Sustainable and profitable rice processing

by Sujit Pande
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With rice being the staple diet of 40-50% of the world’s population, there already exists a strong imperative to gain maximum yield from every hectare of paddy.

Moreover, given that the world’s population is predicted to increase by a further 2 billion by 2050, largely within those countries where rice is the main diet, that imperative will be even greater in the coming years. This has implications for rice growers, especially with agricultural land likely to diminish alongside a growing population that needs to be housed.

However, the pressure is arguably even greater on rice processors, charged with delivering a consistent quality of product to an ever growing, ever more demanding market place.

Processes need to become more efficient, in terms of returning maximum head rice yields from paddy grain, but also in terms of energy efficiency. This is because rice processors, in common with all factories, also face the challenge of increasing energy prices (and a potential shortage of energy supplies) all in the context of political pressure to reduce carbon emissions and other environmental impacts.

It is a scenario in which rice processors, and indeed the wider food industry, are under pressure to process their supplies in the most sustainable, hygienic and safe manner; maximizing yield, improving quality and reducing their use of energy and other resources.


Reducing the energy costs and environmental impacts of rice milling are major drivers of change in the industry. Smaller millers, operating at 2 tph, generally on outdated equipment, are inevitably operating at low energy efficiency and, moreover, are unable to meet the quality/quantity demands of non-local markets.

The challenge then is to maximize value from every kilo of raw material, via the introduction of increasingly efficient and effective production processes, the elimination of losses and efficient resource utilization (energy, water, air).

Extensive analysis carried out at Bühler’s rice research & development division indicated that economies of scale are important in improving energy efficiency and this analysis led Bühler to develop UltraLine, a high capacity paddy to rice conversion system, focusing on energy saving and high end product quality.


Of course, for energy savings to be truly significant, the yield of end product must also increase. Rice is a notoriously difficult commodity to process. If rice is over-processed, perhaps because it is handled too harshly or too often, it breaks. Yet the process must be rigorous enough to achieve the required quality output after whitening and polishing, and of course, to reject inherent defects in the color, size or shape of grains, as well as to eliminate foreign bodies and signs of disease.

Again, the specific challenges that face different processors are different. The quality and species of the incoming rice is a factor, so too the quality standards expected by the processor’s customers. However, whatever the constraints imposed by the raw material and customers, all processors can benefit from recent innovations that allow processors to define the exact quality level for their rice and to optimize their production processes to deliver significantly higher yields.


In the paddy to rice conversion process, the whitening and polishing stages consume the maximum energy and are instrumental in determining the finish of the end product. Hence, Bühler has introduced the UltraWhite (DRWA) whitener and UltraPoly (DRPG/J) polisher as flagship products of UltraLine.

Both incorporate patented technologies unique to Bühler. These include shaft-less milling in the UltraWhite (DRWA), which permits air to pass freely around rice kernels for uniform and gentle whitening, and the innovative sieve geometries of the UltraPoly (DRPG/J), which contribute to improvements in quality, increases in capacity and reductions in energy use.

The UltraLine range also features the SORTEX S UltraVision optical sorter. Optical sorting technology has been available for more than six decades and it has already revolutionized the speed and throughput of rice processing. However, technology has moved on and developments in areas such as data processing, intelligent computing, textured LED illumination and camera optics have provided an opportunity to increase the capacity, accuracy and yield of optical sorters, at the same time as reducing the energy burden.

From the perspective of IT, for example, this new generation of optical sorter incorporates in-built intelligence, allowing it to make decisions about which grain is good and which grain should be rejected. Consistency of sorting performance is further enhanced with Intelligent Automation, which essentially describes the ability of the machine to self-learn as the product changes. This allows it to adjust itself automatically, according to the quality of the raw material, thereby removing the need for costly manual intervention.

Light emitting diodes have revolutionized lighting in many areas of life, being more stable, more controllable and more energy efficient. So, too, within the SORTEX S UltraVision. Along with improved camera optics, textured LEDs permit an illumination environment in which the most subtle color defects can be detected, individually and simultaneously. This includes varying degrees of purples, greys, yellows, streaks, pecks, black tips, spots, chalky and immature or rotten grains.

However, detection is nothing without precise ejection of the unacceptable grain, and innovations in this area also mean that this new generation of sorters can target just the right amount of air at the grain that needs to be removed, thereby removing fewer of the good grains with the reject.

These ground-breaking technologies give processors unprecedented control over their output, as they can define the exact “accept” levels necessary to meet their customers’ requirements, which help to eliminate waste and boost profit.


Individually, each of the innovations described above (and others not mentioned) bring an appreciable improvement to yield and process performance. Taken together, installed in plants designed for maximum food safety and worker protection, these technological advances represent a major leap forward in high capacity, energy-efficient rice processing.

For individual processors, these advances represent the best chance of profitability in a highly competitive market. For the industry as a whole, they represent the best chance of meeting a growing demand for rice, in an era of rising energy prices and a need for sustainability. Leading rice processing technology providers such as Bühler are encouraging the adoption of more sustainable rice processing to drive down processing costs and increase resource utilization.

Bühler’s UltraPoly polisher and UltraWhite whitener are designed to deliver high-capacity with lower processing costs per tonne in a smaller machine footprint. Photos courtesy of Bühler.

Sujit Pande, global product manager, Rice Milling, manages the global product mix of Bühler’s product line for the rice processing sector to ensure it meets changing market requirements and customer expectations.

He may be contacted at: or Tel: 918067770182