Zhou, P.G., Cox, J.A., Roberts, D.D. and Acree, T.E. 1993.
b-Damascenone Precursors in apples.
In Progress in Flavour Precursor Studies: Analysis-Generation-Biotechnology. P. Schreier and P. Winterhalter (Ed.), 261-273. Allured Publishing Corporation, Carol Stream, Illinois.
Beta damascenone contributed 32% of the total aroma potency of heated apple juice, and only 1.6% of the total aroma of fresh apple juice as determined by gas chromatography-olfactometry (GCO). Thus, the majority of the beta damascenone in heated apple juice was generated from precursors. During three months of the 1989 growing season, beta damascenone precursors in Empire apples increased initially, then changed very little and finally increased during the last month. Mutsu apples had the highest activity, followed by Northern Spy, Empire and Cortland.
A purification scheme was developed to isolate beta damascenone precursors from Empire apples using Amberlite XAD-2 eluted with ethyl acetate and methanol. These fractions were further purified by C-18 reversed phase HPLC with a linear gradient mobile phases that varied from 10% to 100% methanol in water in 35 min. After rechromatography, at least 7 beta-damascenone precursors were separated from Empire apples. All of the precursors are more polar than beta-damascenone. 70% recovery of total precursor activity was obtained.