The influence of diets containing either conventional corn, conventional corn with choice white grease, high oil corn, or high oil high oleic corn on belly/bacon quality

Meat Science 64 (2003) 459–466 www.elsevier.com/locate/meatsci G. Rentfrowa, T.E. Sauberb, G.L. Alleea, E.P. Berga,* a University of Missouri, Department of Animal Sciences, Columbia, MO 65211, USA b Pioneer—A DuPont Company, Des Moines, Iowa, USA Received 15 March 2002; received in revised form 1 August 2002; accepted 1 August 2002 Abstract The objectives of this study were to evaluate diets possessing different fatty acid profiles (as influenced by corn type) with regard to fatty acid profile and firmness of pork bellies. Crossbred barrows (n=196) were fed one of four corn-based diets consisting of conventional corn (CONV), CONV with choice white grease (CWG), high oil corn (HOC), or high oleic, high oil corn (HOHOC). Following 98 days on test, two animals representing the average pen weight (118 kg) were selected for harvest (n=56). A 50-g fat sample was removed from each belly for fatty acid profile analysis. Lateral and vertical flex tests were performed to determine belly firmness. Bellies were pumped and cooked according to a commercial protocol. Total saturated fatty acids increased (P< 0.001) and total unsaturated fatty acids decreased (P< 0.05) when CWG was added to the CONV diet or when HOC or HOHOC were sub- stituted for CONV corn. Pigs fed CONV corn had firmer bellies, while those fed HOC were softer. No differences were observed across treatment for percentage pump retention, smokehouse yield, or slicing yield (P >0.05). Based on the results of this study, corn type influences fatty acid profile, and belly firmness, but does not affect pump retention, or slicing yields. # 2003 Elsevier Science Ltd. All rights reserved. Keywords: Belly; Bacon; Corn-type; Fatty acid profile Pilkington, 1992; Miller et al., 1990). One method of 1. Introduction altering the fatty acid profiles of pork tissue is to feed oils/oil seeds high in oleic acid (Miller et al., 1990; Typically pork fat contains high concentrations of Shackelford et al., 1990; St. John et al., 1987) or other saturated fatty acids and lower concentrations of mono- unsaturated fats (Leszczynski et al., 1992; Mazhar et al., and poly-unsaturates (Miller, Shackelford, Hayden, & 1990; Miller et al., 1990; Myer, Johnson et al., 1992; Reagan, 1990). The fatty acid profile of pork fat can Myer, Lamkey, Walker, Brendemuhl, & Combs, 1992; influence processing properties (Shackelford et al., 1990; Romans, Johnson, Wulf, Libal, & Costello, 1995a, St. John et al., 1987), while the consumption of satu- 1995b; Shackleford et al., 1990). While decreasing the rated fatty acids by humans may increase ldl-choles- content of saturated fat in pork may provide a human terol, resulting in an increased risk of coronary heart health benefit, feeding diets high in mono- and poly disease. Research in swine nutrition has shown that the unsaturates may have adverse affects on pork belly/ fatty acid profile of pork fat can be altered by feeding bacon quality (Shackelford et al., 1990; St. John et al., diets that contain variations in the concentrations of 1987). Utilizing traditional plant breeding techniques, fatty acids (Fontanillas, Barroeta, Baucells, & Guar- high oil corn varieties with either high linoleic acid or diola, 1998; Larick, Turner, Schoenherr, Coffey, & high oleic acid/low polyunsaturated fatty acid profiles have been developed. The objective of this research was to characterize the effects of feeding these corn * Corresponding author. Tel.: +1-573-882-3176; fax: +1-573-884- varieties with modified fatty acid content on belly/ 4606. bacon parameters. E-mail address: bergep@missouri.edu (E.P. Berg). 