CORRELATION BETWEEN SPECTROPHOTOMETRIC AND COLORIMETRIC METHODS FOR DETERMINATION OF PHOTOSENSITIVITY AND THERMOSENSITIVITY OF TOMATO CAROTENOIDS

Abstract

The search for natural pigments for application in foods and the challenge of their industrial production has been motivating researchers to investigate their stability to light, temperature, pH and oxygen. A lycopene mixture, obtained from tomato pulp and mineral oil, was prepared to study the photosensitivity and the thermal sensitivity of the pigment. Spectrophotometric and colorimetric determinations were made during the storage period. Light effect was more destructive than the largest temperature evaluated (80°C), and it was observed an abrupt discoloration in some samples, after 30 days of storage. The pigment was little affected when stored under dark at 40°C. Significant correlations between the reduction of absorbances values and the colorimetric coordinates "a*", "b*" and h were obtained. These colorimetric coordinates explained in a best way the variations happened to the pigment.