Development of Soy Protein Isolate-Based Antimicrobial Edible Film Enhanced With Sage Essential Oil in Fresh Kashar Cheese Coating.

Abstract

This research investigated the potential of sage essential oil incorporated soy-protein based edible films in extending the shelf-life of fresh kashar cheese. Cheese samples were coated with three different types of films. The first group was coated with a film containing soy protein isolate (SPIG) and 3% (w/v) glycerol, while group 2 (SPISEO1) and group 3 (SPISEO2) were coated with films including 1%-2% sage (Salvia officinalis L) essential oil, respectively. Uncoated cheese samples were used as control (C). The major active ingredients of sage essential oil were found as α-thujone (39.46%), d-camphor (14.67%) and 1,8-cineole (eucalyptol) (9.79%). Sage essential oil significantly influenced film properties, when compared to the control group, 2% SEO containing films increased film thickness (from 0.176 to 0.183 mm), elongation at break point (from 35.0% to 52.0%) and water vapor permeability (from 6.73 to 6.80 g mm m-2 h-1 kPa-1), while decreased moisture content (from 20.9% to 19.2%), water solubility (from 61.4% to 59.9%), and tensile strength (from 4.52 to 3.20 MPa) of the films. Fresh kashar cheese samples were inoculated with Escherichia coli O157:H7, Staphylococcus aureus, Listeria monocytogenes, and Penicillium spp. and the antimicrobial effect of the films was assessed over 30 days, and the higher SEO concentrations enhanced the antimicrobial activity of the films, reducing E. coli O157:H7 by approximately 3 log, S. aureus by 3.5 log, L. monocytogenes by 4.25 log and Penicillium spp. by 3.5 log units. The results demonstrated that antimicrobial edible films were successfully developed from soy protein isolate and sage essential oil.