This study proposes classification models for the prediction of the quality parameters of cattle and sheep leathers. In total, 375 leather samples were directly analyzed by laser-induced breakdown spectroscopy (LIBS). Exploratory analysis using principal component analysis (PCA) and classification models employing K-nearest neighbor (KNN), soft independent modeling of class analogy (SIMCA), and partial least squares – discriminant analysis (PLS-DA) were the chemometric tools used in the multivariate analysis. The goal was to classify the leather samples according to their quality. The calculated models have satisfactory results with correct prediction percentages ranging from 75.2 (for SIMCA) to 80.5 (for PLS-DA) for the calibration dataset and from 71.6 (for SIMCA) to 80.9 (for KNN) for the validation samples. The proposed method can be used for preliminary leather quality inspection without chemical residues generation.

This paper presents a study on attributes reduction, comparing five discriminant analysis techniques: FisherFace, CLDA, DLDA, YLDA and KLDA. Attributes reduction has been applied to the problem of leather defect classification using four different classifiers: C4.5, kNN, Naïve Bayes and Support Vector Machines. The results of several experiments on the performance of discriminant analysis applied to the problem of defect detection are reported.

The objective of this study was to evaluate the influence of crossings between sheep breeds on the intrinsic quality of leather. It was used the skins of 36 lambs (18 females and 18 males), resulting from crosses between ewes of a native breed from the Brazilian state of Mato Grosso do Sul and rams of the same native breed as well as the Texel and Santa Inês genetic groups. The animals were raised in confinement until slaughter weight, from 28 to 32 kg. After slaughter, samples were taken from the skins for histological analysis. The skins were tanned with chromium, retanned and greased. It was taken from the leather samples for electromicrographs and for tests for tensile and tear strength (intrinsic quality). Morphological aspects from the skin as well as from the leather help to understand the results found and they evidence that breeds or crossings among breeds interfere in the intrinsic quality of leather and skin of sheep

Objetivando-se analisar as características físico-mecânicas do couro de caprinos, após o curtimento, utilizaram-se 16 animais machos mestiços Alpinos, com idades a partir dos 180 dias de vida, abatidos em intervalos de 45 dias (quatro animais por abate). As peles foram curtidas e recurtidas e dos couros retiraram-se três corpos-de-prova das regiões dorsal, paleta, ventral, anca e lateral, nas direções paralelas e perpendicular ao eixo crânio-caudal, para realização dos ensaios físico-mecânicos: distensão da "flor" no lastrômetro, rasgamento progressivo, resistência à tração, análises químicas de extração de lipídios, óxido de cromo, pH e cifra diferencial. A idade do animal exerceu efeito positivo no ensaio de resistência à tração, com superioridade para os caprinos de 315 dias de vida. A região e a posição em todos animais estudados apresentaram efeito significativo no ensaio de resistência ao rasgamento progressivo, nas quatro idades, atingindo o valor de referência mínima de 80 kgf/cm. A resistência do couro à distensão da "flor" dos caprinos estudados foi superior ao mínimo de 7 mm, demonstrando grande elasticidade dos couros, sem influência de idade ou região.