Tradition and innovation in rice preservation techniques

12/06/2024

Rice is characterized by a long shelf life. Its ability to be stored and transported is one of the advantages of this ingredient and one of the reasons for its vast popularity all over the world.

Especially in its shelled or dried forms, rice can be stored for long periods without significantly losing quality, as long as it’s kept under suitable conditions that reduce exposure to moisture and pests.

Therefore, rice has become an ideal food for emergency supplies and in settings where other food sources may be less reliable. In addition, it can be easily stored and transported without the need for refrigeration. This has facilitated its large-scale trade and distribution, making it one of the most important and accessible foods worldwide.

However, for the product to remain unaltered, techniques should be used to preserve it for as long as possible without damaging the organoleptic characteristics.

Conservation during processing: paddy rice

Rice preservation does not only concern the post-sale phase but also the production phase. This phase is more appropriately referred to as paddy rice storage. When the rice is still uncooked, it’s more likely to be attacked by pests or deteriorate due to moisture.

This process begins immediately after harvest when the rice is transported to storage facilities for processing. Proper storage of rice at this stage aims to prevent degradation and loss of nutrients.

Environmental control: The first strategic element for the conservation of paddy rice is controlling the storage environment. It’s essential to maintain low relative humidity, generally below 14%, to prevent mold growth and insect proliferation. Likewise, the temperature must be kept constant to avoid condensation and preserve the integrity of the rice. In some cases, cold storage is used, especially for rice intended to be stored for long periods.
Protection from pests: Pests pose a significant threat to paddy rice conservation. Prevention begins by cleaning the warehouse thoroughly before storing a new crop. Preventive measures include sealing all entrances to block access to rodents and birds and installing physical barriers. The use of insecticides and fumigants, such as those based on deltamethrin or cypermethrin, is often necessary to control populations of harmful insects, such as weevils and moths.
Monitoring and early intervention: An effective monitoring program is essential to detect early signs of infestation or deterioration. Pheromone traps and light traps are common tools for detecting the presence of insects. These tools help to intervene early before pests can cause significant damage. In addition, regular temperature and humidity checks help identify and resolve critical conditions quickly.

Traditional techniques and innovations for storing paddy rice

Over the centuries, rice preservation techniques have been based on traditional wisdom and technological innovations.

Traditionally, rice was stored in large silos or warehouses made of materials that promote good ventilation, such as wood or brick. Sun drying was a common method of reducing the moisture content of freshly harvested rice to prevent mold growth and spoilage during storage. Moreover, in many cultures, practices such as storage in burlap sacks or ceramic containers helped create a dry and protected storage environment.

Today, rice preservation techniques use advanced technologies, making them even more effective.

Mechanical drying: The introduction of mechanical dryers has enabled more precise moisture control, reducing the time needed to bring rice to moisture levels that are safe for long-term storage.
Refrigerated silos and atmospheric control: Modern refrigerated silos and atmospheric control systems actively regulate temperature and humidity, preventing the development of pathogens and the proliferation of insects. These systems can also include modified atmospheres with low oxygen levels to further slow biological degradation.
Real-time monitoring technologies: Advanced sensors and real-time monitoring systems offer manufacturers the ability to keep a constant eye on storage conditions, intervening quickly at the first sign of a problem.

These innovations not only improve conservation efficiency but also help make the process more sustainable. For example, using renewable energy to power refrigerated silos and dryers reduces the carbon footprint associated with rice storage.

Post-sale storage: storing rice at home

Once rice has been milled and sold, maintaining optimal characteristics, certain precautions should also be taken for home storage.

Much like during the processing phase, the critical concerns to preserving this grain are environmental conditions, particularly humidity, and possible pest damage.

Therefore, these directions should be followed:

Package integrity: The durability of rice is only guaranteed if its package remains intact. It’s important to check that the package is still vacuum-sealed. Check that the bag is compact, and the grains don’t move freely inside it. This indicates that the rice is well insulated from the external environment and can retain its quality.
Storage of opened rice packages: Once the package is opened, we should transfer the remaining rice to a container with an airtight seal. Airtight containers not only protect rice from moisture and pests, but also help preserve the flavor and prevent the absorption of unwanted odors. We recommend using non-porous and easily washable containers.
Efficient labeling: It’s good practice to label containers with the original opening date and expiration date of the rice. This helps keep track of the freshness of the rice and ensure that it’s used within the appropriate time frame.
Dark and temperature-controlled storage: Rice should be stored in a dark location to limit the proliferation of pests. Light can degrade the quality of rice and promote mold development. In addition, keeping rice in a cool environment, away from heat sources such as stoves or heaters, helps preserve its integrity.
Vacuum storage: Household vacuum-sealed bags can be used to extend the shelf life of rice. When properly sealed, these bags prevent air and pests from getting inside, prolonging the shelf life of the rice. However, it’s important to remember that vacuum packing doesn’t sterilize food; therefore, rice must still be stored under optimal conditions from the beginning.
Freezer storage: An effective method of storing rice for the long term is freezing it. Frozen rice, especially when vacuum-packed, can be stored for long periods without spoiling, due to the low water activity in the grains that prevents the formation of harmful ice crystals.