Written by Charisma Love B Gado

 

A long time ago in an Asian folklore, when a brave youth in Java, Indonesia stole the rice plants from the heavens, the goddess Dewi Sri instructed him to harvest the plants carefully.

Unfortunately, the words of the goddess are long forgotten as data from the Philippine Center for Postharvest Development and Mechanization shows a 15 percent postproduction loss for rice. The Agricultural Training Institute published on its website that “this amount of losses when saved is equivalent to the volume of rice the country exports annually.”

Experts on postproduction at the Philippine Rice Research Institute (PhilRice) said that handling rice from harvesting until milling is as important during its cultivation because it ensures the good quality of grains brought by the consumers. Rice postproduction involves harvesting, drying, storing, and milling.

Harvesting

PhilRice experts had emphasized the importance of draining before harvesting as this makes harvesting faster and easier especially when mechanical harvesters will be used.

If the soil is heavy, the clay or the clay loam type, drain the field with 5-cm standing water 10 to 14 days before harvest time and 5 to 7 days in light soils, the sandy or sandy-loam type. During dry season, however, delay field draining by 5 to 10 more days.

Timing also affects the quality of harvested rice. Engr. Eden C. Gagelonia of the Rice Engineering and Mechanization Division said that timely harvesting produces the best rice quality, increases rice marketability, and consumer acceptability.

“Harvest rice when 15 to 20 percent of the grains at the base are in the hard dough stage. To do this, press a grain from the base of the panicle between the thumb and forefinger to assess hard dough stage. Most of the grains in the panicle will be golden yellow,” Gagelonia, also the Farming without Fossil Fuel program lead, said.

She said that delays in harvesting expose the grains to weather hazards resulting in kernel deterioration, fissuring, and shattering; while reaping too early results in a larger percentage of immature grains and in lower milling recovery.

In the PalayCheck system, an integrated crop management system for rice, the country`s lead agency in rice research and development advised farmers to thresh the palay not later than two days in for the dry season; and not later than a day after reaping for wet season.

Experts also discouraged farmers to pile the reaped crop in the field for more than a day as this results in heat buildup in the grain, which leads to grain discoloration and lowers the quality of milled rice.

Cleaning

Removing straw, chaff, unfilled/half-filled grains and other impurities from the grain can be made efficiently with the PhilRice seed cleaner. It can clean the palay 1.5 tons/hour for initial cleaning after threshing and up to 2 tons/hour for final cleaning after drying.

Easy to operate, highly mobile, and powered by 6hp gasoline engine, the machine has 97 percent purity after two passes.

Drying

To prevent spoilage and attain a safe level for storage, rice experts encouraged farmers, traders, and millers to properly reduce grain moisture.

“Majority of the 15 percent loss is attributed to postproduction practices of traders and millers while 5 percent owes to farmers’ practice.

In pre-drying handling of wet paddy, Gagelonia informed the traders and millers to dry extremely wet paddy within 24 hours after harvest or as soon as possible to prevent grain discoloration.

She also urged them to separate grains based on variety clusters and moisture content and clean the wet paddy using a pre-cleaning or scalping machine with aspirators before drying especially if field cleaning was not thoroughly done.

Farm laborers must not also pile wet threshed grain in bags, but rather leave the rice on the floor to minimize heat build-up.

Based on PhilRice technology bulletin on postproduction practices, grain temperature should not exceed 430C when using a flatbed dryer to prevent grain fissuring. However, higher drying air temperatures (600C) for short period is recommended to quickly remove surface moisture from wet grains.

When using sun drying method, experts advised farmers to stir palay every 30-60 minutes for uniform drying and to choose a surface where the palay will not be ran over by vehicles.

Storing

Efficient rice storage means following a good level of moisture content. When storing for 2-3 weeks, required moisture content for safe storage is 15-18 percent; 8- 12 months, 14 percent or less; more than a year, 10 percent or less.

“When the recommended moisture content is not considered, problems including molds, discoloration, heat  build up, pest damage, poor eating quality, and loss of viability will occur,” Gagelonia said.

Milling

Removing the husk and bran layers is better using multipass rice mills. Single pass mills such as kiskisans break the grain leading to low milling recoveries.

Rice postproduction experts added that palay for milling should be of good quality. The rice has uniform mature kernels of consistent size and shape, no weed seeds, no discolored grains, 2 percent maximum amount of foreign matters and damage kernels, and 3 percent maximum amount of immature grains.

Before the goddess left the youth who stole the rice grains from the heavens to be planted on earth, she warned him, “If you don`t pay attention to my orders, I will send natural calamities to destroy your work.”  Folklore or not, farmers, millers, and traders may consider following the PhilRice recommendation on postproduction not only to assure quality, but more importantly, to avoid losses for the country to provide enough rice for the Filipinos.

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Philippine Rice Research Institute (PhilRice) is a government corporate entity attached to the Department of Agriculture created through Executive Order 1061 on 5 November 1985 (as amended) to help develop high-yielding and cost-reducing technologies so farmers can produce enough rice for all Filipinos.

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Philippine Rice Research Institute