Extraction and encapsulation of Laurus nobilis leaf extract with nano-liposome and its effect on oxidative, microbial, bacterial and sensory properties of minced beef

Abstract

The aim of this study was the effect of nanoliposome-encapsulated extract and free extract of bay leaf (Laurus nobilis) on shelf-life of minced beef during 16 days storage in refrigerator (4 ± 1 °C). First, the leaf extract was extracted using ultrasound and various solvents (aqueous, alcoholic and hydroalcoholic) and the amounts of phenolic and flavonoid compounds, antioxidant and antimicrobial activity were determined. The results showed that the highest values of phenolic and flavonoid compounds, antioxidant and antimicrobial activity were observed in hydroalcoholic solvent extract (p < 0.05). The hydroalcoholic extract was nanoencapsulated with liposome, the particle size was 99.05 ± 2.98 nm and the encapsulation efficiency was 73.76 ± 1.10%. Then, it was used for investigate the effect of bay leaf extract on shelf life of minced beef. Five treatments including control, 1000 ppm extract, 1500 ppm extract, 1000 ppm nano-extract and 1500 ppm nano-extract. Chemical and microbial parameters were detected periodically, as well as the effect of different treatments on minced beef inoculated with Escherichia coli and Staphylococcus aureus were examined. The results showed that the extract has an antimicrobial and antioxidant properties and the nanoencapsulation process enhances the attributes mentioned, so that bacterial spoilage and oxidation process delayed in the minced meet contains 1500 ppm of the nano-extract (p < 0.05). This treatment also inhibited the growth of E. coli and Staph.aureus and had sensory ratings approved by the evaluators. Therefore, it seems that nano-extract of bay leaf can be used as a natural preservative with appropriate antioxidant and antimicrobial properties in meat and meat products.