Electrospun plant protein-based nanofibers loaded with sakacin as a promising bacteriocin source for active packaging against Listeria monocytogenes in quail breast.

The main objective of this study was to fabricate nanofibers from zein incorporated with two concentrations of sakacin (9 and 18 AU/mL) with anti-Listeria properties by electrospinning technique. The efficacies of the resulting active nanofibers against L. innocua, in quail breast during 24 days of refrigerated storage (4 ± 1 °C) were evaluated. The minimum inhibitory concentration (MIC) of bacteriocin against L. innocua was approximate 9 AU/mL. Fourier-transform infrared spectra of bacteriocin-loaded nanofibers indicated characteristic peaks of zein and sakacin and that the nanofibers showed an encapsulation efficiency close to 91.5 %. The thermal stability of sakacin increased by electrospinning. Scanning electron microscopy images showed that nanofibers prepared from electrospinning zein/sakacin solutions exhibited smooth and continuous nanofibers with no defects with an average diameter between 236 and 275 nm. The presence of sakacin led to decreased contact angle properties. Nanofibers with 18 AU/mL sakacin exhibited the highest zone of inhibition of 226.14 ± 8.05 mm. The lowest L. innocua (6.1 logs CFU/cm2) growth after 24 days at 4 °C were obtained in quail breast wrapped with zein containing 18 AU/mL sakacin. The results demonstrate an outlook for the potential use of zein nanofibers containing sakacin to reduce L. innocua contamination in ready-to-eat (RTE) products.

Bioactive gliadin electrospinning loaded with Zataria multiflora Boiss essential oil: Improves antimicrobial activity and release modeling behavior.

This study aimed to produce electrospun gliadin nanofibers containing Zataria multiflora Boiss essential oil (ZMEO) (5, 10, and 15% w/w), thereby developing active, sustained-release antimicrobial mats. By increasing the level of the ZMEO, the zeta potential and electrical conductivity increased, but the viscosity and consistency index decreased. All feed solutions demonstrated shear-thinning behavior, and the power law model was the best model. Field emission scanning electron microscopy (FESEM) images proved that the gliadin nanofibers showed a uniform, beaded-free structure at different levels of ZMEO, with an average diameter of between 403.87 ± 15.29 and 522.19 ± 11.23 nm. Increments in the level of ZMEO decreased the mats' tensile strength and Young's modulus but increased their elongation at break. Fourier transform infrared (FTIR) and differential scanning calorimetry (DSC) analysis confirmed that the ZMEO was well loaded within these structures, augmenting its thermal stability. The studied Gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa) were more resistant to the ZMEO than the Gram-positive bacteria (Bacillus cereus and Staphylococcus aureus). The Peleg model was the most suitable model for describing the ZMEO release behavior, the mechanism of which was primarily Fickian diffusion.

Antibacterial activity of some Lamiaceae species against Staphylococcus aureus in yoghurt-based drink (Doogh).

Doogh is a dairy drinkable fermented product, whose shelf-life and quality is mostly affected by bacteria such as Staphylococcus spp.. This study investigated the antibacterial activity of essential oils (EOs) from Thymus vulgaris L., Mentha piperita L. and Ziziphora tenuior L., alone or in combination, against Staphylococcus aureus in industrial doogh. A three-level and three-variable face centered central composite design experiment was used. Results showed that EOs significantly inhibited S. aureus growth after 1 and 7 days of storage. According to the model, the maximum inhibition was obtained in the presence of 0.2% of EO, independently of the type, and no synergistic or additive effects were observed. Slightly lower S. aureus survivals were observed at the maximum concentration of Z. tenuior EO. In spite of the antimicrobial activity of these EOs, further research is needed to assess their performance in food matrix and, in particular, in dairy product.

The effect of packaging material and storage period on microwave-dried potato (Solanum tuberosum L.) cubes.

The effect of three packaging materials (transparent biaxially oriented polypropylene laminate (BOPP); semi-transparent BOPP; polyethylene-polyamide (PE-PA) laminate) in three packaging conditions (vacuum, N2, natural atmosphere) and in two temperature treatments (blanching in hot water; steam) on microwave-dried potato (Solanum tuberosum L.; Solanaceae) cubes was studied. After storage for 60 and 120 days, the amount of ascorbic acid (AA), shrinkage and rehydration were determined. Dried potato cubes packaged under N2 atmosphere had the highest rehydration value (3.142 %). Since there is a direct relationship between the amount of water loss and shrinkage, samples packaged in PE-PA laminate packages under vacuum showed 4.947 % less shrinkage than transparent BOPP or semi-transparent BOPP due to low permeability of these packages. Potatoes stored for 120 days resulted in 7.89 % more shrinkage than those stored for 60 days. The least loss in AA occurred in PE-PA laminate packaging. The shelf-life of potato cubes can be increased and their quantitative and qualitative characteristics can be best preserved by package-drying in PE-PA laminate under vacuum conditions.