Using Spectrophotometric Color Measurement to Optimize Quality and Efficiency in Rice Production

color quality rice
With growing cost of rice production, quality control is becoming more important than ever to improve yields and optimize efficiency. Image Source: Shutterstock user WR.SISI

There are about 482 million metric tons of rice produced globally every year and even relatively small farms typically have high output.1 The average rice farm contains about 600 acres of productive growing land and this much acreage, coupled with the product, requires significant oversight through both growing and production. At a time when the cost of production is growing, this oversight becomes more important than ever to maintain profitability; in the past ten years, expenses in producing rice have jumped significantly, reaching an average of $115 per active acre.2 With rising costs and high production volume, rice farmers must now take extra steps to ensure maximum quality with every harvest.  

Maintaining the quality of output, however, can be a challenge. As such, many modern farms integrate sophisticated technologies throughout the production process, facilitating crop management, harvesting, and milling. Today, a key component of optimizing quality control is the use of spectrophotometers that measure rice color, an important indicator of quality.

color quality rice
Color is often a clear indicator of rice quality. Image Source: Unsplash user Vitchakorn Koonyosying

Key Indicators of Rice Quality

There are many types of rice plants and potentially thousands of rice varieties which can be created by crossbreeding those plants. Due to the variation of rice from plant to plant, there’s no universal system for establishing rice quality.3  There are, however, a variety of factors known to indicate quality and farmers use these factors to develop their own quality criteria. They include:

  • Milling degree: The milling degree is a clear indicator of quality, as it determines viable rice production per batch of rough, unprocessed rice. The more rice must be milled to reach optimum quality, the more product volume is lost as milling removes the outer surface of the rice, making it smaller with each pass. Meanwhile, insufficient milling can impact cooking behavior and compromise usability.
  • Whole vs. damaged grains: The optimum size of rice grain is not determined by quality, but on overall demand. Some consumers may prefer long grain, others short. As such, rice farmers tend to grow for their market. However, one thing that is a definite quality indicator is the amount of rice which remains whole after processing, as brittle rice cooks poorly and is therefore undesirable to consumers.
  • Chalkiness: Malformed starch granules cause rice to develop areas of thick, opaque white rather than a slightly translucent appearance throughout. This chalky white rice has a higher tendency to break during milling and is considered undesirable in most markets.
  • Whiteness/Color: Both white and brown rice can be tested based on a whiteness scale, with different levels of white represented as numbers from one to 100, with 100 representing perfect white. For example, brown rice may measure as a 20 on this scale, while white rice measures as a 40.  Anything brighter would indicate chalky rice. This scale is important to ensure all varieties of rice conform to color expectations based on successful growing practices and have an attractive appearance to consumers. The scale can also be used to correlate color to milling processes and determine how well-milled the rice needs to be to achieve optimum results.4

With a high volume of rice to test, most manufacturers face challenges in finding effective ways to review issues of quality in rice production and streamline their systems. Because color can provide important guidance regarding a number of quality parameters, color measurement is an important strategy rice farmers can implement to overcome these challenges and ensure quality, streamline production, and maximize efficiency. As such, spectrophotometers are increasingly being used in both farming and milling, facilitating rapid and accurate quality assessment.

color quality rice
Integrating modern technologies, including spectrophotometers, throughout the rice production process is imperative to optimizing quality. Image Source: Shutterstock user wk1003mike

The Role of Spectrophotometers in the Rice Industry

Spectrophotometers can be used to boost useable volume production in virtually all parts of the rice farming process, from growth to milling, as color can offer a clear indicator to ensure rice is adequately cared for and milled effectively. In order to obtain the meaningful color data necessary to optimize quality, spectrophotometric testing can be implemented at a number of points in the production process, including:

  • During growth: Early rice color can be indicative of anything from incorrect moisture levels to potential fungus issues. Spectrophotometric color measurement can help to detect early issues so they can be resolved prior to harvest.
  • Before and during milling: The color of rice both before and during milling is a clear indicator of how much processing will be required to create good, food grade rice; the darker the husk, the more milling will be needed to create white rice. By reviewing test samples with a spectrophotometer, the producer can ensure their milling practices are suitable, allowing you to gain the most usable product from every milled batch.  
  • After milling: Overall rice quality is established after the product has been milled, allowing the producers to correctly price their products according to quality. This step can also assist in creating a target color for all future rice yields.

Spectrophotometers offer proven results when it comes to establishing the ideal quality of rice. However, choosing the right spectrophotometer is imperative to ensure accuracy, precision, and speed of color measurement. The ideal spectrophotometer is one that will allow for testing of irregular sample using sophisticated technologies that can account for height and texture. HunterLab’s Aeros, for example, is a state-of-the-art non-contact instrument specifically designed for this type of color measurement. With SMART features such as automatic height positioning, a rotating platform, and a large sample area, you can achieve the highest level of color measurement accuracy every time. Because the Aeros is designed for simplicity of use, this cutting-edge spectrophotometer eliminates the need for complex sample preparation and drastically reduces the risk of operator error, improving speed and guarding against incorrect results. Combined with our EasyMatch QC Essentials software and advanced communication features, you are able to gain extraordinary insight into color behavior to improve the efficacy of your color quality control process and, ultimately, your product.

Consumer demand for rice is showing no signs of slowing down, but the cost of growing rice rises with the costs of seeds, water, and energy. Rice farmers need to ensure they’re able to maximize their viable product from every harvest to manage production cost increases without compromising the quality of output.  Spectrophotometric technology such as the Aeros can thus be an invaluable tool to increase yields, control costs, and enhance quality.

HunterLab Technology

HunterLab’s comprehensive range of spectrophotometers is ideally suited to manage rice production and eliminate waste. With over 60 years of experience in the field, our instruments are designed to meet the diverse needs of our customers, keeping accuracy, durability, and ease of use in mind. For rice producers, this can translate into improved production processes and products as the result of enhanced quality control. Contact us to learn more about our renowned spectrophotometers, customizable software packages, and world-class customer support services and let us help you select the right tools for your needs.

  1. “Rice – Statistics & Facts.” https://www.statista.com/topics/1443/rice/
  2. “Agricultural Resource Management Survey: U.S. Rice Industry.” https://www.nass.usda.gov/Surveys/Guide_to_NASS_Surveys/Ag_Resource_Management/ARMS_2014_Rice_Highlights.pdf
  3. “Aromatic Rice.” http://books.irri.org/8120414209_content.pdf
  4. “Rice Knowledge Bank.” http://www.knowledgebank.irri.org/training/fact-sheets/postharvest-management/rice-quality-fact-sheet-category/item/physical-quality-of-milled-rice-fact-sheet