Effects of harvesting time and cultivars on yield and quality of stem chicory for frozen and 'ready to use' products.

Chicory (Cichorium intybus L.) includes large types of plants, different for morphological traits and for the edible portion. Stem chicory (SC) is mainly cultivated in southern Italy for its tender stems and leaves, both eaten raw or cooked. This research provides information on the effect of different cultural practices on yield, quality and the suitability to prepare frozen and 'ready to use products' (RTUP). Seedlings of three cultivars, 'Galatina', 'Otrantina' and 'Brindisina', were transplanted each year in September and harvested 90-100-110-120-135 and 150 days after planting. Total yield and biometric traits were determined at each harvest. To prepare RTUP, stems were trimmed and then stored in sealed plastic bags at 4°C for 15 days. For the freezing, stems were blanched in boiling water for 1-2-3 minutes, deep frozen at -40°C and then stored for 3-6-9 months at -20°C. Panel tests were arranged on the frozen and RTUP during the storage period to evaluate organoleptic attributes; the results were graphically represented by sensorial profiles; in addition colour measurements were taken on fresh and frozen stems. The cv. Otrantina and 'Galatina' produced higher yields than 'Brindisina'. Stems from first and second harvests, blanched for 2 minutes and stored for 3 months, were more appreciated for their organoleptic attributes, whereas fibre content was higher in the stems for the two latest harvests. After 3 months storage, browning was observed on frozen stems blanched for 1 minute. Quality of RTUP products declined after 9 days storage.