Introduction: Pear fruits is an ascending fruits with high ethylene production rate, high softening speed and sensitive to physical and physiological defects as well as water loss. These characteristics limit the transportation and marketing of pear fruit from farms to distant markets as well as their storage in cold storage. Since pears are highly perishable after harvesting, it is necessary to develop suitable solutions to increase the shelf life of pears after harvesting, in order to use them in all seasons of the year. One of the the strategies is using natural products such as hexanal and others products to extend pear fruits storability.

Hexanal is a volatile natural substance, which is produced in plants through the lipoxygenase pathway and can play an important role in defense against natural spoilage caused by fungi. Hexanal is known as a safe substance for human health. This substance can inhibit the activity of the phospholipase enzyme, which plays an essential role in membrane destruction, and prolongs the life after harvesting of agricultural products. Various researches have shown that the use of hexanal alone or in some special formulations preserves the quality and increases the shelf life of fruits and vegetables The enhanced freshness formulation (EFF) is an inhibitor of membrane destruction, which contains hexanal and antioxidant compounds. Geraniol and alpha-tocopherol, which are naturally present in geranium essential oil and paper pumpkin seed oil, are the main compunds of EFF with hexanal. Essential oils are a group of natural monoterpene compounds used in the control of post-harvest diseases, which dissolve in water in a very small amount and have anti-pathogenic effects. The fragrant geranium plant is one of the medicinal plants that contains essential oil containing geraniol, citronellol, tripeneol and alcohols. Paper seed pumpkin is also a herbaceous, annual plant belonging to the gourd family. Its seed contains 41-59% oil, which contains valuable substances such as vitamin E, phytosterol and protochlorophyll.

The use of natural and organic compounds in the production and maintenance of agricultural products, in addition to the production of products free of dangerous and harmful chemicals, will also increase its nutritional and medicinal value. So that, the purpose of this research was to investigate the effect of some natural compounds such as hexanal on some quantitative and qualitative characteristics of Louise bonne cultivar.

Materials and Methods: The research was carried out to investigate the effect of hexanal, enhanced freshness formulation (EFF) and the combination of pelargonium essential oil plus cucurbita pepo oil (PGEO+CPO) on some quantitative and qualitative characteristics of pear fruit (Pyrus communis cv. Louise bonne) during cold storage. After applying treatments, the pear fruits were transferred to the cold storage (0±1ﹾC) and at six different times (including 0 (start of storage), 15 days, 30 days, 45 days, 60 days, and 75 days after the start of storage), some of their quantitative and qualitative characteristics such as texture firmness, titratable acidity, soluble solid content, vitamin C, total phenol, antioxidant activity and color indices were measured.

Results and Discussion: The evaluations carried out during different storage periods showed that pear fruit's quantitative and qualitative characteristics decreased significantly during cold storage. The results showed that after 75 days of storage of pear fruit, texture firmness, titratable acidity, soluble solid content, vitamin C, total phenol, and antioxidant activity were 18.86, 32.04, 9.81, respectively 33.52, 34.13 and 31.10% respectively, but the pH of fruit juice increased. Also, color indices L*, a*, b*, and total color changes (ΔE) increased significantly during cold storage. The application of hexanal, EFF, and the combination of pelargonium essential oil- cucurbita pepo oil did not have a significant effect on the color indices L*, a*, b* as well as the total color changes (ΔE), but the quantity and quality of pear fruit significantly increased. Compared to the hexanal and combination of pelargonium essential oil- cucurbita pepo oil treatments, EFF had a more significant effect on improving the quantitative and qualitative characteristics of pear fruit. The EFF increased the tissue firmness, vitamin C, total phenol, and antioxidant activity by 8.14, 8.18, 12.31, and 18.69%, respectively.

Conclution: According to the results of the present study, using the EFF to improve the quality and increase the shelf life post-harvesting the fruit is recommended.