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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

Our experience with FTC has been more than satisfactory, not only for the quality of the equipment you’ve got but for the post selling service that has proved to be excellent.

Any problem that we had, it took nothing more than a simple mail or phone call to have your immediate answer. We want to thank you very much for the quality of service provided.

 

 

Gonzalo Moraes, Arrozur S.A. Montevideo – Uruguay

I have been working with FTC for the past 3 years, we bought in that lapse of time 2 texture analyzers with different probes fixtures for all kind of applications at our Monterrey Plant. We have always been able to count on the technical support of FTC who kindly answers our requests in a prompt manner and with the best disposition.

As we continue developing our process to achieve better results at our company, we will for sure rely on FTC for technical support and equipment upgrades that will deliver us the best possible results.

Claudia Rojas, Hershey Monterrey Plant - Mexico
Asst. Staff Scientist
https://www.hersheys.com

As a Meat Scientist and program leader for the University of Nevada, Reno, I need to ensure that equipment I use in my lab is reliable, durable, versatile, and accurate. For texture analysis of meats, there are many systems available in the market. Over the last 15 years of my career, I¹ve worked with many of them and had great and bad experiences with different brands.

Last year, I decided to try a different system for my lab, the TMS-Pro Texture Analyzer from Food Technology Corporation. The system has all the attributes I was expecting to conduct texture and shear force analysis in a quick and not complicated way. The customer support provided by them is outstanding and their technicians are always ready to walk me through new procedures and initial set up. If you are looking for a reliable system for food texture analysis and special customer service, the TMS-Pro is the system to go for and the Food Technology Corporation is the one that can deliver the support.

Amilton de Mello
Assistant Professor of Agriculture, Meat Science and Food Safety
https://www.unr.edu/anvs