Pg. 15-17 Maintaining market quality of fresh litchis during storage Part I: Control of browning

The effects of polyethylened packaging, S0₂, Prochloraz and Benomyl treatments at different storage temperatures on browning of litchi fruit were investigated in a simulated export trial. In cv Mauritius and Madras, the commercial SO₂ fumigation gave acceptable control of browning.
In cv Madras, polyethylene packaging only reduced browning in combination with Prochloraz or Benomyl treatments and there was a tendency towards more browning in fruit stored at 6°C as compared to fruit stored at 2°c.

Summary:

• The study investigates effects of polyethylene packaging, SO₂ fumigation, and fungicides (Prochloraz, Benomyl) at different storage temperatures on browning and quality of litchi cultivars Mauritius and Madras in simulated export conditions.
• SO₂ fumigation was effective in controlling browning in both cultivars; untreated fruit showed complete browning after storage.
• Polyethylene packaging reduced browning notably in Madras litchis, especially when combined with Prochloraz or Benomyl treatments.
• Storage temperature influenced browning; fruit stored at 6°C showed more browning than at 2°C.
• Relative humidity inside packaging reduced water loss and browning, but excessive humidity increased decay risk, indicating a need for balance.
• SO₂-treated fruit remained pale initially and developed a sulfur taste, a notable drawback.
• Weight loss was significant in untreated fruit but reduced by polyethylene packaging and fungicidal treatments.
• Total soluble solids (TSS) generally increased during cold storage, contrary to some previous reports, while acidity decreased across treatments.
• Semperfresh coating did not prevent browning or moisture loss in litchis.
• Browning results from moisture loss causing enzymatic oxidation of anthocyanins in the skin; maintaining humidity reduces this effect.
• Litchis are non-climacteric and do not ripen post-harvest, requiring careful harvest timing for optimal storage quality.
• The study highlights the need to minimize chemical treatments for food safety while balancing browning control, decay, and weight loss during storage for export purposes.