1967, Canning Trade, Volume 89, Issue 1 − Volume 90, Issue 26, page 458,A series of taste tests compared natural nootkatone with 2 synthetic nootkatones, one more highly purified than the other.
1973, Chemoreception Abstracts, Volume 1, page 25,Significant differences, both in odor strength and in odor character, have been found between all enantiomeric pairs and are particularly large for the nootkatones.
1999, Joe Schwarcz, Radar, Hula Hoops, and Playful Pigs, unnumbered page,One of the main flavor compounds in grapefruit is nootkatone, which is found in the fruit in very small amounts and is hard to extract.
1972, Walton B. Sinclair, The Grapefruit: Its Composition, Physiology, and Products, page 252,A constituent which corresponded to an unidentified GLC (gas-liquid chromatographic) peak in cold-pressed grapefruit oil was isolated and identified as nootkatone (figure 71).
2010, Milind Ladaniya, Citrus Fruit: Biology, Technology and Evaluation, page 176,The sesquiterpene ketone, nootkatone, which gives the characteristic aroma to grapefruit, has the same skeleton as valencene, the major sesquiterpene of oranges (Macleod, 1965).
