EFFECTS OF PROCESSING ON PIGMENTS OF CERTAIN SELECTED VEGETABLES

The effects of thermal processing and the pH of the cooking media were investigated on pigments of beet roots, carrots, fenugreek and tomato es. The pH had a substantial effect on betanins and chlorophyll and ma rginal effects on beta carotene and lycopene. Heat treatments affected some of the pigments, bur between methods of heat treatment, i.e., pr essure cooking or steam cooking, variations were not generally encount ered. Batch-to-batch variations were observed in certain pigments, whi ch may be due to the level of maturity of the vegetable varieties and production variables. Sensory analysis of samples revealed a large var iation in responses of panelists. There was a close correlation betwee n instrumentally measured and visually analyzed color parameters, the largest effect was due to the cooking media treatment.