Pg. 37-40 Alternative treatments to replace sulphur dioxide fumigation

Investigations on developing alternative treatments to replace sulphur dioxide fumigation were carried out during the 2004/05 growing season. This study was confined to the major export cultivar McLean’s Red. Modified Atmosphere Packaging (MAP) was used in combination with hot water treatments to retain the postharvest quality of litchi fruit during long-term storage. Fruit were exposed to 50°C x 2 min, 55°C x 1 min and 60°C x 1 sec regimes; blower dried for 3 min; packed in MAP, heat sealed and stored at 2°C and 95% RH for 40 days. Quality assessment indicated that hot water dips at high temperatures affected the colour retention of the fruit. The light intensity, L, chroma C, colour coordinates a and b showed a decline, while the hue angle H0 showed an increase. Exposure to higher temperatures affected the fruit firmness and higher weight loss was observed. Soluble solids concentration (Brix) was low and titratable acidity was high in fruit exposed to higher temperatures. Although hot water dip treatments combined with MAP minimized the incidence of fungal decay, higher decay incidence was observed at 50°C. It was evident from this study that fruit stored in MAP alone without any hot water dip treatment retained quality the most effectively.