Aging time of muscles longissimus and triceps brachii of Nellore steers, fed with in natura or protected linseed oil

Author(s)

Laís Regina Simonetti

• Document type: Master's Dissertation
• Press: Jaboticabal. 2016-07-11.
• Institution: Universidade Estadual Paulista (Unesp). Faculdade de Ciências Agrárias e Veterinárias. Jaboticabal
• Defense date: 2016-06-13
• Advisor: Wignez Henrique

Abstract

The objective was to evaluate different aging times of the longissimus and triceps brachii muscles, and their influence on the physical and chemical meat aspects from fattening Nelore steers. The animals were kept in individual pens and received diet with no added oil, with in natura or protected linseed oil, during 105 days of feedlot. The roughage used was corn silage (40% of the MS) and diets with addition of oil were isoenergetic (76.0% NDT and 6.1% EE). The animals were slaughtered with 522.71 ± 27.99 kg of body weight and 21-22 months of age. From the left half carcass, muscles were removed and sliced; steaks were aged during zero, seven and 14 days, between 0 and 2 °C in Biochemical Oxygen Demand chamber. Aging time affected the meat lightness, the intensity of red and the water holding capacity. The other variables showed interaction between aging time and muscle, and cooking losses also showed the effect of interaction between aging time and diet. Shear force presented significant effect of aging time on the day 0 and 14; at day 0, the triceps muscle showed lower shear force, while at day 14, longissimus was softer. Both muscles decreased the shear force by aging time in a quadratic way. Interaction among aging time and muscle were found for most of fatty acids quantity, except for linoleic (C18:2 n-6), α-linolenic (C18:3 n-3), conjugate linoleic (C18:2 cis trans 11 9), arachidic (C20:0), eicosadienoic (C20:2), eicosatrienoic (C20:3 n-6), arachidonic (C20:4 n-6), eicosapentaenoic-EPA (C20:5 n-3), docosatetraenoic-DTA (C22:4 n-6) and nervonic (C24:1 n-9) acids. For linoleic and eicosadienoic acids, it was observed only significant effect of aging time, with a linear increasing (P=0.0343) behavior for the first and quadratic (P=0.0191) for the last. There was no interaction between factors for the polyunsaturated fatty acids, n-6, n-3 and n-6:n-3 relation, and aging times affected only n-6 acids. The relationship polyunsaturated:saturated showed no differences between diets and for aging times, this ratio decreased only using control diet. The relation n-6:n-3 fatty acids decreased with the inclusion of both oil forms, but in natura oil was more effective. It is concluded that the fact aging time improves the tenderness of the meat, but it was not beneficial to improve the fatty acid profile of the meat. The muscles should be studied independently as the aging time process, justifying not aged triceps brachii but the longissimus, for a period of approximately 7 days. The addition of linseed oil to both forms, in the finishing phase of Nellore, appears to cause a reduction in the effects of aging time on the meat fatty acid profile. (AU)

• FAPESP's process: 14/00916-8 - Ageing effects over longissimus and triceps brachii quality of Nellore steers finished at feedlot, fed protected or unprotected linseed oil
• Grantee: Laís Regina Simonetti
• Support Opportunities: Scholarships in Brazil - Master