ISHS Acta Horticulturae 69: II International Symposium on Pear Growing
REFLECTANCE AND LIGHT TRANSMITTANCE TECHNIQUE FOR MEASURING MATURITY AND RIPENING OF ELDORADO AND BARTLETT PEARS |
| Authors: | John T. Worthington, T. Zwet, Harry L. Keil |
| Abstract:
Nondestructive light-transmittance measurements using the ΔO.D. (difference in optical density) at 600–740 nm or 690–815 nm were found effective for assessing maturity and ripeness of intact pears. As the fruit becomes more mature or ripens, the internal optical density decreases. As the fruit ripens there is more free water in the tissues; this changes the tissues' light-scattering properties, which changes their optical density. Measurements of skin color using Hunter Color Difference Meter and L, aL, bL reflectance values indicated striking skin color changes in the Bartlett pear after 4 months at 0°C but only slight change for the Eldorado skin. Bartlett was soft after 4 months whereas Eldorado pears were still firm. Eldorado pears harvested in September and held at 18.3°C with no cold storage reached soft-ripe stage after 25 days. During the 25-day period the ΔO.D. decreased from .56 to .39. The optical density of Eldorado pears decreased from ca. .582 for the August 6 harvest to .213 for the October 8 harvest. Visibly, the difference between the skin color of Eldorado pears harvested on these two dates, was very slight; however, their aL values of ca. -14.0 and -10.0, respectively, were significantly different. | |
Download Adobe Acrobat Reader (free software to read PDF files) | |