0309-1740/03/$ - see front matter # 2003 Elsevier Science Ltd. All rights reserved. PII: S0309-1740(02)00215-2 460 G. Rentfrow et al. / Meat Science 64 (2003) 459–466 Table 1 Phase 5 Finisher diet (all ingredients are shown as a percentage of the composition of the diet) Ingredient CONV CWG HOC HOHOC Ground normal corn 86.25 79.785 – – Ground high oil corn (HOC) – – 85.745 – Ground high oil, high oleic corn (HOHOC) – – – 85.27 Soybean meal (48%) 11.35 12.95 11.90 11.90 Choice white grease – 4.91 – – Dicalcium phosphate 0.840 0.840 0.840 0.840 Limestone 0.650 0.640 0.640 0.640 Salt 0.500 0.500 0.500 0.500 Swine vitamin mixa 0.150 0.150 0.150 0.150 Swine mineral mixb 0.100 0.100 0.100 0.100 l-Lysine HCL 0.100 0.100 0.100 0.100 Antibiotic premixc 0.025 0.025 0.025 0.025 a Supplied per kilogram of diet: vitamin A, 6600 IU; vitamin D3, 660 IU; vitamin E, 13.2 IU; vitamin K, 2.39 mg; vitamin B12, 0.018 mg; ribo- flavin, 4.95 mg; pantothenic acid, 16.83 mg; niacin, 19.80 mg. b Supplied mg/kg diet: Zn, 110; Fe, 110; Mn, 22; Cu, 11; I, 0.198; Se, 0.198. c Supplied mg/kg: bacitracin methylene disalicylate. formulated based on the chemical analysis of the corn 2. Materials and methods used. Both high oil corns were included in the diets at the same percentage since they had similar fat contents 2.1. Animals (6.5%). Barrows had ad libitum access to feed and water and were fed to an average end weight of 118 kg. Crossbred barrows (EBÂGenepacker; n=196) were The University of Missouri Animal Care and Use blocked by weight and randomly assigned to one of four Committee approved the production and research pro- treatments consisting of a control finishing diet con- tocol. Following 98 d on test, two pigs representing the taining normal corn and no added fat (CONV), normal pen average (118 kg), were selected from each pen for corn and choice white grease (CWG), high-oil corn humane slaughter at the University of Missouri abattoir (HOC), and high-oil, genetically enhanced corn to be (n=56). high in concentration of oleic acid (HOHOC). Pigs were fed a five-phase corn-soybean meal diet sequence, with a constant ratio of lysine to metabolizable energy (ME). 2.2. Fresh belly fabrication and measurements Experimental diets were formulated based on the che- Bellies were removed from the carcasses side and mical analysis of the corn used. Both high oil corn were processed according to Institutional Meat Purchasing included in the diets at the same percentage, since they Specifications (IMPS #408; NAMP, 1997). Spareribs had similar (6.5%) fat content. An example of the phase and related cartilage were removed, the bellies were 5 finisher diets are shown in Table 1. Fatty acid profiles squared (approximately 35.6Â48.3 cm), and all remain- of the corn sources can be found in Table 2. Pigs were ing leaf fat removed. The fresh bellies with the skin on arranged seven pigs per pen in 28 pens for a total of 49 were evaluated by an objective flex test performed by pigs per treatment, and fed a five-phase corn-soybean centering the squared belly, fat side down, on a 7.6 cm meal diet sequence, where each diet had a constant ratio diameter polyvinyl chloride (PVC) pipe mounted per- of lysine to metabolized energy. Experimental diets were pendicular to a board marked with a 2.54-cm grid matrix (Fig. 1). Lateral and vertical flex were deter- Table 2 mined from the degree of belly flex relative to the grid Fatty acid profiles of the various corn sources matrix. A lateral belly flex of zero meant the belly was completely parallel to the floor and was completely Fatty acid (%) CONV HOC HOHOC stiff. A vertical belly flex of 6 meant that the belly Palmitic, 16:0 10.3 9.90 9.40 flexed to a point where there were 15.2 cm between the Palmitoleic, 16:1 0.10 0.10 0.10 ends of the squared belly. Thus, a lower vertical and a Stearic, 18:0 1.90 2.90 2.20 Oleic, 18:1 33.1 37.2 58.2 higher lateral flex would indicate a firmer belly. Upon Linoleic, 18:2 52.0 49.2 27.7 completion of the belly flex test, each squared belly Linolenic, 18:3 1.20 1.00 1.10 was individually tagged with the appropriate identifi- cation, vacuum packaged, and frozen at À22 C for CONV=Conventional corn; HOC=high oil corn; HOHOC=high later