WSU Apple Breeding Program Picks Unique Taste-Testing Device

Mohr MDT-1 Crispness Measurements to Be Used to Help Develop New Apple Varieties

Everybody knows a good apple when they bite into one, and it turns out that an apple's crispness is rated among its most important qualities by consumers. However, despite the size and economic importance of the U.S. apple market, an estimated 231 million bushels in 2009, the industry has not established a reliable automated method for measuring fruit crispness, instead relying primarily on taste-testing that is both subjective and labor-intensive. Now, new research confirming the capabilities of a unique texture-testing instrument suggests this is about to change.

Researchers with the Washington State University Apple Breeding Program (WABP, Pullman, WA), led by Assoc. Prof. Kate Evans, compared the sensory attributes of a variety of apple selections, rated by an expert taste-testing panel, with measurements obtained by the Mohr MDT-1 penetrometer. According to their report published in the Dec. 2010 issue of HortTechnology, the researchers found a significant correlation (R2 = 0.56, P < 0.0001) between the MDT-1's Crispness (Cn) measurements and the apples' crispness and overall eating quality. The MDT-1 is a next-generation replacement for the hand-operated Magness-Taylor (MT) penetrometer the industry has relied on for decades to measure fruit firmness, manufactured by Mohr and Associates (Mohr).

The researchers conclude the MDT-1's unique measurements are likely more informative than standard MT penetrometer tests or acoustic resonance techniques with which the industry has more recently experimented. The report goes on to state that the WABP intends to use the the MDT-1's Cn measurements to reduce the need for labor-intensive taste-testing as they develop new apple varieties.

According to Brandt Mohr, Mohr's chief technologist, the MDT-1 measures some of the same fruit characteristics as a consumer. "Think of the MDT-1's plunger as a mechanical tooth," said Mohr. "The MDT-1 measures the energy released by the crunch of the apple as plunger advances in a way that is repeatable and operator-independent. Fruit firmness alone is not adequate because a firm apple is not necessarily a crisp apple." According to Mohr, the WABP team's results confirm the company's internal findings and provide a solid basis for wider adoption of the technology throughout the horticultural research community and industry.

About Mohr Digi-Test (MDT) Series Penetrometers

Mohr Digi-Test (MDT) Series computerized penetrometers include the MDT-1 and the new MDT-2 instrument planned for release Q2 2011. The instruments can measure numerous fruit quality parameters. Standard software and fixtures enable accurate high-volume testing of fruit and other agricultural products. Available features include automated report generation, barcode scanner integration, and custom fixtures for general materials testing. To learn more, please visit

About Mohr and Associates

Established in 1982, Mohr and Associates develops innovative test and measurement instrumentation for a wide range of applications. Mohr and Associates' website is at

Contact: Brandt Mohr
Phone: +1 (888) 852-0408
Fax: +1 (509) 946-4395

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