Measuring Lycopene, Tomato and Citrus Scores with the ColorFlex EZ

By Susanne Hauder

Eighty-five to ninety percent of the color of a red, ripe tomato is due to the presence of lycopene. The skin of the tomato has the highest lycopene content of all its parts. Since tomato skins are discarded in large quantities during the processing of tomatoes into paste, sauce, ketchup, etc., lots of lycopene is being lost. The potential exists to use this skin waste as a source of lycopene as a red colorant, primarily for foods. Lycopene is also beginning to be marketed as a nutritional supplement, since it is an excellent antioxidant and can help prevent heart disease and some forms of cancer. Of course, raw tomatoes and, especially, processed tomatoes, are rich in this healthy lycopene.

“Customers around the world trust our solutions. We have pioneered easy to use solutions for hard to measure samples.”
-Christian Jansen, European Manager Sales HunterLab

HunterLab already has a great deal of experience measuring processed tomato products (the ColorFlex and LabScan XE are currently deemed suitable for measurement of tomato paste, sauce, catsup, and juice by the United States Department of Agriculture), so it is not surprising that the red color of lycopene can be measured using HunterLab instruments. In fact, the lycopene concentration correlates to colorimetric ratios, implemented into our new ColorFlex EZ. Beside standard scales like the CIE L*a*b or CIE XYZ the tomato version includes in addition TPS - Tomato Paste Score, TSS - Tomato Sauce Score, TCS - Tomato Catsup Score, TJS - Tomato Juice Score, Tomato a/b Ratio and the Lycopene Index. The tomato version includes a calibrated tomato tile as well.

This method of analysis is quicker and easier than high-performance liquid chromatography and does not require use of hazardous solvents like acetone and hexane.

Color is often used as an indication of quality and freshness for food products. This is the case for orange juice as well. Originally, orange juice manufacturers used subjective methods for measuring color. The subjective method used involved the visual comparison of orange juice in a standard glass tube to a set of United States Department of Agriculture (USDA) plastic comparators, also in glass tubes. As with any subjective method, the results were inconsistent.

In the 1950s and 60s, research was done by a number of companies in the hopes that they could produce an instrument for objective measurement of the color of orange juice. HunterLab developed the D45 Citrus Meter which is still used in the industry today although it is no longer manufactured. The current HunterLab instrument meant for measurement of orange juice is the ColorFlex EZ.

The ColorFlex EZ Citrus Color Meter measures Citrus Number, Citrus Redness and Citrus Yellowness. These indices were primarily intended to score orange juice concentrate, but in practice have also been used for grapefruit and lemon juices.

The Citrus Color Meter eliminates the subjectivity of visual methods and gives reproducible objective measurements. In addition to the citrus values, the instrument can also measure in terms of the Hunter Lab scale as well as other widely used color scales. Thus the system can also be used to measure the reflected color of virtually any opaque or semi-opaque liquid.

HunterLab systems measure reflected and transmitted color of food products. They give numerical values that correlate to what you see and are ideal for measuring raw materials through final product. These include liquids such as sauces and juices, solids such as spices and meats, as well as non-uniform products such as cereals and snack foods. Portable, bench and on-line systems are available.

HunterLab's next generation Color Flex EZ spectrophotometer takes color quality control to its highest level with 45/0 design for the ultimate in color measurement preciseness. Combining versatility, simplicity and performance: The ColorFlex EZ reflects almost 60 years of color measurement innovation in one easy-to-use, compact instrument from the world's most trusted experts in color quality.

45/0 Design: For Relentless Perfection in Color Quality

HunterLab's ColorFlex EZ offers the advantage of 45/0 design ensuring that you not only get your colors right - but perfect every time. It is the optimal and only instrument design that measures your samples the way the human eye does. It lets you see your colors exactly the way your customers do, not just in the lab but in the real world.

The HunterLab Advantage

The ColorFlex EZ is backed by over 5 decades of color quality innovation and experience from HunterLab, the world's most trusted color quality experts. With an unmatched reputation for delivering the right solution for the right challenge, HunterLab tailors products and technologies for every color measurement need and budget offering the broadest range of color measurement solutions in the industry.

About HunterLab:

HunterLab is the world leader in the color measurement of food products.  A wide range of portable, laboratory and on-line color measurement systems are available to meet specific application requirements. Their corporate philosophy is focused on total customer satisfaction. HunterLab is a global company that provides worldwide support through local representation in more than 65 countries.

For more information, please call HunterLab at (703) 471-6870, send e-mail to info@hunterlab.com or visit www.hunterlab.com.