Suitability to freezing of two broccoli raab (Brassica rapa L.) cultivars

The trial was carried out in Bari, in southern Italy. Two cultivars: Locale di Bari and 'Locale di Fasano' were directly seeded in the field in December 1992, with a density-of nearly 67.000 plants ha"', and harvested in March 1993. The heads were blanched in boiling 0,7% citric acid solution for 30-60-90-150 seconds and then frozen. Colour characteristics and the peroxidase activity on blanched heads were assayed. After three months storage, a panel-test was made on frozen product to evaluate appearence, odour, flavour, colour, firmness, fibre, and global value. Total yield was 32 and 39 t ha"*l respectively in 'Locale di Bari' and Locale di Fasano'. Weight, length, width and dry matter of the stem, number and weight of leaves and secondary heads were higher in the cv. Locale di Fasano. The peroxidase activity decreased from 47.3 in the unblanched sample to 4.3 and 1.2 U/g of fresh product respectively in 30 and 60 seconds blanched heads. Unblanched and 30" blanched heads reached 10% higher QDA score compared to average, while the 150" blanched sample had 15% lower value than the average score. Colour, peroxidase activity and organoleptic attributes were not different in both cultivars.