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Graphical abstract Highlights • Four GTE were compared regarding their antioxidant capacity, TPC and TFC. • Active PLA films incorporated with GTE were developed. • Mechanical properties (e.g. tensile strength and strain at break) were evaluated. • Water vapour transmission of the films improved with higher amounts of GTE. • PLA/GTE films protected the smoked salmon from lipid oxidation during storage. Abstract A new antioxidant active packaging film has been developed based on polylactic acid (PLA) in which green tea extract (GTE) has been immobilized by extrusion. Two GTE concentrations were tested, 1% (w/w) and 2% (w/w). Four GT samples were compared regarding their antioxidant capacity (by DPPH radical scavenging method and β-carotene bleaching method), total phenolics content (TPC) and total flavonoids content (TFC). The commercial GTE presented with highest antioxidant capacity by the DPPH radical assay (EC 50 = 0.12 ± 0.00 mg/mL) and the highest TPC (416 ± 9.95 mg gallic acid equivalents (GAE)/g extract) and it was selected to be incorporated in the active film. Films were evaluated regarding their mechanical properties (e.g. tensile strength decreased 12% with the incorporation of GTE in the PLA matrix and strain at break increased 9.6 and 36% with the addition of 1 and 2% of GTE) and water vapour transmission rates (water-vapour barrier properties improved with the addition of higher amounts of GTE). The study of the effectiveness of PLA/GTE films against lipid oxidation was performed by the following methods: peroxide value, p -anisidine value, thiobarbituric acid reactive substances (TBARS) assay and hexanal monitoring, after packaging smoked salmon slices during different storage times (0, 7, 15, 30, 45 and 60 days). The results showed that the incorporation of GTE in the PLA films protects the smoked salmon from lipid oxidation in the different storage times tested. However, additional studies should be performed to better understand the GTE mechanism of action as the results suggest a pro-oxidant effect of PLA/GTE 2% after 60 days of storage and to evaluate the potential antimicrobial activity of active films. [ABSTRACT FROM AUTHOR]

One of the most detrimental processes in fatty foodstuffs is lipid oxidation, which occurs during production and storage, and influences food composition and safety. Polylactic acid (PLA), a commercially available biopolymer, is biodegradable thermoplastic aliphatic polyester derived from renewable resources. Polymer layered silicate (PLS) nanocomposites have shown potential for enhancing physical, chemical, and mechanical properties of both conventional materials and biopolymers. In the present work nanocomposite films were prepared by incorporating unmodified montmorillonite clay (Cloisite ® Na + ) in the PLA. Moreover, the lipid oxidation status of a processed meat product packaged with a film incorporating this nanocomposite was evaluated. In line with this, hexanal, Thiobarbituric Acid Reactive Substances (TBARS) and p- anisidine value were monitored after packaging salami during different storage times (15, 30, 60 and 90 days). The results of this study showed that the presence of montmorillonite (MMT) in the polymer film can reduce the lipid oxidation of processed meat products, extending their shelf life and, thus, suggesting that the new film is a potential good alternative to conventional bioplastics. [ABSTRACT FROM AUTHOR]

Abstract Background About one-third of the world's food production is lost or wasted every year. Food waste is when foods, that are still good for human consumption, are thrown away by retailers or consumers, representing, according to FAO, 40% of food losses in developed countries. Frequently fruits reach the consumer in formulations such as juices and pastes instead of their whole form. The by-products of these formulations possess some powerful biological activities, making them potential sources of bioactive compounds. Scope and approach This paper carries out an exhaustive review of the scientific literature, on the main active compounds of some fruits by-products and their biological activities, assessing their potential uses and risks for human health. Key findings and conclusions The potential application of fruits by-products is assessed in the paper. The extraction processes, in their majority, are simple and resort to eco-friendly solvents such as ethanol or water. Pomegranate and grape seed extracts present high antioxidant and antimicrobial activity, which makes them excellent candidates to be used as natural additives or active compounds in the food and food packaging industries. Highlights • Pomegranate and grape by-products are a potential source of active compounds. • Reutilization of fruit by-products can be a solution for food waste accumulation. • Pomegranate and grape by-products have powerful antioxidant and antimicrobial activities. [ABSTRACT FROM AUTHOR]

This study focused on the recovery of antioxidant compounds from lemon and tomato by-products for use as natural additives in the development of active food packaging formulated using three different polymeric matrices that included low-density polyethylene (LDPE), polylactic acid (PLA), and G-polymer (GP). The films were characterized according to chemical-physical, thermal analyses, and their barrier and mechanical properties. Migration assays were performed to evaluate the release of active compounds from polymeric matrices, which were quantified in the food simulant by high-performance liquid chromatography with a diode array detector and then confirmed via liquid chromatography coupled to mass spectrometry. The antioxidant capacities of the films were determined to evaluate their applicability for use as antioxidant-active packaging. The incorporation of extracts into polymers resulted in different structural changes and enhanced properties according to the nature of the polymeric matrix based on the interactions of the –OH groups of polyphenols and the chemical groups of the polymers. The lemon (LE) and tomato (TE) extracts lead to a substantial improvement in water barrier properties of PLA and GP-based films. The active PLA and GP films released high amounts of polyphenolic compounds (up to 65% for GP containing LE); mainly hesperidin and eriocitrin for LE films, and chrologenic acid for TE films. PLA loaded with lemon extract at 4% was selected as the most suitable for use as antioxidant packaging to extend the shelf-life of foods with high fat content. • Active films were developed using lemon (LE) and tomato (TE) by-product extracts. • LE and TE incorporation lead to significant structural changes in the active films. • TE significantly improved the hydrophobicity of the LDPE polymer. • GP and PLA films exhibited good release properties for active compounds. • PLA active films are rich in polyphenols and displayed the best antioxidant properties. [ABSTRACT FROM AUTHOR]