14B-35

A. L. S. C. LEMOS, Centro de Tecnologia de Carnes, Instituto de Tecnologia de Alimentos, Av. Brasil, 2880, Jardim Chapadão, Campinas - SP, 13073-001, Brazil, O. Rusig, Dept. de Tecnologia de Alimentos, FEA/UNICAMP, Campinas - SP, 13083-970, Brazil, and A. A. Vitali, Centro de Tecnologia de Hortifrutícolas, Instituto de Tecnologia de Alimentos, Brazil.

Most of the work in the literature refers to understanding the stability of specific paprika carotenoids in different model systems. However, little research has been reported about the stability of paprika oleoresin, which has been widely used as a colorant in food products.

The objective of this study was to determine what effects the presence or absence of light and oxygen have on the kinetics of the decoloring reaction of paprika oleoresin in an aqueous medium.

Oleoresins were extracted by percolation with hexane and hexane/acetone/alcohol ispropyl(3:2:1), at ambient temperature, paprika/solvent ratio 1:4. The extracts were cleaned up with a 10% NaCl solution. Aqueous solutions of paprika oleoresins emulsified with Tween-80 were used for the study. The percentage of color retention was related to time in days by the different mathematical fits in accordance with a possible zero-order or first-order kinetics.The results were compared to those obtained with a commercial paprika oleoresin under the same conditions.

Light showed a strong degradative effect on the colour retention of all oleoresins studied and a zero-order kinetics was observed in the presence or absence of air. The oleoresin extracted with hexane/acetone/isopropyl alcohol (3:2:1) was the least stable, especially in the presence of air.In darkness and in the presence of air, an induction period became evident for all oleoresins and the oleoresin extracted with hexane/acetone/ isopropyl alcohol (3:2:1) showed a color degradation rate constant 1,8 times higher than the others. Overall, the commercial oleoresin was shown to be the most stable of all the samples tested, problably due to the addition of antioxidant. A first order kinetics was observed in the absence of light for all oleoresins.

The stability of paprika oleoresin was shown to be strongly dependent on light and on the type of solvent used for its extraction.