The effect of SO2 treatment on the overall quality of longan fruit (‘Shixia’) during cold
storage (4o
C) was investigated. The results indicated that the content of anthocyanin in
longan pericarp decreased and the fruit colour was improved after SO2 treatment. No obvious
effect on fruit TSS and Vitamin C in the pulp was observed while the titratable acid
content was increased. Most of the SO2 residue was located in the pericarp. Appropriate
SO2 treatment lowered the SO2 residue level in the pulp to as low as 10µg/g . The eating
quality was maintained during the early stage of storage and the shelf life was extended as
compared with the control fruit. Fruit taste worsened and the shelf life shortened as the
storage prolonged. SO2 treatment caused the pulp to partially redden during the later stage
of storage.