Effects of chitosan coatings incorporating with free or nano-encapsulated Satureja plant essential oil on quality characteristics of lamb meat

There is a growing demand for bio-based and active packaging as one of the preferred emerging technologies to improve food quality and extend shelf-life. The objectives of this study were to formulate a novel biodegradable coating embedded with nano-encapsulated Satureja khuzestanica essential oils (SKEO) and to compare effect of chitosan coatings containing free or nano-encapsulated SKEO on chemical, microbial, and sensory properties of lamb meat samples over a 20 day period at 4 °C. Nanoliposomes with the average sizes of 93-96 nm were prepared using different concentrations of soy-lecithin ratios (60:0, 50:10, 40:20, and 30:30) by thin-film hydration-sonication method. Size distribution and encapsulation efficiency (EE) of nanoliposomes were calculated 0.83-0.88 and 46-69%, respectively. Nanoliposomes with the lower droplet size and maximum EE were selected for coating of meat samples. The results indicated that the coating treatments could effectively retard microbial growth and chemical spoilage, which reflected itself in lower pH and 2-thiobarbituric acid values (P < 0.05). Encapsulation decelerated the release of SKEO and led to a prolonged antimicrobial and antioxidant activity and also improved sensory attributes. The study suggests that chitosan coating containing encapsulated SKEO can be a promising candidate for extending the shelf-life of lamb meat.