52a Reunião Anual da Sociedade Brasileira de
Zootecnia
Zootecnia: Otimizando Recursos e Potencialidades
Belo Horizonte – MG, 19 a 23 de Julho de 2015
Efeitos do tempo de maturação de diferentes músculos de novilhos Nelore, alimentados com óleo de linhaça in
natura ou protegido da degradação ruminal1
Laís Regina Simonetti2, Wignez Henrique3, Thiago Martins Pivaro4, Victor Galli Carvalho4, Emanuel de Almeida
Oliveira4, Claudia Cristina Paro de Paz5, João Paulo Ramos Costa4
1
Parte da Dissertação de Mestrado da primeira autora
Aluna de Mestrado do Programa de Pós-Graduação em Zootecnia da FCAV/Unesp, Jaboticabal, SP. Bolsista da FAPESP. email:
[email protected]
3
APTA, São José do Rio Preto
4
FCAV/Unesp, Jaboticabal, SP
5
Instituto de Zootecnia/APTA, Sertãozinho, SP
2
Resumo: Dentre as características de qualidade da carne bovina, a maciez é um atributo que assume posição de
destaque, assim como o pH. O objetivo foi avaliar o efeito da maturação sobre a maciez e o pH dos músculos
Longissimus e Triceps brachii maturados por até 14 dias, provenientes de novilhos Nelore terminados em
confinamento e alimentados com uma dieta controle, com óleo de linhaça in natura ou com esse óleo protegido da
degradação ruminal. Utilizou-se 21 machos castrados, abatidos com peso corporal de 522,72 ± 27,99 kg, sendo os
músculos retirados após 24 horas de resfriamento das carcaças. Foi utilizado um delineamento inteiramente ao acaso,
em esquema fatorial, e os tempos de maturação considerados como medidas repetidas. Foi observada interação
significativa entre tempos de maturação e músculos para as variáveis estudadas. Foi encontrada diferença significativa
(P=0,003) entre músculos para pH, e entre tempos de maturação (P<0,0001) para força de cisalhamento, apresentando
um comportamento quadrático (P<0,0001). O Triceps apresentou maior (P<0,05) pH, e a maturação reduziu (P<0,05)
a força de cisalhamento. A melhora da qualidade da carne com adição de óleo de linhaça, in natura ou protegido, na
dieta de bovinos em terminação não é prejudicada pelo processo de maturação. O processo de maturação da carne
afeta de forma diferente músculos de funções distintas no corpo do animal, apesar do pH ter estado sempre dentro do
limite desejado para obtenção de uma carne de qualidade.
Palavras–chave: Longissimus, maciez, óleo vegetal, qualidade da carne, Triceps brachii, zebuínos
Effects of aging time of different muscles of Nellore steers, fed unprotected or protected linseed oil from
ruminal degradation1
Abstract: Among beef quality traits, tenderness is an attribute that assumes an important position, as well as the pH.
The objective was to assess the effect of aging (up to 14 days) on pH and tenderness of Longissimus and Triceps
brachii muscles from Nellore steers finished in feedlot and fed with a control diet or with addition of unprotected or
protected linseed oil from degradation ruminal. Twenty one steers were slaughtered with an average body weight of
522.72 ± 27.99 kg and both muscles were removed after 24 hours of carcasses cooling. It was used a completely
randomized design, in factorial scheme, and the aging times considered as repeated measures. A significant
interaction between aging times and muscles was observed for both variables. Significant difference of pH was found
(P = 0.003) between muscles, and for shear force among aging times (P < 0.0001), showing a quadratic effect (P <
0.0001). The Triceps showed higher (P < 0.05) pH than the Longissimus and the aging reduced (P < 0.05) shear force.
Aging did not affect the improvement of beef quality traits of animals fed in natura or protected linseed oil. The aging
process affect differently muscles with distinct functions on animal body, although the pH was always within the
desired range for obtaining a meat quality.
Keywords: Bos indicus, Longissimus, meat quality, shear force, Triceps brachii, vegetable oil
Introduction
Among beef quality traits, tenderness is an attribute that assumes an important position, and this sensory
characteristic is considered the most important for consumers’ acceptance (Alves and Mancio, 2007). The pH is a
measure related to meat quality and is directly related to muscle color and tenderness. The high ultimate pH, greatly
affects meat quality as producing dark cuts, increasing bacterial spoilage and reducing flavour.
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52a Reunião Anual da Sociedade Brasileira de
Zootecnia
Zootecnia: Otimizando Recursos e Potencialidades
Belo Horizonte – MG, 19 a 23 de Julho de 2015
Aging is the process of meat tenderization that occurs that occurs after rigor mortis during refrigerated storage
though the action of endogenous muscle enzymes. This process is often used by slaughterhouse plants seeking to
improve the qualitative aspects of beef, especially tenderness (Pivaro, 2011).
The objective was to assess the effect of aging time on pH and tenderness of Longissimus and Triceps brachii
muscles, aged for up to 14 days, from confined Nellore steers fed unprotected or protected linseed oil from ruminal
degradation at the fattening phase.
