by Rajat Ramesh, Product Manager, Bühler India


Rice has long been the staple food for more than 50 percent of the world's population, and the importance of rice in the global food market is undisputed. At the same time, the industry is going through paradigm shifts, especially in terms of technological innovations to improve the quality of rice.

Paddy to rice milling process

The processing of paddy to rice can be understood in terms of processing sections. Principally, there are seven sections in a typical rice mill – cleaning, hulling, whitening, polishing, sorting, grading and packing. During this process, the paddy gets converted to white rice in different stages. Like any other manufacturing process, processors need to get the business economics right. This means ensuring the highest level of output while minimising wastage and downtime, so process optimisation is absolutely critical.

Importance of whitening in rice processing

The bigger challenge facing the rice processing industry is how to meet the ever-rising quality standards, and consistency in the product output quality is what customers want. Also known as the heart of the rice mill, the rice whitener almost dictates the quality of the end product and its consistency, and rice processing equipment manufacturers like Bühler are central to this process. Being a pioneer of the rice industry for nearly half a century, Bühler fully understands these rising customer demands and has been instrumental in the evolution of the art of rice whitening.

Whitening of rice occurs when bran is removed from brown rice to convert into white rice through the abrasive effects of rice kernels rubbing against grinding stones in the rice whitener. The presence of brake bars reduces the speed of the whitening chamber, thus increasing the whitening time and improving whitening efficiency. Historically, the industry has adopted a horizontal design for whiteners but unfortunately this design had shortcomings in terms of lower efficiency. Bühler changed this trend by adopting a vertical, split-stone arrangement. This design meant less broken rice as well as ease of maintenance, and resulted in a machine that was reliable, operator friendly and that minimised downtimes. The second step change was the introduction of the patented shaft-less milling chamber design. This allowed air to pass freely around rice kernels resulting in cooler and cleaner kernels, free from the bran. A further upgrade to this design was the introduction of diamond grinding stones that helped increase the lifetime of the stones by almost five times.

Introducing the Automatic Whitener from Bühler

Bühler is now revolutionising the rice whitening process yet again by adopting an automatic whitening technology with its new Automatic DRWC Whitener. This new Automatic Whitener offers an overload protection mechanism with a universal touchscreen machine control that enables easy recipe setting options and higher operational efficiency. In other words, manual machine control has been completely automated, making it a winner in terms of efficiency and user-friendliness, while another key feature is the energy savings achieved through process optimisation. This means yet another step-change in whitening evolution since the automatic whitener enables self-adaptive whitening pressure that improve whitening consistency.

Leading the market through quality

As highlighted before, process optimisation is critical in the rice milling business – it is the winning edge in the industry. At the same time whitening is also the most important part of the processing chain, so the automatic whitener helps in the optimisation of this process and offers a number of significant benefits:

Output consistency: The multifunctional control screen provides clear information on operational parameters for precise control. The ampere settings can be varied to achieve the highest level of whiteness at the lowest pressure on grain. This also results in incremental savings in broken rice leading to an overall increase in performance through process optimisation

Remote maintenance: With a simple connection to Bühler's existing automation systems, the automatic whitener also makes remote maintenance possible. This helps in reducing labour costs, which represent a significant portion of the operating costs for processors and is also in line with the Industry 4.0 revolution, making the machine truly future-proof

Energy savings: The manufacturing industry needs play its part in sustainability, and the automatic whitener accounts for as much as 10 percent energy savings thanks to its automatic control. Not only does this translate into benefits for the environment but also cost savings for the processors

Food safety: End consumers across the globe have realised the vital importance of food safety. With the rise in disposable incomes, there has been a proportional rise in demand for products that are made through genuinely food-safe processes. The design and performance of the automatic whitener are also aligned with these rising food safety requirements.

RiceLinePro Sensor: Quality quantified

As mentioned earlier, consumer preferences are changing and people are looking for higher quality products. While rice processors are constantly faced with the challenge of meeting these rising demands, rice quality remains a very subjective topic and is not easy to define or quantify. It is based on several variables such as the intended application and the market segment, and the current mechanism of rice quality measurement is undoubtedly primitive. This means that there is significant scope for improvement of the measurement process through use of artificial intelligence (AI) and machine learning technology. The other important challenge that needs to be addressed is the fact that the quality of rice needs to be measured during the processing, which calls for real-time (in-line) measurement of quality.

Bühler has constantly strived to address the gaps in the market, and the market need identified in terms of in-line rice quality measurement has been fully met by its RiceLinePro sensor. The company's expertise has enabled it to identify three main parameters that help to measure the quality of rice – shine, smoothness and whiteness.

The RiceLinePro can be used as a retrofit solution with existing whiteners and polishers to improve these three main quality parameters. The sensor uses complex machine learning algorithms to simplify the entire measurement process to improve the head rice yield and consistency of the output. The fact that the sensor works in real-time enables operators to take corrective actions in case of any deviations or mismatches between the input settings and the final outputs. This is yet another revolution in the rice processing industry as the RiceLinePro sensor helps create quality benchmarks that simply did not exist before.


In summary, it is important to understand that rice whitening is vital in the entire rice processing chain. Bühler's new Automatic Whitener helps in establishing a winning edge in the market by offering a host of benefits to rice processors. It is a genuine example of sustainable innovation and helps to contribute not only towards solving global food security issues but also protecting the environment.

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