Influence of Production Practices and Storage On Grapefruit Vitamin C and Flavanones

Increased consumer awareness of the potential health benefits of foods produced with minimal chemical use is partly responsible for increased organic production. Studies related to the impact of the production system (organic or conventional) and storage on Rio Red grapefruit (Citrus paradisi Macf) bioactives are limited. Grapefruits were harvested in October 2008 from organic and conventional orchards and packed in a commercial packing shed in Mission, Texas. Furthermore, grapefruits were stored at room temperature and 9 ºC for five weeks and analyzed for vitamin C (ascorbic acid and dehydroascorbic acid) and flavanones each week. Later, the grapefruits were subjected to sensory evaluation. Significantly higher levels of vitamin C were found in organically grown grapefruits compared to conventional grapefruits. No significant losses in vitamin C were found during the five week storage. Among the flavonoids analyzed, narirutin concentrations were 41 % higher in organically-grown fruits compared to conventional fruits, whereas, the levels of poncirin were 10.5 % higher in conventional grapefruits. Naringin (928.41µg/g), neohesperidin (30.89µg/g) and didymin (75.85µg/g) levels present in organic grapefruits were not significantly different compared to conventional grapefruits. These results suggested that the production system and storage have an influence on grapefruit bioactives with no significant effect on fruit taste and flavor.