Measuring intact fruit with a colorimeter could be a quick way to estimate anthocyanin concentration and reduce waste disposal. Five fresh fruit from each of 134 plots were measured with a Minolta tristimulus colorimeter in 1994. Samples were frozen and anthocyanins extracted with acidified ethanol and measured with a spectrophotometer. The hue angle and anthocyanin concentration had r 2 = 0.51. L*, a*, b* and C* were significantly correlated with anthocyanin concentration with r 2 = 0.31, 0.32, 0.42, and 0.34, respectively. In 1995, five fruit from each of 20 plots were measured as before. In 1995, the hue angle and anthocyanin concentration had r 2 = 35. A regression equation with hue angle, b* and a* estimated anthocyanin concentration with R 2 = 0.62. In 1995, the same 20 samples were also measured with a colorimeter immediately after thawing. The hue angle and anthocyanin concentration had r 2 = 0.55. A regression equation with hue angle, b* and L* estimated anthocyanin concentration with R 2 = 0.76. It may be possible to estimate anthocyanin concentration by measuring intact fruit with a colorimeter after freezing and thawing the samples.
Aparna Gazula, Matthew D. Kleinhenz, Joseph C. Scheerens, and Peter P. Ling
), geraniums ( Behe et al., 1999 ), and Satsuma mandarins ( Campbell et al., 2004 ). Earlier, colorimeter readings were related to a color chart to help substitute instrumented measures for color visualization ( Voss, 1992 ). Such evaluations reinforce that the
I. Iglesias, J. Graell, G. Echeverría, and M. Vendrell
The influence of supplemental sprinkler irrigation on fruit color of `Oregon Spur Delicious' (Trumdor) apples (Malu×domestica Borkh.) was evaluated in the area of Lleida (NE Spain) over a 3-year period. Cooling irrigation was applied for 2 hours daily for 25-30 days preceding the harvest. Three treatments were evaluated: 1) control without overtree sprinkler irrigation; 2) sprinkler irrigation applied at midday; and 3) sprinkler irrigation applied at sunset. Fruit color was significantly affected by the cooling irrigation and also by the weather of the particular year. Increased red color and higher anthocyanin content resulted from sprinkler irrigation, especially when applied at sunset. At harvest, anthocyanin content was correlated with a*/b* and hue angle, suggesting that the colorimeter measurements could provide a nondestructive estimate of anthocyanin content.
Monika Schreiner, Angelika Krumbein, Ilona Schonhof, Stefanie Widell, and Susanne Huyskens-Keil
A new approach for nondestructive quality assessment based on color measurement was developed for red radishes (Raphanus sativus L.). Postharvest changes in hue angle corresponded with changes in soluble and insoluble pectic substances linked to textural characteristics in `Nevadar' radishes. Changes in glucosinolates were related to changes in chroma and were associated with radish flavor. However, monosaccharides were not related to root color during the 4 days of postharvest period. Nevertheless, the data suggest that root color may be used as a rapid, inexpensive and reliable indicator of quality during the postharvest distribution of radish.
Peter J. Landschoot and Charles F. Mancino
This study was conducted to determine: 1) if the Minolta CR-310 Chroma Meter can detect color differences among bentgrass (Agrostis stolonifera L., A. capillaris L.) cultivars maintained as a turf; 2) how the CR-310 parameters of hue angle, lightness, and chroma compare with visual color assessments; and 3) if the CR-310 can provide consistent color measurements among evaluators. Differences were detected among cultivars with respect to hue angle, lightness, and chroma. Hue angle and chroma were significantly correlated with visual color assessments when data were averaged across all evaluators. Lightness was not strongly associated with visual color assessment. Differences were found among evaluators for visual color assessment, lightness, and chroma, but not for hue angle measurements. Thus, hue angle appears to be the most consistent CR-310 parameter for measuring color of bentgrass turf. These results indicate that the CR-310 can be used to evaluate the color of bentgrass cultivars maintained as a turf and provides consistent hue angle measurements among evaluators, regardless of experience in rating turf color. The CR-310 is probably best used for measuring relative color differences and may be useful if cultivars of similar color are desired in blended turfs.
Audrey Darrigues, Jack Hall, Esther van der Knaap, David M. Francis, Nancy Dujmovic, and Simon Gray
, and high-throughput manner. We evaluated a tomato population for color and color uniformity using TACT and a colorimeter and estimated variance components associated with these parameters. To assess the applicability of TACT to crops other than tomato
Rachel A. Itle and Eileen A. Kabelka
reproducible and highly sensitive process that can separate, identify, purify, and quantify carotenoid levels. In contrast, colorimeters, which objectively measure and describe visible color, are relatively inexpensive and easy to use. The most preferred
Taku Shimizu, Kazuma Okada, Shigeki Moriya, Sadao Komori, and Kazuyuki Abe
measurement error that arises from differences in brightness owing to sample position, or they correct for this error using a colorimeter. Correcting for these errors without using a colorimeter may simplify the system and facilitate its broader use. In
J. Steven Brown, Raymond J. Schnell, Tomás Ayala-Silva, J. Michael Moore, Cecile L. Tondo, and Michael C. Winterstein
evaluation of mango color has been subjective, based on visual ratings, and large errors are generally associated with such ratings. The use of the colorimeter has been demonstrated by Ayala-Silva et al. (2005) to accurately quantify fruit color and to