HIGH-FIELD PROTON NMR-STUDIES OF APPLE SLICES

High-field (11.7 and 14 T) proton high-resolution NMR spectra of apple juices obtained fi om a variety of cultivars are reported and partial spectral assignments are made, There are significant spectral differe nces between cultivars, which mag be of value in identifying the origi ns of apple juices, The results also indicate that the method is likel y to be of value in the authentication of fruit juices. Careful spectr al analysis shows that same differences arise simply as a result of th e differences in the pH of the juices and that microbiological and oxi dative effects must be taken into account, Care must therefore be exer cised in the application of multivariate methods to the data as spurio us or trivial correlations may be obtained, It-is concluded that the r ichness of the spectra;and the ease wish which they may be obtained in dicate that high-field proton NMR will prove valuable not only in spec iation and authentication studies, hut also ist the analysis of bioche mical changes occurring in fruits and their juices. (C) 1997 John Wile y & Sons, Ltd.