The 2012 ASHS Annual Conference

The impacts of the production system (organic or conventional) and post-harvest handling practices (storage duration and temperature) on bioactive compounds in grapefruit (Citrus paradisi Macf; variety Rio Red) were investigated. Grapefruits were harvested in November, 2008, and stored at 23 °C (room temperature) and 9 ºC for four weeks. Stored fruits were analyzed for carotenoids, limonoids and fruit quality attributes such as TSS and total acidity (TA) at 0, 7, 14, 21, and 28 days after storage. Grapefruits grown under a conventional production system had more than double the amount (26.26 µg/g) of lycopene compared to organic grapefruits (12.83 µg/g) at 0 days after harvest. The antioxidant levels of organic  and conventional grapefruit were also not significantly different except second week after harvest. The organic grapefruits had 77 % higher (P ≤ 0.05) nomilin than conventional grapefruits, but limonin was not significantly different in both production systems at the time of harvest. The sensory evaluation results were consistent with TSS and TA levels in the organic and conventional grapefruits. The overall appearance of organic and conventional grapefruits was not significantly different (P ≤ 0.05), except for fruit interior color, which is brighter in conventional grapefruit. Overall, the grapefruits stored at room temperature and 9 ºC had severely degraded both carotenoids and limonoids. Additionally, the production system had a differential effect on carotenoids and limonoids.