Gassman, K.

Larsen, S. T.

Parrish, F. C., Jr.

Swan, J. E.

Trenkle, A. H.

Wiegand, B. R.

English

Wiegand, B.

Swan, J.

Parrish, F.

Trenkle, A.

Larsen, S.

Digital Repository @ Iowa State University (ISU)

2001 Beef Research Report — Iowa State University131Conjugated Linoleic Acid (CLA) in Diets of Beef Steers Results inHigher Red Color Scores and Lower Lipid Oxidation ofIrradiated Ground Beef PattiesA.S. Leaflet R1764B. R. Wiegand, Illinois State University;K. Gassman, Cargill; J. E. Swan, Elanco Animal Health;and F. C. Parrish, Jr., A. H. Trenkle, and S. T. Larsen,Iowa State UniversityIntroductionFeeding CLA 60 to market pigs resulted in decreasedthiobarbituric acid (TBA) values (less oxidative rancidity) infresh pork chops and increased Hunter a* values (reddercolored patties) in fresh pork patties.  Also, fresh porkpatties from pigs supplemented with CLA had increasedHunter a* values and decreased TBA values in irradiatedfresh pork patties when compared with control pork patties.These results prompted us to ask if we could improve thequality of irradiated beef patties containing CLA.Our hypothesis was that feeding CLA 60 during thefinishing phase to beef steers would result in increasedlevels of CLA 60 in the ground beef product, thusimproving red color and decreasing oxidation afterirradiation of ground beef patties.The objectives of this study were to:1) feed finishing beef steers two levels of dietary CLA 60,2) formulate and irradiate lean (90/10) beef patties, and3) determine color and lipid oxidation values of irradiatedbeef patties from CLA-supplemented steers.Materials and MethodsThirty continental-crossbred steers (360 kg) wererandomly allotted to dietary groups by live weight andultrasound 12th rib fat depth.  Three diets of 0, 1 and 2.5%CLA were formulated with Ca++ salts of CLA 60 to protectagainst rumen degradation.  All steers averaged 130 d onfeed.Steers were harvested according to standard operatingprocedures.  Individual beef inside round samples werecollected and ground through a 1/2” plate and frozen.  Thenindividual beef samples were pooled by pen, and regroundand mixed.  Each meat block was pattied, and patties wereboxed and frozen according to pen and diet group.One half of each batch of patties within a pen and dietgroup were subjected to electron beam irradiation.  Thesebeef patties were irradiated in a single layer on styrofoamtrays with oxygen permeable PVC covering.  The irradiationdose was set at 3 Kgy with a conveyor speed of 12.29feet/min.Three replications of each pen x diet group wereevaluated for Hunter color and lipid oxidation.  L*, a*, andb* values were obtained by using a Hunter Labscan system,and lipid oxidation was measured by using the thiobarbituricacid method.Fat percentage was determined by difference using theFolch extraction method.  Extracted lipids were methylatedw/ sodium methoxide to obtain fatty acid methyl esters(FAMEs).  FAMEs were analyzed for fatty acid and CLAprofile by using gas chromatography and internal standards.Fatty acid peaks were compared with known retention timesof the standards to determine quantity of fatty acids.The statistical analysis was a completely randomizeddesign with fixed effects of diet, pen, replication, and levelof irradiation.  The General Linear Model procedure of SAS(1990) was employed and statistical significance was set atP < 0.05.Results and DiscussionColor of patties was improved significantly by feeding2.5 percent CLA (Table 1).  Hunter a* values (redder) werehigher (> 0.05) for patties irradiated by 3 kilogray (Kgy)(Table 1).  These results demonstrate that antemortemfeeding of CLA to market steers would improve the color ofground beef patties.2001 Beef Research Report — Iowa State University132Table 1.  Hunter color values for ground beef patties by irradiation and CLA levels.Irradiation Level 0 KGy 3 KGyCLA (%) 0 1.0 2.5 0 1.0 2.5 SEML* 37.9a 37.9a 39.3b 37.1a 36.9a 38.6b 0.20a* 14.0 14.9 15.0 7.13a 6.88a 9.57b 0.40b* 12.3a 12.5ab 12.9b 10.4a 10.3a 11.4b 0.12Means within a row by irradiation dose with different letters are significant at P <0.05.As observed in Figure 1, TBA values were lower (lessoxidation products) in ground beef patties from beef steersfed CLA.  This would suggest these patties would have amore desirable flavor and longer shelf life.  Data in Table 2show that the percentage of saturated fatty acids increasedwith the percentage (14:0, 16:0, and 18:0) of dietary CLA.Linolenic acid (18:3), however, increased as the dietarylevel of CLA increased.Table 2.  Percentage of fatty acids in ground beef patties by dietary CLA level.Dietary (CLA %)Fatty Acid 0 1.0 2.514:0 2.8a 3.7b 3.5b16:0 24.9a 25.6b 25.9b18:0 14.6a 15.4b 17.2c16:1 3.4 3.2 2.718:1 39.6a 35.6b 31.3c18:2 3.4 3.3 3.418:3 5.8a 7.7b 9.4c20:4 0.7 0.6 0.5 SEM = .219Means within a row with different letters are significant at P <0.05.Three major isomers were observed to increase in groundbeef patties with increasing level of percentage dietaryCLA.  These results suggest that consumption of groundbeef patties with higher amounts of CLA isomers could bemore healthful.  CLA in the diets of lab animals has beenshown to prevent/reduce cancer, heart disease, and obesity,and enhance the immune system.  Consequently, eatingfoods containing CLA may be more healthful.Table 3.  CLA Isomers (%) in Ground Beef Patties by Dietary CLA LevelDietary (CLA%)CLA isomer 0 1.0 2.5cis 9, trans 11 0.49 0.65 0.78trans 10, cis 11 0.00 0.17 0.34trans 9, trans 11 0.005a 0.55b 1.06cSEM = .219Means within a row with different letters are significant at P <0.05.The conclusions drawn from this study of feeding dietaryCLA to beef steers were:1) The red color of irradiated ground beef as measured byHunter a* values was improved.2) TBA values for control and irradiated ground beef weredecreased.3) Saturated fatty acids were increased, and unsaturatedfatty acids were decreased in lean ground beef.4) The CLA isomer content of ground beef patties wasincreased over controls.ImplicationsThe inclusion of dietary CLA calcium salts tofinishing beef cattle diets could prove useful inretaining a more desirable color.  And decreasinglipid oxidation values could prove to give a moredesirable ground beef flavor to irradiated groundbeef patties.

Conjugated Linoleic Acid (CLA) in Diets of Beef Steers Results in Higher Red Color Scores and Lower Lipid Oxidation of Irradiated Ground Beef Patties

https://dr.lib.iastate.edu/handle/20.500.12876/11050

Conjugated Linoleic Acid (CLA) in Diets of Beef Steers Results in Higher Red Color Scores and Lower Lipid Oxidation of Irradiated Ground Beef Patties

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