RESUMO
The objective of this study was to evaluate the electrical impedance spectroscopy (EIS) prototype, to select the hams on the basis of meat quality characteristics in commercial conditions. Measurements of meat quality were made on 95 commercial hams (11.10±0.76 kg) to evaluate quality characteristics [ham weight, conformation (H), fat thickness in the rump (FTR), visual fatness (VF), pH(45), electrical conductivity (QM(45)) and ultimate pH (pH(24,) pH(36)) in the semimembranosus muscle]. The electrical parameters, Ro, Rinf, Ratio (Rinf/Ro), Fc and α, were obtained with the EIS equipment and was applied in five different regions of the ham (M, SM, M1, M2 and AD) at 36 h post-mortem. Principal component (PC) analysis has been used to describe the relationships between meat quality and electrical parameters in the ham meat. Two regions were selected, SM and M, showing the best correlations with pH(45) and fat characteristics in relation to electrical parameters Rinf and Ratio, respectively. Multiple regression analysis of the data confirmed that electrical variables, Ratio, α and Fc contributed to predict pH(45) (R(2)=0.50). In order to better predict visual fatness (VF), conformation and ham weight were included in the multiple regression. A R(2) of 0.59 was obtained with H, Rinf, ham weight and α. In conclusion, the results of this study have demonstrated that ratio in the SM region may classify with 88.46% accuracy the technologically normal meat (pH(45) > 6.10) from the PSE meat. In relation to visual fatness of the ham 84.21% of the samples with a Rinf in the M region > 56 had a score of > 2.5.
RESUMO
One hundred forty individually tagged rainbow trout (Oncorhynchus mykiss) were fed diets supplemented with astaxanthin (100 mg/kg) or canthaxanthin (80 mg/kg) during sexual maturity. Only 20 subjects were followed to the end of experience. Blood sampling was withdrawn each month to evaluate pigment concentrations. In females a decrease took place 1 month before spawning, whereas in males variations were not so marked. Females had a higher carotenoid concentration than males. Mean serum levels of astaxanthin ranged in female rainbow trout from 2.80 to 3.33 µg/mL and from 0.67 to 2.32 µg/mL for canthaxanthin. Serum astaxanthin levels in male trout ranged from 0.99 to 3.28 µg/mL and for canthaxanthin from 0.78 to 1.28 µg/mL. Between-subject (V(b)) and within-subject (V(s)) variations appeared. Serious error can occur when single measurement are used to categorize individuals. Carotenoid levels in the serum of trout during spawning period would not be an adequate indicator for muscle pigmentation.
