Publications by authors named "Jennifer L Aalhus"

21 Publications

  • Page 1 of 1

Carcass and Primal Composition Predictions Using Camera Vision Systems (CVS) and Dual-Energy X-ray Absorptiometry (DXA) Technologies on Mature Cows.

Foods 2021 May 18;10(5). Epub 2021 May 18.

Lacombe Research and Development Centre, Agriculture and Agri-Food Canada, Lacombe, AB T4L 1W1, Canada.

This study determined the potential of computer vision systems, namely the whole-side carcass camera (HCC) compared to the rib-eye camera (CCC) and dual energy X-ray absorptiometry (DXA) technology to predict primal and carcass composition of cull cows. The predictability (R) of the HCC was similar to the CCC for total fat, but higher for lean (24.0%) and bone (61.6%). Subcutaneous fat (SQ), body cavity fat, and retail cut yield (RCY) estimations showed a difference of 6.2% between both CVS. The total lean meat yield (LMY) estimate was 22.4% better for CCC than for HCC. The combination of HCC and CCC resulted in a similar prediction of total fat, SQ, and intermuscular fat, and improved predictions of total lean and bone compared to HCC/CCC. Furthermore, a 25.3% improvement was observed for LMY and RCY estimations. DXA predictions showed improvements in R values of 26.0% and 25.6% compared to the HCC alone or the HCC + CCC combined, respectively. These results suggest the feasibility of using HCC for predicting primal and carcass composition. This is an important finding for slaughter systems, such as those used for mature cattle in North America that do not routinely knife rib carcasses, which prevents the use of CCC.
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http://dx.doi.org/10.3390/foods10051118DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8158109PMC
May 2021

Effect of Feeding Barley, Corn, and a Barley/Corn Blend on Beef Composition and End-Product Palatability.

Foods 2021 Apr 29;10(5). Epub 2021 Apr 29.

Lacombe Research and Development Centre, Agriculture and Agri-Food Canada, Lacombe, AB T4L 1W1, Canada.

This study evaluated the relationship among palatability attributes, volatile compounds, and fatty acid (FA) profiles in meat from barley, corn, and blended (50:50, barley and corn) grain-fed steers. Multiple correspondence analysis with three dimensions (Dim) explained 62.2% of the total variability among samples. The Dim 1 and 2 (53.3%) separated pure from blended grain-fed beef samples. Blended grain beef was linked to a number of volatiles including (E,E)-2,4-decadienal, hexanal, 1-octen-3-ol, and 2,3-octanedione. In addition, blended grain-fed beef was linked to fat-like and rancid flavors, stale-cardboard, metallic, cruciferous, and fat-like aroma descriptors, and negative categories for flavor intensity (FI), off-flavor, and tenderness. A possible combination of linoleic and linolenic acids in the blended diet, lower rumen pH, and incomplete biohydrogenation of blended grain-fed polyunsaturates could have increased ( ≤ 0.05) long-chain n-6 fatty acids (LCFA) in blended grain-fed beef, leading to more accumulation of FA oxidation products in the blended than in barley and corn grain-fed meat samples. The Dim 3 (8.9%) allowed corn separation from barley grain beef. Barley grain-fed beef was mainly linked to alkanes and beef positive FI, whereas corn grain-fed beef was associated with pyrazines, in addition to aldehydes related to n-6 LCFA oxidation.
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http://dx.doi.org/10.3390/foods10050977DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8146225PMC
April 2021

Relationship between meat quality and intramuscular collagen characteristics of muscles from calf-fed, yearling-fed and mature crossbred beef cattle.

Meat Sci 2021 Mar 19;173:108375. Epub 2020 Nov 19.

Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta T6G 2P5, Canada. Electronic address:

Intramuscular Ehrlich Chromogen (EC) and pyridinoline (Pyr) concentrations in the gluteus medius (GM) and semitendinosus (ST) from crossbred Angus calf- (n = 14) and yearling-fed (n = 14) steer and mature cow (MC, n = 12) carcasses were related to collagen and intramuscular connective tissue (IMCT) thermal stability and peak Warner-Bratzler shear force (WBSF). In both muscles, Pyr density was greater in MC, while EC concentrations were comparable in calf- and yearling-fed steer muscles and lowest in MC muscles. Thermal denaturation temperature and enthalpy of IMCT were highest in both muscles when from MC, although only total collagen was correlated with WBSF in calf fed-yearling fed steer data. Results confirmed that EC concentration contributed to collagen thermal stability in steer muscles, but decreased it in MC muscles, while Pyr was consistently associated with collagen thermal stability.
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http://dx.doi.org/10.1016/j.meatsci.2020.108375DOI Listing
March 2021

Rapid and non-destructive determination of lean fat and bone content in beef using dual energy X-ray absorptiometry.

Meat Sci 2018 Dec 10;146:140-146. Epub 2018 Jul 10.

Lacombe Research and Development Centre, Agriculture and Agri-Food Canada, 6000 C&E Trail, Lacombe, Alberta, T4L 1W1, Canada.

Dual energy X-ray absorptiometry (DXA) was evaluated for its accuracy in predicting total lean, fat and bone in beef carcass sides and primal cuts. Left carcass sides (n = 316) were broken down into primal cuts, scanned using DXA and then dissected to fat, lean and bone. The DXA estimates for bone, lean and fat from the primals (n = 237) were used to calibrate partial least squares regression (PLSR) models for predicting tissue weights. Models were validated using 79 additional carcass sides, which were broken into primals, scanned using DXA, and subsequently dissected to fat, lean and bone. Models were highly accurate for predicting tissue weights for the entire carcass side (lean R = 0.991, fat R = 0.985 and bone R = 0.941) and within most primal cuts. Results suggest DXA technology can be utilized to accurately predict carcass tissue composition for whole carcass sides and within most primals.
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http://dx.doi.org/10.1016/j.meatsci.2018.07.009DOI Listing
December 2018

Determination of optimum oven cooking procedures for lean beef products.

Food Sci Nutr 2015 Nov 24;3(6):475-85. Epub 2015 Apr 24.

Agriculture and Agri-Food Canada Lacombe Research Centre, 6000 C & E Trail Lacombe Alberta T4L 1W1 Canada.

In order to determine optimum oven cooking procedures for lean beef, the effects of searing at 232 or 260°C for 0, 10, 20 or 30 min, and roasting at 160 or 135°C on semimembranosus (SM) and longissimus lumborum (LL) muscles were evaluated. In addition, the optimum determined cooking method (oven-seared for 10 min at 232°C and roasted at 135°C) was applied to SM roasts varying in weight from 0.5 to 2.5 kg. Mainly, SM muscles seared for 0 or 10 min at 232°C followed by roast at 135°C had lower cooking loss, higher external browning color, more uniform internal color, and were more tender and flavorful (P < 0.05). Roast weights ≥1 kg had lesser cooking loss, more uniform internal color and tender compared to 0.5 kg (P < 0.05). Consequently, roasting at low temperature without searing is the recommended oven cooking procedure; with best response from muscle roast weight ≥1 kg.
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http://dx.doi.org/10.1002/fsn3.229DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4708649PMC
November 2015

Pork as a Source of Omega-3 (n-3) Fatty Acids.

J Clin Med 2015 Dec 16;4(12):1999-2011. Epub 2015 Dec 16.

Agriculture and Agri-Food Canada, Lacombe Research Centre, Lacombe T4L 1W1, AB, Canada.

Pork is the most widely eaten meat in the world, but typical feeding practices give it a high omega-6 (n-6) to omega-3 (n-3) fatty acid ratio and make it a poor source of n-3 fatty acids. Feeding pigs n-3 fatty acids can increase their contents in pork, and in countries where label claims are permitted, claims can be met with limited feeding of n-3 fatty acid enrich feedstuffs, provided contributions of both fat and muscle are included in pork servings. Pork enriched with n-3 fatty acids is, however, not widely available. Producing and marketing n-3 fatty acid enriched pork requires regulatory approval, development costs, quality control costs, may increase production costs, and enriched pork has to be tracked to retail and sold for a premium. Mandatory labelling of the n-6/n-3 ratio and the n-3 fatty acid content of pork may help drive production of n-3 fatty acid enriched pork, and open the door to population-based disease prevention polices (i.e., food tax to provide incentives to improve production practices). A shift from the status-quo, however, will require stronger signals along the value chain indicating production of n-3 fatty acid enriched pork is an industry priority.
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http://dx.doi.org/10.3390/jcm4121956DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4693156PMC
December 2015

The scope for manipulating the polyunsaturated fatty acid content of beef: a review.

