Ethanol production and chlorophyll fluorescence in heat stressed apple fruit during storage.
Fan L., Song J., Forney C., Jordan M.A.
5th International Postharvest Symposium . Volume of Abstract . Verona, Italy 6-11 June 2004, p 43.
2004
บทคัดย่อ
Ethanol production and chlorophyll fluorescence in heat stressed apple fruit during storage.
Ethanol concentration and chlorophyll fluorescence were measured as signs of heat stress in apple fruit [Malus sylvestris (L.) Mill. var. domestica (Borkh.) Mansf.].‘Mclntosh’, ‘Cortland’, ’Cortland’, ‘Jonagold’, and ‘Northern Spy’ apples were held at 46 °C for 0, 4, 8, or 12 h.Following treatments, fruit were stored at 0 °C and evaluated after 0, 1, 2 or 3 months.Ethanol and ethylene production, chlorophyll fluorescence, skin color, soluble solids, titratable acidity, peel and flesh browning, and firmness were measured.Increases in ethanol were apparent following 12 h heat treatments and reflected the degree of heat-induced fruit injury.After 2-3 months of storage, ethanol concentration peaked and were as much as 111-fold greater than that of controls.Heat treatments also reduced ethylene production and chlorophyll fluorescence.After 3 month storage, chlorophyll fluorescence (Fv/Fm) was about 0.2 in fruit held at 46 °C for 12 h compared with 0.5-0.6 for control fruit.Exposure to 46 °C for 12 h also caused severe flesh browning in all cultivars.Severity of flesh browning increased with increasing heat treatment time and storage time.‘Northern Spy’ apple fruit were most susceptible to heat stress based on the degree of flesh browning.
The increase in ethanol production and decrease in chlorophyll fluorescence correlated with heat-induced injury, and may be used to predict the severity of injury that develops during storage.