Preservative activity of free and nano-encapsulated pomegranate peel extract obtained using cold plasma and ultrasound-assisted method in increasing the shelf life of thigh mutton mince

Abstract

The aim of this study is to investigate the antioxidant and antimicrobial potential of pomegranate peel extract (PPE) in both free and nano-encapsulated forms in Marv (Salvia macrosiphon) seed gum, in order to extend the shelf life of minced meat. Pomegranate (Punica granatum) peel is the main byproduct of the pomegranate processing factories with potential as a food ingredient to prevent microbial growth and lipid oxidation. In this study, the hydroalcoholic PPE (80 % ethanol/water solution (v/v)), because of its antioxidant and antimicrobial potential, was obtained using ultrasonic-assisted extraction (UAE) and cold plasma (CP) pretreatment. The content of phenolic, flavonoid, and anthocyanin compounds in UAE (298.36 mg GAE/g DM, 109.65 mg QE/g DM, and 6.50 mg cy-3-glu/g DM) was lower than CP-UAE (365.74 mg GAE/g DM, 149.04 mg QE/g DM, and 9.25 mg cy-3-glu/g DM). The antioxidant activity of both extracts which evaluated by DPPH, ABTS, and FRAP methods increased in a concentration-dependent manner. The CP pretreatment has a significant effect on antimicrobial activity against S. aureus and E. coli. Nano-encapsulated PPE was created by adding 7 % PPE (obtained by CP-UAE (400 ppm)) to the 25 % Span 80 and 68 % sunflower oil. The PPE extract obtained using UAE and CP pretreatment at concentration of 400 ppm in two free and encapsulated forms was added to minced mutton meat. During 12 days of storage at 4 °C, the sample treated with PPE exhibited higher quality in terms of lipid oxidation, microbial growth and physical parameters. The results of this study suggested the use of nano-encapsulated PPE in marv seed gum to extend the shelf life of minced mutton meat.