Wen 丨 Dongdong does not like to move
Editor丨 Dongdong does not like to move
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preface
Each country conducts research on its main fruit chains to identify major losses and provide solutions to reduce them. When the shelf life of the fruit cannot be extended, processing will avoid the fruit from spoiling. An estimated 1.3 billion tonnes of food are lost and wasted globally each year.
In Salvador, Brazil, the commercial loss of highly perishable fruits such as bananas, papayas and tomatoes is estimated at 9.5 tonnes. In Sri Lanka, about 210,000 metric tons of fruit are lost annually during postharvest operations, equivalent to 30-40% of the harvest and equivalent to a loss of US$ 90 million.
Mexico is a major producer of cactus plants, with 230,000 hectares of land, of which 67,000 hectares are used for fruit production.
Mexico is also a world leader in exporting fresh mangoes in 2019. Postharvest losses of fresh mango in Pakistan have been reported to average 69%, but sometimes reach 100% in disease-friendly environments. In the 2014 season, an increase in stem end rot in Israeli mango resulted in a loss of 30-40% of harvested fruit. This disease occurs in mango, avocado, and citrus fruits.
The peel or exocarp consists of hard nut shells or watermelon shells. The peel is shaped into a fruit peel, while the edible part of the pulp or fruit is the endocarp. The skin or rind of a fruit or vegetable appears as its outer protective layer. Watermelon is a round fruit with a hard outer layer and a white inner layer. The edible red or yellow flesh inside is the endocarp.
The outer wall of the epidermal cells of all plant organs is covered with an epidermal membrane. The physical properties and chemical composition of the fruit epidermis change significantly during its development.
During early fruit development, the maximum cuticle deposition rate per unit area appears to increase the thickness of the stratum corneum. The composition of the stratum corneum changes after deposition of waxes, phenolic compounds and polysaccharides.
The stratum corneum and vegetative organs of fleshy fruits have similar compounds, but the stratum corneum of the fruit is thicker. The hydrophobicity of the fruit epidermis makes it an effective barrier to reduce water loss. Mango fruits exposed to sunlight differ in cuticle permeability between mango fruits that grow in shade from the canopy.
Intradermal wax restricts the entry of surface moisture into the fruit and reduces transpiration. The wax content of the epidermis increases during fruit development, resulting in a thickening of the mango epidermis when ripe.
Mangoes after harvest on the farm
Postharvest mango quality depends on proper picking and better production practices. Mangoes are usually picked by hand or retrieved with a pole fitted with a cutting blade and bag. The peduncle is broken at the end of the leaf and the latex covers the peel. Although removing the juice after harvest avoids peel sap burns, it reduces the protective effect of the fruit against anthrax and stem end rot.
The main cause of mango juice burns is attributed to the deposition of volatile compounds through the pores. Cutting the stems can cause latex stains to settle on the surface of the fruit. The juice stored in the fruit tube under high pressure falls on the skin of the mango.
Degumming can be performed by inverting the freshly destemmed fruit on a plastic or steel grid frame for 30 min. Another technique is to immerse the freshly destemmed fruit in a 1% alum solution for 1 min.
The fruit should be dried before packaging. Contact of latex with mango peel can induce discoloration of the pores, resulting in erythema caused by anthocyanin synthesis, which can also be caused by cold damage. Resorcinol and gallitannin inhibit major postharvest pathogens including anthrax.
If the 1 cm long peduncle is still attached to the fruit after harvest, the latex will not leave the fruit, avoiding sap burns. More than 80% of the fluid flow is observed in the first minute of stem removal.
The pH of the sap varies between 4.43 and 4.6, and the ratio of non-aqueous fluids to aqueous fluids is 1:6.5. The best time to harvest mango fruit is after noon. Early morning harvesting results in a rapid outflow of sap from the end of the peduncle.
High solar radiation and insufficient water vapor pressure increase stem water flow within ripe fruits in the morning and decrease after noon. The peduncle cut does not affect the sap output flow. If the stem is cut off from the zone, it will cause the mango fruit to ripen lately.
The two main diseases of mango fruit are anthrax and stem end rot. Collosporine anthracnose caused by anthracnose is undetectable in the green phase, and infection is noticed when the mango is ripe.
Anthrax produces polygalacticuronic enzymes and pectinases that degrade cell walls. If the mango fruit is healthy, polyphenol oxidase enzymes are present in chloroplasts and phenolic compounds are present in vacuoles, and the two are separated, avoiding any reaction.
Stem end rot disease is a species of cocoa bean produced by Lasiodiplodia. Initially, it appears as a small dark brown area in the peel around the base of the end of the stalk, progressing to soft rot at the end of the stem. Ethylene is a plant hormone that controls most of the ripening events associated with jumping fruits. A small amount of ethylene maintains the fruit's resistance to pathogens.
Mango stem treatment
If the latex remains inside the fruit at the time of harvesting, it reduces the development of anthrax and stem end rot during ripening. Fruit ripening parameters are not affected by peduncle length, and the number of diseases that appear is significantly reduced compared to fruits harvested without stems.
When the long-stemmed mango fruit is harvested in real time, anthrax lesions will be reduced. SER in short peduncle fruits occurs later than in stemless fruits. The aqueous phase of latex containing chitinase contributes to the resistance of the fruit to SER, and two systems have been developed to minimize latex dejuice.
Mango harvested on Mexico's Pacific coast is green, fruity and begins to ripen. The developed gripper for holding the fruit comes with an integrated cushion to protect the fruit and move it to cut the stem. Two linear knives were used for dressing the equipment. One knife is secured while the other knife is ejected by a 24VDC linear actuator.
