Peach fruit ripening and quality in relation to picking time, and hypoxic and high CO2 short-term postharvest treatments
C. Bonghi, A. Ramina, B. Ruperti, R. Vidrih and P. Tonutti
Postharvest Biology and Technology Vol: 16 Issue: 3 Pages: 213-222.
1999
บทคัดย่อ
Peach fruits (Prunus persica L. Batsch, cv Springcrest) were
harvested at two ripening stages (flesh firmness of 60 N, first harvest, and 45
N, second harvest) and maintained at 20°C in air (control) or for 24
and 48 h in streams of ultra low (<1%) oxygen (ULO) or high (30%) CO2
concentration and then transferred to air for up to 8 days. The decline in
flesh firmness was strongly reduced by ULO and CO2 treatments in
fruits of both harvests, although the effect was stronger in fruits picked
earlier in which ethylene biosynthesis remained at the basal level. In fruits
of the second harvest, endo 
-1,4-glucanase
(EGase) activity was lower in ULO- and CO2-treated fruits than in
control fruits at the end of the 24 h treatment and the following two days in
air. Acetaldehyde (AA) gradually accumulated in control fruit and the highest
concentrations were detected during late ripening. Both treatments induced a
strong accumulation of AA but, with the exception of the 24 and 48 h CO2
treatments performed on fruits of the second harvest, a decrease in AA content
was observed when the fruits were transferred to air. A slight increase in
ethanol (EtOH) was found throughout the ripening process in control fruits; ULO
and CO2 strongly stimulated EtOH production. When fruits were
transferred to air, EtOH concentration declined rapidly. Alcohol dehydrogenase
(ADH) activity significantly increased in control fruit only in the late stages
of ripening. Greater ADH activity was found throughout the experimental period
in fruits of the first harvest treated for 24 h in ULO and CO2,
whereas, at day 8, control and treated fruits of the second harvest showed
similar ADH activity values. Hypoxic and, to a lesser extent, CO2-enriched
atmospheres stimulated Adh gene expression.