Sunday, April 26, 2015
Overlooked Benefits of Rice By-Products
Rice by-products including rice straw, rice husk (or hall), and rice bran are largely considered as waste products by Iranian farmers who either burn them or feed them to the cattle. However, a number of possible uses for these products could help maximize the farmers’ profits and create more jobs.
Rice is grown in 16 provinces of Iran, covering an area of more than 600,000 hectares. However, more than 80 percent of rice is produced in two northern provinces of Gilan and Mazandaran, thanks to the abundant precipitation in the Caspian region.
Though favorable, the natural conditions in Gilan and Mazandaran are not optimal, owing to the cold winter weather that limits the growing season to one crop a year. Furthermore, the farmers’ profits have shrunk over the past years due to use of inefficient traditional irrigation techniques, high labor costs especially during the sowing season and irregular imports of cheap rice.
A general practice in the northern provinces is to burn the rice residue, causing severe air pollution. An alternative, residue incorporation into the soil also causes methane emissions from rice fields, contributing to climate change.
An article by Forsat-e Emruz newspaper suggests that investing in development of industries to turn rice by-products into useful commodities would not only increase the value-added by the sector, but also help reduce environmental pollution.
Minimizing Loss
Available data suggests that about 27% of the rice cultivated in Iran is wasted in various stages of production, including the sowing and postharvest losses. A rough estimate by Ta’adol indicates that reducing wastage by only 1% would result in a profit of about 200 billion rials ($6 million at market exchange rate) for the sector.
Policies adopted so far to reduce the losses include improvement in packaging, storage and transport techniques, optimizing the efficiency of the milling processes and conducing educational courses for farmers and those working in the processing industries.
But, developing the necessary industries that would complement agricultural production is globally viewed as a suitable solution for sustainable agricultural activities.
By-Products
Experts list as many as 40 different products that can be made from rice residue including rice straw, rice husk and bran. These products find uses in various industries including food, medicine and building material.
Rice straw is the vegetative part of the rice plant and major forage in rice-producing areas. Straw may be used as part of animal feed diet. It has also been tested for use in biogas plants to see if higher gas yields were attainable. The use of straw in large-scale biomass power plants is becoming mainstream in Europe. A mixture of clay and straw can be used as a building material. Other uses include basketry, bedding, packaging, pulp for paper production, etc.
The rice husk is the outermost layer of the paddy grain that is separated from the rice grains during the milling process. Around 20-22% of paddy weight is husk. Rice production in Asia produces about 770 million metric tons of husk annually. Iran produces about 3.5 million tons of husk annually.
Rice husk is used for various purposes. Cellulose, a main constituent of rice husk, is used as raw material for pulp and paper making. Combustion of rice hulls affords rice husk ash, which is used in the production of Portland cement. Rice husk is also used as fuel to provide energy for rice mill operation, fertilizer, insulation material, filter for fruit juice extraction, fiber board production, pillow stuffing, and many more.
Rice bran is a byproduct of the rice milling process (the conversion of brown rice to white rice), and contains various antioxidants that impart beneficial effects on human health. Rice bran oil, extracted from rice bran, is widely used in Asian countries.
According to head of Gilan Science and Technology Park, Majid Mottaghitalab, a plant for producing cellulose from rice straw has been established in the northern province and will become operational by August. Mottaghitalab and his team are prepared to guide and help draw business plans for any individual or company planning to establish factories for development of rice by-products.
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