processing. oleic, high oil corn. 461 G. Rentfrow et al. / Meat Science 64 (2003) 459–466 Fig. 1. Measuring lateral and vertical belly flex. (a) This illustrates a lower lateral, higher vertical flex; firmer belly. (b) This illustrates a higher lateral, lower vertical flex; softer belly. commercial bacon press (Anco, Cherry-Burrell AMCA 2.3. Fatty acid profiles International Anco/Votator Division, Louisville, KY) One slice was removed from the shoulder (cranial) and then sliced by a high-speed slicer at nine slices per end of the fresh belly slab and a 50-g sample of leaf 2.54 cm. The full sliced bacon drafts were placed on (peritoneal) fat was collected from each belly, individu- slip-sheets (complete with all ends and pieces) and ally packaged, and frozen for transport to Dupont Spe- placed in wax-coated boxes. Boxes were sealed and cialty Grains (Des Moines, IA) for fatty acid profile properly labeled for delivery to the University of Mis- analysis. Fatty acid analysis was performed using the souri Meat Science Laboratory. modified method described by Park and Goins (1994), During high-speed slicing, it was necessary to use and Loor and Herbein (1998). In addition, the various more than one slip-sheet to accommodate the entire corn samples utilized during the finishing period were bacon slab. During collection of the sliced bacon slabs, analyzed with the same procedure as stated above. some partial slabs were placed in the boxes out of order. Therefore, 29 full bacon slabs were positively identified by matching lean and fat patterns within the bacon sli- 2.4. Bacon processing and measurements ces or on the exterior of the sparerib side of the slab. Uncooked bellies were thawed (4 C) for 24 h and Slicing yield was the only processing variable affected by transported to a commercial packing plant where they the mishandling. The number of bacon slabs remaining were skinned, and weighed before (green weight) and for analysis were as follows; CONV, n=7; CWG, n=7; after injection (pumped weight). The bellies were HOC, n=6, and HOHOC, n=9. Slicing yield was pumped fat side down using a Townsend multi-needle determined by weighing (Fairbanks model H90–167–1, bacon injection pump (Townsend Inc., Des Monies, Fairbanks Scales, St. Johnsbury VT) the center portions IA). A commercial brine (Excel Inc., Ottumwa, IA) was of the bacon slab after the removal of comb marks and injected to 112% of the bellies green weight and allowed all incomplete slices. The remaining bacon slab, con- to drain to 110% of the green weight. The commercial taining only commercially acceptable slices, was divided brine consisted of 1.5% salt, 0.3% sugar, 0.3% sodium into five separate sections and labeled as, A, B, C, D, phosphate, 0.055% sodium erythorbate, 0.012% and E (Fig. 2; Mandigo, 1998). The first two slices from sodium nitrite. Bellies were hung by a bacon comb the cranial end were removed from each section and attached at the flank end and heat processed according evaluated for fracture analysis. A trained person eval- to the plants commercial protocol. Following proces- uated fracture analysis by rolling the bacon slice over sing, bacon was removed from the smokehouse, showered the forefinger. A fracture was considered as lateral or for 10 min, drip dried for 10 min, and then chilled over- vertical cracks in the structural integrity of the bacon night at 3 C. The following morning, individual bacon slice. Subjective fracture analysis was performed by dividing the slice into four quadrants along the length of slabs were weighed to determine smokehouse yield and placed in a tempering cooler (À4 C) to facilitate optimal the bacon slice and assigning a score for each quadrant. The scores were then averaged for each slice. A score of pressing and slicing. Full bacon slabs were pressed using a 462 G. Rentfrow et al. / Meat Science 64 (2003) 459–466 Fig. 2. Sampling diagram for draft of sliced bacon. 