Characterization of antioxidant-antibacterial quince seed mucilage films containing thyme essential oil.

In this study thyme essential oil (TEO) concentrations ranging from 0% to 2.0%, incorporated in quince seed mucilage (QSM) film were used. Antibacterial activity, physical, mechanical, barrier and antioxidant properties of QSM films were evaluated. The antimicrobial activity of the QSM films incorporated with thyme essential oil was screened against 11 important food-related bacterial strains by agar disc-diffusion assay. Films containing 1% of thyme essential oil were effective against all test microorganisms and exhibited a strong inhibitory effect on the growth of Shewanella putrefaciens, Listeria monocytogenes and Staphylococcus aureus. QSM films exhibited some antioxidant activity, which was significantly improved by the addition of the essential oil. A reduction of the glass transition temperature, as determined by differential scanning calorimetry (DSC), was caused by addition of thyme essential oil into the QSM films. Scanning electron microscopy was carried out to explain structure-property relationships. Incorporating thyme essential oil into edible QSM films provides a novel way to improve the safety and shelf life of ready-to-eat foods.

Jouki M ，Mortazavi SA ，Yazdi FT ，Koocheki A ... -  《-》

Physical, barrier and antioxidant properties of a novel plasticized edible film from quince seed mucilage.

In this study, we investigated the potential of quince seed mucilage (QSM) as a new source for preparation of edible films and determined the physical, mechanical, barrier, antioxidant, microstructural and thermal properties. QSM films were prepared by incorporation of three levels of glycerol (25-50%, w/w). As glycerol concentration increased, water vapor permeability (WVP), oxygen permeability (O2P), elongation at break (EB), water solubility and moisture content of QSM films increased while, tensile strength (TS), density and surface hydrophobicity decreased significantly. The measurement of color values showed that by the increasing of the glycerol concentration in polymer matrix, the b and L values increased while ΔE value decreased. Microscopic views indicated smooth and uniform surface morphology without obvious cracks, breaks, or openings on the surfaces after the incorporation of glycerol as a plasticizer. The results of the present study suggest that QSM as a new antioxidant edible film with interesting specifications can potentially be used for packaging of a wide range of food products.

Jouki M ，Yazdi FT ，Mortazavi SA ，Koocheki A ... -  《-》

Effect of quince seed mucilage edible films incorporated with oregano or thyme essential oil on shelf life extension of refrigerated rainbow trout fillets.

The effects of quince seed mucilage film (QSMF) containing oregano (O) or thyme (T) essential oil on shelf life extension of rainbow trout (Oncorhynchus mykiss) fillets during refrigerated storage (4°C) were evaluated over a period of 18days. Films were prepared in four different concentrations of essential oils, including 0, 1, 1.5 and 2%. The control and the wrapped fillet samples were analyzed periodically for microbiological (aerobic and psychrotrophic count, Pseudomonas spp., H2S-producing bacteria, lactic acid bacteria, and Enterobacteriaceae), chemical (TBA, TVB-N, TMA-N), and sensory characteristics. Bacteria grew most quickly in trout fillets stored in air, followed by those wrapped with QSMF and the lowest counts were in wrapped samples with QSMF+2%T. Pseudomonas spp., Enterobacteriaceae and LAB counts were significantly lower in samples wrapped with QSMF+2%T. The lowest TBA value was obtained in fillets wrapped QSMF containing 2% oregano essential oil. The strong antioxidant activity of QSMF+2%O was related to the composition of oregano essential oil. The GC analysis of essential oil components revealed that carvacrol (81.85%) was the major component of oregano essential oil. TBA value varied for all treatments and remained lower than 2mg MDA/kg throughout storage. The formation of TVB-N, TMA-N increased with time of storage. TVB-N and TMA-N correlated well with the microbiological data, indicating that along with TVB-N, TMA-N may serve as a useful index for fillets spoilage. QSMF extended the microbial shelf life of rainbow trout fillets by 2days, whereas the QSMF+1%O, QSMF+1.5%O, QSMF+2%O, QSMF+1%T, QSMF+1.5%T and QSMF+2%T resulted in a significant shelf life extension of the trout fillets by 3, 5, 9, 6, 10 and 11days, respectively, as compared to the control samples.

Jouki M ，Yazdi FT ，Mortazavi SA ，Koocheki A ，Khazaei N ... -  《-》

Physical, antibacterial and antioxidant properties of chitosan films incorporated with thyme oil for potential wound healing applications.

Altiok D ，Altiok E ，Tihminlioglu F 《-》

Physical and antibacterial properties of açaí edible films formulated with thyme essential oil and apple skin polyphenols.

Thyme essential oil (TEO) and apple skin polyphenols (ASP) are natural compounds considered as generally recognized as safe by FDA, with biological effects against bacteria and fungi. This work aimed to evaluate physical and antimicrobial properties of açaí edible films formulated with TEO and ASP at 3% and 6% (w/w) individually or combined at 3% (w/w) each. Physical properties studied include mechanical resistance, water vapor permeability (WVP), color, and thermal resistance. Antimicrobial activity against Listeria monocytogenes was determined using the overlay diffusion test. Addition of ASP resulted in improved mechanical properties. TEO at 6% (w/w) resulted in increased elongation. ASP films had significant higher WVP than control film. ASP films were lighter and had more red color than other films. Incorporation of ASP resulted in improved film thermal stability, whereas TEO caused rapid thermal decomposition. Presence of clusters was observed on the surface of films. Addition of ASP resulted in a smoother surface, whereas addition of TEO led to the formation of crater-like pits on the film surface. Açaí edible film incorporated with 6% (w/w) TEO presented the highest antimicrobial activity. However, both antimicrobials are necessary in the açaí films in order to obtain edible films with suitable physical-mechanical properties. The results of the present study showed that TEO and ASP can be used to prepare açaí edible films with adequate physical-mechanical properties and antimicrobial activity for food applications by direct contact. Developed açaí edible films presented antimicrobial activity against L. monocytogenes and good physical-mechanical properties, showing the potential use of açaí edible films in food preservation.

Espitia PJ ，Avena-Bustillos RJ ，Du WX ，Chiou BS ，Williams TG ，Wood D ，McHugh TH ，Soares NF ... -  《-》