DIFFERENCES OF VOLATILE AND NONVOLATILE CONSTITUENTS BETWEEN MATURE AND RIPE GUAVA (PSIDIUM-GUAJAVA']JAVA LINN) FRUITS

During the ripening of guava (Psidium guajava L.) fruits, the contents of total pectin, total sugars, reducing sugars, and acidity dropped obviously from the mature to the ripe stage, but the Brix-acid ratio increased inversely. Volatile constituents of mature and ripe guava fruits were identified by GC, GC/MS, and GC/FT-IR. A total of 34 components were identified, in which 17 components were further identified by authentic compounds. In quantitative distribution, total amounts of 134 mg/kg of mature fruit and 93 mg/kg of ripe fruit were determined. The major constituents in mature fruit were 1,8-cineole, (E)-2-hexenal, and (E)-3-hexenal. Ethyl hexanoate and (Z)-3-hexenyl acetate were the major volatile components of ripe fruit.