Title : Effect of 1-MCP and different storage conditions on tomato fruit freshness
Abstract:
Tomato (Solanum Lycopersicum L.) is one of the most important vegetable fruits in the world. Tomato is an important commodity that plays an essential role in the human diet. It has become one of the most profitable fruits providing a higher income to small-scale farmers compared to other vegetable crops. And it contributes up to 16% of horticulture crops in Afghanistan (FAO, 2003). According to the statistic directorate of the Ministry of Agriculture, Irrigation and Livestock of Afghanistan (MAIL), the total tomato production has reached 275222 MT mainly harvested from 24,892 hectares of land with an average of 11.05 MT/ha in 2018 (MAIL, 2019).
Tomato is a climacteric fruit and countinues to ripen after harvest. During ripening process, the green pigment chlorophyll degrades and carotenoids are synthesized (Ghorbani et al..,2012). As ripening process of tomato fruit is highly regulated by ethylene production after harvest both physically and physiologically, researchers, farmers, traders, and other stakeholders who are involved either in the production of the tomato or in its supply chain are required to well understand the ripening mechanism and physiological response of the tomato. It is also important to keep the shelf life longer and decrease the loss level. Tomato quality is rapidly decreasing due to improper post-harvest handling practices and particularly over the post-harvest period at ambient temperature. It should be mentioned that a significant volume of tomatoes are being lost in local storage before reaching the final consumers, causing severe weight loss, softening, decay, rotting, and other physiological disorders.
Tomato fruit is perishable with tender habits (Javid Ullah, 2009, Nasrin et al., 2008 and Mutari and Debbie, 2011), and it contains a large quantity of water as high as 93.5% (Gastélum et al., 2011). Postharvest and yield losses are severe in some case; mostly about 25-40% of the yields are lost because of poor post harvest handling in Afghanistan (Syed Tamjid ur Rahman and Mohamad Hossain, 2005).
According to the MAIL (2018), approximately 35 to 40% losses were noted over the entire post-harvest operations. Poor postharvest handling remained a problematic issue in Afghanistan. A significant volume of tomato loss (30-35%) was observed even in a relatively short storage duration.
1-MCP is an ethylene action inhibitor (Blankenship and Dole, 2003). 1-methyl cyclopropane (1-MCP) can inhibit the effects of ethylene in many fruits and vegetables. The rate of ethylene production in harvested climacteric fruits such as tomatoes induces metabolic activity in the fruit, therefore, the higher the metabolic activity in the harvested fruit, the shorter its shelf life. However, the goal of each post-harvest technology is to slow down the metabolism of harvested products, thereby extending the shelflife. Thus, the use of 1-MCP is essential to extend the shelflife of harvested tomatoes. The use of 1- MCP has been shown to slow down many metabolic activities related to the ripening process, such as color changes, cell wall breakdown, and respiration rate. So it is a useful technique for extending the shelf life of fruits.
Objectives:
Tomato is widely grown in Afghanistan and currently has a higher consumption rate across the country. On the other hand, there are often post-harvest losses during the peak season, which cause huge waste due to poor postharvest handling and farmers suffer a lot from this problem. In this research, the effect of 1-MCP on the cv. Red Hope tomato cultivar will be investigated to find some solution for reducing the post-harvest losses. Moreover, the research will focus on the effect of 1-MCP treatment on the de novo generation of ethylene receptors, ACC 2 synthase and ACC oxidase activities, carotenoid accumulation, softening enzymes like polygalacturonase, and/or pectin esterase, respiration, and metabolomics. The main objectives for this research are as below:
? To reduce the losses by delaying the softening of tomato fruits.
? To keep the quality of tomato fruits (color, flavor, firmness).
? To slow down the repining process and extend the shelf life of tomato fruit.
? To provide tomato fruits in the off-season.
Materials and methods:
Plant material: Tomato fruit, cv. Red Hope provided by Green Farm Co., Ltd. at Namegawa, Saitama.
Storage temperature: 25°C
Treatments:• Control
• 1-MCP (concentration?)
The tomato fruits will be brought to the tropical horticultural science laboratory based on the experimental design (green and pink). The fruits will be divided into control and 1-MCP application. Then the fruits will be stored at 25°C in an incubator for 24 hours, and the interval check will be carried out based on the experimental design regularly. However, some different laboratory tools will be used for this research, to monitor fruit's endogenous ethylene production. For the ethylene assessment, the Gas Chromatography (GC) machine will be used. As for color determination, we will use a colorimeter appliance to check the color values based on the experiment interval. The firmness level will be assessed using a penetrometer. Besides, for further study of gene expression, we will have destructive sampling; the samples will be frozen with liquid nitrogen which later on will be used for the analysis of ripeningrelated genes.
Expected outcomes:
Tomatoes are one of the most popular crops around the world, and in Afghanistan, they are grown extensively. But on the other hand, there is often post-harvest loss during peak seasons as well. This causes huge amounts of waste due to poor postharvest handling, and farmers are affected a lot. Furthermore, fruit softening during storage might result in a huge amount of waste. By implementing 1- MCP, the trend of softening might theoretically be slowed and the shelf life will be extended, which will be acceptable in the market. Since 1-MCP is a cheap and safe material, this research will certainly help extend the shelf life of tomatoes, delaying softening, and ensuring a regular supply of quality tomato products for an extended period for producers, including farmers without a big investment. By applying the results of this research, I believe we can decrease post-harvest losses of tomatoes, which would result in a big return of profit to poor farmers in Afghanistan.
