Evaluation of green tea extract incorporated antimicrobial/antioxidant/biodegradable films based on polycaprolactone/polylactic acid and its application in cocktail sausage preservation

In this study, the active polycaprolactone (PCL)/ polylactic acid (PLA) films containing different ratios of polymers (100:0, 80:20, 70:30) and concentrations of green tea extract (GTE) (10, 20, and 30% w/w) were fabricated. The GTE was extracted by the traditional maceration method and the results indicated that its phenolic content was 64.76 mg gallic acid/g extract and IC50 as antioxidant potential was 0.251 mg/ml. Also, the diameter of the inhibition area in well-diffusion test against E. coli and L. monocytogenes was measured 12 +/- 0.78 and 14 +/- 0.56 mm, respectively. The highest release of GTE components from active composite films was obtained in a lipophilic simulant solution containing 50% ethanol. The variation range of antioxidant activity of films in lipophilic and hydrophilic solutions was 14-64% and 2-6%, respectively. The increase of GTE concentration in films improved their antioxidant and antimicrobial properties. The highest bacterial growth inhibition was 0.45-1.07 Log CFU/ml which was observed in the presence of PCL/PLA films containing 30% (w/w) GTE against pathogenic bacteria (L. monocytogenes and E.coli). The application of PCL/PLA- GTE (30% w/w) film as an active packaging could reduce microbial growth by 35.84% and lipid oxidation by 40% on sausage samples in comparison with the unwrapped control sample. The observations could offer novel PCL/PLA films containing natural active components with antibacterial and antioxidant properties for use as a green biodegradable wrapping and alternative to traditional packaging in the food industry to prolong the food shelf-life.

Automated summary

In this study, active polycaprolactone/polylactic acid films containing different ratios of polymers and concentrations of green tea extract were fabricated. The results showed that the addition of green tea extract improved the antioxidant and antimicrobial properties of the films. This active packaging could effectively reduce microbial growth and lipid oxidation, prolonging the shelf-life of food products.