J Anim Sci Biotechnol 2015 24;6(1):29. Epub 2015 Jun 24.

Agriculture and Agri-Food Canada, Lacombe Research Centre, 6000 C & E Trail, T4L 1 W1, Lacombe, AB Canada.

Since 1950, links between intake of saturated fatty acids and heart disease have led to recommendations to limit consumption of saturated fatty acid-rich foods, including beef. Over this time, changes in food consumption patterns in several countries including Canada and the USA have not led to improvements in health. Instead, the incidence of obesity, type II diabetes and associated diseases have reached epidemic proportions owing in part to replacement of dietary fat with refined carbohydrates. Despite the content of saturated fatty acids in beef, it is also rich in heart healthy cis-monounsaturated fatty acids, and can be an important source of long-chain omega-3 (n-3) fatty acids in populations where little or no oily fish is consumed. Beef also contains polyunsaturated fatty acid biohydrogenation products, including vaccenic and rumenic acids, which have been shown to have anticarcinogenic and hypolipidemic properties in cell culture and animal models. Beef can be enriched with these beneficial fatty acids through manipulation of beef cattle diets, which is now more important than ever because of increasing public understanding of the relationships between diet and health. The present review examines recommendations for beef in human diets, the need to recognize the complex nature of beef fat, how cattle diets and management can alter the fatty acid composition of beef, and to what extent content claims are currently possible for beef fatty acids.
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http://dx.doi.org/10.1186/s40104-015-0026-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4509462PMC
July 2015

Improving beef hamburger quality and fatty acid profiles through dietary manipulation and exploitation of fat depot heterogeneity.

J Anim Sci Biotechnol 2014 24;5(1):54. Epub 2014 Nov 24.

Agriculture and Agri-Food Canada, Lacombe Research Centre, 6000 C and E Trail, Lacombe, Alberta T4L 1 W1 Canada.

Background: Hamburger is the most consumed beef product in North America, but lacks in nutritional appeal due to its high fat content and high proportion of saturated fatty acids (SFA). Objectives of the present study were to improve the FA profiles of hamburgers made with perirenal fat (PRF) and subcutaneous fat (SCF) when feeding steers different diets along with examining differences in sensory attributes and oxidative stability. Diets included a control diet containing 70:30 red clover silage: barley based concentrate, a diet containing sunflower-seed (SS) substituted for barley, and diets containing SS with 15% wheat dried distillers' grain with solubles (DDGS-15) or 30% DDGS (DDGS-30). Hamburgers were made from triceps brachii and either PRF or SCF (80:20 w/w).

Results: Perirenal fat versus SCF hamburgers FA had 14.3% more (P <0.05) 18:0, 11.8% less cis (c)9-18:1 (P <0.05), and 1.82% more total trans (t)-18:1 mainly in the form of t11-18:1. During sensory evaluation, PRF versus SCF hamburgers had greater (P <0.05) mouth coating, but the difference was less than one panel unit. Examining effects of steer diet within PRF hamburgers, feeding the SS compared to the control diet increased (P <0.05) t-18:1 by 2.89% mainly in the form of t11-18:1, feeding DGGS-15 diet led to no further changes (P >0.05), but feeding DDGS-30 diet reduced the proportions of (P <0.05) of t-18:1 chiefly t11-18:1. Feeding SS and DDGS diets had small but significant (P <0.05) effects on hamburger sensory attributes and oxidative stability.

Conclusions: Feeding high-forage diets including SS and 15% DDGS, and taking advantage of the FA heterogeneity between fat depots offers an opportunity to differentially enhance beef hamburgers with 18:2n-6 biohydrogenation products (i.e., t11-18:1) with potential human health benefits without compromising their sensory attributes and oxidative stability during retail display.
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http://dx.doi.org/10.1186/2049-1891-5-54DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4373243PMC
March 2015

Fortification of pork loins with docosahexaenoic acid (DHA) and its effect on flavour.

