In this study, antimicrobial films were developed against Campylobacter jejuni by incorporation of gallic acid (GA) into zein-based films. The zein and zein-wax composite films containing GA between 2.5 and 10 mg/cm 2 were effective on different C. jejuni strains in a concentration-dependent manner. Zein and zein-wax composite films showed different release profiles in distilled water but quite similar release profiles at solid agar medium. Depending on incorporated GA concentration, 60À80% of GA released from the films, while the remaining GA was bound or trapped by film matrix. The GA at 2.5 and 5 mg/cm 2 caused a considerable increase in elongation (57À280%) of all zein films and eliminated their classical flexibility problems. The zein-wax composite films were less flexible than zein films, but the films showed similar tensile strengths and Young's modulus. Scanning electron microscopy indicated different morphologies of zein and zein-wax composite films. This study clearly showed the good potential of zein and GA to develop flexible antimicrobial films against C. jejuni.

a b s t r a c tThe aim of the present study is to use antimicrobial edible film technology and natural phenolic antimicrobials for inhibition of major bacterial plant pathogens such as Erwinia amylovora, Erwinia carotovora, Xanthomonas vesicatoria and Pseudomonas syringae. For this purpose phenolic acids (PAs) (gallic (GA), vanillic (VA), cinnamic acids (CA)), essential oils (EOs) (carvacrol (CAR), thymol (THY), eugenol (EUG) citral (CIT)), phenolic extracts (PEs) from clove (CE), oregano (OE), artichoke stem (ASE) and walnut shells (WSE) were evaluated as antimicrobial zein film components. Films containing PAs between 1 and 4 mg/cm 2 inhibited all pathogens while EOs between 1 and 4 mg/cm 2 and CE between 4 and 8 mg/cm 2 inhibited pathogens except P. syringae. The most potent films were obtained by using GA against E. amylovora and P. syringae, VA against E. carotovora, and CA, THY or CAR against X. vesicatoria. The addition of phenolic compounds into films increased the porosity of films. The phenolic containing films also become more flexible and lost their brittleness. This study is important in that it prepared the basis of using edible antimicrobial coatings in outdoor applications on infected tree stems, soil surfaces and agronomy tools or in classical fruit and seedling coating applications to control bacterial contamination or spoilage.

Cellulose nanocrystals (CNCs) are unique, renewable top-down nano particles from which coatings with improved gas barrier properties and new functionalities can be prepared. In this paper, the potential for obtaining such high performing nanocrystals from low-cost lignocellulosic by-products or raw materials is proved by a comparison study on CNCs obtained both from cotton linters and kraft pulp, by means of the ammonium persulfate (APS) process. Morphological and chemical characterization of the nanocrystals obtained, as well as the main functional properties of the poly(ethylene terephthalate) coated films, showed quite similar characteristics and performances of CNCs obtained from pure cellulose raw material (cotton linters) and the nanoparticles produced from a potential discard of paper making processes (kraft pulp). In particular, the gas barrier properties of the coating produced with CNCs obtained from kraft pulp were very promising, providing oxygen and carbon dioxide permeability values hundreds of times lower than those of equal thickness in comparison with common barrier synthetic polymers, over a broad range of temperatures. The results obtained are relevant not only for the outstanding performances achieved, but also because they evoke a possible positive example of industrial symbiosis in the packaging field, merging together the requirements and needs of the paper and plastic industries and addressing the way towards a better management of waste and materials.

The aim of this research was to characterize the extra virgin olive oil samples from different locations in the Aegean coastal area of Turkey in terms of their phenolic compositions for two consecutive years to show the classification of oil samples with respect to harvest year and geography. Forty seven commercial olive oil samples were analyzed with HPLC-DAD, and 17 phenolic compounds were quantified. Hydroxytyrosol, tyrosol, vanillic acid, p-coumaric acid, ferulic acid, cinnamic acid, luteolin and apigenin were the characteristic phenols observed in all oil samples for two harvest years. Syringic acid, vanillin and m-coumaric acid were the phenolic compounds appeared in the olive oil depending on the harvest year. Partial least square-discriminant analysis (PLS-DA) of data revealed that oils from the north Aegean and south Aegean areas had different phenolic profiles. The phenolic compounds, which played significant roles in the discrimination of the olive oils, were tyrosol, oleuropein aglycon, cinnamic acid, apigenin and hydroxytyrosol to tyrosol ratio. The Aegean coastal region is the largest olive oil producer and exporter of Turkey. This study shows that the olive oils from different parts of the region have their own defining characteristics that can be used in the authentication studies and geographical labeling of Turkish olive oils.

No abstract

The aim of the present study is to use antimicrobial edible film technology and natural phenolic antimicrobials for inhibition of major bacterial plant pathogens such as Erwinia amylovora, Erwinia carotovora, Xanthomonas vesicatoria and Pseudomonas syringae. For this purpose phenolic acids (PAs) (gallic (GA), vanillic (VA), cinnamic acids (CA)), essential oils (EOs) (carvacrol (CAR), thymol (THY), eugenol (EUG) citral (CIT)), phenolic extracts (PEs) from clove (CE), oregano (OE), artichoke stem (ASE) and walnut shells (WSE) were evaluated as antimicrobial zein film components. Films containing PAs between 1 and 4 mg/cm 2 inhibited all pathogens while EOs between 1 and 4 mg/cm 2 and CE between 4 and 8 mg/cm 2 inhibited pathogens except P. syringae. The most potent films were obtained by using GA against E. amylovora and P. syringae, VA against E. carotovora, and CA, THY or CAR against X. vesicatoria. The addition of phenolic compounds into films increased the porosity of films. The phenolic containing films also become more flexible and lost their brittleness. This study is important in that it prepared the basis of using edible antimicrobial coatings in outdoor applications on infected tree stems, soil surfaces and agronomy tools or in classical fruit and seedling coating applications to control bacterial contamination or spoilage.