The maturity of avocados—a general review

Abstract

AbstractAvocado maturity is reviewed from a broad perspective. Firstly the terminology related to avocado maturity is discussed, including development, maturation and maturity, ripening, senescence and quality. The distinctions between maturation, maturity and ripening are emphasised. Maturity is taken to mean acceptability of fruit for consumers rather than for processing. Secondly the effects of the properties of avocado trees and fruits on the determination of maturity are outlined. The subjects include origin, distribution and importance of avocados, anatomy, oil content, lipids and other constituents, flowering, seeding, growth, ripening and respiration. Especially relevant to maturity are the lack of external changes in avocados on maturing; the fact that fruits only ripen after picking because the attached fruit is in a juvenile state resulting from the avocado's growth by cell division and cell enlargement; the prolonged flowering causes wide variability in age between fruits. Thirdly the main methods of assessing maturity are considered. Subjects discussed are oil content and properties, dry matter content, sugar content, destructive physical tests and non‐destructive physical tests, especially picking date. Relevant changes in oil, water and sugars during ripening are also considered. Oil content and picking date have been the indices most studied and they seem well related to sensory tests. Other possible indices are dry matter content, iodine number of oil and cuticular wax concentration. Regulatory consequences are considered, especially for the legal minimum oil content in California, the oil contents for different varieties in Queensland and Israel and the comprehensive picking date system for specified weight fruits used in Florida.