EFFECT OF FREEZING METHODS ON DRIP, OIL ABSORPTION AND CAROTENOID RETENTION IN FROZEN CARROTS

The effect of slow-freezing at -20°C and liquid nitrogen freezing (LNF) at -196°C on drip, oil absorption, and carotenoid retention in frozen carrots was investigated. The loss of fluid on thawing as evaluated by centrifugation was 4 % in the slow-freezing samples, and 1 % in the LNF samples. The difference in drip between the two treatments may be attributed to the change in cell wall structre having the alow-freezing process at -20°C. Slow freezing causes damage to the structure and texture of frozen carrots due to crushing and tearing of the tissues during ice formation. When the frozen carrot slices were thawed at room temperature for one hour and then reach 3 %. Oil fried in salad oil at 160 to 170°C for 30 to 60 seconds, the oil absorption by the carrot tissue may absorption by the carrot slices varied with degree of thawing, time of frying, and the methods of freezing. Frying time influences greatly the quantity of oil absorbed by the carrot tissue. Caroten oid pigments in frozen carrots are quite stable. Freezing temperature does not affect the level of provitamin A in the frozen products. There was a slight decrease in provitamin content in the fried product due to the extraction of the carotenoid pigments by the frying oil. Because of the short time of frying at moderate temperature, the retention of the provitamin A in the product was satisfactory. The fried product has an attractive color, aroma and flavor.