0 indicated that no visual cracks or shattering could be detected, the scoring increased in severity with 2, 3, 4, 5, and a score of 6 being indicative of a ‘‘spider-web’’ consistency of shattering within the fat of the bacon slice (Mandigo, 1998). Five bacon slices per slab, representing one slice from each section (described earlier), were cooked (top and bottom plate=177 C; plate height=0.4 cm) on a Magi- Fig. 3. Numeric scale and examples for subjective visual evaluation of cooked bacon slice distortion. Grill PGB-60 (Magikich’n, Quackertown, PA) double belt conveyor cooker. Preliminary testing was con- ducted to verify the degree of doneness (golden brown; 3. Results and discussion not crisp) and an automated setting for conveyor speed and upper and lower belt cooking temperatures. 3.1. Fatty acid profile determination Cooked slice yield was targeted to be 40% of the origi- Several researchers have noted that the level of satu- nal bacon slice weight. Each slice was weighed before rated fat in pork fat could be altered by the inclusion of and after cooking to the nearest 0.1 g (Ainsworth model unsaturated fat in the diet (Fontanillas et al., 1998; CR-8101, Denver Instruments Co., Denver CO). After Larick et al., 1992; Leszczynski et al., 1992; Mazhar et cooking, slices were allowed to cool for 10 min at room al., 1990; Miller et al., 1990; Myer, Johnson et al., 1992; temperature on absorbent paper towels. Cooking loss Myer, Lamkey et al., 1992; Romans et al., 1995a, 1995b; was calculated as ((raw weightÀcooked weight)/raw Shackleford et al., 1990). The fatty acid (FA) profile weight)Â100. Bacon slice length was measured to the obtained from a slice taken from the fresh belly at 24 h nearest 0.3 cm before and after cooking. Bacon slice postmortem differed across dietary treatments (Table 3). cooking shrink (length change) was calculated as ((raw The total saturated fatty acids (SFA) decreased lengthÀcooked length)/raw length)Â100. Subjective (P < 0.01) and total unsaturated fatty acids (UFA) evaluation of cooked slice visual distortion was eval- increased (P < 0.05) with the addition of CWG, HOC, uated using a 5-point distortion scale where 1 repre- or HOHOC to the diet. The highest concentration of sented a mostly flat slice, and as severity of curling monounsaturated fatty acids (MUFA; P < 0.05) was increased samples were rated 2, 3, 4, and 5 where 5 found in the fat of pigs fed HOHOC, whereas the lowest indicated a slice that completely curled with no flat concentration was found in the fat of pigs fed the areas on the slice (Fig. 3). CONV and HOC treatments. The increase in UFA and the decrease in SFA agree with other studies that have 2.5. Statistical analysis fed high oleic feedstuffs to pigs (Mazhar et al., 1990; Miller et al., 1990; Myer, Johnson et al., 1992; Myer, The data was analyzed utilizing the Proc GLM pro- Lamkey et al., 1992; Shackelford et al., 1990). Past cedure of SAS (SAS Institute, Cary, NC) and Least research has shown a decrease in SFA and an increase Square means were tested with the fixed effect of the in MUFA and PUFA concentrations when diets were treatments and then least square means tested for least supplemented with oil seeds (sunflower, safflower, and significant differences. An alpha of P < 0.10 was con- canola) high in oleic acid (Miller et al., 1990; Myer, sidered a trend and a significant difference was set as an Lamkey et al., 1992), however, Myer, Lamkey et al. alpha of P < 0.05. Pearson correlation coefficients were (1992) only noted a slight increase in MUFA concentra- calculated between fatty acid profiles, processing para- tion. In the current study, the highest concentration in meters, and belly quality (flex test). 