Packaging technology for improving shelf-life of fruits based on a nanoporous-crystalline polymer

Preparation, physicochemical and application evaluation of raspberry anthocyanin and curcumin based on chitosan/starch/gelatin film

Raspberry anthocyanin (RA) from Rubus idaeus L. (Rosaceae) and curcumin (Cur) from Curcuma longa L. (Zingiberaceae) can effectively improve the physicochemical properties of composite films, and as bioactive pigment components, they can impart pH-responsive properties to the film. In this study, RA and Cur were added to chitosan/starch/gelatin composite film (CSG) to prepare CSG-RA, CSG-Cur, CSG-RA/Cur₈₂ and CSG-RA/Cur₇₃ color films by solution casting method. The color films could change color under different pH conditions and had higher antioxidant activities using ABTS (2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid)) assay. The results from fourier transform infrared spectroscopy and scanning electron microscopy showed that RA and Cur were well dispersed in the CSG matrix and improved the structure of the composite films. The hydrophobic Cur increased the tensile strength from 6 Mpa (CSG) to 14 Mpa (CSG-Cur), but reduced the elongation at break from 55 % (CSG) to 40 % (CSG-Cur). These color films had a good fresh-keeping effect and freshness monitoring, in particular, CSG-RA/Cur₇₃, had the better opacity, water solubility, thickness, moisture content and water vapor permeability than the other films. Briefly, binary pigment films had the potential to become a pH-sensitive indicator/packing film.

Towards Impact of Modified Atmosphere Packaging (MAP) on Shelf-Life of Polymer-Film-Packed Food Products: Challenges and Sustainable Developments

In this article, we report in detail the use of protective gases to extend the shelf-life of polymer-film-packed foodstuff and reduce the most typical bacteria and microorganisms that negatively affect the quality and lifetime of a given packaging. This article provides significant information about the most important advantages of using protective gases and examples of gases or gas mixtures which can be used for almost every kind of foodstuff depending on the application. We also discuss how protective gases change the level of microorganisms in food using gases and how the shelf-life of food can be enhanced using correct gases or gas mixtures. The article also provides imperative information on the selection of correct protective gases for specific applications, especially for food production, to preserve against the most typical threats which can appear during the packaging or production process. Packaging innovations can reduce the environmental impact of food and polymer packaging waste by prolonging products’ shelf-lives and by reducing waste along the production and distribution chain and at the household level.

Axial Orientation of Co-Crystalline Phases of Poly(2,6-Dimethyl-1,4-Phenylene)Oxide Films

Films exhibiting co-crystalline (CC) phases between a polymer host and low-molecular-mass guest molecules are relevant for many applications. As is usual for semi-crystalline polymers, axially oriented films can give relevant information on the crystalline structure, both by Wide Angle X-ray diffraction fiber patterns and by polarized Fourier-transform infrared spectroscopy. Axially oriented CC phases of poly(2,6-dimethyl-1,4-phenylene)oxide (PPO) with 1,3,5-trimethylbenzene (mesitylene) can be simply obtained by the stretching of CC PPO films. In fact, due to the plasticization effect of this highly boiling guest, PPO orientation can occur in a stretching temperature range (170-175 °C) nearly 50 °C lower than that generally needed for PPO films (220-230 °C). This low stretching temperature range allows avoidance of polymer oxidation, as well as formation of the mesomorphic dense γ PPO phase. Axially oriented CC phases of PPO with toluene, i.e., with a more volatile guest, can be instead obtained by the stretching (in the same low temperature range: 170-175 °C) of CC PPO blend films with polystyrene.

The Influence of Film and Storage on the Phenolic and Antioxidant Properties of Red Raspberries (Rubus idaeus L.) cv. Erika

In this paper, the effect of the packaging material and storage method on red raspberries produced at Reggio Calabria (Italy) was studied. For this purpose, the fruits were stored immediately after harvest in different conditions: in the fridge at 1 °C and in the freezer at -20 °C, using different packaging materials, two new patented films (nanoactive A) and (nanoactive B), one common packaging film (polyethylene terephthalate), and other fruits were left without any packaging material. Chemical parameters were analysed at harvest to have the initial characteristics without any conditioned storage and to distinguish the post-harvest effect on the fruits, then daily for storage in the fridge and monthly for storage in the freezer. The aims of our project were first to determine the qualitative characterization of these red raspberries, the optimization of their shelf-life during time in the fridge or freezer, using the different types of packaging materials and finally to highlight the usefulness of the new patented packaging materials. Nanoactive A film showed the best shelf-life in the fridge, and after 14 days the values, given as mg/100 g fresh weight, were: total phenolics (166.70), monomeric anthocyanin content (50.82), flavonoids (24.64), ascorbic acid (32.42), and 1, 1-diphenyl-2-picrylhydrazyl (DPPH) assay (95.93).