Grapefruit gland oil composition is affected by wax application, storage temperature, and storage time

The effect of wax application, storage temperature (4 or 21 degrees C), and storage time (14 or 28 days after wax application) on grapefruit gland oil composition was examined by capillary gas chromatography. Wax application decreases nonanal and nootkatone levels. beta-Pinene, alpha-phellandrene, 3 -carene, ocimene, octanol, trans-linalool oxide, and cis-p-mentha-2,8-dien- 1-ol levels increase, but limonene levels decrease, with temperature. Level s of alpha-pinene, limonene, linalool, citronellal, alpha-terpineol, neral, dodecanal, and alpha-humulene decrease with time. Levels of alpha-phelland rene, 3-carene, ocimene, and trans-linalool oxide increase with time. No co mpound level was affected by the interactive action of temperature and wax application, suggesting that these two factors cause grapefruit oil gland c ollapse (postharvest pitting) through means other than changing gland oil c omposition. Compounds that are toxic to the Caribbean fruit fly (alpha-pine ne, limonene, alpha-terpineol, and some aldehydes) decrease with time, thus suggesting grapefruit becomes increasingly susceptible to the fly during s torage.