463 G. Rentfrow et al. / Meat Science 64 (2003) 459–466 Table 3 Fatty acid LSMEANS and standard error for fresh bellies by treatment Fatty acid Structure CONV CWG HOC HOHOC SE Significance Capric C10:0 0.084ab 0.078a 0.088b 0.084b 0.002 P< 0.05 Lauric C12:0 0.074 0.074 0.078 0.079 0.002 NS Myristic C14:0 1.410 1.388 1.426 1.486 0.130 NS Palmitic C16:0 25.212b 24.057a 24.024a 24.583ab 0.236 P< 0.01 Palmitoleic C16:1 2.722 2.707 2.716 2.758 0.084 NS Heptadecanoic C17:0 0.363 0.328 0.328 0.338 0.020 NS Heptadecanoic cis10 C17:1 0.333 0.307 0.283 0.304 0.019 NS Stearic C18:0 12.627c 11.464b 10.601a 10.922ab 0.208 P< 0.01 Oleic C18:1trans 0.264b 0.292c 0.222a 0.250b 0.007 P< 0.01 Oleic C18:1cis 44.228a 45.666b 43.752a 47.438c 0.350 P< 0.01 Linoleic C18:2trans 0.080a 0.107b 0.080a 0.084a 0.006 P< 0.01 Linoleic C18:2cis 9.046b 9.814c 12.871d 8.197a 0.270 P< 0.05 Arachidic C20:0 0.234b 0.186a 0.220ab 0.202ab 0.012 P< 0.01 Eicosenoic C20:1 0.813 0.805 0.728 0.831 0.028 NS Linolenic C18:3 0.343a 0.386b 0.353a 0.359a 0.008 P< 0.05 Eicosadienoic cis11, 14 C20:2 0.399b 0.430b 0.496c 0.326a 0.015 P< 0.01 Eicosadienoic cis8, 11, 14 C20:3gamma 0.075a 0.083b 0.087b 0.069a 0.003 P< 0.05 Eicosadienoic cis11, 14, 17 C20:3 0.048a 0.054b 0.043a 0.045a 0.002 P< 0.05 Arachidonic C20:4 0.223a 0.262b 0.273b 0.226a 0.009 P< 0.01 Docosatetraneoic C22:4 0.091a 0.103b 0.114c 0.088a 0.003 P< 0.05 CLA 0.145a 0.164b 0.144a 0.141a 0.005 P< 0.01 SFA 40.003b 37.574a 36.764a 37.694a 0.376 P< 0.01 UFA 58.664a 61.016bc 62.018c 60.975b 0.368 P< 0.05 MUFA 48.359a 49.778b 47.701a 51.581c 0.376 P< 0.05 PUFA 10.306b 11.238c 14.317d 9.395a 0.300 P< 0.05 Means within a row with different letters differ significantly. CONV=Conventional corn; CWG=Choice white grease; HOC=High oil corn; HOHOC=High oil, high oleic corn; CLA=Conjugated linoleic acid; SFA=Saturated fatty acids; UFA=Unsaturated fatty acids; MUFA= Monounsaturated fatty acids; PUFA=Polyunsaturated fatty acids. Correlation coefficients between selected FA con- MUFA occurred in the pigs fed HOHOC. The HOC centration and fresh belly and bacon parameters are treatment possessed the highest concentration of UFA reported in Table 6. Significant correlations were seen in this study and tended to have the highest slicing yield between PUFA and lateral and vertical belly flex (exhibiting a trend at P< 0.10; Table 4). The pigs fed (r=0.3906 and À0.4773, respectively) and shatter score CONV possessed the highest percentage of SFA and (r=À0.5835). In this study, the saturated fat palmitic the lowest USF concentration, and had the lowest ver- acid was more highly correlated with lateral tical (a lower vertical flex=a firmer belly) and highest (r=À0.5000) and vertical (r=0.4705) belly flex than lateral flex test (a higher lateral flex=a firmer belly). was stearic acid. Palmitic acid also had a significant Likewise, the HOC fed pigs had bellies with the highest (P=0.02) positive correlation (r=0.3384) with shatter percentage of UFA and the highest vertical and lowest score, suggesting that evidence of shattering increases as lateral flex (Table 5). Which would indicate a ‘‘softer’’ the percentage of palmitic acid increases. Significant belly; however, the softer belly did not result in poorer correlations were seen between linolenic acid (C18:2) slice-ability. and lateral (r=0.3810) and vertical (r=À0.4713) belly According to Pork Composition and Quality Assess- flex and shatter score (r=À0.5844). Mazhar et al. (1990) ment Procedures (NPPC, 2000), quality pork fat must and Shackleford et al. (1990) noted that the addition of have < 15% polyunsaturated fatty acids (PUFA) and canola (ground or oil) to the diet produced softer > 15% stearic acid (18:0). Furthermore, pork fat con- bacon, as evaluated by a trained sensory panel. In taining > 14% linolenic acid (C18:2) is associated with addition, Miller et al. (1990) found that pig diets sup- soft fat. In the present study, HOC approached the 15% plemented with high oleic oil seeds (sunflower, saf- limit for PUFA (14.32%; Table 3). None of the dietary flower, and canola oils) had softer, oilier fat than treatments resulted in deposition of > 15% stearic acid controls. Furthermore, Myer, Johnson et al. (1992) and and none contain > 14% linolenic acid. The results of Myer, Lamkey et al. (1992) found that pigs fed high oil this study would suggest that even though dietary fatty peanuts and/or canola oil had softer fat, than their un- acid profile was altered, an acceptable FA composition supplemented counterparts. was achieved across each treatment group resulting in A primary focus of this study was to evaluate geneti- adequate belly firmness and, subsequently, acceptable cally enhanced high oleic, high oil corn. Table 3 shows slice-ability. 