J Anim Sci Biotechnol 2013 Nov 20;4(1):46. Epub 2013 Nov 20.

Agriculture and Agri-Food Canada, Lacombe Research Centre, 6000 C&E Trail, Lacombe T4L 1 W1AB, Canada.

Pork is traditionally low in docosahexanoic acid (DHA, C22:6n-3) and deficient in omega-3 fats for a balanced human diet. DHA as triglycerides was commercially prepared from the microalgae Schizochytrium and injected into fresh pork loins. Treatments of a mixed brine control (CON), 3.1% sunflower oil in mixed brine (SF) and a 3.1% DHA oil in mixed brine (DHA) were injected into pork loins at 10 mL/100 g and grilled at 205°C. After cooking, the CON and SF pork loins contained 0.03 to 0.05 mg DHA/g of pork and the DHA injected loins contained approximately 1.46 mg DHA/g. This also changed the fatty acid profile of omega-6: omega-3 from, 5 to 1 in the CON pork, to a ratio of 1.7 to 1 in DHA pork. The appearance, odor, oxidation rates and sensory taste, as judged by a trained panel, determined the DHA injected meat to be, 'slightly desirable' and gave lower 'off flavour' scores, relative to the CON and SF injected pork. Pork can be fortified with DHA oil to 146 mg/100 g serving, which would meet half the recommended daily omega 3 fatty acid requirements for adult humans and would be desirable in taste.
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http://dx.doi.org/10.1186/2049-1891-4-46DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4222727PMC
November 2013

Subcutaneous fatty acid composition of steers finished as weanlings or yearlings with and without growth promotants.

J Anim Sci Biotechnol 2013 Nov 4;4(1):41. Epub 2013 Nov 4.

Agriculture and Agri-Food Canada, Lacombe Research Centre, 6000 C & E Trail, Lacombe, Alberta T4L 1 W1, Canada.

Background: The current study evaluated the subcutaneous fatty acid (FA) composition of calf- and yearling-fed steers with or without growth promoting implants. Crossbred steers (n = 112; 267 ± 5.0 kg) of the same contemporary group were allocated to one of four production system and implant strategy based treatments in a completely randomized design with a 2 × 2 factorial arrangement of treatments.

Results: There were no interactions (P > 0.05) between production systems and growth promoting implants for the total and individual subcutaneous FA. Yearling as opposed to calf finishing reduced (P < 0.05) subcutaneous proportions of C20:3n-6, trans (t)12-18:1, C14:0, several minor cis-monounsaturated FA (c-MUFA; c9-14:1, c11-16:1, c11-18:1, c12-18:1, c13-18:1, c9-20:1 and c11-20:1), and increased (P < 0 .05) subcutaneous proportions of t11c15-18:2, total and individual branched-chain FA. Subcutaneous fat from steers implanted with growth promotants had higher (P < 0.05) proportions of total polyunsaturated FA (PUFA), total n-6 PUFA, C18:2n-6 and individual t-18:1 isomers (t6 to t10) compared to non-implanted steers.

Conclusions: Overall, current findings show that production systems and growth promotants led to only minor differences in subcutaneous FA composition of beef steers.
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http://dx.doi.org/10.1186/2049-1891-4-41DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3874639PMC
November 2013

Introducing an angle adjustable cutting box for analyzing slice shear force in meat.

J Vis Exp 2013 Apr 26(74):e50255. Epub 2013 Apr 26.

Lacombe Research Centre, Agriculture and Agri-Food Canada.

Research indicates the fibre angle of the longissimus muscle can vary, depending upon location within a steak and throughout the muscle. Instead of using the original fixed 45 ° or 90 ° cutting angle for testing shear force, a variable angle cutting box can be adjusted so the angles of the knives correspond to the fibre angle of each sample. Within 2 min after cooking to an internal temperature of 71 °C on an open-hearth grill set at 210 °C, a 1 cm by 5 cm core is cut from the steak, parallel to muscle fibre direction, using 2 knife blades set 1 cm apart. This warm core is then subjected to the Slice Shear Force protocol (SSF) to evaluate meat texture. The use of the variable angle cutting box and the SSF protocol provides an accurate representation of the maximal shear force, as the slice and muscle fibres are consistently parallel. Therefore, the variable angle cutting box, in conjunction with the SSF protocol, can be used as a high-throughput technique to accurately evaluate meat tenderness in different locations of the longissimus muscle and, potentially, in other muscles.
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http://dx.doi.org/10.3791/50255DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3671771PMC
April 2013

Type of packaging affects the colour stability of vitamin E enriched beef.

