Development of halochromic electrospun labels for non-invasive shelf life assessment of rainbow trout (Oncorhynchus mykiss): Incorporation of barberry anthocyanin extract in protein-based smart packaging.

Using barberry (Berberis vulgaris L.) as a natural dye in combination with electrospinning technology represents a promising approach for the development of intelligent packaging systems. In this study, the influence of different concentrations of zein (16, 18, and 20%) and barberry anthocyanin-rich powder (BARP) (16, 18, and 20%) on the surface tension and rheological properties of the solution were evaluated. The most favorable nanofibers (NFs) were obtained from a solution containing 18% (w/w) zein under constant voltage. The surface morphology, size, and color-changing properties of electrospun NFs derived from zein polymers containing different concentrations of BARP (16, 18, and 20%) under various electrical fields (20, 22, and 24 kV) were evaluated. The Fourier-transform infrared spectroscopy analysis confirmed the interaction of BARP within the zein-based NFs. The results indicated that the concentration of BARP had a noticeable impact on the physicochemical properties of the NFs. Furthermore, efficacy of the appropriately fabricated halochromic label was evaluated for monitoring the packed rainbow trout fillet during refrigerated storage. On the 10th day, a noticeable visual color turned from pink to pale yellow was observed in response to pH variations. Additionally, the TVN value confirmed the effectiveness of halochromic electrospun labels for non-invasive assessment of fish fillet quality.

Fabrication of active whey Protein isolate/oleic acid emulsion based film as a promising bio-material for cheese packaging.

Emulsion is a colloidal dispersion for delivering natural antimicrobial, antioxidant, and bioactive compounds to improve the product's quality. The present study aimed to develop the active emulsion film based on whey protein isolate (WPI) by adding oleic acid (OA) (0, 10, and 20% w/w) and green tea extract (GTE) (0 and 0.5% w/v) for cheese packaging. Results showed that the opacity, flexibility, and water barrier properties of WPI hydrogel-based film were significantly increased by adding 10% OA. Active release from emulsion-based films was governed by pH and the nature of food model systems. The minimum release occurred in the acidic food model system. After 5 h exposure in the acid food model system, the obtained release from the active film containing OA 0, 10, and 20% was 52.39, 48.97, and 57.24% of incorporated GTE, respectively. The log reduction value (LRV) of active emulsion film against bacteria was significantly affected by the food model system. Moreover, packed lactic coagulated cheese delivered more phenolic compound of GTE than processed spread cheese. Korsmeyer-Peppas model and Weibull with lag were suggested as appropriate models to forecast the release kinetic of GTE.

Development and characterization of a novel multifunctional film based on wheat filter flour incorporated with carvacrol: Antibacterial, antifungal, and insecticidal potentials.

Wheat filter flour is a by-product derived from the modern wheat milling process. In this study, the influence of plasticizer type (glycerol (G) and sorbitol (S)) and content (25, 35, and 45 g/100 g polymer) on the wheat filter flour-based film was evaluated. Regardless of plasticizer type, increasing the plasticizer content enhanced moisture content, water solubility, and water vapor permeability of film samples. The S-plasticized films presented the greatest tensile strength and the lowest EAB%. The scanning electron microscope observations confirmed the uniform structure of G-plasticized film. Moreover, antimicrobial and physico-mechanical properties of G-plasticized (25%) film were evaluated at the presence of carvacrol (5 and 10 g/100 g polymer). The considerable improvement was achieved in water affinity (14.2%) and flexibility (8.6%) by incorporating 10% carvacrol in G-plasticized films. The greatest inhibitory properties of active wheat filter flour films were observed against Aspergillus niger. By increasing the carvacrol concentration in film-forming solution, the inhibitory activity against Listeria monocytogenes and Escherichia coli in the liquid food model system was increased by 90.3% and 66.95%, respectively. Moreover, the active wheat filter flour-based film released a considerable insecticidal activity against Sitophilus granarius and Tribolium confusum. This work offers a novel utilization of wheat filter flour as an inexpensive blend polymer to manufacture multifunctional active film, which provides a promising approach for pest management besides enhancing the safety of products.

Evaluation of release mechanism of catechin from chitosan-polyvinyl alcohol film by exposure to gamma irradiation.

This study was conducted to investigate the application of gamma irradiation as a means to control the release rate of catechin from polymer matrix. First, chitosan and polyvinyl alcohol (1:3) were mixed and later chitosan nanoparticles containing catechin were added to the mixture and coated on polylactic acid surface and then films were irradiated at 0, 40 and 60 kGy doses of gamma-ray. Irradiation lowered the water solubility value of the films, furthermore 60 kGy dose reduced the water vapor permeability and tensile strength without significant effect on elongation at break of films. Results of release test indicated that gamma-ray decreased release rate of catechin from polymer matrix and generally release in high-fat simulant was about 2.5 times slower than low-fat simulant. This study was undertaken to design a packaging material with controlled release ability of antioxidant compound over time for further application in oxidation-sensitive foods.

