Active polylactic acid film incorporated with green tea extract: Development, characterization and effectiveness

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 (watervapour 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.

Antioxidant and Cytoprotective Properties of Cyanobacteria: Potential for Biotechnological Applications

“…In brown algae ( Bifucaria bifurcata and Fucus spiralis ) for example, the total phenolic content varied between 1 mg EAG/g and 29.8 mg EAG/g, depending on the extraction solvent [ 24 ]. It is also interesting to compare cyanobacterial results with green tea, which is considered a powerful natural antioxidant, due to its high content of gallic acid, among other compounds [ 25 ]. A study on the applicability of green tea in antioxidant-active food packaging showed a variation of total phenolic content between 272 mg EAG/g and 416 mg EAG/g, in several green tea samples [ 25 ].…”

“…In general, these studies point to an interest in exploring the antioxidant activity of cyanobacteria, considering their richness of compounds such as carotenoids and polyphenols. Inclusively, some of these authors reported antioxidant activity [ 5 , 13 , 16 , 17 , 19 , 20 ] and/or antioxidant contents [ 11 , 14 , 15 , 21 ] in cyanobacteria quite comparable, and sometimes higher, than those found in eukaryotic microalgae, macroalgae or higher plants [ 22 , 23 , 24 , 25 ].…”

The Contribution of a Whey Protein Film Incorporated with Green Tea Extract to Minimize the Lipid Oxidation of Salmon (Salmo salar L.)

“…These two aromatic plant extracts have been applied, as a preservative agent or incorporated in food packaging, to different food matrices aiming to extend its shelf-life. These matrices include seafood [15], sardines [16], chicken nuggets [17], Pacific white shrimp [18], hake fillets [19], and smoked salmon [20].…”

Nanoformulations to Enhance the Bioavailability and Physiological Functions of Polyphenols

“…The release kinetics of polyphenol-PLA/PLGA nanoparticles in vitro show rapid release are at first followed by slow release, which demonstrates the controlled release of polyphenol compounds from PLA/PLGA nanoparticles [ 214 ]. Similar to other nanoparticles, PLA/PLGA also enhances the functional activity of polyphenols, such as anti-inflammatory, antioxidant and anti-cancer properties [ 215 , 216 , 217 ].…”