Pg. 22-24 Die effek van SO₂ – behandeling op na-oesbederfontwikkeling by lietjies

Alhoewel ‘n groot gedeelte van die Suid-Afrikaanse lietsjieoes voordelig plaaslik bemark kan word, is uitvoere die uiteindelike mikpuntvan die meeste produsente. Uitstekende pryse wat oorsee behaal is, het luguitvoere ‘n geriume tyd geregverdig, maar namate die uitvoervplumes groei, is produsente al hoe m·eer op verskeping aangewese. Die lietsjie is egter ‘n hoogs bederfbare produk – veral onder vogtige toestande soos tydens verskeping ondervind word – en tot 100 persent van ‘n besending kan maklik onbemarkbaar wees na aankoms, as gevolg van na-oesbederf. Hierdie ondersoek is gevolglik onderneem om maniere te vind waarvolgens na-oesbederf beheer kan word, tydens en na verskeping na die buiteland.

Summary:

• The study investigated the effect of sulphur dioxide (SO₂) treatments on postharvest decay development in two litchi cultivars: Mauritius and Madras.
• The fruit were stored to simulate overseas shipment conditions at two different temperatures (2°C and 6-8°C) using various plastic packaging materials in standard cartons.
• Ordinary SO₂ fumigation followed by packing in a moisture-permeable plastic bag and storage at 2°C gave excellent control of decay.
• Storage at a slightly higher temperature (6-8°C) resulted in increased decay development.
• SO₂ sheets (used for grapes) were ineffective and gave poor results.
• The cultivar Madras showed poor storage life overall compared to Mauritius.
• SO₂ fumigation prevented browning and splitting of litchi skins and had antifungal properties.
• Packing in moisture-permeable plastic bags (Everfresh) was better than non-permeable (household-type) bags, which caused condensation and poor appearance.
• Treatments with fungicides like prochloraz after SO₂ fumigation, combined with appropriate packaging and storage at 2°C, yielded the best retention of fruit quality for over a month.
• The Madras cultivar responded poorly to these treatments, showing more decay and faster deterioration, especially at temperatures above 2°C.
• Alternative SO₂ application methods using SO₂ sheets resulted in uneven treatment and were not recommended.
• The study confirms that shipping temperature recommendations for litchis should remain at about 2°C to minimize decay without causing cold damage.
• Overall, combining SO₂ fumigation, fungicide treatment, vapor-permeable packaging, and low temperature storage is the best approach to control postharvest decay in litchis for export.
• The research highlights the importance of starting with high-quality fruit and careful selection before postharvest treatment and shipment.