Expressão gênica da calpastatina e características qualitativas em carnes de bovinos Nelore submetidas à estimulação elétrica e maturação
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Data
2021-07-06
Autores
Smaniotto, Bruna Domeneghetti [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
A existência de variabilidade na concentração de calpastatina entre indivíduos do mesmo grupo genético (Bos taurus indicus) contribui para a falta de padronização da maciez dos cortes cárneos oriundos desses animais e resulta em menor valor agregado ao produto, o que afeta negativamente a competitividade do setor brasileiro no mercado mundial. A estimulação elétrica das carcaças e a maturação tem sido importantes ferramentas tecnológicas utilizadas com o intuito de melhorar a maciez da carne bovina. O objetivo do presente estudo foi associar a expressão do gene da calpastatina (CAST) e suas isoformas (CAST 1 e CAST 2) com a dureza da carne de bovinos Nelore submetidos à estimulação elétrica (EE) e à maturação. Foram selecionadas 10 carcaças inteiras, onde as meias carcaças esquerdas foram estimuladas eletricamente, enquanto as suas respectivas direitas, não. Dois grupos experimentais foram formados com base nos valores de força de cisalhamento (WBSF, Warner-Bratzler shear force) das amostras de carnes com 48 horas post-mortem (meias carcaças direitas), sendo: Carne moderadamente dura (CMD, 5,0 ± 0,17 kg) e Carne muito dura (CD, 7,28 kg ± 0,43). Amostras do M. longissimus thoracis et lumborum de ambas meias carcaças foram submetidas à maturação (7, 14, 21 e 28 dias) e análise da qualidade da carne (48 horas, 7, 14, 21 e 28 dias). Amostras de M. longissimus thoracis das meias carcaças direitas foram utilizadas para avaliação da expressão gênica de CAST, CAST 1 e CAST 2. As expressões gênicas de CAST 1 e CAST 2 foram maiores no grupo de CD comparada ao CMD (P < 0,05) e se mostraram superiores à CAST (P < 0,05), independente do grupo experimental. A EE acelerou o declínio do pH nas primeiras 9 horas post-mortem, influenciou (P < 0,05) os parâmetros L*, a*, b*, saturação e tonalidade da carne de ambos os grupos experimentais e eliminou as diferenças de WBSF entre os grupos CD e CMD já com 48 horas post-mortem. Os presentes resultados sugerem que a EE e maturação contribuem para a redução da dureza da carne de bovinos Nelore mesmo daquelas que apresentam maior expressão de CAST 1 e CAST 2.
The existence of variability in the concentration of calpastatin among individuals of the same genetic group (Bos taurus indicus) contributes to the lack of standardization of the tenderness of meat cuts from these animals and results in lower added value to the product, which negatively affects the competitiveness of the sector Brazilian market in the world. The electrical stimulation of carcasses and maturation have been important technological tools used in order to improve the tenderness of beef. The aim of the present study was to associate the expression of the calpastatin gene (CAST) and its isoforms (CAST 1 and CAST 2) with the toughness of meat from Nellore cattle submitted to electrical stimulation (EE) and maturation. Ten whole carcasses were selected, where the left half carcasses were electrically stimulated, while their respective right half carcasses were not. Two experimental groups were formed based on the values of shear force (WBSF, Warner-Bratzler shear force) of meat samples with 48 hours post-mortem (right half carcasses), as follows: Moderately tough meat (CMD, 5.0 ± 0.17 kg) and Very tough meat (CD, 7.28 kg ± 0.43). Samples of M. longissimus thoracis et lumborum from both half carcasses were submitted to maturation (7, 14, 21 and 28 days) and meat quality analysis (48 hours, 7, 14, 21 and 28 days). Samples of M. longissimus thoracis from the right half carcasses were used to evaluate the gene expression of CAST, CAST 1 and CAST 2. Gene expressions of CAST 1 and CAST 2 were higher in the CD group compared to CMD (P < 0.05 ) and were superior to CAST (P < 0.05), regardless of the experimental group. The EE accelerated the pH decline in the first 9 hours post-mortem, influenced (P < 0.05) the parameters L*, a*, b*, saturation and meat hue of both experimental groups and eliminated the WBSF differences between CD and CMD groups with 48 hours post-mortem. The present results suggest that EE and maturation contribute to the reduction of meat toughness in Nellore cattle, even those with higher expression of CAST 1 and CAST 2.
The existence of variability in the concentration of calpastatin among individuals of the same genetic group (Bos taurus indicus) contributes to the lack of standardization of the tenderness of meat cuts from these animals and results in lower added value to the product, which negatively affects the competitiveness of the sector Brazilian market in the world. The electrical stimulation of carcasses and maturation have been important technological tools used in order to improve the tenderness of beef. The aim of the present study was to associate the expression of the calpastatin gene (CAST) and its isoforms (CAST 1 and CAST 2) with the toughness of meat from Nellore cattle submitted to electrical stimulation (EE) and maturation. Ten whole carcasses were selected, where the left half carcasses were electrically stimulated, while their respective right half carcasses were not. Two experimental groups were formed based on the values of shear force (WBSF, Warner-Bratzler shear force) of meat samples with 48 hours post-mortem (right half carcasses), as follows: Moderately tough meat (CMD, 5.0 ± 0.17 kg) and Very tough meat (CD, 7.28 kg ± 0.43). Samples of M. longissimus thoracis et lumborum from both half carcasses were submitted to maturation (7, 14, 21 and 28 days) and meat quality analysis (48 hours, 7, 14, 21 and 28 days). Samples of M. longissimus thoracis from the right half carcasses were used to evaluate the gene expression of CAST, CAST 1 and CAST 2. Gene expressions of CAST 1 and CAST 2 were higher in the CD group compared to CMD (P < 0.05 ) and were superior to CAST (P < 0.05), regardless of the experimental group. The EE accelerated the pH decline in the first 9 hours post-mortem, influenced (P < 0.05) the parameters L*, a*, b*, saturation and meat hue of both experimental groups and eliminated the WBSF differences between CD and CMD groups with 48 hours post-mortem. The present results suggest that EE and maturation contribute to the reduction of meat toughness in Nellore cattle, even those with higher expression of CAST 1 and CAST 2.
Descrição
Palavras-chave
Carne - qualidade, Bovino de corte, Matadouros, Gene expression, Bos indicus, Post-mortem, Proteolysis, Standardization, Tenderness