Post-harvest technologies refer to a range of practices and techniques aimed at preserving the quality and nutritional value of agricultural produce after harvest. The objective of post-harvest technologies is to reduce losses, maintain freshness, and extend the shelf-life of food. The storage of food grains and fruits and vegetables differs in various ways, including the methods used, storage conditions, and duration.
Post-Harvest Technologies for Food Grains
Food grains are a staple food for millions of people worldwide and are a valuable source of dietary energy, fiber, and essential nutrients. However, food grains are highly susceptible to losses due to insect infestation, mold growth, and physical damage. To prevent these losses, different post-harvest technologies have been developed to ensure that food grains are stored safely and maintain their quality over extended periods.
Cleaning and Drying
The first step in post-harvest handling of food grains is cleaning and drying. The process involves removing any unwanted foreign material from the grains, such as stones, soil, and sand. Cleaning is essential to maintain the quality and palatability of the grains. The next step is drying, which involves reducing the moisture content of the grains. Drying is necessary to prevent the growth of microorganisms that cause spoilage and maintain the physical appearance and flavor of the grains.
Storage Structures
After cleaning and drying, the grains are stored in suitable storage structures. The primary aim of storage structures is to protect the grains from environmental factors such as moisture, heat, pests, and rodents. The common storage structures for grains include warehouses, silos, and hermetic storage structures. Warehouses are conventional structures used to store large quantities of grains. Silos are airtight structures designed to hold and protect grains from pests, rodents, and environmental factors. Hermetic storage structures are airtight bags, containers, or drums designed to reduce the oxygen supply within the structure, preventing respiration and microbial growth.
Fumigation
Despite the use of storage structures, food grains are still susceptible to pest infestation. To prevent this, fumigation is applied to grains to eliminate pests and insects that might have contaminated the grains. Fumigation involves releasing chemicals such as phosphine, methyl bromide, or carbon dioxide in the storage structures to eliminate pests. However, fumigation is usually discouraged since it can lead to the development of insects resistant to the applied chemicals.
Monitoring and Quality Control
Monitoring and quality control are essential post-harvest technologies for food grains. Monitoring involves checking the storage temperature, humidity, and ventilation to ensure that the grains remain in good condition. Quality control involves assessing the physical, chemical, and sensory attributes of the grains to determine their quality status. Quality control is crucial in ensuring that grains are stored under the required conditions, and any quality issues are addressed.
Post-Harvest Technologies for Fruits and Vegetables
Fruits and vegetables are highly perishable and require specific post-harvest technologies to maintain their quality and freshness. The post-harvest technologies for fruits and vegetables vary depending on the type of produce, the intended use, and the duration of storage. The following are some of the post-harvest technologies used in the storage of fruits and vegetables:
Precooling
Precooling is the process of removing the field heat from fruits and vegetables immediately after harvest to reduce respiration, enzymatic activity, and microbial growth. Reducing respiration delays ripening and senescence, and maintains the freshness and quality of the produce. Precooling can be done using different methods, such as forced-air, hydrocooling, or vacuum cooling. Each method has benefits and drawbacks, and the choice depends on various factors such as the type of produce, the volume of produce harvested, and the availability of equipment.
Storage Conditions
Fruits and vegetables require specific storage conditions to maintain their quality and shelf-life. Proper storage conditions include temperature, humidity, and ventilation. The storage temperature varies depending on the type of produce, with some requiring low temperatures of below 10 degrees Celsius, such as lettuce and broccoli, while others can be stored at room temperature, such as tomatoes and onions. Humidity levels of 85-95% are recommended for most produce to prevent desiccation and maintain freshness. Ventilation is also vital in providing adequate air circulation to prevent the buildup of carbon dioxide and ethylene, which can cause spoilage and off-flavors.
Packaging
Packaging is an essential post-harvest technology for fruits and vegetables. Packaging materials should be chosen based on the specific produce and intended use. Packaging materials should provide adequate protection from physical damage, moisture, and gases such as oxygen and carbon dioxide. The choice of packaging materials ranges from traditional materials such as wooden crates to modern materials such as plastic bags and trays. In recent times, the use of modified atmosphere packaging (MAP) has increased, where the produce is sealed in an airtight container with low oxygen levels and high carbon dioxide levels, creating an environment that slows down the ripening process and prolongs the shelf-life of the produce.
Post-Harvest Handling
Proper post-harvest handling is crucial in maintaining the quality and freshness of fruits and vegetables. Handling involves different activities, such as grading, sorting, and handling. Grading entails sorting fruits and vegetables according to size, shape, and color. Sorting involves separating produce based on blemishes or defects. Handling involves moving the produce from one point to another without causing physical damage. Proper handling reduces bruising and mechanical damage and prolongs the shelf-life of the produce.
Avoiding Ethylene Exposure
Some fruits and vegetables, such as apples and bananas, produce ethylene gas during the ripening process. Ethylene exposure can cause accelerated ripening and senescence in other produce, leading to spoilage and off-flavors. To prevent ethylene exposure, it is essential to store ethylene-producing and ethylene-sensitive produce separately.
Subcribe on Youtube - IGNOU SERVICE
For PDF copy of Solved Assignment
WhatsApp Us - 9113311883(Paid)
0 Comments
Please do not enter any Spam link in the comment box