Dipesh Prema

Rapid Determination of Total Conjugated Linoleic Acid Content in Select Canadian Cheeses by 1H NMR Spectroscopy

The application of (1)H nuclear magnetic resonance (NMR) spectroscopy to the measurement of conjugated linoleic acid (CLA) content in the lipid fraction of dairy products is both a novel and inviting alternative to traditional methods such as gas chromatography (GC), which can require time-consuming sample derivatization. In this work, a newly developed, rapid, and reliable lipid extraction protocol was combined with simple, nondestructive (1)H NMR spectroscopic analysis to measure the total CLA content in CLA standards and in various Canadian cheeses from conventional, organic, and grass-fed dairy sources. The total CLA concentrations (mg/g cheese) obtained using these new extraction and analysis methods were consistent with amounts found using the modified Folch extraction and GC analysis (correlation coefficient of 0.948). Results showed that cheeses from exclusively grass-fed dairy cows were significantly higher in total CLA content than either conventional or organic cheese.

Safety, bioavailability and mechanism of action of nitric oxide to control Bovine Respiratory Disease Complex in calves entering a feedlot.

Bovine Respiratory Disease Complex (BRDc), a multi-factorial disease, negatively impacts the cattle industry. Nitric oxide (NO), a naturally occurring molecule, may have utility controlling incidence of BRDc. Safety, bioavailability, toxicology and tolerance/stress of administering NO to cattle is evaluated herein. Thirteen, crossbred, multiple-sourced, commingled commercial weaned beef calves were treated multiple times intranasally over a 4 week period with either a nitric oxide releasing solution (treatment) or saline (control). Exhaled NO, methemoglobin percent (MetHg) and serum nitrites demonstrated biological availability as a result of treatment. Cortisol levels, tissue nitrites, behavior and gross and macroscopic pathology of organs were all normal. Moreover, preliminary in vitro studies using Mannheimia haemolytica, Infectious Bovine Rhinotracheitis, Bovine Parainfluenza-3 and Bovine Respiratory Syncytial Virus, suggest a potential explanation for the previously demonstrated efficacy for BRDc. These data confirm the bioavailability, safety and lack of residual of NO treatment to cattle, along with the bactericidal and virucidal effects.

Separation of dietary omega‐3 and omega‐6 fatty acids in food by capillary electrophoresis

A lower dietary omega-6/omega-3 (n-6/n-3) fatty acid ratio (<4) has been shown to be beneficial in preventing a number of chronic illnesses. Interest exists in developing more rapid and sensitive analytical methods for profiling fatty acid levels in foods. An aqueous CE method was developed for the simultaneous determination of 15 n-3 and n-6 relevant fatty acids. The effect of pH and concentration of buffer, type and concentration of organic modifier, and additive on the separation was investigated in order to determine the best conditions for the analysis. Baseline separations of the 15 fatty acids were achieved using 40 mM borate buffer at pH 9.50 containing 50 mM SDS, 10 mM β-cyclodextrin, and 10% acetonitrile. The developed CE method has LODs of <5 mg/L and good linearity (R(2) > 0.980) for all fatty acids studied. The proposed method was successfully applied to the determination of n-3 and n-6 fatty acids in flax seed, Udo® oils and a selection of grass-fed and grain-fed beef muscle samples.

Dinuclear zinc(II) complexes of symmetric Schiff-base ligands with extended quinoline sidearms†‡

The synthesis of two 2-formylquinolines is reported via the Skraup method followed by SeO(2) oxidation. Each aldehyde is condensed with (1R,2R)-diaminocyclohexane and (R)-BINAM, yielding four enantiomerically-pure bis(imine-quinoline) ligands. The neutral ligands are reacted with ZnCl(2) to give complexes with bis(bidentate) coordination of ZnCl(2) units. X-Ray structural characterization of three complexes shows them to have a single-stranded helical motif, with M helicity, except in one case where a 1:1 mixture of M and P helices is seen. The ligands and complexes are further characterized spectroscopically by solution (1)H and (13)C NMR, UV-vis and ECD.

Comparison of fatty acids in beef tissues from conventional, organic and natural feeding systems in western Canada

Turner, T. D., Jensen, J., Pilfold, J. L., Prema, D., Donkor, K. K., Cinel, B., Thompson, D. J., Dugan, M. E. R. and Church, J. S. 2015. Comparison of fatty acids in beef tissues from conventional, organic and natural feeding systems in western Canada. Can. J. Anim. Sci. 95: 49-58. The effect of production system on intramuscular and associated trim fatty acid (FA) profiles of retail ribeye steaks from conventional and niche market organic and natural (grain- or grass-fed) beef were compared. Meat from organic grain- and grass-fed systems was leaner, containing greater proportions of polyunsaturated FA, i.e., 18:3n-3, 20:5n-3, 22:5n-3, 22:6n-3. Correspondingly, the n-6/n-3 ratios of organic grain- and grass-fed systems were 3:1, while conventional and natural grain systems had ratios of 8:1. High forage-to-grain ratio production systems increased proportions of desirable biohydrogenation intermediates (BI), including t11-18:1 and c9,t11-18:2, whereas conventional and natural grain systems elevated t10-18:1. Trim fat was similarly affected by production system, and was a relatively richer source of BI. Overall, proportions of desirable FAs, including n-3 and BI, were greater for organic grain- and grass-fed systems, emphasizing the importance of a high forage-to-grain ratio to enhance the healthfulness of beef, whereas conventional and natural grain-fed systems were largely equivalent.

Rapid determination of n-6 and n-3 fatty acid ratios in cereal grains and forages by 1H NMR spectroscopy

Abstract: Herein we describe a new method to rapidly determine the n-6/n-3 fatty acid ratios in cereal grains and forages (hydroponically-grown cereal sprouts and haylage) using 1H nuclear magnetic resonance (NMR) spectroscopy. This NMR method was found to be consistent with more established but time-consuming gas chromatographic methods (R = 0.994).

Fatty acid profile of British Columbia suckler beef

Abstract: In this study, the influence of feeding system on the fatty acid (FA) profile of suckler beef (SB), moderate grain-fed (MG), and grass-fed (GF) beef was compared. It was found that total saturated FA content was not affected; however, greater 14:0, total polyunsaturated FA content, and lower n-6/n-3 ratio suggest some transmittance of milk FA in SB calves (P < 0.001).