Advanced maturity at harvest enhances oxidative stress of 'Blanquilla' pears during cold storage
Jordi Giné, Ma Angeles Chiriboga, Christian Larrigaudière, Inmaculada Recasens
Abstracts of 7th International Postharvest Symposium 2012 (IPS2012). 25-29 June, 2012. Putra World Trade Centre (PWTC), Kuala Lumpur, Malaysia. 238 pages.
2012
บทคัดย่อ
Changes in antioxidant metabolism of fruits are common features in response to cHanging environmental conditions including low-temperature stress. In the present study, 'Blanquilla' pears were harvested at three different maturities within their commercial window (optimum harvest date (OHD), OHD -14 days and OHD +7 days) and stored at regular cold temperature (0.5°C) for four months. Changes in fruit quality, H2O2 levels, antioxidants and key enzymes involved in oxidative metabolism (viz. CAT, APX and POX) were monitored at regular time intervals during cold storage and shelf-life. In comparison to fruits harvested at earlier stages, more mature fruits had lower H2O2 levels during storage resulting from greater APX activities (3-fold). In consequence, late harvested fruit also exhibited lower levels of ascorbate (AsA) and higher levels of dehydroascorbate (ca.1.5-fold). Similarly to AsA concentrations, the antioxidant capacity oflate harvested fruits, as determined by different in vitro assays, tended to be lower throughout storage. In contrast, no clear patterns were found for CAT and POX between fruits from different maturities. Collectively, these results showed that an advanced maturity at harvest enhances the oxidative processes during cold storage, mainly H2O2 scavenging via electron transfer from AsA to APX. Resulting decrease in endogenous antioxidant capacity may be associated to reduced storage potential and higher sensitivity to physiological disorders.