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Non-destructive harvest measurement can predict rate of softening of fast- and slow-melting peaches
- Eccher Zerbini, P., Weksler, A., Lurie, S., Friedman, H.
- Acta horticulturae 2015 no.1084 pp. 829-834
- absorbance, analytical methods, chlorophyll, color, cultivars, equations, firmness, fruit maturity, fruits, harvesting, monitoring, peaches, prediction, probability, ripening, shelf life
- Peaches are harvested selectively based on size and color, both peel background color and extent of blush. The background color of the fruit changes from green to yellow as chlorophyll disappears, and in many cultivars with red coloration this is hard to determine. A portable instrument that measures IAD (the index of absorbance difference between 670 and 720 nm) was used for monitoring the progression of ripening in two peach cultivars. IAD was measured at harvest in âOdedâ (an early season, fast melting flesh peach) and âSeptember Snowâ (a late season, slow melting flesh peach). After harvest the fruits were divided into comparable lots and held at 20Â°C. The IAD and firmness were measured daily on a different lot. Two analytical methods were applied to the data. In the first, firmness decrease during shelf life was analyzed by non-linear regression, using the IAD measured at harvest to determine the maturity of the fruit, and to estimate the biological shift factor (BSF) which is related to the biological age of fruit. In the second, a prediction equation for firmness was developed as a function of initial IAD, giving a table of the probability of a fruit to be less than 20 N on each day of shelf life. In both these methods the measurement of IAD at harvest could be used to separate fruit into different groups according to their rate of softening, and, therefore, potential shelf life.