Showing papers by "John K. G. Kramer published in 2011"
TL;DR: The ionic liquid SLB-IL111 column, available from Supelco Inc., is a novel fused capillary gas chromatography (GC) column capable of providing enhanced separations of fatty acid methyl esters (FAMEs) compared to the highly polar cyanopropyl siloxane columns currently recommended for the separation of cis- and trans isomers of fatty acids (FAs).
158 citations
TL;DR: The authors investigated changes in fatty acid profiles of cows fed grass hay or barley silage-based diets, with or without flaxseed supplementation, and found that both flax seed and hay feeding increased levels of α-linolenic acid (LNA; 18:3n-3) in longissimus thoracis and backfat.
68 citations
TL;DR: Intensively finishing cattle on a high-grain diet is generally used to enhance marbling, whereas extensively finishing on grass is known to provide improved muscle fatty acid profiles, whereas grass finishing was judged to provide a healthier beef fatty acid profile.
Abstract: Intensively finishing cattle on a high-grain diet is generally used to enhance marbling, whereas extensively finishing on grass is known to provide improved muscle fatty acid profiles. The objective of this study was to evaluate to what extent intensive concentrate finishing (0, 1 or 2 months) can be combined with forage feeding without negatively affecting the fatty acid profile of genetically lean animals. Bulls from the ‘Asturiana de los Valles’ breed were reared under grazing conditions with/without final finishing on a barley-based concentrate: 0 months (control; n = 7), 1 month (n = 10) and 2 months (n = 7). Yearling bulls were slaughtered commercially at an average live weight of 516 ± 9.8 kg. Increasing the finishing time on concentrate significantly increased the saturated and monounsaturated fatty acids, whereas polyunsaturated fatty acids (PUFAs) tended to decrease and it was not possible to increase the long-chain PUFA content in muscle tissue of this breed. An increase was observed for total trans-18:1 (average 5.5% with grain v. 3.7% for grass). The 11t-18:1/10t-18:1 ratio was significantly higher in grass-fed (average 8.1) compared with grain-finished animals (average 1.1). Grass or limited concentrate finishing reduced the n-6/n-3 ratio in muscle tissue (average 3.6 for 0 and 1 month, and 4.9 for 2 months on grain finishing). The beef was within or close to the recommended values for human consumption (i.e. polyunsaturated/saturated > 0.45, n-6/n-3 < 4.0), and total trans-FA content was low. However, finishing increased the content of undesirable trans-18:1 and conjugated linoleic acid isomers, particularly after 2 months, whereas grass finishing was judged to provide a healthier beef fatty acid profile.
59 citations
TL;DR: Dugan et al. as mentioned in this paper reviewed trans-forming beef to provide healthier fatty acid profiles and found that trans fatty acid consumption was associated with coronary heart disease and led to recommendations to reduce their consumption.
Abstract: 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 ...
59 citations
TL;DR: Using attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectroscopy, collaborating scientists in ten different laboratories measured (in duplicate) the total trans fat content of ten fat or oil test samples, two of which were blind duplicates as discussed by the authors.
Abstract: Using attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectroscopy, collaborating scientists in ten different laboratories measured (in duplicate) the total trans fat content of ten fat or oil test samples, two of which were blind duplicates. The procedure used entailed measuring the height of the negative second derivative of the IR absorption band at 966 cm−1. This absorption is attributed to the C–H deformation vibration that is characteristic of isolated (non-conjugated) double bonds with the trans configuration. The precision of ATR-FTIR results in this international collaborative study was satisfactory and led to the approval of this validated procedure as official method AOCS Cd 14e-09 in late 2009. This official method is also suitable for analysis of total isolated trans fat and oil products containing, or supplemented with, trans conjugated linoleic acid (CLA) isomers. Although this method does not require derivatization of the oil or fat test materials, as required for GC, fats and oils in foods must be extracted with organic solvents before analysis. This method is also rapid (5 min) and does not require any weighing or quantitative dilution of unknown neat fat or oil test samples in any solvent. The AOCS Cd 14e-09 method is suitable for determination of test samples with zero trans fat, which is defined according to the US labeling regulations as 0.5 g trans fat per serving or 1.8% trans fat, as a percentage of total fat.
19 citations
TL;DR: It is proposed that FT‐NIR is an ideal method for safe repeat measurements in large trials or in screening and monitoring individuals during interventions in which changes in body fat will occur, and is a lower cost, easy to use and transport, and an accurate method to measure body fat content.
Abstract: Even though BMI is the most commonly used method for assessing and monitoring obesity, it does not take into account the individual’s body fat content assuming instead that body mass is closely associated with body fat, which is a tenuous assumption. The aim of this study was to make a direct comparison between measurements of body fat content using a convenient and rapid Fourier transform near-infrared (FT-NIR) spectroscopy and dual-energy X-ray absorptiometry (DXA). We recruited 52, premenopausal women (age range 19–45), all of whom had a BMI that classified them as either overweight or obese (range: 27–40 kg/m 2 , mean: 31.1 ± 3.7 kg/m 2 ) and indicated a statistically significant linear relationship between the fat content in kilograms measured by FT-NIR and DXA (r = 0.95, P < 0.001). Bland–Altman analysis showed that almost all the differences between two measurements fell within 2 s.d. We report here that the FT-NIR method provided comparable measurements of subcutaneous body fat content similar to those of total fat obtained using DXA. The FT-NIR method is a lower cost, easy to use and transport, and, based on comparison with DXA, an accurate method to measure body fat content. We propose that FT-NIR is an ideal method for safe repeat measurements in large trials or in screening and monitoring individuals during interventions in which changes in body fat will occur.
12 citations