Tomato ripeness is currently assessed by a subjective visual classification scheme based on external color while maturity of green fruit is based on a destructive evaluation of internal locule development. In an effort to develop an objective method of tomato maturity and ripeness classification, external color measurements were performed on fresh, sized (6×7) `mature-green' tomatoes (cv “Sunny') initially and through ripening using a Gardner XL-845 colorimeter. Hue angle (tan-1 b/a, designated θ) provided the best objective means of ripeness classification with proposed ranges for mature-green (θ>114), breaker (101<θ<114), turning (85<θ<101), pink (64<θ<85), light red (36<θ<64) and red (θ<36) classes using average hue at the circumference. Hue angle at the blossom end was 2-12° lower than at the circumference due to initiation of color development at the blossom end. Colorimetry was not able to distinguish differences in physiological maturity of mature-green tomatoes as determined by the length of time required to develop from mature-green to breaker which varied from 1 to 22 days in the test.
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