Determinação de gordura intramuscular de carne de bovino por métodos não destrutivos
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2018-01-30
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O método de avaliação e os critérios utilizados para avaliar a qualidade da carne bovina têm tido um crescente desenvolvimento em muitos países. O marmoreado é um dos principais indicadores da qualidade da carne referente à “Classificação da Qualidade da Carne”, este pode ser dividido em quatro níveis, entre eles o “muito rico”, “rico”, “marmoreado médio” e “pouco rico” espaçando cada nível com 0,5 pontos. É neste panorama que se enquadra o presente trabalho e no qual será dado destaque à técnica de análise de imagem vídeo (do inglês video image analysis - VIA) aplicada à estimativa da gordura intramuscular do músculo Longissimus thoracis et lumborum (IMF_LTL) e de determinação da sua relação com a cor e o pH da carne. O presente trabalho está organizado em três partes. Na primeira parte foi elaborada uma introdução sobre o conteúdo do trabalho. Na segunda parte foi elaborada uma breve revisão bibliográfica sobre a estrutura e o desenvolvimento da gordura intramuscular, o efeito do marmoreado nas características sensoriais da carne, a utilização da gordura intramuscular na classificação das carcaças e por fim os métodos para a determinação da IMF por análise de imagem e imagem espectral. Na parte três apresenta-se o trabalho experimental desenvolvido com base na revisão bibliográfica realizada. Para estimar a IMF e a relação desta com a cor e com o pH da carne foram determinados parâmetros físico-químicos como a percentagem de IMF, os valores de L*, a* e b* bem como os parâmetros da análise de imagem como o número de partículas, a área total de partículas (mm2), a área média das partículas (mm2), a fração da área (%), o perímetro das partículas (mm), o maior eixo das partículas (mm), o menor eixo das partículas (mm), a circularidade, a solidez, a espessura das partículas (mm), a espessura mínima das partículas (mm), a espessura máxima das partículas (mm) e a percentagem de IMF que foi estimada por análise de imagem. Os coeficientes de correlação de determinação foram estabelecidos entre as variáveis obtidas pelo sistema de análise de imagem.
Para avaliar a relação entre os valores de cor da carne de bovino, no espaço CIELab foram utilizadas 85 amostras do músculo LTL de bovinos. As características colorimétricas L* (luminosidade), a* (vermelho) e b* (amarelo) foram medidas através de um colorímetro Minolta CR-10. Os resultados observados nesta tese sugerem que a análise de imagem é uma ferramenta precisa para estimar a IMF química do músculo LTL sem destruir a costeleta, e que os resultados envolvendo o sistema de imagem sustentam as conclusões de outros trabalhos sobre a capacidade do sistema em estimar os cortes da carcaça, a composição da carcaça em tecidos e a gordura intramuscular.
The evaluation method and the criteria used to assess the quality of beef have been growing in many countries. Marbling is one of the main indicators of meat quality and according to the industry standard for "Meat Quality Classification", it can be divided into four levels, among them "very rich", "rich", "marbling medium" and "little rich" spacing each level with 0.5 points. It is in this panorama that the present work is framed and in which the technique of video image analysis (VIA) applied to the estimation of the intramuscular fat of the Longissimus thoracis and lumborum muscle (IMF_LTL) and the establishment of its relation to the color and pH of the meat. This paper is organized in three parts. The first part elaborated an introduction on the extensive content of the work. In the second part, a brief bibliographical review on the structure and development of intramuscular fat, the effect of marbling on the sensorial characteristics of the meat, the use of intramuscular fat in the carcass classification and finally the methods for the determination of the IMF by analysis of image and spectral image. In part three we present the experimental work developed based on all the literature review. In order to estimate the IMF and its relation with the color and pH of the meat, physicochemical parameters such as the percentage of IMF, L *, a * and b * values were determined as well as the parameters of the image analysis as the number (mm2), the area of the particles (mm2), the fraction of the area (%), the perimeter of the particles (mm), the largest axis of the particles (mm), the smallest axis of the particles particle size (mm), particle thickness (mm), particle thickness (mm), particle thickness (mm) and percentage of IMF estimated by image analysis. The determination correlation coefficients were established among the variables obtained by the image analysis system. To evaluate the relationship between the beef color values, in the CIELab space, 85 samples of the LTL muscle of cattle were used. The colorimetric characteristics L * (brightness), a * (red) and b * (yellow) were measured using a Minolta CR-10 colorimeter. The results observed in this thesis suggest that the image analysis is an accurate tool to estimate the chemical IMF of the LTL muscle without destroying the chop, and that the results involving the image system support the conclusions of other studies on the system's ability to estimate the primary sections, the composition of the carcass in tissues and the intramuscular fat.
The evaluation method and the criteria used to assess the quality of beef have been growing in many countries. Marbling is one of the main indicators of meat quality and according to the industry standard for "Meat Quality Classification", it can be divided into four levels, among them "very rich", "rich", "marbling medium" and "little rich" spacing each level with 0.5 points. It is in this panorama that the present work is framed and in which the technique of video image analysis (VIA) applied to the estimation of the intramuscular fat of the Longissimus thoracis and lumborum muscle (IMF_LTL) and the establishment of its relation to the color and pH of the meat. This paper is organized in three parts. The first part elaborated an introduction on the extensive content of the work. In the second part, a brief bibliographical review on the structure and development of intramuscular fat, the effect of marbling on the sensorial characteristics of the meat, the use of intramuscular fat in the carcass classification and finally the methods for the determination of the IMF by analysis of image and spectral image. In part three we present the experimental work developed based on all the literature review. In order to estimate the IMF and its relation with the color and pH of the meat, physicochemical parameters such as the percentage of IMF, L *, a * and b * values were determined as well as the parameters of the image analysis as the number (mm2), the area of the particles (mm2), the fraction of the area (%), the perimeter of the particles (mm), the largest axis of the particles (mm), the smallest axis of the particles particle size (mm), particle thickness (mm), particle thickness (mm), particle thickness (mm) and percentage of IMF estimated by image analysis. The determination correlation coefficients were established among the variables obtained by the image analysis system. To evaluate the relationship between the beef color values, in the CIELab space, 85 samples of the LTL muscle of cattle were used. The colorimetric characteristics L * (brightness), a * (red) and b * (yellow) were measured using a Minolta CR-10 colorimeter. The results observed in this thesis suggest that the image analysis is an accurate tool to estimate the chemical IMF of the LTL muscle without destroying the chop, and that the results involving the image system support the conclusions of other studies on the system's ability to estimate the primary sections, the composition of the carcass in tissues and the intramuscular fat.
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análise de imagem vídeo , carcaça , carne , gordura intramuscular