2013 Meeting Abstract - Factors that affect CIELAB and Hunter Lab color scales

Poster Presentation
Quality & Analytical Methods

177-P

Factors that affect CIELAB and Hunter Lab color scales
Y. LIU (1), C. E. Carter (1), F. A. Manthey (1)
(1) North Dakota State University, Fargo, ND, U.S.A.

CIELAB and Hunter Lab are two color scales where L-value indicates brightness on a scale of 0 to 100 where 0=black and 100=brightness; a-value indicates greenness when negative and redness when positive; and b-value indicates blueness when negative and yellowness when positive. Color is an important attribute for determining the quality of semolina and pasta. Semolina color usually is characterized by CIELAB using a black cell with a quartz glass window, while pasta color is characterized by Hunter Lab using a black tile with 1 cm of depth. Experiments were conducted to determine the effect of background color and sample depth on measured semolina and pasta color scores. Six different spaghetti and semolina samples of poor, medium, and high color quality were used. Color scores of semolina and spaghetti were determined using a Minolta 410 colorimeter. Background colors evaluated were black, blue, green, red, white, and yellow. CIELAB values for semolina and Hunter Lab values for spaghetti varied depending on background color. For semolina, background color did not affect CIE L-value or a-value; but the b-value was greater with green or red than with black background. For spaghetti, Hunter L-value and b-value were higher with white or yellow than with black background; and the a-value was greater with red, yellow or white than with black background. As the depth of spaghetti increased from 0.25 to 1 cm, the Hunter L-value increased from 51.08 to 52.21, a-value increased from 2.13 to 3.79, and b-value increased from 23.34 to 24.32. These data demonstrate the importance of specifying the depth of spaghetti and the color of background when using the CIE or Hunter color scales.