Material and Methods
Twenty one Nellore steers with 18 months of age and 397.74 ± 14.07 kg body weight were used. Three diets
were evaluated (40% corn silage and 60% concentrate); 1) without oil; 2) with addition of unprotected linseed oil
(3.4% DM diet); and 3) with addition of protected linseed oil (4.5% DM diet). After 126 days of feedlot, the animals
were slaughtered with 522.72 ± 27.99 kg of body weight and the carcasses were chilled for 24 hours. After this
period, a section of Longissimus muscle (between the 6th and 13th ribs) and the Triceps brachii muscle were removed,
sliced in steaks 2.54 cm thick, which were individually vacuum packed and refrigerated at 2 °C for seven or 14 days.
In steaks after 0, 7 and 14 days of aging, the pH was determined, using a pHmeter with a penetration electrode, and
the shear force measured by the force required to cut across a cylinder of 1.27 cm diameter by a texturometer with
Warner Bratzler blade, sampling six cylinders of each steak. The data were evaluated in a completely randomized
design using the MIXED procedure of SAS (SAS, 2008) in a factorial 3 (control diet, with added unprotected or
protected linseed oil) x 2 (muscles Longissimus and Triceps brachii) x 3 (0, 7 and 14 days of aging times), and the
treatment means compared by 5% Tukey test, the aging times considered as repeated measures and their effects
analyzed by orthogonal polynomial contrasts.
Results and Discussion
A significant interaction between aging times and muscles for the two variables was obtained, demonstrating
that aging time modify differently the pH and the tenderness of the Longissimus and the Triceps brachii (Table 1).
The Longissimus and Triceps brachii muscles showed significant differences (P = 0.003) for pH (Table 2), and higher
value had been observed for the Triceps brachii muscle. Distinct muscles differ depending on their anatomical
location as well as the intensity of their activity, and as a result, varying the proportion of red and white fibers
(Felício, 1999). Because of this, there are differences in tenderness and pH of the meat when comparing muscles of
the hindquarter and the forequarter of the animal (Joo et al., 2013), since in the hind region, there is greater amount of
sustentation muscles as the Longissimus, and in front, traction muscles like the Triceps brachii, justifying what
happened in this work with the pH. We need to asseverate that the meat pH for all diets, muscles and aging times
were within the range considered ideal for beef, which is consistent with the standards of the meat industry, since in
Brazil, slaughterhouse export only meat with pH below 5.8 (Fernandes et al., 2008).
Table 1. pH and shear force of the Longissimus (L) and Triceps brachii (TB) muscles of Nellore
steers finished in feedlot, receiving control diet, unprotected or protected linseed oil, aged for different
times
Aging time (days)
Diet²
Muscles
Variable1
SE3
SE3
SE3
0
7
14
C
OL
OLiP
L
TB
pH
5.53
5.59
5.58
0.043
5.59
5.56
5.56 0.063
5.45
5.69
0.047
SF
5.04
3.59
3.66
0.127
4.18
4.10
4.01 0.149
4.03
4.16
0.122
1
³
SF = shear force; ²C = control diet; OL = unprotected linseed oil; OLiP = protected linseed oil; Standard error
Table 2. Probabilities for pH and shear force of polynomial orthogonal contrasts (COP) of aging times (T), diet (D)
and muscle (M), and their interactions, of Nellore steers finished in feedlot
COP para T
Factor
Interaction
Variable1
Linear2
Quadratic3
T
D
M
TxD
TxM
pH
NS4
NS4
0.200
0.936
0.003
NS4
0.003
SF
<0.0001
<0.0001
<0.0001
0.745
0.444
NS4
0.0001
1
SF = shear force; ²linear or 3quadratic regression for aging time the meat (0, 7 e 14 days); 4NS = not significant.
Shear force was different (P <0.0001) between the aging times evaluated, reducing with greater time of aging,
and showing a quadratic effect (P <0.0001) (Table 1). The meat tenderness is one of the attributes increasingly
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52a Reunião Anual da Sociedade Brasileira de
Zootecnia
Zootecnia: Otimizando Recursos e Potencialidades
Belo Horizonte – MG, 19 a 23 de Julho de 2015
required by Brazilian consumers. It is a constant concern in the markets seeking ways and means to improve this
attribute, being the aging times one of these processes.
King et al. (2003) subjected the Longissimus thoracics and Triceps brachii muscles to rapid freezing or aging
times for 14 days, and observed that the muscles that have been frozen on the first day had higher shear strength
values, while the muscles submitted to aging times for 14 days showed lower values, resulting in more tenderness
meats. As in this work, the muscles, on the first day, showed 5.04 kgf shear force, and aged for seven and 14 days
showed 3.59 and 3.66 kgf, respectively.
Conclusions
The improvement in qualitative aspects of beef achieved by adding the linseed oil, unprotected or protected, on
animals’ diet is beneficial altered by the aging process of meat up to 14 days, because of the tenderness increasing.
Muscles with different locomotors functions in bovine body respond differently to the aging process up to 14
days, but there is always an improvement in meat tenderness.
Acknowledgements
We sincerely acknowledge the FAPESP (Fundação de Amparo à Pesquisa do Estado de São Paulo) for
supporting the project and the first author master’s scholarship, and the CNPq (Conselho Nacional de
Desenvolvimento Científico e Tecnológico) by the project support.
References
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