Acid Content Of Beef Research Articles

Production of Hydroxy Fatty Acids, Precursors of γ-Hexalactone, Contributes to the Characteristic Sweet Aroma of Beef.

Aroma is an essential factor for meat quality. The meat of Japanese Black cattle exhibits fine marbling and a rich and sweet aroma with a characteristic lactone composition. The mechanism of lactone formation associated with beef aroma has not been elucidated. In this study, we examined the precursors of γ-hexalactone, an indicator of the sweet aroma of beef and identified the mechanism underlying γ-hexalactone production. A low-temperature vacuum system was used to prepare beef tallow from Japanese Black cattle and Holstein cattle. The odor components were identified using headspace–gas chromatography. The analysis revealed that γ-hexalactone, γ-dodecalactone, δ-tetradecalactone, and δ-hexadecalactone were present as sweet aroma components of beef tallow prepared from marbling and muscle. Since we previously reported that γ-hexalactone formation correlates with linoleic acid content in beef, we analyzed ten oxidized fatty acids derived from linoleic acid by liquid chromatography–triple quadrupole mass spectrometry and detected two hydroxy-octadecadienoic acids (9S-HODE and 13S-HODE) in beef tallow. Significant differences in arachidonic acid 15-lipoxygenase and cyclooxygenase protein expression levels among subcutaneous fat, intramuscular fat, and muscle tissue were observed. Our results suggest that the combination of linoleic acid and the expression of lipid oxidase derived from beef muscle and intramuscular fat produce hydroxy fatty acids that result in a sweet aroma.

Transcriptional Regulation of the Bovine Fatty Acid Transport Protein 1 Gene by Krüppel-Like Factors 15.

Simple SummaryThe nutritional value and qualities of beef are enhanced when the unsaturated fatty acid content is increased. Fatty acid transport protein 1 (FATP1), also called SLC27A1, an integral membrane protein that facilitates long-chain fatty acid influx, is involved in the genetic network for oleic acid synthesis in beef. Polymorphisms in bovine SLC27A1 gene are most significantly associated with oleic acid. Its expression exhibits significant positive correlations with bovine intramuscular fat content in the longissimus thoracis muscle. However, the transcription factors that contribute to the control and regulation of its expression have not been characterized extensively. In this study, we determined the tissue distribution of SLC27A1 mRNA and found that bovine SLC27A1 was highly expressed in subcutaneous adipose tissue and the longissimus thoracis muscle. Furthermore, we analyzed the molecular mechanisms involved in SLC27A1 regulation and found that the transcriptional activity of SLC27A1 gene was dependent on KLF15 transcription factor. These results may lead to an enhanced understanding of the regulation of SLC27A1 expression in other models, as well as provide new insights into the regulatory mechanism and biological functions of the SLC27A1 gene in determining the lipid composition in beef.Oleic acid is a major monounsaturated fatty acid, which accounts for about 33% of the fatty acid content in beef and is considered to have the least negative effect on serum cholesterol levels. Fatty acid transport protein 1 (FATP1), an integral membrane protein that facilitates long-chain fatty acid (LCFA) influx, is involved in the genetic network for oleic acid synthesis in beef. Its expression exhibits significant positive correlations with intramuscular fat (IMF) content in the longissimus thoracis. However, the expression mechanism of SLC27A1 or FATP1 is still unclear. To elucidate the molecular mechanisms involved in bovine SLC27A1 regulation, we cloned and characterized the promoter region of SLC27A1. By applying 5′-rapid amplification of cDNA end analysis, we identified two alternative splice variants of this gene. Using a series of 5′ deletion promoter plasmids in luciferase reporter assays, we found that the core promoter was 96 base pairs upstream from the transcription initiation site. Electrophoretic mobility shift assay combined with a site-directed mutation experiment demonstrated that KLF15 binding to the promoter region drives the SLC27A1 transcription. KLF15 plays an essential role in adipogenesis and skeletal muscle lipid flux. Thus, these results might provide further information on the regulatory roles of SLC27A1 gene in mediating the lipid composition in beef.

Contenido de ácidos grasos en carne de bovinos cebados en diferentes sistemas de producción en el trópico colombiano

Background: Meat is a highly nutritious food and a major component of the basic food basket. Consumers select foods not only for taste and satisfaction, but also for their effects on human nutrition and health. In addition there is very little knowledge about the quality of meat produced in the Colombian systems and their fatty acid content which undoubtedly affect human health. Objetive: To determine the content and composition of fatty acids in meat from steers managed in different Colombian systems. Methods: Meat (Longissimus dorsi) samples were obtained from Zebu cattle from four production systems inthe Colombian tropics: Two silvopastoral arrangements (Cotove Research Center, National University of Colombia and Montenegro, Quindio), improved pastures (Montenegro, Quindio) and a traditional grazing system (Monteria, Cordoba). Fat was extracted from 64 meat samples in the laboratory of Analytical Chemistry of the National University of Colombia, and a quantitative analysis of fatty acids was performed by gas chromatography in the laboratory of Instrumental Analysis of the National University of Colombia in Medellin. The results were evaluated following a complete randomized design and means were separated by the Duncan test. Results: There were significant differences in the content of myristic and palmitic acids between meat from the traditional and improved pasture system, with both acids being higher in the traditional system. There were also differences in the content of linoleic and linolenic acid, being lower in the Cotove silvopastoral system. There were significant differences in the content of unsaturated acids, with the meat from silvopastoral system Quindio and the improved pastures showing the highest fatty acid saturated: polyunsaturated ratio (0.19). In the linoleic: α-linolenic ratio there were no differences. Conclusions: Although the composition and the fatty acid content in beef varied between systems evaluated, the main components of such systems fat were palmitic acid and oleic acid (30.73 and 35.62 g/100 g fatty acid).

Influence of Feeding Soybean Oil on Conjugated Linoleic Acid Content in Beef

Forty-eight steers were used to study the influence of feeding soybean oil (SO) on the conjugated linoleic acid (CLA) content of beef. Steers were fed either a control diet containing 954 g/kg of dry matter (DM) corn-based concentrate (CTL) or a control diet supplemented with SO at 20 (SO2) or 40 g/kg (SO4) of diet DM for 105 days. Adipose tissue samples were collected from the M. longissimus dorsi (LD) and from the M. semitendinosus (ST) on days 0 and 63 of the experiment. Adipose and muscle tissue samples were collected from the LD and ST immediately after slaughter. Feeding 40 g/kg of DM as SO increased the proportions of trans-C(18:1) in beef lipid as compared to CTL and SO2 treatments. The C(18:2) cis-9, trans-11 isomer of CLA as a proportion of total fat was not different in adipose and muscle across treatments. Supplementing SO increased C(18:2) trans-10, cis-12 CLA in adipose tissue of the LD. Supplementing high-grain finishing diets with SO is not an effective strategy to enhance the C(18:2) cis-9, trans-11 isomer of CLA in beef.