application of extracted tomato carotenoids in heated and unheated foods: study of color stability during storage

carotenoids are the main pigments of tomato, of which 93% is lycopene. lycopene has desirable physiological effects in human sush as cancer prevention. recent years, because of harmful side effects of synthetic colouring agents used in food products, employing of natural food colouring agents has become very important. in this research firstly, solvent extraction method was used for tomato carotenoids extraction. the optimum conditions for solvent extraction method was a mixture of solvent (n-hexan, ethanol and acetone with ratio of 1:1:2), boiling temperature (50 ºc), extraction time of 6 hours and equal ratio of solvent volume to tomato sqwash (crushed tomato after removing of skin and seeds). after extraction of tomato carotenoids, applicability of the extracted colour was considered by using the colour in sausage (13.977, 9.501 and 7.03 gr colour per 100 kg sausage) and ice cream (4.21, 8.42 and 12.63 gr colour per 100 kg ice cream). the best percentage of the added colour to those products were determined by performing of a taste panel. finally, the stability of the colour in the products was examined by storing them at 0-4ºc (for sausages) and -21ºc (for ice cream) and their colour changes were measured by hunterlab colorimetry system. results of sensory evaluation showed that addition of 9.501 gr of extracted colour per 100 kg susages and 8.42 gr of extracted colour per 100 kg ice cream are acceptable for consumers. from viewpoint of colour changes of surface and cross section of susages, there was significant difference between first and second period of storage, but there was no significant difference between third and forth period of storage (p <0.01). there was significant difference in colour changes of ice cream during first five days of storage, but there was no significant difference during second and third five days of storage (p <0.01).