This study aimed to fabricate electrospun zein/polyvinyl alcohol (ZN/PVA) nanofiber, as well as ZN/PVA nanofiber containing 4% thymoquinone (TQ), and electrosprayed with ZN nanoparticles containing ...2% resveratrol (RS) (ZN/PVA-TQ-RS). The effects of these nanofibers on the bacterial, oxidative, and sensory qualities, as well as the microbial safety (following inoculation with Escherichia coli O157:H7), of rainbow trout fillets during 12-day storage period at 4 °C were evaluated. According to the results of scanning electron microscope analysis, the average diameters of the ZN/PVA nanofibers, ZN/PVA nanofibers containing 4% TQ, and ZN nanoparticles containing 2% RS were measured at 207.5, 275.6, and 255.5 nm, respectively. Fish fillets wrapped with ZN/PVA-TQ-RS nanofibers exhibited significantly lower total viable counts (7.6 log10 CFU/g), psychrotrophic bacteria counts (7.1 log10 CFU/g), peroxide values (0.95 meq/kg lipid), thiobarbituric acid reactive substances values (0.62 mg MDA/kg sample), E. coli O157:H7 counts (5.7 log10 CFU/g), and demonstrated better sensory characteristics (overall acceptability: 4.8) compared to the other experimental groups (P ≤ 0.05). Thus, the ZN/PVA-TQ-RS treatment was able to extend the shelf life of fish fillets by at least 3 days, as determined by acceptable microbial, oxidative, and sensory thresholds. The present findings suggest that ZN/PVA-TQ-RS can be employed as an active packaging material containing natural preservatives to prolong the shelf life and enhance the microbial safety of refrigerated fish fillets in the packaging industry.
•ZN/PVA and ZN/PVA-TQ-RS nanofibers were prepared.•Diameter of ZN/PVA nanofibers containing TQ and ZN nanoparticles containing RS were determined.•Effects of nanofibers on the shelf life of trout fillet were evaluated during 12-day storage at 4 °C.•Effects of nanofibers on inoculated E. coli O157:H7 were assessed during 12-day storage at 4 °C.•ZN/PVA-TQ-RS showed a high potential to enhance the shelf life and microbial safety of fish fillets.
New technologies of non-thermal disinfection such as pulsed light (PL) have emerged lately as an alternative to traditional (thermal and chemical) disinfection and preservation methods. PL can be ...used to decontaminate a great variety of foods as well as to decontaminate contact surfaces, thus improving safety in foods and extending their shelf life. Moreover, this technology can prevent or reduce some of the detrimental effects of traditional methods on nutrients and bioactive compounds of food products.
The combination of PL with other techniques such as ultraviolet light (UV), thermosonication (TS), pulsed electric fields (PEF), manothermosonication (MTS), etc., can improve the effectiveness of the decontamination process. Therefore, in this review, some of the most relevant studies evaluating the potential application of PL treatments to decontaminate food samples, and its impact of nutritional and physicochemical quality parameters will be discussed.
PL treatments are suitable for microbial decontamination in transparent drinks and for surface contaminated foods without complex microstructures. They also can be used for meat, fish and their by-products However, it is still necessary to evaluate the appropriate treatment conditions (number of light flashed, voltage, distance between sample and flash light, spectral range of light flashes and contamination) for each food and microorganism separately to improve the effectiveness and minimize the appearance of negative attributes reducing the quality of product as, in some cases, PL can have a negative effect on the photosensitive compounds and sensory characteristics of food products.
•Pulsed light (PL) have emerged lately as an alternative to traditional disinfection and preservation methods.•The combination of PL with other techniques can improve the effectiveness of the decontamination process.•PL can have a negative impact on the sensory properties of food products.
The use of high pressure processing (HPP) for development of stable emulsion-based delivery systems has been recently increased. Under adequate conditions, application of high pressures modifies the ...functionality of protein and polysaccharide molecules and significantly promotes the emulsifying activities. Application of high pressures also modulates the emulsion microstructure without any destabilization and gelation of protein molecules. The lipid oxidation in HPP-treated emulsions can be accelerated, particularly with higher pressure levels, while the HPP utilization on emulsions in acidic conditions can highly inhibit the growth of spoilage and pathogenic microorganisms. In this study, the effects of HPP on the physicochemical, rheological and antimicrobial properties of emulsion-based delivery systems are reviewed. Physicochemical mechanisms dominant over the destabilization of emulsion systems and knowledge gaps related to the practical exploitations of HPP in the design and manufacture of food-grade colloidal delivery systems are also addressed.
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•HPP treatment changes the physical stability and rheology of food-grade emulsions.•HPP treatment improves the emulsion viscoelasticity and particles homogeneity.•Application of HPP at pressures >400 MPa decreases the emulsifying activity index.•HPP treated emulsions are more prone to lipid oxidation.