Food Chem 2012 Dec 29;135(3):1868-72. Epub 2012 Jun 29.

Lacombe Research Centre, 6000 C & E Trail, Lacombe, Canada AB T4L 1W1.

Colour stability is a very important parameter for meat retail display, as appearance of the product is the deciding factor for consumers at time of purchase. This study investigated the possibility of extending appearance shelf-life through the combined use of packaging method (overwrapping - OVER, modified atmosphere - MAP, vacuum skin packaging - VSP and a combination of modified atmosphere and vacuum skin packaging - MAPVSP) and antioxidants (vitamin E enriched beef). Retail attributes (appearance, lean colour, % surface discolouration), as well as colour space analysis of images for red, green and blue parameters were measured over 18days. MAPVSP provided the most desirable retail appearance during the first 4days of retail display, while VSP-HB had the best colour stability. Overall, packaging type was more influential than α-tocopherol levels on meat colour stability, although α-tocopherol levels (>4μgg(-1) meat) had a protective effect when using high oxygen packaging methods.
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http://dx.doi.org/10.1016/j.foodchem.2012.06.055DOI Listing
December 2012

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

Meat Sci 2012 Jun 25;91(2):203-6. Epub 2012 Jan 25.

Instituto de Ganadería de Montaña, Grulleros, León, Spain.

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.
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http://dx.doi.org/10.1016/j.meatsci.2012.01.011DOI Listing
June 2012

Beef quality attributes as affected by increasing the intramuscular levels of vitamin E and omega-3 fatty acids.

Meat Sci 2012 Mar 10;90(3):764-9. Epub 2011 Nov 10.

Agriculture and Agri-Food Canada, Lacombe Research Centre, 6000 C & E Trail, Lacombe, AB, Canada T4L 1W1.

In order to investigate the effects of increasing beef n-3 fatty acid content and the protective effects of vitamin E antioxidant activity on meat quality characteristics, 80 feedlot steers were fed 4 different diets (control, high vitamin E, 10% ground flaxseed or high vitamin E-10% ground flaxseed). While dietary treatments had no effect (P>0.05) on meat composition or tenderness values, the increase in oxidation products was lower (P=0.046) in meat from vitamin E supplemented steers and higher (P=0.006) in meat from flaxseed fed animals. The increase in α-tocopherol tissue levels (P<0.001) in meat from animals fed flaxseed and increased dietary vitamin E resulted in the lowest drip loss values (P=0.013). As expected, display time had a large effect on retail traits in both steaks and patties (P<0.001). While retail traits of steaks were not affected by the dietary treatments (P>0.05), feeding flaxseed decreased (P<0.05) ground beef retail scores, which were not corrected by higher levels of dietary vitamin E. Finally, although no effect (P>0.05) was observed among treatments for sensory attributes in steaks, the correlations of a combined n-3:α-tocopherol ratio against retail and sensory attributes (P<0.05) suggest that increased n-3 fatty acids levels require increased dietary antioxidants, such as vitamin E to avoid negative effects on meat quality from a loss in oxidative stability.
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http://dx.doi.org/10.1016/j.meatsci.2011.11.010DOI Listing
March 2012

Effects of vitamin E and flaxseed on rumen-derived fatty acid intermediates in beef intramuscular fat.

Meat Sci 2011 Jul 2;88(3):434-40. Epub 2011 Feb 2.

Agriculture and Agri-Food Canada, Lacombe Research Centre, 6000 C & E Trail, Lacombe, AB, Canada T4L 1W1.

