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Rice White and Brown Rice Firmness

Situation

Rice cooking in wokFor most consumers, the option of white or brown rice comes down to a preference in texture versus a desire for the healthy option. The two varieties are very similar– white rice is produced from brown by the removal of the outer bran and germ layers – however, producers aim to increase the similarity in terms of mouthfeel by further processing techniques on the white variety.

Is there an objective method to measure the firmness of brown rice and white rice to ensure consistency and save time over a subjective sensory study? Here we demonstrate a method that enables correlation with the subjective sensory data by testing each variety of rice with a food texture analyzer.

 

 

 

Method

rice testThe test utilized a Food Technology Corporation (FTC) TMS-Pro Texture Analyzer fitted with a 2.5 kN intelligent loadcell and a CS-1 Kramer shear compression cell. This type of test cell most faithfully replicates the way a food item is actually consumed, in addition to allowing the testing of products in bulk form— producing more consistent results through averaging the texture across the whole sample.

The rice was cooked in accordance with the supplier’s instructions and immediately placed in the Kramer shear cell to capacity. The FTC TL-Pro control and analysis software program moved the blades of the test cell down at a speed of 250 mm/min to a distance far enough to ensure that the product was completely expressed through the bottom. On completion of each test cycle, the software automatically calculated the peak compression force or ‘firmness’ of the sample.

 

 

Results

The graphical representation from TL-Pro, of the test results for the six samples, is shown here (force applied, against cumulative displacement).

rice test results graph

The two types of rice samples cluster, with the peak firmness higher for the brown variant, somewhere around 50% more firm. The slope rises first with the white rice, indicating slightly greater initial firmness, but this characteristic is quickly overtaken by the curves for the brown rice. This is probably explained by the starchy stickiness of the white rice’s outer surface providing more initial resistance than the smoother husk of the brown.

The same results with additional calculations are shown here.

rice test chart

  • Average = arithmetic mean
  • SD = standard deviation
  • CV = coefficient of variation(SD/Mean) x 100

 

Significance

Consistency in the results, with a low coefficient of variation, demonstrates that this method of testing is a reliable, accurate and repeatable way of objectively measuring the texture of rice. The clear clustering of the two variants correlate well with the historical subjective knowledge that brown rice feels firmer. Any slight variance in each sample group is most likely a consequence of cooking time and/or temperature variations – an effect that would be present when the consumer prepares the product. The fact that the results still clearly differentiate between white and brown varieties further emphasizes the value of using a texture analyzer in the quest to produce brown rice with the preferred firmness of white.

Trusted by customers across the world

Excellent customer service. Consistently followed up and offered help without asking. Relatively low priced - provides good value. 

Easy to switch different load cells. Used it for 5 lab sessions for 68 students this semester and performed well.

 

 

Professor Jeyam Subbiah, University of Nebraska
https://nebraska.edu/

The University of Arizona’s Nutritional Sciences Food Lab acquired a Texture Analyzer from Food Technologies about 5 years ago. The company has a great product, which is tailored to food needs. 

We have used the Texture Analyzer for both research projects and as a tool to demonstrate to students how food manufacturers can employ objective testing in product evaluation to show how differing ingredients in the same product can affect quality attributes. Its use adds another dimension to the foods labs.

Drew Lambert has been instrumental in helping with set up for testing and providing support whenever there’s a question. He has been a pleasure to work with and is always accommodating with our needs and schedules.  He has even sent us special attachments for special projects.  We couldn’t ask for a better technical support.  Thanks for a great product and great service.

Patricia Sparks, Ph.D.
Assistant Professor of Practice
https://www.arizona.edu

As a seasonal vegetable processor, understanding crop maturity and the accuracy of this measurement is key to staying ahead of crop and knowing when to make the move from value to premium product as harvest time constraints permit.

The TU units provided by FTC give us the accuracy to work to much tighter tolerances, replacing older less accurate analogue equipment which in turn can affect final product grading and profitability.

The units are well designed, very low maintenance and are backed up with a strong support service which will allow them to provide many years of accurate, reliable service.

Colven Wilson
Technical Manager
http://www.eyefreeze.co.uk/