Multivariate statistical {using factor and discriminant} analyses of some selected chemical and physical freshness indicators of fish [ Scomberomorus brasiliensis (carite)] muscle tissue samples

Abstract

Seventy-eight samples of [ Scomberomorus brasiliensis (carite)] muscle tissue were analyzed for % fat, hypoxanthine content (determined by a flow injection method), total volatile acids and bases, total bacterial count, and textural parameters (firmness, hardness, fracturability, cohesiveness, chewiness, and elasticity) were subjected to discriminant and factor analyses. The apparent error rate obtained by discriminant analysis with all the parameters in the analysis was about 5.6%. However, classification was not improved (apparent error rate 6.9%) when cohesiveness and chewiness were excluded from the analysis. The stepwise methods of selection (Wilks and Minresid) H×FI ranked second, and fourth when the Mahal and Maxminf methods were used. In the factor analysis, using the principal component analysis, five factors were extracted. Factor loadings relate factor 1 (tastiness) with hypoxanthine concentration, total volatile acids and bases: factors 2, 3, 5 (texture) with the textural attributes; and factor 4 (rancidity) with the % fat content. Rotation of the reference axes showed that factors 1, 2 and 5 remained unchanged, while factors 3 and 4 were interchanged.