemical and biochemical transformations into epithelial cells. These processes are endogenous factors that greatly influence the bioavailability of nutraceuticals. In addition to endogenous factors, the bioavailability of nutraceuticals is also affected by exogenous factors, such as: physicochemical properties of nutraceuticals, food matrix, food processing and storage, and so forth. Both the endogenous and exogenous factors are comprehensively analyzed in this review. Thus, the physicochemical and enzymatic processes involved in food digestion are described, highlighting the role of each stage of gastrointestinal tract (mouth, stomach, and intestine) in nutraceuticals bioaccessibility. The structure and functions of the mucus and epithelial layers, the mechanisms involved in the active and passive transport of nutraceuticals through the cell membrane, and phase I and phase II metabolism reactions are also discussed. Finally, this review focuses on several types of bioactive‐loaded nanocarriers such as lipid‐based, surfactant‐based, and biopolymeric nanocarriers that improve the bioavailability of nutraceuticals.     

Evaluation of the environmental impacts of rare earth elements production

This study aims to estimate the emissions and evaluate the environmental impacts from the production of rare earth elements (REEs). The life cycle assessment method was used to evaluate the environmental load from the production of each metal. To understand the environmental impacts of REEs production, they were compared with the impacts from the production of base metals and precious metals. The findings of this study should present a scientific baseline for the environmental profile for producing these REEs, which might help lessen their impacts and improve production processes and technologies.     

Comparison of chitosan–gelatin composite and bilayer coating and film effect on the quality of refrigerated rainbow trout

The effect of chitosan–gelatin coating and film on the rancidity development in rainbow trout (Oncorhynchus mykiss) fillets during refrigerated storage (4 ± 1 °C) was examined over a period of 16 days. Composite and bilayer coated and film wrapped fish samples were analysed periodically for microbiological (total viable count, psychrotrophic count) and chemical (TVB-N, POV, TBARS, FFA) characteristics. The results indicated that chitosan–gelatin coating and film retained their good quality characteristics and extend the shelf life of fish samples during refrigerated storage .The coating was better than the film in reducing lipid oxidation of fillets, but there was no significant difference between them in control of bacterial contamination.     

Antibiotic resistance of Salmonella isolated from hog, beef, and chicken carcass samples from provincially inspected abattoirs in Ontario

The emergence of antimicrobial-resistant Salmonella organisms, especially Salmonella Typhimurium DT104, has been reported in many countries, including the United States and Canada. The purposes of this study were to determine the antimicrobial resistance patterns of Salmonella isolated from hog, beef, and chicken carcasses from provincially inspected abattoirs in Ontario and to determine the agreement between the agar dilution method and the microbroth dilution method for measurement of antimicrobial resistance of the isolates. Antimicrobial resistance of Salmonella isolates from hogs (n = 71), beef (n = 24), and chicken (n = 295) to amikacin, ampicillin, cephalothin, chloramphenicol, ciprofloxacin, gentamicin, streptomycin, sulfamethoxazole, and tetracycline was determined using the two methods. None of the 390 isolates were resistant to ciprofloxacin at levels of 0.125 microg/ml. All chicken and hog isolates were sensitive to amikacin, whereas all beef isolates were sensitive to both amikacin and gentamicin. Multiple antimicrobial resistance (resistance to more than one antimicrobial) was found in 29% of bovine isolates and 42% of porcine isolates using both methods for testing and in 42% by the agar dilution and 33% by the microbroth dilution methods in the chicken isolates. Overall, there was good agreement between the two test methods for resistance to most of the antimicrobials, with disagreement found in the results in 1.3% of the isolates for ampicillin and sulfamethoxazole, 8.2% for streptomycin, 5.6% for cephalothin, and 1.0% of the isolates for tetracycline. The lack of agreement between the two test methods was found mostly among the chicken isolates.     

Thermal,mechanical, and corrosion resistance properties of vinyl ester/clay nanocomposites for the matrix of carbon fiber‐reinforced composites exposed to electron beam

Vinyl ester/clay nanocomposites with 1, 3, and 5% nanoclay contents were prepared. X‐ray diffractography patterns and Scanning Electron micrographs showed that nanocomposites with the exfoliated structure were formed. Thermogravimetric analysis, water absorption test, and Tafel polarization method, respectively, revealed the improvements in thermal resistance, water barrier properties, and corrosion resistance properties of the samples with an increase in the amount of the incorporated nanoclay. Tensile tests showed that nanoclay also enhanced the mechanical properties of the polymer, so that the tensile strength of the samples with 5% nanoclay was more than 3 times higher than tensile strength of pure vinyl ester samples. Overall, the best properties were observed for the samples containing 5% nanoclay. Pure vinyl ester and nanocomposite with 5% nanoclay content were exposed to the electron beam radiation and their mechanical properties improved up to 500 kGy irradiation dose. Finally, pure vinyl ester and vinyl ester/nanoclay (5%) matrixes were reinforced with carbon fiber and the effect of electron beam irradiation on their mechanical properties was examined. The tensile strength and the modulus of the samples initially increased after exposure to the radiation doses up to 500 kGy and then a decrease was observed as the irradiation dose rose to 1000 kGy. Moreover, nanoclay moderated the effect of the irradiation. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42393.     

Thermal,mechanical, and barrier properties of polyethylene/surlyn/organoclay nanocomposites blown films prepared by different mixing methods

(Low‐density polyethylene) (LDPE)/clay nanocomposites were prepared by melt blending in a twin‐screw extruder by using different mixing methods. Zinc‐neutralized carboxylate ionomer was used as a compatibilizer. Blown films of the nanocomposites were then prepared. The effect of mixing method on the clay dispersion and properties of the nanocomposites was evaluated by wide‐angle X‐ray diffraction analysis, mechanical properties, thermal properties, and barrier properties. The structure and properties of nanocomposites containing different amounts of nanoclay prepared by selected mixing techniques were also investigated. It was found that melt compounding of Surlyn/clay masterbatch with pure LDPE and Surlyn (two‐step‐a method) results in better dispersion and intercalation of the nanofillers than melt mixing of LDPE/Surlyn/clay masterbatch with pure LDPE and surlyn (two‐step‐b method) and direct mixing of LDPE with clay. The films containing ionomer have good barrier properties. A wide‐angle X‐ray diffraction pattern indicates that intercalation of polymer chains into the clay galleries decreases by increasing the clay content. Barrier properties and tensile modulus of the films were improved by increasing the clay content. In addition, tensile strength increased in the machine direction, but it decreased in the transverse direction by increasing the clay content. DSC results showed that increasing the clay content does not show significant change in the melting and crystallization temperatures. The results of thermogravimetric analysis showed that the thermal stability of the nanocomposites decreased by increasing the clay content more than 1 wt%. J. VINYL ADDIT. TECHNOL., 21:60–69, 2015. © 2014 Society of Plastics Engineers     

Encapsulation Efficiency of Food Flavours and Oils during Spray Drying

Microencapsulation is a rapidly expanding technology which is a unique way to package materials in the form of micro- and nano-particles, and has been well developed and accepted within the pharmaceutical, chemical, food and many other industries. Spray drying is the most commonly used encapsulation technique for food products. A successful spray drying encapsulation relies on achieving high retention of the core materials especially volatiles and minimum amounts of the surface oil on the powder particles for both volatiles and non-volatiles during the process and storage. The properties of wall and core materials and the prepared emulsion along with the drying process conditions will influence the efficiency and retention of core compounds. This review highlights the new developments in spray drying microencapsulation of food oils and flavours with an emphasis on the encapsulation efficiency during the process and different factors which can affect the efficiency of spray drying encapsulation.