Development and Evaluation of the Properties of Active Films for High-Fat Fruit and Vegetable Packaging.

ß-cyclodextrin and allyl isothiocyanate inclusion complexes (ß-CD:AITC) have been proposed for developing fresh fruit and vegetable packaging materials. Therefore, the aim of this research was to develop active materials based on poly(lactic acid) (PLA) loaded with ß-CD:AITC and to assess changes in the material properties during the release of AITC to food simulants. PLA films with 0, 5 and 10 wt.% ß-CD:AITC were developed by extrusion. Surface properties were determined from contact angle measurements. Films were immersed in water, aqueous and fatty simulants to assess the absorption capacity and the change in the thermal properties. Moreover, the release of AITC in both simulants was evaluated by UV-spectroscopy and kinetic parameters were determined by data modeling. Results showed that a higher concentration of ß-CD:AITC increased the absorption of aqueous simulant of films, favoring the plasticization of PLA. However, the incorporation of ß-CD:AITC also avoided the swelling of PLA in fatty simulant. These effects and complex relationships between the polymer, inclusion complexes and food simulant explained the non-systematic behavior in the diffusion coefficient. However, the lower partition coefficient and higher percentage of released AITC to the fatty simulant suggested the potential of these materials for high-fat fruit and vegetable active packaging applications.

Electrospinning and cyclodextrin inclusion complexes: An emerging technological combination for developing novel active food packaging materials.

This review was focused on describing the combination of electrospinning and cyclodextrin inclusion complexes as one of the newest alternatives for the development of food packaging materials with antimicrobial and/or antioxidant properties. The advantages of this technological combination, the routes to design the active materials, the characterization and application of such materials were reviewed. Electrospinning has allowed developing active packaging materials composed by fibrillary structures with a high ratio surface-to-volume. On the other hand, cyclodextrin inclusion complexes have maintained the properties of active compounds when they have been incorporated in packaging materials. Both methods have been recently combined and novel active food packaging materials have been obtained through three different routes. Polymeric solutions containing preformed (route 1) or in-situ formed (route 2) cyclodextrin inclusion complexes have been electrospun to obtain packaging materials. Furthermore, cyclodextrin inclusion complexes solutions have been directly electrospun (route 3) in order to produce those materials. The developed packaging materials have exhibited a high active compound loading with a long lasting release. Therefore, the protection of different foodstuff against microbial growth, oxidation and quality decay as well as the maintenance of their physical and sensory properties have been achieved when those materials were applied as active packaging.

Effects of Aqueous Extracts from Amazon Plants on Plutella xylostella (Lepidoptera: Plutellidae) and Brevicoryne brassicae (Homoptera: Aphididae) in Laboratory, Semifield, and field trials.

We evaluated the insecticide activities of aqueous extracts of five species of plants from the Ecuadorian Amazon (Deguelia utilis (ACSm.) AMGAZEVEDO (Leguminosae: Papilionoideae), Xanthosoma purpuratum K. Krause (Alismatales: Araceae), Clibadium sp. (Asteracea: Asterales), Witheringia solanacea L'Hér (Solanales: Solanaceae), and Dieffenbachia costata H. Karst. ex Schott (Alismatales: Araceae)) plus Cymbopogon citratus Stapf. (Poales: Poaceae) under laboratory, open-field conditions in Plutella xylostella L. (diamondback moth), and semifield conditions in Brevicoryne brassicae L. Tap water was used as a negative control, and synthetic insecticides were used as positive controls. In a laboratory bioassay, aqueous extracts of D. utilis resulted in P. xylostella larval mortality. In contrast to chlorpyrifos, all botanicals were oviposition deterrents. All extracts except Clibadium sp. decreased leaf consumption by P. xylostella larvae. In semifield experiments, D. utilis, Clibadium sp., D. costata, and X. purpuratum initially controlled the population of B. brassicae, but 7 d after application, all botanicals except the D. utilis lost their ability to control the pest. In field experiments on broccoli crops in both dry and rainy seasons, the extracts did not control the abundance of P. xylostella, where as a mixture of two insecticides (chlorpyrifos + lambda cyhalothrin) did. These results show some incongruences from laboratory to semifield and field conditions, indicating that more studies, including the identification of the chemicals responsible for the biological activity, its stability, and the effects of chemotypes on insecticidal activity, are needed to understand the potential of these plant species as botanical insecticides.

Development of Inclusion Complexes With Relative Humidity Responsive Capacity as Novel Antifungal Agents for Active Food Packaging.

Background: Allyl isothiocyanate is an excellent antimicrobial compound that has been applied in the development of active food packaging materials in the last years. However, the high volatility of this compound could prevent a lasting effect over time. In order to avoid this problem, cyclodextrin inclusion complexes have been proposed as an alternative, being beta-cyclodextrin (ß-CD) as the main candidate. In addition, ß-CD could act as a relative humidity-responsive nanoparticle. In this regard, the aim of this study was to develop inclusion complexes based on ß-CD and AITC as relative humidity-responsive agents, which can be used in the design of active food packaging materials. Methods: Two different ß-CD:AITC inclusion complexes (2:1 and 1:1 molar ratios) were obtained by the co-precipitation method. Entrapment efficiency was determined by gas chromatography, while inclusion complexes were characterized through thermal, structural, and physicochemical techniques. Antifungal capacity of inclusion complexes was determined in a headspace system. Furthermore, the AITC release from inclusion complexes to headspace at different percentages of relative humidity was evaluated by gas chromatography, and this behavior was related with molecular dynamic studies. Key Findings and Conclusions: The entrapment efficiency of inclusion complexes was over to 60%. Two coexisting structures were proposed for inclusion complexes through spectroscopic analyses and molecular dynamic simulation. The water sorption capacity of inclusion complexes depended on relative humidity, and they exhibited a strong fungicide activity against Botrytis cinerea. Furthermore, the AITC release to headspace occurred in three stages, which were related with changes in ß-CD conformational structure by water sorption and the presence of the different coexisting structures. In addition, a strong influence of relative humidity on AITC release was evidenced. These findings demonstrate that ß-CD:AITC inclusion complexes could be used as potential antifungal agents for the design of food packaging materials, whose activity would be able to respond to relative humidity changes.