Influence of processing steps and fruit maturity on volatile concentrations in juices from clementine, mandarin, and their hybrids
Résumé
During growth, ripening, and post-harvest, the quality of fruits can be modified by various stresses. Ample maturation allows prolonged storage and increases the quality of citrus fruits. The eight major volatile compounds in fresh juices from mandarin (Citrus reticulata Blanco var. Willow Leaf), clementine (Citrus reticulata 9 Citrus sinensis var. Commune), and their six cross-pollinated hybrids were quantified by gas chromatography. Mandarin juice contained the highest volatile concentration (2177.6 ± 110.6 mg L-1), whereas the total aromatic compounds of the hybrid and clementine juices were lower (1060.6 ± 81.6-1724.2 ± 138.5 mg L-1 and 864.8 ± 67.8 mg L-1, respectively). Limonene was the major compound (667.3 ± 53.7-1259.9 ± 98.4 mg L-1) in all juices. We observed significant differences according to the process of juice extraction used (with and without peel). The relative volatile concentration was higher when the juice was extracted with peel, and the juicing process induced differences in the relative volatile concentrations of between 20 and 40%. The levels of volatile compounds in the juice changed according to the degree of fruit maturity. The concentrations of the eight major juice components increased during ripening and until the commercial maturity stage when the juice was obtained from peeled fruits, whereas their concentrations increased until the post-maturation stage when the juices were produced from whole fruits. These two factors determined the contributions of these compounds to the characteristic aromas of Citrus juices