Noelia Aldai

The influence of breed and mh-genotype on carcass conformation, meat physico-chemical characteristics, and the fatty acid profile of muscle from yearling bulls

The influence of breed and mh-genotype on carcass conformation, meat physico-chemical characteristics and the fatty acid profile of muscle were studied. Samples from 16 yearling bulls from Asturiana de los Valles (AV, n=12) and Asturiana de la Montaña (AM, n=4) were collected. AV animals were classified into three groups according to the presence of the gene causing double-muscling (AV double-muscled (mh/mh), n=4; AV heterozygous (mh/+), n=4; AV normal (+/+), n=4). Double-muscled animals displayed better carcass traits, lower total fat (comprised of subcutaneous (SC), intermuscular (IT) and intramuscular (IM) deposits), higher lean, moisture and drip loss, and lighter meat than AV normal animals. Heterozygous animals showed intermediate characteristics. AM animals, being a more rustic and smaller breed, showed lower conformation, higher total fat (SC, IT and IM), lower moisture and darker meat. According to the intramuscular fatty acid profile, mh/mh animals showed a lower proportion of SFA and MUFA, and a higher proportion of PUFA with an equal proportion of CLA in total fatty acid content. The P/S ratio increased with increasing number of mh alleles (or double-muscling character), while no differences between animal groups were found for the n-6/n-3 ratio.

Survey of the fatty acid composition of Canadian beef: backfat and longissimus lumborum muscle.

A survey of Canadian retail beef was undertaken with emphasis on the trans fatty acid (TFA) and conjugated linoleic acid (CLA) isomers, and compared with current health recommendations. Thirty striploin steaks were collected in the winter and summer from major grocery stores in Calgary (Alberta, Canada). Steak fatty acid compositions (backfat and longissimus lumborum muscle analysed separately) showed minor seasonal differences with lower total saturates (Pu2002<u20020.05) and higher total monounsaturates (Pu2002<u20020.01) in winter, but no differences in total polyunsaturated fatty acids. The ratio of n-6 and n-3 polyunsaturated fatty acid in longissimus lumborum averaged 5.8. The average TFA content in longissimus lumborum was 0.128 g 100 g-1 serving size, and 10t-18:1 was found to be the predominant isomer (32% of total trans), while vaccenic acid was second most abundant (15% of total trans). The CLA content in longissimus lumborum was similar to that of backfat, ranging from 0.43 to 0.60% and rumenic acid represent...

Review: Trans-forming beef to provide healthier fatty acid profiles

Dugan, M. E. R., Aldai, N., Aalhus, J. L., Rolland, D. C. and Kramer, J. K. G. 2011. Review: Trans- forming beef to provide healthier fatty acid profiles. Can. J. Anim. Sci. 91: 545–556.Trans fatty acids are found naturally in foods, particularly in those derived from ruminant animals, such as beef and dairy cattle. Over the past few decades, human consumption of trans fatty acids has increased, but this has been mainly from products containing partially hydrogenated vegetable oils. The correlation of trans fatty acid consumption with diseases such as coronary heart disease has been cause for concern, and led to recommendations to reduce their consumption. Trans fatty acids, however, have differing effects on human health. Therefore, in foods produced from ruminant animals, it is important to know their trans fatty acid composition, and how to enrich or deplete fatty acids that have positive or negative health effects. This review will cover the analysis of trans fatty acids in beef, their origin, how to ...

Evaluation of wheat or corn dried distillers’ grains with solubles on performance and carcass characteristics of feedlot steers

A study was conducted on crossbred steers (n = 275; 376 ± 24 kg) to evaluate performance and carcass quality of cattle fed wheat or corn dried distillers’ grains with solubles (DDGS). The control ration contained 86.6% rolled barley grain, 5.7% supplement and 7.7% barley silage (DM basis). The four treatments included replacement of barley grain at 20 or 40% of the diet (DM basis) with wheat or corn DDGS. Steers were slaughtered at a common end weight of 645 kg with 100 steers randomly (n = 20 per treatment) selected for determination of the retail yield of sub-primal boneless boxed beef (SPBBB). Data were analyzed as a completely randomized design using pen as the experimental unit. Feeding increasing levels of wheat DDGS led to a quadratic increase in dry matter intake (DMI) (Pu2002<u20020.01), whereas increasing levels of corn DDGS led to a quadratic decrease in DMI (P = 0.01). Average daily gain was not influenced (P = 0.13) by feeding wheat or corn DDGS, but cattle fed corn DDGS exhibited a quadratic increas...

Extended ageing time and temperature effects on quality of sub-primal cuts of boxed beef

Most of the information indicating ageing improves tenderness has been collected on the loin and rib-eye muscles over relatively short ageing times, assuming that all muscles will react similarly. In the present study, the effect of extended ageing times on instrumental texture (56 d) and sensory characteristics (42 d) of six different beef sub-primals [striploin (SL), inside round (IR), outside round (OR), eye of round (ER), blade eye (BE) and chuck tender (CT)] was studied. The effects of two ageing temperatures (1 and 5°C) were also compared. In general, ageing increased tenderness (Pu2002 u20020.05) and resulted in a decrease in tenderness of OR (Pu2002<u20020.05) until day 35, with a later increase after 42 d of ageing. Increasing ageing temperature (5°C) had limited effect on tenderness, but ageing time and temperature increases led to lower flavour and higher...

