- D Sivakumar and L Korsten
- Department of Microbiology and Plant Pathology, University of Pretoria, Pretoria, 0002, South Africa
- 2007
The present investigations aim to replace sulphur dioxide fumigation as a post-harvest treatment to ensure product quality and shelf life. Litchi fruit cv. McLean’s Red harvested during the late season were subjected to 1-MCP fumigation at two different concentrations (moderate and lower) for 3 h, and thereafter held under two different controlled atmosphere conditions (CA-1, 17% 02 + 6% CO2; CA-2, 7% CO2 + 3% O2) separately at 4°C to simulate export conditions. After 21 days cold storage, fruits were packed in MAP (17% 02 + 6% CO2) and stored at 10°C to simulate the supply chain on the European Union side. Fruits fumigated with 1-MCP at moderate concentration-A, held at CA-1 (17% O2 + 6% CO2) controlled fungal decay and retained the natural pinkish red colour of the litchi pericarp. However, 1-MCP at moderate concentration-A with CA-2 (7% CO2 + 3% O2) showed a deep red colour with higher a and b values. Although the higher CO2 (7% CO2 + 3% O2) under CA-2 conditions showed limited yeast decay, the physico-chemical properties, SSC/TA and ascorbic content were slightly affected by this treatment. Therefore, 1-MCP at moderate concentrations has potential for commercial applications during transport under CA. However, the optimized moderate concentrations of 1-MCP must be tested on the extension of post-harvest life of cv. Mauritius as a fumigation agent prior to storage under CA. In order to confirm the commercial application, future trials should be carried out in pack houses from different locations and early vs. late seasonal fruit.
Summary:
- The study investigates 1-Methylcyclopropene (1-MCP) as an alternative to sulphur dioxide fumigation to maintain post-harvest quality and extend shelf life of litchi fruit (cv. McLeans Red).
- Litchis were fumigated with 1-MCP at two concentrations, then stored under two controlled atmosphere (CA) conditions: CA-1 (17% O2, 6% CO2) and CA-2 (7% CO2, 3% O2) at 4°C for 21 days.
- After CA storage, fruits were packed in modified atmosphere packaging (MAP) with 17% O2 and 6% CO2 and stored at 10°C for 9 days to simulate export supply chain conditions.
- 1-MCP treatment at moderate concentration combined with CA-1 preserved the fruit’s natural pinkish-red pericarp color and controlled fungal decay effectively.
- The CA-2 atmosphere with higher CO2 led to a deeper red color but affected physicochemical properties like firmness, sugar/acid ratio, and ascorbic acid content, probably due to yeast decay.
- Fruits treated with lower 1-MCP concentration showed less color retention and more browning compared to moderate concentration.
- Stand-alone CA storage without 1-MCP caused increased browning and fungal decay; SO2 treatment showed color loss and higher decay caused by Penicillium spp.
- Fungal decay at stem ends was controlled by 1-MCP moderate fumigation, showing synergistic effects for decay control during CA storage.
- The study suggests 1-MCP fumigation at optimized moderate concentrations under CA-1 conditions has commercial potential for litchi transport and storage.
- The authors recommend further trials with different litchi cultivars (including Mauritius), seasonal fruit variations, and locations to confirm commercial application.
- Incorporation of biocontrol agents alongside 1-MCP could further improve decay control.