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United States Department of Agriculture

Agricultural Research Service

Title: Pecan Kernel Color: Standards Using the Munsell System of Color

Authors
item Thompson, Tommy
item Grauke, Larry

Submitted to: American Society for Horticultural Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 1, 1996
Publication Date: N/A

Interpretive Summary: Most pecans are shelled before being retailed. Kernel color is very important for the consumer to determine the age and quality of the pecans. As pecan kernels age, they become dark or reddish brown, and often taste rancid. The lighter the kernel color, the better the quality. This paper investigated the use of a standard way of recording kernel color. The Munsell System of Color is a standard color system that is used worldwide to record color of many different things. It is available to all scientists and industry personnel. It is a system of color chips to which a pecan kernel color can be matched. Each chip has a number that can be recorded. We found that 91 standard colors were needed to define all pecan kernel colors. We used these colors to develop a much simpler system in which only six Munsell color chips are needed to define kernel color. Hopefully, this system will be used by all scientists to standardize color notation in npecan kernels.

Technical Abstract: The Munsell Color System was used to study pecan [Carya illinoinensis (Wangenh.) K. Koch] kernel colors and color changes for 21 clones, 11 locations, and 4 storage methods for nuts collected over a four-year period. Hue readings ranged from 10.0 (10 Red) to 22.5 (2.5 Yellow). Value readings ranged from 2.5 to 8.0, and chroma readings ranged from 1.0 to 8.0. A total of 91 colors (individual combinations of hue, value, and chroma) were needed to describe variability in kernels. Overall, one color [15.0/5/4 (Hue/Value/Chroma)] accounted for 3,979 of the 32,078 readings taken, and the 15 most common colors accounted for 80.7 percent of all the readings. The Munsell system of color determination was well suited for pecan color determinations. The total variability in pecan kernel color was subdivided into 6 color classes. This simplified system is routinely used as a part of our breeding and genetics program to define this very important quality trait in pecan.

Last Modified: 9/22/2014
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