Caratterizzazione biochimica di nuove cultivar di carciofo propagate per seme

The vegetative propagation of artichoke (Cynara cardunculus L. var. scolymus (L.) Fiori) is often cause of physiological and pathological diseases of this crop. To overcome these problems new seed grown cultivars, open pollinated or hybrids, are recently introduced. Among biochemical constituents of artichoke, polyphenols (mono- and di-caffeoylquinic acids and flavonoids), sugars and inulin have an important role both from nutritional and technological point of view. The presence of these biochemical constituents could affect the qualitative performance of artichoke heads in order to their different utilisation. In particular, polyphenolic compounds, specially in presence of high iron concentration, can contribute to the browning of fresh tissues with both enzymatic and chemical mechanisms. Moreover, the presence of high content of the fructan inulin, that confers some nutritional properties to the fresh product, could affect the suitability for processing because of the production of white precipitates during the storage of hearts preserved in oil. Fifteen hybrid artichoke cultivars propagated by seed were transplanted in July and field grown; GA3 at 5 ppm was applied three times to the foliage, starting 60 days after planting. Secondary buds with a weight of 125±5 g, harvested on March-April, were analysed. On the edible part of the buds, the content of chlorogenic acid, dicaffeoylquinic acids, an apigenin-glycoside, glucose, fructose, sucrose and inulin were determined. Chlorogenic acid and dicaffeoylquinic acid content ranged from 220 to 750 and from 250 to 830 mg 100g-1 f.w.. The average apigenin-glycoside content was about 20 mg 100g-1 f.w. The sugar content (sum of glucose, fructose and sucrose) was found to range from 0,82 to 1,25 g 100g-1 f. w. Inulin content was found to range from 0,79 to 4,50 g 100g-1 f.w. and more than the 50% of cultivars showed an inulin content greater than 3% f.w. The different artichoke cultivars considered in this research showed no qualitative differences as regards the biochemical parameters taken into account; whereas, the presence of a large variability in the content of some important biochemical constituents was pointed out. These findings could contribute to define the suitability of these cultivars for the fresh market and/or for the processing food industry. Because of their relatively low polyphenol content and, in some cases, also very low inulin content, some of them could have high suitability for processing. Such biochemical features could contribute to avoid browning phenomena during processing steps and white precipitates during the storage of hearts preserved in oil. Moreover, cultivars with high inulin content could be well appreciated for fresh consumption, since their nutritional value deriving from the dietetic role of this fructan.