Delaying petal blackening of cut sacred lotus flowers by packaging conditions during storage

The demand for cut flowers of sacred lotus (Nelumbo nucifera Gaertn.), is progressively increasing both in the local and export markets. However, flower marketability is limited mainly due to the rapid blackening of the outer petals after harvest, resulting in a very short vase life of only 2-3 days. The objective of this study was to develop optimal packaging conditions during transport for sacred lotus flowers. Cut lotus flowers were packed in the following conditions: no bags (paper wrap), perforated bags and modified atmosphere packaging (MAP) - sealed bags in which MA was created. All bags were of 30 µ thickness. The packed flowers were stored at 13°C for two days and subsequently transferred to 25°C for additional 4-8 days (market simulation). The results showed that during the storage period under MAP, CO₂ and ethylene accumulated to high levels, while O₂ levels decreased. These treatments reduced the petal blackening after 3-day storage, compared to control bags. However, MAP at 13°C for two days delayed petal blackening by only one day compared to the other packaging treatments. Therefore, we further studied the effect of MAP with bags varying in their thickness (30 and 50 µ) during storage at 25°C. The results show that in the thick MAP bags, the gas levels ranged between 6 and 10% CO₂ and 8-32 µL L^‑1 ethylene, while O₂ continuously decreased up to 5% throughout the storage period. Consequently, the petal blackening was delayed for 10 days, while in the other bags it was delayed for only six days. It seems, therefore, that packaging cut lotus flowers under MAP in sealed 50 µ-thick bags was the best method for delaying their petal blackening. This suggests a protective role for high CO₂ and low O₂ in preventing petal blackening.