Antioxidant Activities and Total Phenolic Content of Malaysian Herbs as Components of Active Packaging Film in Beef Patties.

Active packaging containing natural extracts is a promising innovation to prolong the shelf life of perishable food. The objective of this work was to develop a bioactive edible film from semi-refined carrageenan (SRC) and glycerol (G) as plasticizer incorporated with natural extract. Five Malaysian herbs were evaluated to determine their total phenolic content (TPC) and antioxidant activities. The Persicaria minor (PM) extract demonstrated the highest TPC (1.629 mg GAE/L sample) and radical scavenging activity evaluated by the radicals 2,2'-azinobis [3-ethylbenzothiazoline-6-sulfonic acid] (27.166 mg TE/L sample), 2,2-diphenyl-1-picrylhydrazyl (719.89 mg eq. Trolox/L sample) and α,α'-Azodiisobutyramidine dihydrochloride (5.81 mg TE/L sample). Thus, PM extract was selected for active packaging film at concentrations of 0.4, 1.0 and 2.0% and compared with 0.4% Butylatedhydroxianisole in 2% SRC and 0.9% G film formulation. The meat patties were wrapped in the films and stored under refrigeration (4 ± 2 °C) for 14 days. The film with 2% PM exhibited significantly lower lipid deterioration analysed by the thiobarbituric acid reactive substance assay (p < 0.05) and small changes in % metmyoglobin value which indicated the minimum development of brown colour (p < 0.05). Hence, this film can be used as a packaging material to improve meat quality characteristics.

Study of the Properties of Bearberry Leaf Extract as a Natural Antioxidant in Model Foods.

The common bearberry (Arctostaphylos uva-ursi L. Sprengel) is a ubiquitous procumbent evergreen shrub located throughout North America, Asia, and Europe. The fruits are almost tasteless but the plant contains a high concentration of active ingredients. The antioxidant activity of bearberry leaf extract in the 2,2'-azino-bis-3-ethylbenzothiazoline-6-sulphonic acid (ABTS) radical cation assay was 90.42 mmol Trolox equivalents/g dry weight (DW). The scavenging ability of the methanol extract of bearberry leaves against methoxy radicals generated in the Fenton reaction was measured via electron paramagnetic resonance. Lipid oxidation was retarded in an oil-water emulsion by adding 1 g/kg lyophilised bearberry leaf extract. Also, 1 g/kg of lyophilised bearberry leaf extract incorporated into a gelatin-based film displayed high antioxidant activity to retard the degradation of lipids in muscle foods. The present results indicate the potential of bearberry leaf extract for use as a natural food antioxidant.