Tea (
Camellia sinensis)
is the most widely consumed beverage in the world, with an excellent source of bioactive compounds such as catechins, caffeine, and epigallocatechin. There is an increasing ...trend to extract these bioactive compounds to deliver them as value-added products. Generally, the extraction of polyphenols and other functional compounds from different parts of tea is carried out using different solvents (e.g., water, water–ethanol, ethanol, methanol, acetone, ethyl acetate, and acetonitrile). The extraction efficiency of functional compounds from tea depends on the type and polarity of the solvent as well as the applied process. Several conventional techniques, such as boiling, heating, Soxhlet, and cold extraction, are used to extract bioactive ingredients. However, these procedures are unsuitable for achieving high yields and biological activities due to the long extraction times of cold brewing and the high temperatures in other heating methods. Many efforts have been carried out in food and pharmaceutical industries to replace conventional extraction techniques with innovative technologies (e.g., microwave (MAE), ultrasonic (UAE), pressurized liquid (PLE), pulsed electric field (PEF), and supercritical fluid (SFE)), which are fast, safe, energy-saving, and can present eco-friendly characteristics. These innovative extraction techniques have proven to improve the recovery rate of phenolic-based antioxidant compounds from tea and increase their extraction efficiency. In this review, the application of novel processing technologies for the extraction of value-added compounds from tea leaves is reviewed. The advantages and drawbacks of using these technologies are also highlighted.
The present study aimed to introduce a novel biocompatible food packaging system based on electrospun polycaprolactone (PCL) nanofiber containing Ganoderma lucidum extract (GLE) to improve the ...chemical and microbial stability of fresh rainbow trout fillets. For this purpose, PCL nanofibers containing 1–8% of GLE (w/w) were prepared and characterized. Also, their in vitro antibacterial and antioxidant properties were evaluated. Then, the effects of the PCL nanofibers without GLE and containing GLE 8% were investigated on the chemical and microbial qualities of fish fillets during 12-day storage at 4 °C. Results indicated that increasing GLE concentrations enhanced the in vitro antioxidant properties of PLC and the highest antioxidant activities belonged to PCL-GLE 8% (P ≤ 0.05). Moreover, trout fillets wrapped with PCL-GLE 8% nanofiber showed significantly better antioxidant results compared to the other experimental groups at the end of storage time (P ≤ 0.05). Neither in vitro nor fish model studies showed any significant antibacterial activity for PCL-GLE 8%. The following scores belonged to the control, PCL, and PCL-GLE 8% groups, respectively: pH (7.62, 7.42, and 6.93), peroxide value (8.33, 8.27, and 5.28 meq/kg lipid), thiobarbituric acid reactive substance (1.38, 1.34, and 1.06 mg MDA/kg of fish fillet), total carbonyl content (0.82, 0.60, and 0.50 nmol/mg protein), total viable counts (9.2 log10 CFU/g for all experimental groups), and total volatile basic nitrogen (36.54, 33.32 and 14.14 mg N/100 g sample). The findings of this study revealed that PCL-GLE 8% nanofiber can be employed as an active food packaging material for improving chemical stability of fresh rainbow trout fillets.
•Electrospun PCL nanofibers containing 1–8% of GLE were prepared and characterized.•In vitro antioxidant and antibacterial effects of PCL-GLE nanofibers were compared.•Fish fillets were wrapped with PCL and PCL-GLE 8% nanofibers and stored at 4 °C for 12 days.•PCL-GLE 8% nanofiber had the highest in vitro antioxidant activity.•Fish fillets wrapped with PCL-GLE 8% nanofiber had better oxidative stability than other groups.
•Formation of microemulsions is dependent on the oil type and fatty acid chain length.•Short chain monoglycerides could be used to prepare transparent microemulsion.•β-Carotene encapsulated in ...microemulsion was resistant to degradation.•Toxicity of the microemulsions was minimal at low concentrations.
The impact of oil type and fatty acid chain length on the development of food-grade microemulsions for the entrapment of β-carotene was investigated. The microemulsion region of a ternary phase diagram containing short chain monoglycerides was larger than for di- and triglycerides when Tween 80 was used as surfactant. The cytotoxicity of microemulsions composed of a 30% monoglyceride oil, 20% Tween 80 and 50% aqueous buffer were evaluated using an in vitro cell culture model (human epithelial colorectal adenocarcinoma, Caco-2). The cytotoxicity test showed that the viability of Caco-2 cells against β-carotene microemulsions at concentrations of 0.03125% (v/v) was higher than 90%. This study suggests that short chain monoglycerides could be used with Tween 80 to prepare transparent β-carotene-encapsulated O/W microemulsions in the particle size range of 12–100nm.