Subcutaneous fat composition of youthful and mature Canadian beef: emphasis on individual conjugated linoleic acid and trans-18:1 isomers

A comprehensive evaluation of the fatty acid composition of subcutaneous adipose tissue from beef cattle produced in western Canada was undertaken to determine if the current Canadian grading system is able to distinguish classes of animals with value added potential due to their fatty acid composition. Grades included youthful Canadian Yield Grade 1 A/AA beef, under (YUTM) and over (YOTM) 30 mo of age and the four mature grades (D1, D2, D2 and D4). Subcutaneous fat between the 12th and 13th ribs over the longissimus muscle was obtained from 18–21 animals per grade. Fatty acids were analyzed using a combination of silver-ion HPLC and GC with a highly polar 100 m column. There were no differences in total trans-18:1 content amongst grades, but adipose tissue from grade D1, D2 and D4 had more 11t-18:1 than YUTM (P < 0.05), whereas adipose tissue from YUTM carcasses had more 10t-18:1 than all other grades (P < 0.05). Adipose tissue from YUTM carcasses also had less total CLA (P < 0.05) than the D grades, mai...

Dietary vitamin E inhibits the trans 10-18:1 shift in beef backfat.

Forty feedlot steers were fed a barley-grain-based finishing diet typical for western Canada, with two levels of supplementary vitamin E (468 or 1069 IU head-1 d-1) and the effect on backfat trans-18:1 isomeric profile was determined. Feeding 1068 IU vitamin E reduced the total trans-18:1 content in backfat (Pu2002<u20020.01), as well as the percentage of trans 10-18:1 (Pu2002<u20020.001), which are related to an increased risk for cardiovascular diseases. On the other hand, trans 11-18:1 (vaccenic acid) the precursor for cis 9,trans 11-18:2 (rumenic acid), which have several purported health benefits, increased (Pu2002<u20020.01). Vitamin E could, therefore, be used to decrease trans-18:1 in beef and improve its isomeric profile.Key words: Beef, trans fatty acid, vaccenic acid, vitamin E

Rapid determination of total CLA concentration in beef fat

Conjugated linoleic acid (CLA) has many potential healthful properties, and beef is naturally enriched with CLA. Simple and rapid methods to measure total CLA were investigated to enable sorting of beef carcasses with potential enhanced economic value. Direct alcohol extraction combined with measuring absorbance was simple, accurate and perhaps the most viable method for rapid carcass sorting compared to methods using saponification or methylation followed by extraction. Key words: Beef, fat, conjugated linoleic acid, rapid methods

Red blood cell trans-18:1 isomeric profile correlates with subcutaneous fat and muscle profiles in beef cattle

Due to significant variation in polyunsaturated fatty acid biohydrogenation products in beef it would be useful to determine if levels of trans-18:1 isomers in samples collected ante-mortem are correlated with those collected post-mortem. Beef blood (RBC), subcutaneous fat (SC) and muscle (intramuscular fat; IM) samples were collected from an experiment with dietary vitamin E with/without flaxseed (n=80) and fatty acids analyzed. Across treatments, correlation analysis of total and individual trans-18:1 isomers were performed between tissues. Correlations between SC and IM were highly significant for all individual and total trans-18:1. RBC trans-18:1 were also well correlated with other tissues except for vaccenic acid. Levels of 10t-, 12t- and 13t/14t- were amongst the best correlated between RBC and SC and IM profiles. Levels of 6t/7t/8t-, 9t-, and 15t-18:1 showed significant but lower correlation factors particularly between RBC and SC. These results confirm the possibility of utilizing blood as a non-destructive sample to predict the total and isomeric profile of trans-18:1 in beef.

CHAPTER 7:Analysis of Conjugated and Other Fatty Acids

Analysis of conjugated fatty acids (CFA) is both convenient and challenging. Convenient, because CFA have a unique double bond system with chemical properties not common to other fatty acids (FA) that can be used for their selective analysis. Challenging, because CFA exist in many isomeric forms just as other unsaturated FAs, and most FAs have different biological properties. Therefore, the choice of method used depends on whether a selective or a complete analysis of all FAs in any given matrix is desired. For routine analysis, gas chromatography (GC) as their fatty acid methyl esters (FAME) is the method of choice. The choice of the separation column depends on the FA complexity of the matrix and how well CFA isomers separate from other FAMEs and among themselves. Currently, there is no single GC method to analyse all geometric/positional isomers of FAMEs that might occur in natural fats or synthetic mixtures. Analytical techniques can be combined considering the complexity of the matrix, the selectivity of GC columns, choice of supportive techniques, and keeping analyses per sample to a minimum. In this review, the benefits and limitations of different GC columns are evaluated and supported by selective techniques. Combinations of methods are suggested to obtain a comprehensive analysis of as many conjugated and non-conjugated FAs as possible.