Effect of Modified Atmosphere Packaging and Orange and Lemon Essential Oils on Microbial Population and Sensory Properties of Processed Prunes

In this project, the effect of different concentrations of three types of gas mixtures (carbon dioxide, nitrogen) ,as well as vacuum condition and ordinary condition as control and also essential oils  of orange and lemon were evaluated for extending shelf life of processed prunes  at 25 0C  in one 4-layer container. Non-gas and essential oils injection packaging as control samples, were compared with four types of modified atmosphere packaging 1)80% CO2 + 20% N2 ; 2) 20% CO2 + 80% N2 ; 3) 50% CO2 + 50% N2, and 4) under vacuum condition , combined with injection of orange and lemon essential oils and samples without essential oil.Experiments were performed on samples as follows microbial test (aerobics count, mold and yeast count ) and chemical pH test and organoleptic test during 2 month.The results were analyzed in a completely randomized design using SPSS statistical software (Ver:22) and Duncan’s multiple range test method, with confidence level of 95% (P <0.05). The shelf life ,of processed prunes samples were reported with orange essential oil under conditions, vacuum;80% CO2 ; 50% CO2 & 20% CO2 ; 60, 60, 45,40 days, respectively,  and ordinary conditions 30 days, with lemon essential oil under, vacuum conditions 55 days , in gas compositions  80% CO2 ; 50% CO2 ; 20% CO2 & control conditions 55, 40, 30 , 20 days, without essential oils,under conditions vacuum;80% CO2 ; 50% CO2 ; 20% CO2 & ordinary conditions 45, 45, 30, 25 , 15 days, respectively. The best conditions belonged to samples containing orange essential oil under vacuum and 80% CO2 , which were prolonged the shelf life of processed prunes for 60 days, and had desirable effects on amount of pH and also sensory properties , and were evaluated due to high antimicrobial properties of these factors .