Tips to Minimize Rice Postproduction Losses
According to the Bureau of Postharvest Research and Extension, rice farmers usually experience postharvest losses as high as 30 percent. Majority, or 15 percent, is attributed to postproduction practices of traders and millers, while 5 percent is ascribed to the practice of farmers.
Phil Rice-developed flatbed dryer is being recommended to ensure that grains are properly dried. It has a capacity of 1 to 6 tons per batch and removes moisture at a rate of 1 percent per hour.
To help farmers address postharvest problems such as low milling recovery and quality, the research team from the Philippine Rice Research Institute (PhilRice) composed of Engr. Artemuio B. Vasallo, Engr. Eden C. Gagelonia, Engr. Ricardo F. Orge, Dr. Manuel Jose C. Regalado, Dr. Eulito U. Bautista, Dr. Dante B. de Padua, Susan F. Brena, and Riza Abilgos-Ramos developed a guide in threshing, cleaning, drying, storing, and milling.
THRESHING
Threshing must be done right away after harvesting to prevent grain losses. To do this, farmers must separate grains from the panicle by rubbing, impact or stripping using either manually or mechanically operated threshers.
According to the researchers, there are two recommended kinds of threshers according to method of feeding. These are the hold-on-type, which strips the panicle without damaging the straw or the grain, and the throw-in-type, which has a separating and cleaning mechanism.
They also averred that “farmers can also choose threshers according to the movement of material to be threshed.” They explained that the through-flow thresher can separate the grain while driving the straw out of the thresher, while the axial-flow thresher can separate the grain while moving the straw around the axial cylinder to be discharged at the end of the machine.
The researchers also said that it is also necessary to consider the speed of the threshing drum since this affects the quality of the grains.’ “For throw-intypes, the speed must range from 14.50 meters per second (m/s) to 18.25 m/s, while for the hold-on type, it must range from 10.75 m/s to 13.25 m/s,” they added.
CLEANING
Cleaning the grains before drying, according to the research team, is another important postproduction activity.
The team recommends the use of IRRI grain cleaner, which has a cleaning capacity of 0.25 to 1 ton per hour and a purity output of 99 percent, and the PhilRice hybrid rice/inbred seed cleaner, which has a cleaning capacity of 1 ton per hour and purity output of 98 to 99 percent.
Farmers are also advised to clean the grains again after drying since most of the impurities are not easily removed from wet rice during the pre-cleaning process.
DRYING
“Farmers must also see to it that grains arc properly dried,” the researchers said. Proper drying of the grains is important to lessen the risk of spoilage, prevent insect activity, and avoid grain discoloration caused by grain heating at high moisture content. Some farmers prefer sun drying because it is cheap, does not entail cost for energy consumption, and because there are drying areas in most places.
To ensure the quality of harvested grains, reduce postharvest losses and dependence on weather conditions for harvest and allow more time for postharvest field work. PhilRice promotes mechanical dryers such as the flatbed dryer. The dryer, according to the researchers, has a capacity of 1 to 6 tons per batch and removes moisture at a rate of 1 percent per hour.
STORING
Storage plays a significant role in ensuring the availability of stocks. It also provides reserves for unpredictable circumstances such as drought, flood, and war. The research team advises farmers to store grains at a safe moisture level of 14 percent wet basis or lower for prolonged storage.
MILLING
In milling rice, farmers must use the multipass rice mills because according to the researchers, these have an average milling recovery of above 60 percent. Whereas, a single pass mill has a low milling recovery of only 55 percent. They also said that a 14 percent moisture content is needed to mill rice.
Moreover, farmers must also consider the quality of palay, milling setup, and the knowledge and efficiency of mill operators.
