In the early stages of the Florida citrus industry, Hood reported wide variation in quantity of rind oil in several Florida citrus cultivars. DeVillers later reported that the navel oranges in South Africa contained less oil that Valencia oranges. Feliu, working with Spanish sour oranges, found that oil content decreased progressively during the growing season in relation to both fruit weight and surface area. Bartholomew and Sinclair expanded these finding by reporting that microenvironment and climate influenced peel oil content and that the stylar end of the fruit contained more oil than the stem end. Also, oil yield was related to fruit size on a weight basis and small fruit contained more oil than large fruit due to an increased surface area of small fruit.
Kesterson and coworkers differentiated citrus species and varieties by gas liquid chromatography of leaf oils. Seora and Bitters showed that rind oil varied widely with the position of the fruit on the tree and fruit maturity. Hendrickson and coworkers indicated that the quantity of peel oil in Florida Valencia oranges increased per given unit of surface area as well as per unit of fresh weight as the fruit matured. Also, the larger the fruit the greater the quantity of peel oil per unit of peel area.