Characterization of cross-linked whey protein isolate-based films containing Satureja Khuzistanica Jamzad essential oil

Whey protein films containing antimicrobial compounds provide another layer of protection and thereby may extend the shelf life of food products. In this research, the effect of Satureja khuzistanica Jamzad essential oil (SKJEO) at the concentrations of 0 (as control), 0.5, 1, and 2% (wt/wt, in the film forming solution) on the characteristics of cross-linked whey protein isolate-based films was studied. The films incorporated with SKJEO had significantly (p<.05) lower moisture content (MC), total soluble maters (TSM), and tensile strength (TS) but the higher water vapor permeability (WVP) and elongation at break (EB) compared to the control. Control had uniform microstructure, while the films incorporated with SKJEO showed lumpy surface. The films incorporated with the SKJEO had good antimicrobial properties, the higher SKJEO concentration, and the stronger antimicrobial activity. Pseudomonas aeruginosa was the most resistant bacteria, and Staphylococcus aureus was the most sensitive bacteria against SKJEO. Based on our results, it is suggested to use of the SKJEO as a natural antibacterial agent in food packaging particularly those that are highly sensitive to microbial deterioration. Practical applicationsEdible films and coatings have been developed in food conservation for many years. Antimicrobial packaging is a form of active packaging that could extend the shelf life of product and provides microbial safety for consumers. Whey proteins films have good barrier properties against organic vapor, gas, and oil as related to artificial films. Our study showed that the SKJEO has remarkable antibacterial activity, which can be applicable to prevent of various food-related diseases caused by bacteria. Nevertheless, further studies are required to understand the mechanisms of antimicrobial action of SKJEO against microorganisms and more information is mandatory on safety, efficacy, and toxicity for its usage as a natural preservative in different food products. The cross-linked WPI-based film containing SKJEO is a favorable resource for the packaging industry since it offers a maintainable and biodegradable packaging material that provides all the packaging materials requirements.