Preliminary tests have shown that the stem can be successfully cut with just one action. Mangoes enter the delivery system, but not all fruits are accompanied by peduncles. Those with peduncles are cut with a warm knife at a temperature of 35 ° C. Acquire images of mango peduncles or shedding areas using an X800 digital microscope. After the fruit is ripe, the effect of anthrax infection is analyzed.
Cactus pear is an important fruit, but its consumption is limited by its surface thorns and hooks. Fresh-cut instant cactus pears are more popular than whole fruits. In fact, the cactus pears in the yellow-green ripening stage are processed into ready-to-eat fruits and stored for 9 days in modified atmosphere packaging at 4°C. Green-yellow fruits show medium skin thickness and flesh softness, suitable for peeled and RTE fruits.
Cauterization prototypes were developed to extend the shelf life of prickly pears and reduce fruit diseases. Combustion technologies including high-temperature contact and low-temperature cautery are reviewed, both of which are patented.
The cauter used to harvest the fruit applies a pressure of 100 kPa at 200 °C for 30 sec. The cauterized cactus pear is cut partially on the top peduncle, leaving a 13cm2 sealed area. The system effectively controls postharvest diseases, but its overheating can lead to expensive energy consumption. After heating the fruit at 200 °C for 45 seconds, the pulp temperature rises to 86 °C.
Prickly prickly prickly and its branches have natural polymers, and several eco-friendly materials are being developed. Cactus mucus can be used as a gelling agent, stabilizer, or encapsulant. The use of this biopolymer material opens up new opportunities for food packaging. It is also used as a flocculant for heavy metals in water. All these properties open up new economic opportunities for cactus products.
The stratum corneum of mango is thin and cannot resist the high thermal gradient required for cauterization operations. Therefore, heat treatment must be applied with caution, mainly at the mango fruit shed-peduncle interface.
The fruit is harvested in a very green phase and shows low TSS, acidity and pH. As the fruits ripened after 9 days, the hardness of Haden, Kent and Keitt dropped to 25.73, 16.93 and 32.91 N, respectively. After the mango is harvested, quality loss occurs, affecting the nutrient content at different points in the processing chain.
summary
The increase in the quality and shelf life of mangoes and prickly pears will increase their marketing worldwide. The first step in improving the quality of mangoes is to reduce fungal diseases such as anthrax and stem rot due to environmental changes.
Heat treatment of mango fruit preserves its quality and reduces post-harvest disease. Mango fruit must be harvested with care as mechanical damage at the stem end can begin to rot in the fruit. Latex juice removal after field harvest will reduce fruit juice burns.
Mango latex containing antifungal resorcinol and chitinase should be retained in the fruit to reduce anthrax and stem end rot. After cauterization or application of liquid paraffin, the thickness of the stem channel where the latex flows decreases. Two systems were developed to hold the latex after harvest.
In the first system, the gripper grabs the mango fruit and then cuts the stem through two hot knives maintained at 45 °C. The cauterized peduncle presents charred cells on the surface and is reduced towards the stem end.
Compared to dejuvenated mango fruit, this technique reduced anthrax infection rates by 50% after 11 days of storage. TSS concentration decreases after peduncle cauterization. In the second device, warm paraffin wax is applied to mango fruits without stem ends with a conventional gun. The average foci of anthrax with paraffin wax after 11 days of storage were 38% smaller than untreated infected mangoes.
Prickly prickly prickly is a native fruit of Mexico, grown in arid regions and has very important nutritional properties. Cauterization extended the shelf life of the cactus fruit by more than two months.
The hot and cold cauter equipment extends shelf life without pathogen damage, as the handling seals the fruit and avoids dehydration. Two fixtures were developed to freeze cauterized cacti because the system is more energy efficient than thermal cautery. The first fixture presses the thick peel with two fingers without damaging it.
The biggest disadvantage in this robotic system is the reduced duration of the dry ice pad. The warm air moves around the dry ice pad and melts within 5 hours, so it must be replaced. The second robotic system is more efficient because the dry ice cubes are located indoors isolated from the air. The dry ice lasted more than a day.
bibliography
SantosSF, CardosoR, BorgesÍM, AlmeidaAC, AndradeES, FerreiraIO, etc. Postharvest losses of fruits and vegetables in the Supply Center in El Salvador, Brazil: analysis of determinants, volumes, and reduction strategies. Waste management. 2019; 101：161-170。 DOI：10.1016/j.wasman.2019.10.007
RajapakshaL、GunathilakeDM、PathiranaSM、FernandoTN。 Reducing post-harvest losses of fruits and vegetables to ensure food security – Sri Lanka as an example. MOJ Food Processing & Technology. 2021；9(1):7-16。 DOI：10.15406/mojfpt.2021.09.00255
LosadaHR、VieyraJE、LunaL、CortésJ、VargasJM。 Economic indicators of Teotihuacan, Mexico, capacity of the cactus (opuntiamegacantha) ecosystem and environmental services supply urban consumption. Journal of Agricultural and Environmental Sciences. 2017; 6 pcs: 85-91. DOI：10.15640/jaes.v6n1a9
Hernández-GuerreroS, Balois-MoralesR, HermosilloYA, LopezG, Berumen-Varela G, Bautista-RosalesP and others. A new edible coating of starch-based narrow fruit mango extends the shelf life of mango "Ataulfo" fruit. Journal of Food Quality. 2020. p. 9. Article ID 1320357. DOI：10.1155/2020/1320357
RehanaNS、ManshaN、KhaskheliMA、KhanzadaLAM。 Chemical control of mango stem end rot disease caused by Lasiodiplodiatheobromae. Pakistan Journal of Plant Pathology. 2014; 26:201-206