Chitosan films incorporated with thyme oil for potential applications of wound dressing were successfully prepared by solvent casting method. The water vapor permeability, oxygen transmission rate, and mechanical properties of the films were determined. Surface and crosssection morphologies and the film thicknesses were determined by Scanning Electron Microscopy (SEM). Fourier transform infrared (FT-IR) spectroscopy was conducted to determine functional group interactions between the chitosan and thyme oil. Thermal behaviors of the films were analyzed by Thermal Gravimetry (TGA) and Differential Scanning Calorimetry (DSC). In addition, the antimicrobial and the antioxidant activities of the films were investigated. The antimicrobial test was carried by agar diffusion method and the growth inhibition effects of the films including different amount of thyme oil were tested on the gram negative microorganisms of Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa and a gram positive microorganism of Staphylococcus aureus. The minimum thyme oil concentration in chitosan films showing the antimicrobial activity on all microorganisms used in the study was found as 1.2 % (v/v). In addition, this concentration showed the highest antioxidant activity due to mainly the carvacrol in thyme oil. Water vapor permeability and oxygen transmission rate of the films slightly increased, however, mechanical properties decreased with thyme oil incorporation. The results revealed that the thyme oil has a good potential to be incorporated into chitosan to make antibacterial and permeable films for wound healing applications.

The biomass growth, lactic acid production and lactose utilisation kinetics of lactic acid production from whey by Lactobacillus casei was studied. Batch fermentation experiments were performed at controlled pH and temperature with six different initial whey lactose concentrations (9-77 g dm −3 ) in a 3 dm 3 working volume bioreactor. Biomass growth was well described by the logistic equation with a product inhibition term. In addition, biomass and product inhibition effects were defined with corresponding power terms, which enabled adjustment of the model for low-and high-substrate conditions. The Luedeking-Piret equation defined the product formation kinetics. Substrate consumption was explained by production rate and maintenance requirements. A maximum productivity of 2.5 g dm −3 h −1 was attained with an initial lactose concentration of 35.5 g dm −3 .

The effect of zeolite treatment on color change, 5-hydroxymethyl furfural (HMF), total phenolic compounds (TPCs), ionic composition and texture of sweet pear pekmez was investigated for two different zeolite concentrations during pekmez production. HMF was not detected in clarified pear juice and pekmez samples subjected to 5 g/L (5ZP) and 10 g/L (10ZP) zeolite adsorption. HMF content of pekmez sample without zeolite treatment (PP) was measured as 2.76 ± 0.07 mg/kg. The addition of zeolite just after the clarification results in the reduction of the HMF content of pekmez samples. The highest TPC was determined as 4,958.1 ± 167 mg GAE/kg dry weight in PP sample. Application of zeolite together with conventional clarification resulted in 31.4% and 33.2% reduction in TPC of 5ZP and 10ZP, respectively, compared to PP samples. Zeolite application improved the color quality of pekmez samples. While the amount of fluoride, chloride, bromide, and potassium decreased with the zeolite treatment, the amount of calcium, sodium and magnesium in pekmez samples increased significantly. Zeolite treatment did not significantly affect the texture of the samples.

The silk fibroin (SF)/chitosan (CHI) blend films were prepared by dissolving them in formic acid. The morphology of the films was examined by scanning electron microscopy (SEM). The roughness of the membranes was determined by atomic force microscopy (AFM). These films were treated with the extracts of Pistacia terebinthus, Pistacia lentiscus, and Hypericum empetrifolium. Folin-Ciocalteu assay was used to determine the amount of total phenols adsorbed on these blend films. The antibacterial properties of films were tested using disc diffusion and turbidity measurement methods against Escherichia coli and Staphylococcus epidermidis. The release of adsorbed phenolics from the film surface resulted in antibacterial properties. © The Korean Fiber Society and Springer Netherlands 2010.Natural Products Research Development Unit (NPRDU/DUAG

In the present study, “sweet pomegranate pekmez” (PP), was produced by three different methods as open pan evaporation (OPE), application of activated carbon prior to open pan evaporation (AC), and vacuum evaporation (VE). The effects of activated carbon treatment and production methods on pH, density, soluble solids, water activity, total phenolic content, HMF formation, mineral content, and texture characteristics were investigated. Textural properties of PP increased with increasing soluble solids content. HMF was not detected in AC and VE products. HMF content of OPE product was measured as 2.77 ± 0.28 mg.100 g. Activated carbon treatment resulted in significant reductions in mineral, HMF, and TPC contents of pekmez samples. HMF formation kinetics of PP was investigated at various accelerated storage temperatures. HMF formation was well described by the zero‐order reaction model among five kinetic models applied. The rate of reaction was determined as highly temperature‐dependent by an Arrhenius equation. Practical applications In recent years, consumer interest and demand for potentially health‐promoting products has motivated the production of such food products. In this context, in this study, sweet pomegranate pekmez is introduced as a potentially healthy product produced by different methods, and the production stages and conditions that may enlighten the industrial production of this traditional product are provided. In addition, the application of activated carbon used in the production of pekmez has been presented as an alternative method to reduce the potential formation of HMF during heat treatment.