Abstract:

The effects of different harvesting times on postharvest quality, decay rate and chilling injury of Newhall navel
orange (Citrus sinensis Osbeck) during storage at low temperature were studied to determine the optimal harvesting time
for cold storage of navel orange. The contents of otal soluble solids (TSS), total sugar, titratable acid (TA) and vitamin C
(VC), total sugar/TA ratio, ,chilling injury index, weight loss rate and decay rate were determined. At the end of storage, an
increase in total sugar/TA ratio was observed in fruits from all harvesting times, whereas the contents of total sugar, TA and
VC decreased significantly at the same time. The content of TA decreased sharply and chilling injury index was higher in
fruits harvested in late October and early November, 2012. The quality of fruits harvested between late November and early
December was maintained well. Conversely, harvesting time had a clear influence on decay rate with 9.67% of decay in fruits
harvested at mid-December versus 0.67% in fruits harvested in late October. These results indicated that a period between
the mid-November and early December could be the optimal harvesting stage for cold storage of Newhall navel orange.

Key words: harvesting time, Newhall navel orange, cold storage