Rationale
Mango (Mangifera indica L.) is a highly valued tropical fruit enjoyed globally, cultivated commercially in over 80 countries It is primarily consumed in two forms: fresh and processed Renowned for its delightful flavor and appealing taste, mangoes are also rich in valuable pigments like carotenoids They provide essential dietary fiber and are an excellent source of vitamins, particularly vitamin C, which constitutes 28-37% of its content Additionally, mangoes are recognized for their abundant antioxidants and phytochemicals, enhancing their nutritional profile.
Mango, recognized for its strong antioxidant properties due to phenolic compounds and flavonoids, has become a vital fruit crop, especially in Thailand In 2010, global mango production surpassed 31.82 million tons, and by 2015, Thailand's mango production reached 33,000 tons, solidifying its status as a key exporting fruit.
Mangoes are highly susceptible to postharvest diseases, resulting in significant losses of approximately 25-30% (Mahto and Das, 2013) The primary postharvest diseases affecting mangoes are anthracnose and stem-end rot, which compromise fruit quality and reduce shelf life Anthracnose is caused by the common fungus Colletotrichum gloeosporioides (Penz.) (Fitzell et al., 1984; M.A and Haggag, 2010; Zainuri et al., 2001), while stem-end rot is attributed to pathogens such as Lasioidplodia theobromae (Alvindia and Acda, 2015; Johnson et al., 1992; Kobiler et al., 2001) These diseases are significant challenges for the mango export industry in Thailand (Jitareerat et al., 2007).
Mango is classified as a climacteric fruit, meaning it continues to ripen and undergo respiratory processes even after being harvested from the parent plant This characteristic leads to a rapid softening and ripening during postharvest storage.
Mangoes are climacteric fruits that can ripen within just four days under ambient temperature conditions However, once fully ripe, their quality declines rapidly This brief ripening period highlights the need for timely handling and consumption to maintain their freshness and flavor.
2 affects to storage and delivery, which has negative influence on mango’s economic value, limits potential marketing opportunities in domestic and foreign markets
To address postharvest challenges in mangoes, various technologies have been implemented, including the application of organic acids These methods effectively delay ripening and manage postharvest diseases, specifically those caused by Alternaria alternata, ensuring the preservation of fruit quality.
Research has shown that pathogens such as Collectotrichum gloeosporioides and Lasiodiplodia spp significantly affect mango fruit quality (Kobiler et al., 2001; Prusky et al., 2006; Zheng et al., 2007) The application of plant hormones, particularly salicylic acid, enhances the activity of defense enzymes like phenylalanine ammonia lyase and β-1,3-glucanase, thereby improving the fruit's resistance (Zeng et al., 2006) Additionally, studies by Jitareerat et al (2007) have demonstrated the positive impact of chitosan on reducing postharvest diseases and maintaining mango quality Moreover, treatments involving UV and gamma irradiation have been reported to effectively delay the onset of anthracnose disease in mangoes (Aguilar et al., 2001; Sripong et al., 2015; Terao et al., 2015).
Electron beam (E-beam) irradiation is an effective food-processing technique used to maintain the quality of fruits and vegetables by extending shelf life, inhibiting sprouting, disinfecting insects, and eliminating microorganisms (Moreno et al., 2006; Reyes and Cisneros-Zevallos, 2007) This process utilizes high-energy electrons, offering a superior dose rate compared to gamma rays, and can be converted to X-rays for increased penetration depth, all at a lower cost than gamma irradiation (Cleland, 1983) Due to the U.S Environmental Protection Agency's ban on chemical treatments like ethylene dibromide, which is commonly used to control pests in imported produce, alternative methods such as E-beam irradiation are essential for ensuring the safety and quality of agricultural products exported to the U.S (Moreno et al., 2007).
Recent studies on electron beam (E-beam) technology focus on enhancing food quality and extending shelf life by effectively inactivating foodborne pathogens while preserving antioxidants and nutritional value Research has shown that E-beam treatment can minimize sensory quality changes and volatile compound alterations in various foods, including fruits and vegetables Notably, investigations into optimizing electron beam irradiation for "Tommy Atkins" mangoes have provided valuable insights into its benefits for this specific fruit.
Research has demonstrated the impact of Electron Beam Irradiation on various properties of “Tommy Atkins” mangoes (Mangifera indica L.), including their physical, textural, and microstructural characteristics (Moreno et al., 2006) Additionally, studies have shown that Electron-Beam Ionizing Radiation influences the antioxidant constituents of mango fruit both before and during postharvest storage, highlighting its effects on the fruit's quality and longevity (Reyes and Cisneros-Zevallos, 2007; Moreno et al., 2007).
Currently, there is a lack of information regarding the effects of E-beam irradiation on antioxidants and postharvest diseases in Thai mangoes This research aims to investigate how E-beam treatment influences the quality and postharvest disease resistance of Thai mangoes.
Hypothesis
- E-beam irradiation has a better effect on delay the ripening, softening and extending the mango’s storage life than the control treatment
- E-beam irradiation has influence on antioxidants of mango fruit
- E-beam irradiation indirectly affects postharvest diseases to mango fruit by introduction of plant defense enzymes.
Material and equipment
Mangoes of the Nam Dok Mai Si Thong variety are harvested from a commercial orchard in Ratchaburi province, Thailand, 90 to 100 days after fruit set The selection process ensures that the fruit is uniform in size, color, and shape, while being free from physical damage and disease symptoms After purchase, the stems are cut, and the fruit undergoes surface sterilization using a 100 ppm sodium hypochlorite solution, followed by natural air drying at ambient temperature Finally, the mangoes are covered with fruit foam netting and packed in cartons for distribution.
Mangoes are individually labeled and transported to the E-beam irradiation facility at the Thailand Institute of Nuclear Technology in Bangkok At this facility, samples undergo treatment with varying doses of E-beam radiation at ambient temperature, specifically 0.5, 1.0, 1.5, and 2.0 kGy, while control samples remain unirradiated The appropriate dosage is monitored using dosimetry labels affixed to the surface of the fruit.
Final, it is stored at 13 o C in cool room to analysis of parameters
1 Calorimeter (Model CR - 400, Konica Minolta, Japan)
2 Gas chromatograph (Shimadzu GC - 14B, Bara scientific, Japan)
3 Fruit texture analyzer (Model: TA - XT2, Stable micro-system, England)
6 Digital refractometer (Model PAL - 1, ATAGO, Japan)
7 Homogenizer (Kinematica Polytron PT 3100, Switzerland)
8 Centrifuge (High speed refrigerated centrifuge – model 6000, Japan)
9 Spectrophotometer (UV - 1800; Shimadzu Co., Kyoto, Japan)
11 pH measuring instrument (Eutech Instruments PC 700)
Quality
Table 3.1 Effect of E-beam on Color parameter of mango peel during storage at 13 o C
16 87.44a 85.19ab 85.31ab 81.48b 74.76c ** 6.30 Duncan's Multiple Range Test compared between mean of treatments With a row, mean not followed by the same letter are significantly different at ** (p