Over 20 sulfur containing peaks were observed. At least three peaks had aroma activity. Thermal processing and storage appreciably impacted the number and amounts of volatile sulfur containing compounds in grapefruit juice. FL 33850 Coumarins are secondary metabolites which have significant biological and physiological activity. Limes, lemons and sour oranges contain the greatest concentrations of these compounds.
Most studies are of peel oil.
To evaluate the coumarins in grapefruit juice and cold pressed peel oil, both normal and reverse phase HPLC procedures were developed. Coumarins in juice were isolated and concentrated using a C-18 solid phase microextraction sample preparation technique using tetrahydrofuran, to elute coumarins from the extraction column. This procedure worked well for grapefruit juices. The normal phase procedure was developed to allow the convenient recovery of the individual coumarins for flavor evaluation and instrumental analysis. Analysis time is 37 min.