464 G. Rentfrow et al. / Meat Science 64 (2003) 459–466 Table 4 Least squares means and standard errors for slicing yield of bacon slabs after high-speed slicing Variable CONV CWG HOC HOHOC SE Significance a 7 7 6 9 Number of bacon slabs used in evaluation High-speed slicing yieldb(%) 78.24ab 70.27a 84.07b 70.12a 4.90 P< 0.10 Means within a row with different letters differ significantly. a Slicing yield evaluated on full center section bacon slabs positively identified at the Excel packing plant. b Slicing yield=(weight of intact, full-length center slices/cooked pressed weight)Â100. LSMEANS indicating that the HOHOC treatment 3.2. Processing and cooking yields resulted in a significantly higher concentration of oleic No differences were observed across treatments for acid in the fat tissue of the fresh pork belly. These green weight, pumped weight, pressed center weight, or results are in agreement with other studies that showed smokehouse yield (Table 5). Furthermore, no differ- an increase in oleic acid deposited in fat tissue when ences were observed across dietary treatments for the diets were supplemented with oils high in oleic acid cooked bacon parameters of cooking loss, cooked concentrations (Miller et al., 1990; Myer, Johnson et al. length shrink, or visual distortion score (Table 5). It can 1992; Shackelford et al., 1990). Oleic acid (C18:1 cis) be concluded that dietary treatment had no affect on the concentrations had no significant correlation with any yield of fresh pork belly, yield of processed un-sliced of the processing parameters reported in Table 6, how- bacon, or cooking yield. Pigs fed HOC had lower bacon ever, a significant (P=0.038) negative correlation slice fracture scores (P < 0.01), however no differences (r=À0.3877) was observed for slicing yield (Table 6), were observed between the other dietary treatments indicating that as the concentration of C18:1 cis (Table 5). These data coincide with findings of Shack- increased, slicing yield decreased. The variant C18:1 elford et al. (1990) in which pump yield and overall yield trans was significantly (P=0.049) correlated only to of bellies/bacon were not affected by supplementing pig shatter score (r=0.2888). Shackelford et al. (1990) indi- diets with animal fat, sunflower oil, safflower oil, or cated an increased concentration of oleic acid (18:1) in canola oil. However, Shackelford et al. (1990) did find pork fat noting a decrease in bacon slicing yields as a that dietary treatments produced higher cooking yields result of supplementing canola oil, which is in agree- than controls, and the addition of canola oil lowered ment with this study. Table 5 Least squares means and standard errors for bacon processing Variable CONV CWG HOC HOHOC SE Significance a 14.14a 16.13b 16.00b 15.42b 0.459 P< 0.05 Fresh belly, Vertical flex (inches) Fresh belly, Lateral flex (inches)b 10.21c 8.32ab 7.71a 8.89abc 0.535 P< 0.05 Green weight (pre-pump) (lbs.) 8.31 8.90 8.60 8.85 0.250 NS Pump percentagec (%) 13.98 13.42 13.37 13.82 0.269 NS Cooked pressed center weight (lbs.) 6.87 7.11 7.65 7.00 0.635 NS Smokehouse yieldd (%) 88.54 90.21 91.59 91.14 1.398 NS Shattere 3.46b 3.44b 2.55a 3.46b 0.243 P< 0.01 Bacon slice cooking lossf (%) 58.00 60.04 57.89 57.46 1.13 NS Bacon slice cooking shrinkg (%) 29.75 31.39 30.38 31.14 1.19 NS Cooked bacon slice visual scoreh 2.18 2.36 2.21 2.27 0.121 NS Means within a row with different letters differ significantly. a Recorded as the summation of vertical flex from right and left ends of loin or belly whereby zero flex would be flat; a vertical flex reading of ‘‘800 would be equivalent to the left side of the loin/belly flexing to a point of 4-inches on the left and 4-inches on the right. A lower vertical flex would be a firmer loin/belly. b Recorded as the summation of lateral flex from right and left ends of loin or belly whereby a zero lateral flex would be a complete folding of the loin/belly; a lateral flex reading of ‘‘800 would be equivalent to 8 inches separating the opposing ends. A higher lateral flex would be a firmer loin/ belly. c Pump percentage=((pumped belly weightÀgreen weight)/green belly weight)Â100. d Smokehouse yield=(Cooked pressed center weight/pumped weight)Â100. e Subjective evaluation of slice integrity (fracture) from 0 to 6 where 0=intact slice possessing no shatter and 6=‘‘spider-web’’ fracture. f Bacon slice cooking loss=((raw weightÀcooked weight)/raw weight)Â100. g Bacon slice cooking shrink=((raw lengthÀcooked length)/raw length)Â100. h Subjective evaluation of slice appearance (curling, cooked distortion) from 0 to 6 where 0=flat slice with no distortion and 6=extreme curling and distortion. Pearson correlation coefficients (and probability>|R| under Ho) between select bacon processing parameters and fatty acid content Fresh belly, Pumping Smokehouse Smoked center Slicing Shatter Cooked, Cooked slice Cooked, lateral flex percent yield bacon slab weight yield score weight loss shrinkage visual score À0.2678 À0.0369 À0.0367 À0.0552 À0.1991 À0.0964 (0.0001) 0.4705 (0.0002) (0.0550) (0.7949) (0.8155) 0.0635 (0.7434) 0.3384 (0.0200) (0.7033) (0.1657) (0.5099) À0.0971 À0.0522 À0.1123 (0.0047) 0.3510 (0.0069) 0.0411 (0.7723) (0.4934) (0.7394) (0.5618) 0.2761 (0.0603) 0.1142 (0.4299) 0.1073 (0.4583) 0.0453 (0.7571) À0.0401 À0.0615 À0.0531 À0.2052 À0.1400 (0.3446) 0.1219 (0.3618) (0.7777) (0.6650) (0.7355) 0.2023 (0.2926) 0.2888 (0.0490) 0.0858 (0.5537) (0.1528) (0.3373) À0.1232 À0.3877 (0.9286) 0.0202 (0.8804) 0.2151 (0.1256) 0.1152 (0.4160) (0.4311) (0.0377) 0.2412 (0.1024) 0.1169 (0.4188) 0.1622 (0.2603) 0.2279 (0.1153) À0.1118 À0.0503 (0.2823) (0.4032) 0.1704 (0.2272) 0.2442 (0.0810) 0.0124 (0.9370) (0.7955) 0.0382 (0.7989) 0.3354 (0.0173) 0.2474 (0.0833) 0.1331 (0.3621) À0.4713 À0.0236 À0.0138 À0.5844 À0.1233 À0.0214 À0.0924 (0.0032) (0.0002) (0.8681) (0.9228) 0.1861 (0.2322) 0.2845 (0.1347) (0.0001) (0.3937) (0.8825) (0.5278) À0.2494 À0.0404 À0.2567 À0.2560 (0.3155) 0.1390 (0.2980) (0.0746) 0.0253 (0.8585) (0.7969) 0.1985 (0.3019) 0.2093 (0.1580) 0.0913 (0.5283) (0.0719) (0.0758) À0.1405 À0.0788 À0.0664 À0.0398 À0.0378 À0.0338 (0.0001) 0.4712 (0.0002) (0.3205) (0.5785) (0.6721) (0.8377) 0.3751 (0.0094) 0.0373 (0.7971) (0.7945) (0.8178) À0.5018 À0.0273 À0.4389 À0.0427 (0.0005) (0.0001) 0.1992 (0.1569) 0.0771 (0.5872) 0.0747 (0.6340) (0.8882) (0.0020) (0.7687) 0.0966 (0.5046) 0.0944 (0.5186) À0.1418 À0.3348 (0.9315) 0.0495 (0.7122) 0.1924 (0.1717) 0.0898 (0.5267) (0.3645) (0.0758) 0.2499 (0.0903) 0.0848 (0.5581) 0.1024 (0.4792) 0.1786 (0.2196) À0.4773 À0.0183 À0.5835 À0.1116 À0.0113 À0.0843 (0.0002) 0.0116 (0.9348) (0.8976) 0.1891 (0.2245) 0.2772 (0.1455) (0.0001) (0.4405) (0.9378) (0.5649) (0.0024) 465 G. Rentfrow et al. / Meat Science 64 (2003) 459–466 slicing yields. These observations were not seen in the present study. Mazhar et al. (1990) added ground canola seed to the diet and noted that green weight yield, smokehouse yield, and cooking yield were not affected by treatment; this is consistent with the present study. Canola seed/oil, sunflower oil and safflower oil are all high in oleic acid, which makes these studies a notable comparison to feeding high oleic corn. 4. Conclusions The results of this study indicate that the fatty acid profile of the diet, as influenced by corn type, had no effect on green weight, pumped weight, smokehouse yield, or pressed center weight. In addition, there were no differed for the cooked bacon slice parameters of cooking loss, cooked length shrink, or visual distortion score. 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