Pg. 84-86 Effect of packaging on fruit quality retention of litchi cv. McLean’s Red during long term low temperature storage

Sulphur dioxide (SO₂) fumigation is a commonly adopted commercial treatment to retain the post-harvest quality of litchi (Litchi chinensis Sonn). The present investigations aim to overcome the undesirable after-effect of (SO₂) fumigation during long-term storage and distribution. The fruit of litchi cv. McLean’s Red, harvested during the late season, were packed in three types of packaging: (1) MAP-3, (2) punnets without vents and (3) punnets with vents. The MAP-3 was heat sealed to modify the atmosphere around the fruits. The packed fruits were placed in commercial cardboard cartons and held at 2°C, 95% RH for 30 days to simulate refrigerated sea shipment conditions and thereafter, at market shelf condition at 14°C for 2 days. Standard commercial SO₂ fumigation was included as a comparative control. Weight loss, firmness, pericarp browning, severity of decay, Hunter colour values, titratable acidity and soluble solid concentrations were determined after cold storage followed by simulated market shelf condition. The modified atmosphere created inside the MAP-3 and the high RH around the fruit minimised the rate of transpiration, preventing weight loss and deterioration of fruit quality. However, the MAP-3 has to be improved further, as a flow-warp consumer packaging to satisfy the requirements of the EU customers.

Summary:

• Sulphur dioxide (SO₂) fumigation is commonly used to preserve litchi quality post-harvest but has undesirable effects such as residue, altered taste, and health hazards.
• The study evaluated three packaging types for litchi fruit: MAP-3 (modified atmosphere packaging with heat sealing), punnets with vents, and punnets without vents.
• Fruits were stored at 2°C and 95% relative humidity for 30 days followed by 2 days at 14°C to simulate refrigerated sea shipment and market shelf conditions.
• MAP-3 packaging created a modified atmosphere that minimized weight loss, reduced pericarp browning, and controlled post-harvest decay better than other packaging or SO₂ treatment.
• Punnets without vents showed the highest post-harvest decay and weight loss, while punnets with vents had higher browning indices.
• MAP-3 maintained higher humidity and an oxygen level of about 17%, which inhibits enzymatic browning and microbial growth.
• SO₂-fumigated litchis showed lower fruit firmness and undesirable color changes.
• MAP-3 packaging helped retain fruit firmness, titratable acidity, and soluble solids closer to freshly harvested fruit levels.
• The type of packaging significantly influenced head-space gas composition, weight loss, firmness, color quality, and decay incidence.
• The study concluded that MAP-3 packaging is an economical and effective method to preserve the quality of litchi fruit during long-term cold storage and simulated market conditions, outperforming SO2 fumigation and conventional punnets.
• Temperature control near 14°C remains critical to maintaining fruit quality during marketing and retail.