Effects of different atmospheric compositions under palliflex system on storage life and biochemical composition of 'Bursa siyahi' fig cultivar

Fig is one of the agricultural products with high strategic importance and economic value for our country and Turkey is an important actor in fig production and marketing. Figs are generally utilized as dry fruit in our country. However, the demand for fresh figs in our country as well as in the world markets has been increased in recent years. Our country has various advantages such as ecology, variety and proximity to European markets in fig production. 'Bursa Siyahı' is our most important cultivar in table fig export. This cultivar has a good position in the world markets with its quality, attractiveness, size, shape and taste. The postharvest life of fresh fig is very limited. In fresh fig, if the proper conditions are not provided, postharvest losses can exceed 50% of the total production. As in other berries, in order to maintain postharvest quality of figs one of the alternative applications to chemicals is changing the atmospheric composition in the storage environment. In this context, increasing the carbon dioxide (CO2) level while reducing the oxygen (O2) level in the product environment in the controlled atmosphere (CA) has produced positive results in many products. However, it is not common for commercially available CA storage systems for products with short storage life such as figs and with rapid circulation in the market. In order to maintain post-harvest quality in products with a short storage preservation period, the atmospheric composition in the product environment must be maintained not only during storage but also during transport and distribution. Therefore, in recent years, the palliflex storage system, which has been formed as a modification of CA storage technique, has started to be used commercially for the storage and transportation of some products. In this storage system, products are stored on a pallet basis and a special atmosphere composition is created in each pallet. This system also allows the storage of different products together. In this study, the palliflex storage potentials of figs harvested in commercial (2/3 colored) and full (full colored) maturity stages were investigated. For this purpose, four different atmospheric compositions in palliflex environment were applied to fruits at 0 ± 0.5°C temperature and 90 ± 5% relative humidity for 28 days. These atmospheric compositions were 3% O2 + 10% CO2, 3% O2 + 15% CO2, 3% O2 + 20% CO2 and 21% O2 + 0.03% CO2 (Control) treatments. To determine the shelf life, figs were kept in a room with 20 °C temperature and 60-65% relative humidity for 3 days. It was determined that fruit firmness was higher in figs harvested at commercial maturity stage than those harvested at full maturity stage. But glucose and fructose contents were opposite. They were lower in fruits harvested at commercial maturity stage than that of full maturity stage whereas the sucrose content was higher in fruits that were harvested at commercial maturity stage. It was determined that the figs harvested in the commercial maturity stage were more resistant to decay than the figs harvested at full maturity stage. It can be concluded that 3% O2 + 15% CO2 level in storage atmosphere was found to be the most effective treatment for controlling decay as well as maintaining postharvest fruit quality of fig fruit cv. 'Bursa Siyahı' harvested at both full and commercial maturity stages. When the effects of different atmospheric compositions on fruit quality were examined, figs treated with high CO2 had lower weight loss in both years compared to controls. In terms of the fruit firmness, 3% O2 + 15% CO2 treatment was more effective than other treatments in both years. In the first year of the study, 3% O2 + 15% CO2 and 3% O2 + 20% CO2 treatments caused higher fructose content in fruit compared to that found in the other CA and control treatment. In the second year, fruits in all CA treatments had higher fructose content than controls. In the first year of the study, the highest amount of glucose was determined in fruits treated with 3% O2 + 15% CO2 and followed by 3% O2 + 20% CO2 treatment. The highest glucose content in the second year was determined in fruits stored in 3% O2 + 15% CO2 conditions while the lowest content was found in control treatment. Figs stored in high CO2 compositions had higher sucrose amount than those stored in the regular air (control) conditions. The ethylene production and respiration rates of the figs stored in atmospheric compositions containing high CO2 were lower than controls. Decay prevention was also much better in figs stored in CA conditions to those stored in control conditions. The lowest decay was found 3% O2 + 20% CO2 treatment while the lowest decay in shelf life conditions was determined on figs stored in 3% O2 + 15% CO2 atmospheric conditions. In terms of the tested paramaters, 3% O2 + 15% CO2 treatment was the most successful treatmen in both harvest maturity stages of fruits of 'Bursa Siyahı' fig cultivar. Fruit of this fig cultivar could be stored for 28 days under this condition.