The aim of the present study was to develop and characterize edible films produced from whey protein concentrate (WPC) and plasticized with different contents of glycerol (Gly) and/or trehalose (Tre) in order to evaluate new edible film formulations for their potential use in food packaging applications. Additionally, potential changes in the film mechanical properties during storage at ambient and freezing conditions were considered. Moisture content, solubility, thickness, transparency, microstructure, colour parameters, and mechanical properties were assessed. The films incorporated with Tre were more insoluble in water than WPC/Gly films, being more suitable for food applications. WPC/Gly and WPC/Tre films were clear enough to be used as see-through packaging. However, when Tre was included into WPC/Gly film formulations, film opacity increased. Scanning electron microscope (SEM) images suggested that this phenomenon may be related to the growth of Tre crystals in the film matrix. Moreover, when Tre concentration increased in the WPC/Gly matrix, film surface was more heterogeneous. Interestingly, the presence of Tre in WPC-based films was effective in preventing Maillard reaction after heating. WPC/Tre films were the most rigid but the least stable for storage, resulting more susceptible to rupture and cracking. Only WPC/Gly and WPC/Gly-Tre 8% films were rather flexible, manageable, and stable up to 90 days of storage under ambient and freezing conditions. These findings can be used to better design applications of edible films containing plasticizers that may crystallize over time in order to optimize film formulation in a rational manner towards their eventual application as food packaging.

In this work, chitosan films were prepared by a casting/solvent evaporation methodology using pectin or hydroxypropylmethyl cellulose to form polymeric matrices. Miconazole nitrate, as a model drug, was loaded into such formulations. These polymeric films were characterized in terms of mechanical properties, adhesiveness, and swelling as well as drug release. Besides, the morphology of raw materials and films was investigated by scanning electron microscopy; interactions between polymers were analyzed by infrared spectroscopy and drug crystallinity studied by differential scanning calorimetry and X-ray diffraction. In addition, antifungal activity against cultures of the five most important fungal opportunistic pathogens belonging to Candida genus was investigated. Chitosan:hydroxypropylmethyl cellulose films were found to be the most appropriate formulations in terms of folding endurance, mechanical properties, and adhesiveness. Also, an improvement in the dissolution rate of miconazole nitrate from the films up to 90% compared to the non-loaded drug was observed. The in vitro antifungal activity showed a significant activity of the model drug when it is loaded into chitosan films. These findings suggest that chitosan-based films are a promising approach to deliver miconazole nitrate for the treatment of candidiasis.

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This paper demonstrates for the first time the power of a chemometric second-order algorithm for predicting, in a simple way and using spectrofluorimetric data, the concentration of analytes in the presence of both the inner-filter effect and unsuspected species. The simultaneous determination of the systemic fungicides carbendazim and thiabendazole was achieved and employed for the discussion of the scopes of the applied second-order chemometric tools: parallel factor analysis (PARAFAC) and partial least-squares with residual bilinearization (PLS/RBL). The chemometric study was performed using fluorescence excitation-emission matrices obtained after the extraction of the analytes over a C18-membrane surface. The ability of PLS/RBL to recognize and overcome the significant changes produced by thiabendazole in both the excitation and emission spectra of carbendazim is demonstrated. The high performance of the selected PLS/RBL method was established with the determination of both pesticides in artificial and real samples.

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This paper presents a novel approach for the simultaneous determination of two widely used fungicides in a very interfering environment, combining the advantage of a spectrofluorimetric optosensor coupled to a flow-injection system and the selectivity of second-order chemometric algorithms. The sensor is based on the simultaneous retention of thiabendazole and fuberidazole on C18-bonded phase placed inside a flow-cell. After the arrival of the analytes to the sensing zone, the flow is stopped and the excitation-emission fluorescence matrix is read in a fast-scanning spectrofluorimeter. Parallel factor analysis (PARAFAC) and unfolded and multidimensional partial least-squares coupled to residual bilinearization (U- and N-PLS/RBL) were selected for data processing. These algorithms achieve the second-order advantage, and are in principle able to overcome the problem of the presence of unexpected interferences. The power of U-PLS/RBL to quantify both fungicides at parts-per-billion levels, even in the presence of high concentrations of spectral interferences such as carbaryl, carbendazim and 1-naphthylacetic acid, is demonstrated. Indeed, U-PLS/RBL allowed us to reach selectivity using a commercial but non-selective sensing support. To the best of our knowledge, this is the first time the potentiality of the 'second-order advantage' is evaluated on a flow-injection system, using an unspecific supporting material and in the presence of three real interferences. Using a sample volume of 2 mL, detection limits of 4 ng mL(-1) and 0.3 ng mL(-1) for thiabendazole and fuberidazol were respectively obtained in samples without interferences. In samples containing interferences, the limits of detection were 17 and 1 ng mL(-1) for thiabendazole and fuberidazol, respectively. The sample frequency, including excitation/emission fluorescence matrix measurements, was 12 samples h(-1). The sensor was satisfactorily applied to the determination of both analytes in real water samples.

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This study focuses on the spectrofluorimetric behavior of the pesticide carbendazim in the presence of selected organized assemblies and also on their potential analytical applications. The relatively weak fluorescence emission band of carbendazim is significantly enhanced by micellar media formed by sodium dodecyl sulfate, hexadecyltrimethylammonium bromide, hexadecyltrimethylammonium chloride, and decyltrimethylammonium bromide. The influence of the surfactant structures, concentrations, and working experimental conditions on the fluorescence spectra of carbendazim was thoroughly evaluated and discussed. Although the interaction of carbendazim with different cyclodextrins is rather weak, it was corroborated that the fluorescence intensity of this compound in the presence of (2-hydroxy)propyl beta-cyclodextrin is increased by a factor of two. Among the studied organized media, the cationic surfactant hexadecyltrimethylammonium bromide produced the largest signals for the compound of interest. Consequently, the optimal working conditions for the spectrofluorimetric determination of carbendazim in the presence of the latter detergent were analyzed, concluding that previous literature reports should be reconsidered.