Investigating the Potential of the Sulfur Dioxide (SO₂) Pad for Decay Control of Brown and Yellow Color Figs

 

 

Carlos H. Crisosto, David Garner, Vanessa Bremer, Ed Stover, and Louise Ferguson

Objective

Evaluate decay incidence and phytotoxicity of the use of SO₂ pad on dark and yellow color figs.

Materials and Methods

'Brown Turkey' (dark skinned) and 'Kadota' (yellow skinned) figs were used to determine the effect of a sulfur dioxide-generating sheet (SO₂ pad) on the quality and decay of fresh figs during cold storage at 32°F for 33 and 24 days, respectively.  All of the fruit were placed in trays inside microperforated box liners (Xpedex, Fresno, CA, USA) in corrugated metric size boxes stored at 32°F.  Half of the boxes had no SO₂ pad (control) and half had a UVASYS SO₂ pad (Grapetek (Pty) Ltd., Epping, South Africa) placed inside the box liner directly on top of the tray of fruit.  For 'Brown Turkey', 6 boxes of 25 fruit per treatment were prepared (total 300 fruit) and for 'Kadota', 3 boxes of 48 fruit per treatment were prepared (total 288 fruit).

Fruit quality was evaluated after 15 and 33 days storage at 32°F for 'Brown Turkey', and 13 and 24 days for 'Kadota'.  SO₂ pads were removed and control and treated figs were stored at 68°F for shelf life evaluation, for up to 4 days after cold storage for both cultivars.  Fruit quality parameters evaluated included percent of sound fruit (commercial fruit), percent of fruit with decay, percent of fruit with off color (color not typical for the cultivar), percent of fruit with growth cracks, percent of fruit with splits, and percent of fruit with other blemishes.

Conclusions

·       Firmness was not affected by SO₂ pad treatment in 'Brown Turkey' nor 'Kadota' (Table 1, 2, & 4).

·       The treatment with SO₂ pad produced higher percent of sound fruit after cold storage at 32°F (Table 2 & 4).

·       In 'Brown Turkey', the SO₂ pad in reduced the percent of decay during the first 2 days of shelf life after cold storage and increased the percent of sound fruit after the first day of shelf life after cold storage (Table 1).

·    In 'Kadota', the SO₂ pad reduced the percent of off color figs during the first 2 days of shelf life after cold storage (Table 3).