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United States Department of Agriculture

Agricultural Research Service

Title: Use of a Laboratory Colorimeter to Measure Pod Brightness in Virginia-Type Peanuts

Authors
item Isleib, Thomas - NCSU
item Pattee, Harold
item Rice, Philip - NCSU

Submitted to: Peanut Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 16, 1997
Publication Date: N/A

Interpretive Summary: Pod brightness is an important characteristic that influences consumers to purchase in-shell peanuts. An instrumental method is needed to measure pod brightness. Studies were conducted to determine whether pod color measurements were related to visual aesthetics rated by a panel representing seven virginia peanut shelling companies. Panel ratings for pod size, shape, and color were highly correlated, indicating they tended to combine their visual impressions into a single desirability score that influenced ratings for size, shape, and color. Hunter L and b color scores were strongly correlated with sheller color ratings. The colorimeter is a useful tool for measuring pod brightness as an adjunct to breeding for improved pod brightness. Use of a larger 95 mm aperture resulted in higher average L, a, and b scores and also significantly reduced the variation among subsamples.

Technical Abstract: Pod brightness is an important characteristic that influences consumers to purchase in-shell peanuts. A method is needed to quantitate pod brightness. Studies were conducted to determine whether pod color measurements were related to visual aesthetics rated by a panel representing seven virginia peanut shelling companies and determine the effect of colorimeter optical aperture size on the measurements obtained. Pod samples from 48 virginia-type genotypes were separated into jumbo and fancy sizes using a Federal-State Inspection Service grading peanut sizer. Pod color was measured on three subsamples of each size using a Hunterlab D25-PC2 colorimeter equipped with a D25-2RAL Reduced Area Viewing for L optical sensor (51 mm diameter sample area). The 96 samples also were rated by 11 Virginia-Carolina area shellers for pod size, shape, and color. Sheller ratings for the three traits were highly correlated, indicating that shellers tended to combine their visual impressions into a single desirability score that influenced ratings for size, shape, and color. Hunter L and b scores were strongly correlated with sheller color ratings. The colorimeter is a useful tool for measuring pod brightness as an adjunct to breeding for improved pod brightness. Use of a 95 mm aperture resulted in greater average L, a, and b scores and also significantly reduced the variance among subsamples. The larger aperture should be used when the quantity of pods available for measurement permits.

Last Modified: 9/22/2014
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