Survey of antimicrobial gelatin-frankincense (Boswellia carteri) bilayer edible film incorporated with ascorbic acid and Hyssopus officinalis essential oil on ostrich fillets shelf life at refrigerator temperature

Ostrich fillets is highly edible and one of most healthy and the least fat red meat samples. Due to carcass contamination along the slaughter chain, it becomes corrupted by the growth of meat microorganisms during storage. Being biodegradable, edible and efficient have caused edible films to be widely investigated and used as a good replacement for synthetic materials in packaging of food products. In this study a gelatin/frankincense (G/F) bilayer film was produced from gelatin and frankincense monolayers using the casting method in two phases. This research investigated antimicrobial activity of various concentrations of acid ascorbic (0, 1%,2%) and Hyssopus officinalis oil (0, 0.75%, 1.5%) in edible bilayer gelatin/frankincense against S.aureus, B.cereus, E.coli and P.aeroginosa. on the other hand, effect of edible film was evaluated on microbial and chemical properties of ostrich meat for 12 day at refrigerator temperature. Diameter of inhibition zone showed that S.aureus and P.aeroginosa were most sensitive and resistant bacteria respectively. Compared with control sample, two treatments (G/F+2%AA+0.75%HO and G/F+2%AA+1.5%HO) decreased total viable count, psychrophilic and lactic acid bacteria significantly (p<0.05). The result also showed with addition Hyssop oil and ascorbic acid, pH and peroxide values notably reduced compared with pure edible film (without oil and acid)( (p<0.05). The gelatin/frankincense films enriched with essential oil and vitamin C delayed tissue breakdown, and increases the pH by reducing the bacterial growth. Therefore, antimicrobial edible film containing Hyssop oil and vitamin C as an economical and biodegradable coating has a good potential for increasing the shelf-life of ostrich meat at the refrigerator temperature.