Characterization of citrus peel maturation: multivariate and multiple regression analyses

S. Alam-Eldein, G. Albrigo, R. Rouseff, A. Tubeileh
This study was designed to understand the role of peel maturation in citrus as it relates to postharvest handling and keeping quality of the fruit. Currently, citrus is harvested based on internal quality (edibility). Peel changes have not been related to best harvest time. Peel physical and chemical characteristics may be used to identify peel maturity more accurately. Principal component analysis was used to show the trend of the data and correlations among variables. Multiple regression was used to obtain a broad picture about the peel maturity window, which related to common postharvest-related problems (weight loss, decay and chilling injury) that limit the storage life of the fruit. Postharvest-related variables showed significant correlation relationships with some physical and chemical characteristics of the fruit. Changes in levels of sugars, glycosidases, abscisic acid and volatile components during maturation coincided with changes in peel color, percent fruit drop and with fruit characteristics during storage (weight loss, decay and chilling injury), and may be useful for establishing harvest date guidelines to avoid harvesting too early (immature fruit) or too late (senescent fruit) so that less postharvest injuries occur and the fruit has acceptable internal quality. Days from bloom date, detachment force and peel firmness were the best indicators for a peel senescence index. The suggested harvest window for 'Marsh' grapefruit and 'Valencia' orange was late January - early March, and mid-April - early June respectively to avoid postharvest problems that may be related to the level of peel maturity.
Alam-Eldein, S., Albrigo, G., Rouseff, R. and Tubeileh, A. (2017). Characterization of citrus peel maturation: multivariate and multiple regression analyses. Acta Hortic. 1160, 349-356
DOI: 10.17660/ActaHortic.2017.1160.50
citrus, maturity, senescence, harvest date, bloom date, principal component analysis, stepwise regression

Acta Horticulturae