Pla Films Loaded with Green Tea and Rosemary Polyphenolic Extracts as an Active Packaging for Almond and Beef

Abstract: The antioxidant capacity and the phenolic compounds of extracts from Green Tea and Rosemary was determined. RE presented a higher antioxidant capacity and higher content of TPC and flavonoids than GTE. While the main phenolic compounds identified in RE were carnosic acid, carnosol and rosmarinic acid, in GTE were catechin, epigallocatechin gallate, epicatechin, rutin and gallic acid. Active PLA films were prepared by the incorporation of GTE and RE at different percentages, followed by the evaluation of their properties. Afterwards, almonds and beef were selected as model foodstuff and packaged with active PLA films.PLA with 4 % of GTE presented a higher WVP and opacity, while PLA with 4% (w/w) of RE presented the highest O2 permeability. PLA with 2 and 4 % (w/w) of GTE presented the highest DPPH inhibition percentage and the highest total content in phenolic compounds and flavonoids at the end of 10 days (at 40 °C), in contact with a fatty food simulant. Regarding the almond packaged with the active films, PLA films with 2 and 4 % of RE were the most effective in the reduction of oxidation, allowing to obtain the lowest malonaldehyde (MDA) content and the lowest peroxides, at the end of 60 days of storage at room temperature. In addition, PLA with GTE and RE inhibited the formation of MDA content in beef stored for 11 days at 4 °C. This study shows that these PLA active packages can contribute for delaying lipid oxidation in foodstuffs with high fat content.

Highlights: Extracts were incorporated into PLA at different concentrations to produce active films; Catechins, rutin and gallic acid were detected in the green tea extract; Rosmarinic acid, carnosic acid and carnosol were present in the rosemary extract; PLA with rosemary extract showed ability to inhibit almond’s lipid oxidation.

Description

Ana Isabel Rito, Departamento de Alimentação e Nutrição, INSA.

Keywords

Polyphenolic Compounds Aromatic Plant Extracts Catechins Lipid Oxidation Packaging Biopolymers Shelf-life Extension Green Tea Rosemary Segurança Alimentar