To elucidate the effects of dietary vitamin E with or without flaxseed on beef fatty acid composition, 80 feedlot steers were fed 4 diets: Control-E (451 IU dl-α-tocopheryl acetate/head/day), Control+E (1051 IU dl-α-tocopheryl acetate/head/day), Flax-E (10% ground) and Flax+E. Vitamin E had no effect on animal growth or carcass weight (p>0.05), while flaxseed-fed steers had greater average daily gain (p=0.007), final live weight (p=0.005) and heavier carcasses (p=0.012). Feeding flaxseed increased the total n-3 fatty acid content of beef and this response was further accentuated by the inclusion of high levels of vitamin E in the diet. Feeding flax increased levels of some 18:3n-3 partial hydrogenation products including c15- and t13/14-18:1 and several 18:2 isomers (p<0.001) but decreased t10-18:1 (p<0.001). Vitamin E enhanced intramuscular levels of 18:3n-3 and its biohydrogenation products leading to greater accumulations of total n-3 fatty acids in lean ground beef. The consequences of increasing the concentrations of partially hydrogenated products on human health have yet to be investigated.
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http://dx.doi.org/10.1016/j.meatsci.2011.01.023DOI Listing
July 2011

Effects of dry-ageing on pork quality characteristics in different genotypes.

Meat Sci 2011 May 9;88(1):117-21. Epub 2010 Dec 9.

Agriculture and Agri-Food Canada, Lacombe Research Centre, 6000 C & E Trail, Lacombe, Alberta, Canada T4L 1W1.

Presumably, dry-ageing enhances flavour attributes of meat by surface desiccation to increase and modify fatty acid content and other organoleptic molecules. However information regarding dry-ageing of fresh pork is limited. To examine the effects of dry-ageing on pork quality, Large White (LW, n = 24) and Large White × Duroc (Duroc, n = 24) barrows were slaughtered and three longissimus thoracis et lumborum sections from each side of the carcass were wet or dry-aged for 2, 7 or 14 d. Dry-aged meat had lower (P < 0.001) moisture and higher (P < 0.001) protein content due to higher purge losses (P < 0.001) when compared with wet aged meat. However no dry-ageing effect (P > 0.05) was observed on sensory characteristics. The increase in the duration of ageing decreased moisture content and drip loss and increased (P < 0.001) protein content, purge loss and L*, chroma and hue values. These changes were more accentuated in dry-aged meat (P < 0.01). Days of ageing dependent increases (P < 0.001) were observed for instrumental and sensory tenderness and juiciness in both ageing types. Moreover, meat from Duroc barrows had lower (P < 0.001) moisture and protein content, and higher (P < 0.01) fat content, L* and hue values. Instrumental and sensory tenderness, juiciness and flavour were higher (P < 0.01) in meat from Duroc than LW barrows. Increases (P < 0.01) in flavour intensity and decreases in off-flavour of meat from LW barrows were greater (P < 0.05) in d 7 than in d 14. Therefore the duration of ageing affected most quality and sensory characteristics, while the changes to quality attributes of dry versus wet-aged pork were attributable to the differences in shrink losses in the present study.
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http://dx.doi.org/10.1016/j.meatsci.2010.12.011DOI Listing
May 2011

Enhancing pork loin quality attributes through genotype, chilling method and ageing time.

Meat Sci 2009 Nov 16;83(3):447-53. Epub 2009 Jun 16.

Agriculture and Agri-Food Canada, Lacombe Research Centre, 6000 C & E Trail, Lacombe, Alberta, Canada T4L 1W1.

The experiment was conducted to examine opportunities for enhancing pork quality through the use of post-mortem ageing when combined with different chilling regimes. Large White (LW, n=24) and Duroc×Large White (Duroc, n=24) barrows were slaughtered and alternate carcass sides were either conventionally or blast-chilled. The longissimus thoracis et lumborum muscle was dissected from the carcass sides (24h post-mortem) and trimmed of cover fat. Three sections (15cm length) were vacuum packaged and assigned to 2, 7 or 14days of ageing (2°C) randomized within muscle location. Blast-chilled meat had lower purge (P=0.009) and drip (P=0.0009) losses and higher hue (P=0.02) than conventionally chilled meat. However chilling by conventional or blast-chilling methods had no effect on sensory characteristics (P>0.1). When breeds were compared, meat from Duroc barrows had lower moisture (P<0.0001) and higher intramuscular fat content (P<0.0001), L∗ (P=0.0003) and hue (P=0.007) values than LW. Overall tenderness (P=0.005), juiciness (P=0.0007) and palatability (P<0.0001), as well as flavour intensity (P<0.0001) and desirability (P<0.0001) values were higher and undesirable flavours were lower (P<0.0001) for meat from Duroc pigs, when compared with LW. Ageing increased purge loss (P<0.0001), L∗ (P<0.0001), hue (P<0.0001), chroma (P<0.0001) and content of protein (P=0.002), with corresponding decreases (P<0.0001) in drip loss and moisture content. Instrumental (P<0.0001) and sensory (initial, P<0.0001 and overall, P<0.0001) tenderness increased from day 2 to 14. Therefore independent of chilling method, ageing improved quality of pork loins. Moreover ageing had greater effect on tenderness, while breed had greater effect on flavour which may be related to differences in intramuscular fat content.
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http://dx.doi.org/10.1016/j.meatsci.2009.06.016DOI Listing
November 2009

