INVESTIGATION OF COLOR CHANGES OF SOME TOMATO PRODUCTS DURING FROZEN STORAGE

The colour changes of frozen tomato pulp were investigated under diffe rent conditions of frozen storage (-25 degrees C; in open bags with pr esence of O-2 and in artificial light or darkness; in closed bags also in artificial light or darkness). In addition the antioxidative effec t of tomato seeds and spices (sage, thyme, rosemary, oregano, majoram) was studied. The colour change of tomato pulp was determined with ins trumental colour measurement, the carotenoid pigments loss was measure d with UV/VIS spectrophotometry. It was found that exposure to light a nd oxygen accelerated the colour loss and oppositely packaging and sto rage in darkness had a colour saving effect. The ground tomato seeds ( 5%) could stabilize the carotenoid pigments after longer time frozen s torage (min. 10 weeks). The commercial spices (0.2%), mainly rosemary and marjoram significantly reduced the pigment degradation. The tomato seeds and the spices did not change significantly the taste of tomato pulp.