Abstract

CORZO, Otoniel; BRACHO, Nelson  and  MILLAN, Rosa. Color changes on sardine sheets during osmotic dehydration. Rev. Cient. (Maracaibo) [online]. 2008, vol.18, n.4, pp.424-430. ISSN 0798-2259.

The changes on the color parameters (L, a, b, DE, whiteness index) of sardine sheets during osmotic dehydration were analyzed at different temperatures and brine concentrations. Sardines (Sardinella aurita) were cut into sheets (20.1x15.0x6.4 mm³), color was measured and 175 groups with 4 sheets in each were formed. Seven groups were introduced simultaneously in an osmotic solution of a desired concentration and temperature for carry out osmotic dehydration, one group was removed at 20; 40; 60; 90; 120; 180 and 240 min, and color of sheets was determined. This procedure was performed for each test condition according to a 5x5 factorial design where the temperature and concentration were 30; 32; 34; 36 and 38°C, 0.15, 0.18, 0.21, 0.24, and 0.27 g NaCl/g brine, respectively. Initial values for L (36.48 ± 0.77), a (6.47 ± 0.64), b (8.74 ± 0.49), DE (0) and WI (37.42 ± 0.69) were obtained. Final values ranged for L from 40 to 47, for a from 4.2 to 2.6, for b from 7.5 to 5.7, for WI from 39.5 to 45.0 and for DE from 5.3 to 10.4 according to dehydration conditions. Values for a and b decreased (P<0.05) with increasing both dehydration time and temperature while those for L, DE and WI index increased (P < 0.05). The decreases in a and b values were lesser with increasing temperature while increases in L, DE and WI values were higher. Models for prediction of color changes as functions of the conditions of osmotic dehydration were obtained.

Keywords : Color; sardine sheets; osmotic dehydration.