Trans-18:1 and conjugated linoleic acid profiles after the inclusion of buffer, sodium sesquicarbonate, in the concentrate of finishing steers.

Meat Sci 2010 Apr 18;84(4):735-41. Epub 2009 Nov 18.

Agriculture and Agri-Food Canada, Lacombe Research Centre, 6000 C&E Trail, Lacombe, AB, Canada T4L 1W1.

Ninety-six European crossbred steers were fed a barley-based finishing diet for differing lengths of time (34-104 days) to investigate if adding dietary buffer (sodium sesquicarbonate at 1.5% as fed) could improve the trans-18:1 (GC-FID) and CLA (Ag(+)-HPLC-DAD) content and isomeric profile of beef produced. Results indicate that the addition of buffer to diets of cattle fed high concentrate diets has limited effects on the overall fatty acid composition of backfat and muscle tissues. However, buffer addition can help to prevent a 10t- shift by maintaining a better (higher) 11t-/10t-18:1 ratio in both meat and backfat during the first 30-60 days of feeding a high grain diet. Over time, however, the effect is lost becoming equal in tissues from animals with or without buffer addition to their diets.
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http://dx.doi.org/10.1016/j.meatsci.2009.11.009DOI Listing
April 2010

Fatty acid composition of muscle fat and enzymes of storage lipid synthesis in whole muscle from beef cattle.

Lipids 2006 Nov;41(11):1049-57

Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton AB T6G 2P5, Canada.

Enhanced intramuscular fat content (i.e., marbling) in beef is a desirable trait, which can result in increased product value. This study was undertaken with the aim of revealing biochemical factors associated with the marbling trait in beef cattle. Samples of longissimus lumborum (LL) and pars costalis diaphragmatis (PCD) were taken from a group of intact crossbred males and females at slaughter, lipids extracted, and the resulting FAME examined for relationships with marbling fat deposition. For LL, significant associations were found between degree of marbling and myristic (14:0, r = 0.55, P < 0.01), palmitic (16:0, r = 0.80, P < 0.001), stearic (18:0, r = -0.58, P < 0.01), and oleic (18:1c-9, r = 0.79, P < 0.001) acids. For PCD, significant relationships were found between marbling and palmitic (r = 0.71, P < 0.001) and oleic (r = 0.74, P < 0.001) acids. Microsomal fractions prepared from PCD muscle were assayed for diacylglycerol acyltransferase (DGAT), lysophosphatidic acid acyltransferase (LPAAT), and phosphatidic acid phosphatase-1 (PAP-1) activity, and the results examined for relationships with degree of intramuscular fat deposition. None of the enzyme activities from PCD displayed an association with marbling fat content, but DGAT specific activity showed significant positive associations with LPAAT (r = 0.54, P < 0.01), total PAP (r = 0.66, P < 0.001), and PAP-1 (r = 0.63, P < 0.01) specific activities. The results on FA compositions of whole muscle tissues provide insight into possible enzyme action associated with the production of specific FA. The increased proportion of oleic acid associated with enhanced lipid content of whole muscle is noteworthy given the known health benefits of this FA.
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http://dx.doi.org/10.1007/s11745-006-5055-0DOI Listing
November 2006

Detection of transgenic and endogenous plant DNA in digesta and tissues of sheep and pigs fed Roundup Ready canola meal.

