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United States Department of Agriculture

Agricultural Research Service


item Widmer, Wilbur
item Barros, S
item Smith, J

Submitted to: Subtropical Technology Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 9/16/2003
Publication Date: 10/16/2003
Citation: Widmer, W.W., Barros, S.M., Smith, J. 2003. Effects of processing parameters on furanocoumarin content in grapefruit juice. Subtropical Technology Conference Proceedings. 54:39.

Interpretive Summary:

Technical Abstract: There has been considerable concern in the citrus industry over the last several years over the reported interaction between grapefruit juice and several prescription drugs. The interaction between grapefruit juice and affected drugs varies with the extent a drug is metabolized by CYP3A4 intestinal enzyme. The amount of grapefruit juice that must be ingested to completely inhibit intestinal CYP3A4 has also been reported to vary. The most compelling evidence to date indicates that furanocoumarins and furanocoumarin dimer compounds present in grapefruit juice are responsible for all or most of the interaction. Field run grapefruit were obtained from a local packing house in early February and early June. They were washed, sized and processed with using soft, medium and hard squeeze extractor settings. Product from each extractor setting was then finished with both soft (30 psi) and hard (55 psi) pressure settings on the finisher. After finishing a portion of juice was frozen raw and another portion was pasteurized. After samples were obtained, the remaining juices were pooled, a composite sample taken and the remainder concentrated using the TASTE evaporator. While there were differences in the content of individual furanocoumarins between the different processing parameters, they were not enough to explain the large differences found in commercial grapefruit juice products.

Last Modified: 08/22/2017
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