In this paper, multilayer pectin-beeswax/colophony-pectin (P-BC-P) films including different proportions of beeswax/colophony mixtures were prepared in order to reduce the water vapor permeability. FTIR, XRD, DSC, polarized light microscopy (PLM), and water vapor permeation assays were performed. Characterization techniques showed (i) polar interactions between beeswax and colophony at the amorphous phase, (ii) changes in beeswax crystalline phase from sponge-like to needle-like structure, and (iii) formation of a eutectic mixture at BC3 70/30 ratio which guides the epitaxial crystallization of beeswax. Pure pectin films showed low resistance to the water vapor permeation (361 × 10⁻¹³ g m m⁻² s⁻¹ Pa⁻¹), while multilayer films showed major control over the transport process. P-BC3-P showed one of the lowest water vapor permeability (WVP) values (56 × 10⁻¹³ g m m⁻² s⁻¹ Pa⁻¹) and the closest WVP value to that of polyethylene films (LDPE 5.8 × 10⁻¹³ g m m⁻² s⁻¹ Pa⁻¹). This result was attributed to the ordered crystalline structure reached by the epitaxial crystallization of beeswax within the hydrophobic phase.

One of the most common materials used for packaging is low density polyethylene film. To improve the water vapour transfer of the film, zeolite¡polymer composite films and perforated films are produced. The solid-low density polyethylene composite films were prepared by extrusion of polyethylene beads coated with hot zeolite particles of a definite size range in an industrial extruder (-420/+212, -212/+106, -106/+53 microparticles/g of polyethylene beads). A needle (0.2, 0.5 and 1.75 mm in diameter) attached to the tip of a soldering gun was used for the production of the perforated polyethylene films (1, 3, 6, 12, 18 and 24 holes per 38.5 cm2). The overall evaluation indicates that the water vapour transfer rates can be modified by the composite and the perforated films, which provides packaging material variety for foods of different moisture content. The solid- polyethylene composite films showed less permeability to water vapour than the polyethylene film. This may be attributed to two reasons: the available polyethylene area is reduced by the presence of solid particles and these solid particles have an important sorption property. The water vapour transfer rates increased by the perforated films.

A synbiotic product of combined Lactobacillus plantarum TISTR 875 with water extracts and crude fibers from corn, mungbean, and soybean was formulated to investigate the survival of L. plantarum during freeze-drying and storage. The impacts of those water extracts and crude fibers on probiotic survival were determined in both a cultural medium and a freeze-drying medium. L. plantarum cultivated in de Man, Rogosa, and Sharpe (MRS) broth containing 2 % of water extract from soybean with 2 % mungbean fiber showed only 0.11 log CFU/ml cell reduction. The survival of L. plantarum harvested at the late log phase, mid stationary, phase and late stationary phase did not show statistical significance (P > 0.05), whereas an initial pH of 6.5 and growth temperature of 37 °C showed greater impact (P < 0.05). The addition of corn extract to the freeze-drying medium as a cryoprotectant had a similar effect on L. plantarum survival as sucrose, but it was better (P < 0.05) than fructo-oligosaccharide and exopolysaccharides from Weissella cibaria A2, soybean extract, mungbean extract, soybean, corn, and mungbean fibers. A protective coating of corn extract was revealed and observed using scanning electron microscopy. The freeze-dried L. plantarum, cultivated in MRS broth containing soybean extract and mungbean fiber with corn extract as a cryoprotectant, retained high viability of 7.21 and 6.88 log CFU/ml after 8-week storage in a vacuum-packed aluminum foil-laminated polyethylene sachet and a nitrogen-flushed glass vial, respectively. ©Springer Science+Business Media New York 2012.

Caprolactam and 2,4-di-tert-butyl phenol (2,4-DTBP) are substances typically found in some food contact materials (FCMs). They are known to often migrate into food, and are difficult to analyse in liquid food simulants using GC. In this work a simple salting-out Liquid-Liquid Extraction (SALLE) for the analysis of both substances in water and the official food simulant A (10 % v/v ethanol, Regulation (EU) No. 10/2011) is presented. The method, which included analytical determination by GC-MS, was optimized and validated to ensure sufficient analytical quality.The method’s LOQs allowed the proper quantification of caprolactam at its EU legislative limit (15 mg kg⁻¹). For 2,4-DTBP the method also revealed good sensitivity, although no official limits have been established yet. Linear regression coefficients (R²) were in all cases higher than 0.999, and recoveries ranged from 87 % and 95% for caprolactam and 2,4-DTBP, respectively. Precision was also acceptable, with the RSDs (%) below 12 %. The method proved to be adequate to be used for routine analysis.The presence of salt during migration of caprolactam and 2,4-DTBP was also investigated in this work. Polyamide/polyethylene FCM multilayer films have been tested with water and simulant A, containing different amounts of NaCl (up to 15 % m/v), and applying different migration conditions (temperature and time). The results indicated that salinity plays an important effect on the migration of caprolactam, with the presence of salt reducing its migration in case of water and increasing it in case of simulant A. These preliminary results seem to indicate that migration testing should consider not only the well-known fatty content of a food, but also its salinity content, as it may end up affecting drastically the migration of polar substances.