J Agric Food Chem 2006 Mar;54(5):1699-709

Agriculture and Agri-Food Canada Research Centres, Lethbridge, Alberta, Canada.

The persistence of plant-derived recombinant DNA in sheep and pigs fed genetically modified (Roundup Ready) canola was assessed by PCR and Southern hybridization analysis of DNA extracted from digesta, gastrointestinal (GI) tract tissues, and visceral organs. Sheep (n = 11) and pigs (n = 36) were fed to slaughter on diets containing 6.5 or 15% Roundup Ready canola. Native plant DNA (high- and low-copy-number gene fragments) and the cp4 epsps transgene that encodes 5-enolpyruvyl shikimate-3-phosphate synthase were tracked in ruminal, abomasal, and large intestinal digesta and in tissue from the esophagus, rumen, abomasum, small and large intestine, liver, and kidney of sheep and in cecal content and tissue from the duodenum, cecum, liver, spleen, and kidney of pigs. High-copy chloroplast-specific DNA (a 520-bp fragment) was detected in all digesta samples, the majority (89-100%) of intestinal tissues, and at least one of each visceral organ sample (frequencies of 3-27%) from sheep and swine. Low-copy rubisco fragments (186- and 540-bp sequences from the small subunit) were present at slightly lower, variable frequencies in digesta (18-82%) and intestinal tissues (9-27% of ovine and 17-25% of porcine samples) and infrequently in visceral organs (1 of 88 ovine samples; 3 of 216 porcine samples). Each of the five cp4 epsps transgene fragments (179-527 bp) surveyed was present in at least 27% of ovine large intestinal content samples (maximum = 64%) and at least 33% of porcine cecal content samples (maximum = 75%). In sheep, transgene fragments were more common in intestinal digesta than in ruminal or abomasal content. Transgene fragments were detected in 0 (esophagus) to 3 (large intestine) GI tract tissues from the 11 sheep and in 0-10 of the duodenal and cecal tissues collected from 36 pigs. The feed-ingested recombinant DNA was not detected in visceral tissues (liver, kidney) of lambs or in the spleen from pigs. Of note, however, one liver and one kidney sample from the pigs (different animals) were positive for a 278-bp fragment of the transgenic cp4 epsps (denoted F3). Examination of genomic libraries from these tissues yielded no conclusive information regarding integration of the fragment into porcine DNA. This study confirms that feed-ingested DNA fragments (endogenous and transgenic) do survive to the terminal GI tract and that uptake into gut epithelial tissues does occur. A very low frequency of transmittance to visceral tissue was confirmed in pigs, but not in sheep. It is recognized that the low copy number of transgenes in GM feeds is a challenge to their detection in tissues, but there was no evidence to suggest that recombinant DNA would be processed in the gut in any manner different from endogenous feed-ingested genetic material.
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http://dx.doi.org/10.1021/jf052459oDOI Listing
March 2006

Conjugated linoleic acid pork research.

Am J Clin Nutr 2004 06;79(6 Suppl):1212S-1216S

Agriculture and Agri-Food Canada, Lacombe Research Centre, Lacombe, Canada.

The driving force behind most conjugated linoleic acid (CLA) research in swine has been related to potential improvements in animal production. Early work that used rodent models indicated that feeding CLA could potentially reduce body fat, increase lean content, increase growth rate, and improve feed conversion efficiency. Producer-backed funding organizations were, therefore, receptive to proposals to extend this research to pigs, and many studies have been completed worldwide. In general, improvements in body composition were found, but evidence indicating that CLA improves growth rate or feed conversion was limited. Inclusion of CLA into pig diets was, however, shown to increase muscle marbling fat and fat hardness, and both of these characteristics have the potential to increase carcass value. Currently, Badische Anilin- & Soda-Fabrik AG (BASF) has the international marketing license to include synthetic CLA in animal feeds, but to date this practice is not approved in Canada or the United States. If and when approval is granted, the next step in realizing CLA's economic potential would be to seek approval for claiming CLA enrichment in pork and pork products. Given the ability of swine to accumulate relatively high amounts of CLA in their tissues, pork and pork products could become an important vehicle for delivery of physiologically significant amounts of CLA to consumers.
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June 2004
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