Effect of sulphur dioxide fumigation and low temperature storage on post-harvest browning and quality of litchi fruits

Litchi (Litchi chinensis Sonn.) fruits were treated with SO2 at 50 or 60 g S/100 kg fruits and stored at 4 +/- 1 degrees C and 85 +/- 5% RH and at ambient condition (32 +/- 2 degrees C with 55 +/- 5% RH) after precooling at 10 +/- 1 degrees C for 2 It. Untreated fruits were also stored as control at both the temperature regimes. Changes in total Soluble Solids (TSS). total Sugar, acidify and ascorbic acid were measured during storage. TSS and total sugars in fruit initially increased followed by a decrease till the end of storage. although the pace and extent of change was much slower at low temperature, All these changes corresponded to change in the browning of pericarp. SO2 treatment at both the levels were effective in stabilising (lie degradative changes towards senescence of fruits after harvest. Rapid browning of litchi fruits occurred in untreated fruits at ambient as well as at low storage temperature. Sulphited fruits exhibited negligible browning up to 25th (Jay when at 4 +/- 1 degrees C with 85 +/- 5% RH. These fruits had very little browning on 7th day when kept at ambient condition. The shelf-life of sulphited fruits were of 25 days at 4 +/- 1 degrees C and 4 days at ambient condition. Untreated fruits were acceptable only for 2 days at ambient condition and 6 days at 4 +/- 1 degrees C.