
%0 Journal Article
%A Whitfield, FB 
%A Sugowdz, G 
%T The 6-(but-2'-enylidene)-1,5,5-trimethylcyclohex-1-enes: Important volatile constituents of the juice of the purple passionfruit <I>Passiflora edulis</I>
%J Australian Journal of Chemistry
%D 1979/04/01
%V 32
%N 4
%P 891-903
%K 
%R https://doi.org/10.1071/CH9790891
%U https://www.publish.csiro.au/paper/CH9790891 
%X Two important flavour components of the juice of the purple passionfruit Passflora edulis (Sims) have been shown by g.l.c., mirco-reaction g.l.c., u.v., i.r., N.M.R., mass spectrometry, and by synthesis to be (6E,2'E)- and (6Z,2'E)-6-(but-2'-enylidene)-1,5,5-trimethylcyclohex-1-ene (2a) and (2b). Evidence is also reported for the presence in this juice of trace amounts of the stereoisomers (2c,d). The 6-(but-2'-enylidene)-1,5,5-trimethylcyclohex-1-enes are very susceptible to oxidation and, in dilute acetic acid solution, are rapidly converted into 'ionene', 1,1,6-trimethyl-1,2,3,4-tetrahydro- naphthalene (10). The significance of this reaction in the loss of flavour during pasteurization of passionfruit juice is discussed. 