Antimicrobial packaging based on a LAE containing zein coating to control foodborne pathogens in chicken soup.

In this study, zein coatings containing Lauroyl-l-arginine ethyl ester monohydrochloride (LAE) were developed to be applied on polypropylene films and manufacture an active food packaging. The concentration of LAE and the addition of a suitable plasticizer (glycerol or oleic acid (OA)) were the main variables considered. Active plasticized zein films, with glycerol or oleic acid were characterized in terms of release kinetics, mechanical, barrier, optical, and antimicrobial properties. Results showed that active agent concentration, (5 and 10%), had no-significant effect on mechanical and WVP properties of the plasticized films. Films plasticized with OA presented greater water resistance, UV-light opacity, and water barrier properties than glycerol-plasticized films. On the contrary, the latter had better antimicrobial properties. The analysis of LAE release kinetics from films to different food simulants revealed different behaviours, depending on both film formulation and food simulant. Despite the lower water resistance of coatings containing glycerol, bags based on polypropylene/glycerol plasticized zein containing 10% of LAE presented a great antimicrobial activity in tests with chicken soup (real food system) contaminated with pathogen bacteria, concretely, the films showed 3.21 Log reduction against Listeria monocytogenes and 3.07 log reductions against Escherichia coli. These results suggest a promising strategy on the use of LAE-containing zein in active food packaging to control foodborne pathogens.

Use of high hydrostatic pressure to inactivate natural contaminating microorganisms and inoculated E. coli O157:H7 on Hermetia illucens larvae.

A chemical and microbiological characterization on Hermetia illucens larvae was carried out as well as an inactivation study of natural contaminating microorganisms and inoculated E. coli O157:H7 in black soldier larvae by using High Hydrostatic Pressure (250 to 400 MPa, for 1.5 to 15 min). Hermetia illucens was mainly composed of proteins (46.49%, d.m.) followed by fat (37.88%, d.m.). Larvae had a high contamination load of Total Aerobic Mesophilic bacteria (AMB) (1.58x107 cfu/g) and Enterobacteriaceae (1.15x106cfu/g). The presence of pathogenic microorganism varied: no Listeria spp. were found, but Salmonella (1.15x106 cfu/g) and E. coli (7.08x105 cfu/g) were detected in the larvae extract. High Hydrostatic Pressure (HHP) was effective against natural contaminating yeasts and molds producing more than 5 log cycle reductions at 400 MPa for any of the times considered (2.5 to 7 min), but a low reduction of total microbial load was achieved. The inactivation level of larvae inoculated with E. coli O157:H7 varied. At 400 MPa for 7 min more than 5 log cycle reductions were achieved. Among the three inactivation models studied, the one that best described the inactivation pattern of the cells, according to the Akaike index, was the Biphasic model.

Incorporating Zataria multiflora Boiss. essential oil and sodium bentonite nano-clay open a new perspective to use zein films as bioactive packaging materials.

Active zein films with different levels of Zataria multiflora Boiss. essential oil were produced successfully. To enhance properties of this biopolymer for food packaging applications, sodium bentonite clay was used at two levels (2 and 4%). The results indicated that the addition of Z. multiflora Boiss. essential oil caused a reduction in tensile strength and Young's modulus and slight increase in the percent of elongation at break of the films. Maximum solubility in water and water vapor permeability was observed by incorporation of 10% Z. multiflora Boiss. essential oil in the zein matrix. Transmission electron microscopy micrographs of zein film were verified by the exfoliation of the layers of sodium bentonite clay in the zein matrix. Stronger films with lower water vapor permeability and water solubility were evident of good distribution of sodium bentonite clay in the zein matrix. According to the results, 2% sodium bentonite clay was selected for evaluation of nano active film properties. Water vapor permeability, UV light barrier, tensile strength, and Young's modulus values of active films were improved by incorporation of 2% sodium bentonite clay. The antibacterial activity of different contents of Z. multiflora Boiss. essential oil in vapor phase demonstrated that use of Z. multiflora Boiss. essential oil in the liquid phase was more effective than in vapor phase. The antibacterial zein-based films showed that active zein film with 5 and 10% Z. multiflora Boiss. essential oil had reductions of 1.68 log and 2.99 log, respectively, against Listeria monocytogenes and 1.39 and 3.07 log against Escherichia coli. Nano active zein film containing 10% Z. multiflora Boiss. essential oil and 2% sodium bentonite clay showed better antibacterial properties against L. monocytogenes (3.23 log) and E. coli (3.17 log).