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The food and pharmaceutical industries aim to develop innovative delivery systems to meet the increasing consumer demand for healthier and safer food products and to improve the ...efficacy of drug formulations, respectively. Many bioactive agents with beneficial physiological and pharmacological activities are difficult to deliver because of their poor water solubility, chemical instability, or low oral bioavailability. Nano- and micro-encapsulation technologies are therefore being developed to overcome these limitations. This review article provides an overview of several lipid-based carriers suitable for the encapsulation of nutraceutical and pharmaceutical molecules, including their structures, constituents, production methods, and applications. It then focuses on the preparation, characterization, and application of solid self-micro-emulsifying delivery system (S-SMEDS). Finally, potential challenges of using S-SMEDS and S-SNEDS as delivery systems in the food and pharmaceutical industries are addressed.
The aim of this work was to investigate the effects of Ohmic heating-assisted hydrodistillation (OAHD), applied at different voltages (100, 150, and 200) V, on the qualitative and quantitative ...characteristics of extracted essential oil from oregano herb (Origanum vulgare subsp. viride), compared to a conventional hydrodistillation (HD) procedure. The compositions of the extracted essential oils (using OAHD and HD) were assessed using gas chromatography - mass spectrometry (GC–MS). A 2,2-diphenyl-1-picrylhydrazyl free radical (DPPH) method was applied in order to evaluate antioxidant activity. The antimicrobial activity as well as the minimum inhibitory concentration (MIC) values of the samples against Bacillus cereus, Escherichia coli O157:H7, Salmonella Typhimurium, Pseudomonas aeruginosa, and Staphylococcus aureus were determined. Among 50 identified compounds; thymol and 4-terpineol were the most abundant components independently of the technique used (OAHD or HD). No significant differences were observed between HD and OAHD (all voltages) methods in terms of extraction yields, and between HD and OAHD (at 100V) in terms of antioxidant activity (the half inhibition concentration values (IC50) were 33.4μg/mL and 31.2μg/mL, respectively). However, the extraction time was significantly reduced when OAHD extraction was used compared to HD. For the antimicrobial activity, the MIC values indicated higher inhibitory activities against S. aureus and B. cereus (with similar MIC values of 6.25μg/mL) than P. aeruginosa (25μg/mL). However, no significant influence was observed between the different applied voltages and the two extraction methods. OAHD could thus be used as “green” extraction method compared to HD.
The production of essential oils at industrial scale is mainly performed using conventional hydrodistillation method. However, the increasing need in applying more efficient and sustainable extraction processes has led researchers to evaluate new alternative non-conventional methods in order to replace the existing ones. Among non-conventional technologies applied to extract essential oils from plant materials, Ohmic-assisted hydrodistillation is of great potential. It allows reducing the extraction time compared to conventional hydrodistillation, which reduces significantly the energy consumption. The implementation of Ohmic-assisted hydrodistillation technology in essential oil producing industries is therefore of great importance.
•Comparison of hydrodistillation (HD) and Ohmic-assisted hydrodistillation (OAHD) techniques•Application of HD and OAHD for the extraction of essential oil from oregano•Similar yields were obtained, but OAHD provided shorter extraction times compared to HD.•Extracted essential oils exhibited high antioxidant and antibacterial activities.
Consumption of protein-based food products has a key role in the improvement of human health. The crosslinking agent microbial transglutaminase (mTGase) is an effective and promising tool to modify ...animal proteins used in the food industry. Improvement in the gelation process, physicochemical and textural quality, and consumer's demand of protein-based food products could be attained by combining mTGase and some non-conventional food processing technologies.
New perspectives and key areas for future research in the development of high-quality food proteins and protein-based products as a function of interaction effect of mTGase and some new processing techniques (e.g. high pressure processing (HPP), ultrasound, microwave (MW) and ultraviolet (UV) irradiation) are reviewed. The effect of conventional thermal and emerging processing methods on the mTGase crosslinking activity and protein gel functionality are also compared.
The crosslinking density and functional properties of protein gels can be strongly promoted by the synergistic action of mTGase and innovative processing methods. Compared to the conventional heating, HPP with further increase of mTGase affinity to proteins can result in products with better physicochemical quality and more complex and firmer gel structure. The yield, water holding capacity, surface hydrophobicity, strength, and viscoelastic characteristics of mTGase-catalyzed protein gels can be significantly increased by ultrasonication treatments. mTGase-crosslinked hydrogels subjected to high-intensity ultrasonic pretreatment have potential to be used as delivery vehicles for a wide spectrum of bioactive compounds. The application of MW and UV light can substantially improve the surface, textural and structural features of gels generated by mTGase-technology.
•Combining TGase and new processing methods improves the quality of protein gels.•The combination of TGase and HPP can develop products with firmer gel structure.•TGase-crosslinked gels after US treatment can be used as delivery vehicles.•The application of MW and UV improves the physical properties of TGase-induced gels.
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