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.
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Patrick P. Moore (1996) studied this question.