The effect of modified atmosphere packaging on the shelf life of Shahanjir and black fig varieties

Modified atmosphere packaging is one of the methods to increase the shelf life of fruits and vegetables. In this technique, the decrease of oxygen (O2) and increased levels of carbon dioxide (CO2) result in decreasing oxidative respiration. Moreover, the energy requirements for other metabolic processes are also influenced. The objective of this study was to examine the effect of different gaseous compositions inside the packaging atmosphere of two Estahban fig varieties and to quantify the effect of modified atmosphere packaging on the kinetics of quality changes in stored Shahanjir and black fig varieties. Different percentages of Oxygen, carbon dioxide and Nitrogen (N2) as treatments G1 (5% oxygen, 70% carbon dioxide and 25% nitrogen), G2 (5% oxygen, 0% carbon dioxide and 95% nitrogen), G3 (5 percent oxygen, 35% carbon dioxide and 60% nitrogen), G4 (5% oxygen, 0% carbon dioxide and 25% nitrogen. partial vacuum) and control (normal air) were used. The shahanjir and black fig varieties were used in the first and second years of study; respectively. An atmosphere modifying device was used to pack and enter the gas inside the package. The packed samples were stored at 4°C until the fruit quality and marketability were lost. Respiration rate, color, texture and weight changes were measured every three days. During the experiment, the fungi infected samples were count and separated in each treatment. Effect of packaging conditions in 5 gaseous treatments and storage time on quality of two fig varieties was demonstrated using a factorial experiment in a completely randomized design with three replications. Results revealed that fruits became softer and color changed by passage of time. During storage, fruits depending on the package atmosphere and storage time, lost their initial weight as 2-21% in Shahanjir and 9-38% in black fig, respectively. The G3 gaseous composition was effective in delaying the occurrence of the respiratory climacteric peak and extending fruits shelf life. Minimal changes in color parameters, firmness and the number and percentage of infected fruits were observedin samples treated with G3 gaseous composition. After determining the best treatment, the fruits packed in modified atmosphere with G3 gaseous composition and control samples were stored at 4, 10 and 15°C until losing marketability and their weight loss, firmness were simultaneously evaluated. This was done to study the kinetics of quality changes during storage. All changes were accelerated at higher temperatures. This trend was observed at higher rates in contol samples compared to G3 treatment. Firmness, L and b values changes followed a first order kinetic model while weight loss, a value and ∆E were adequaltely described by a zero order kinetic model. Temperature sensitivity of rate constant was well described by the Arrhenius model