BIOSYNTHESIS OF BENZALDEHYDE, BENZYL ALCOHOL AND BENZYL BENZOATE FROM BENZOIC ACID IN CRANBERRY (VACCINIUM MACROCARPON)

The aroma complex of cranberry contains benzaldehyde, benzyl alcohol and benzyl benzoate as major components, and [7-14C] benzoic acid was converted into benzaldehyde, benzyl alcohol, benzyl benzoate, and minor amounts of other benzyl and benzoate esters in tissue slices of ripe cranberry. Hydrolysis of the benzyl benzoate indicated that label was about equally distributed between benzoic acid and benzyl alcohol. [7-14C] benzaldehyde was converted in tissue slices into benzyl alcohol and benzyl benzoate, and hydrolysis of the ester indicated that only the alcohol moiety was labeled. Incubation of cranberry tissue slices with [7-14C] benzyl alcohol yielded primarily benzyl benzoate, and only the alcohol portion of the ester was labeled. All biosynthetic products were identified by radio chromatographic analysis and by preparation of derivatives, and the direct incorporation of precursors into biosynthetic products was demonstrated by chemical degradation studies. These results strongly suggest that, in the biosynthesis of benzyl benzoate, benzoic acid is first reduced to benzaldehyde, followed by reduction of the aldehyde to benzyl alcohol which is subsequently esterified. None of the aforementioned transformations of [14C] benzoic acid and its derivatives could be demonstrated in tissue slices from unripe (green) cranberry, suggesting that development of the ability to synthesize volatile benzenoid compounds is associated with ripening.