Consumption of peroxidized lipids has been shown to reduce pig performance and energy and lipid digestibility. Objectives of the current study were to evaluate the effect of feeding soybean oil (SO) with different levels of peroxidation on growth performance, lipid, N, and GE digestibility, plasma Trp, and gut integrity in finishing pigs. Fifty-six barrows (46.7 ± 5.1 kg initial BW) were randomly assigned to one of four diets in each of two dietary phases, containing either 10% fresh SO (22.5 °C) or thermally processed SO (45 °C for 288 h, 90 °C for 72 h, or 180 °C for 6 h), each infused with of 15 L/min of air. Peroxide values were 2.0, 17.4, 123.6, and 19.4 mEq/kg; 2,4-decadienal values were 2.07, 1.90, 912.15, and 915.49 mg/kg; and 4-hydroxynonenal concentrations were 0.66, 1.49, 170.48, and 82.80 mg/kg, for the 22.5, 45, 90, and 180 °C processed SO, respectively. Pigs were individually housed and fed ad libitum for 81 d to measure growth performance, including a metabolism period to collect urine and feces for determination of GE, lipid, N digestibility, and N retention. Following the last day of fecal and urine collection when pigs were in the metabolism crates, lactulose and mannitol were fed and subsequently measured in the urine to evaluate gut permeability, while markers of oxidative stress were evaluated in plasma, urine, and liver. There were no differences observed in ADFI (P = 0.91), but average daily gain (ADG) and gain:feed G:F were decreased in pigs fed 90 °C SO diet (P ≤ 0.07) compared to pigs fed the other SO diets. Pigs fed the 90 and 180 °C SO had the lowest (P = 0.05) DE as a % of GE compared to pigs fed the 22.5 °C SO, with pigs fed the 45 °C SO being intermediate. Lipid digestibility was similarly affected (P = 0.01) as energy digestibility, but ME as a % of DE was not affected by dietary treatment (P = 0.16). There were no effects of lipid peroxidation on N digested, N retained, or the urinary lactulose:mannitol ratio (P ≥ 0.25). Pigs fed the SO processed at 90 and 180 °1C had lower concentrations (P < 0.01) of plasma Trp compared to pigs fed the 22.5 and 45 °C SO treatments. Pigs fed 90 °C SO had the greatest (P < 0.01) concentrations of F2-isoprostane in plasma and urine thiobarbituric acid reactive substances compared to the other SO treatments. These results indicate that the change in FA composition and/or the presence of lipid peroxidation products in peroxidized SO may reduce ADG, G:F, and digestibility of GE and ether extract, but has little impact on N digestibility and balance or on gut permeability.

The objective was to evaluate salts of varying purity levels on lipid oxidation, texture, and sensory properties of fresh ground pork patties. Approximately 160 kg of fresh boneless pork trimmings was used to test a salt typical to industry (treatment A), 3 specialty salts (B, C, and D), and a control (no added salt).\ud Salts were analyzed for Na, Cl, Fe, Cu, Mg, Ca, and Mn content. Experimental treatments were replicated 6 times, for a total of 30 independent batches. Analysis was conducted using the MIXED procedure of SAS as a repeated measure in a complete randomized design. After 11 days of refrigerated storage, there were no differences in lipid oxidation among salts A, C, or D (P 0.15), but salt B had less (P 0.04) lipid oxidation than salts A, C, and D. However, no differences in oxidized flavor or odor (P 0.95) were detected. Overall, salts of varying impurities differed in lipid oxidation but sensory panelists were not able to detect differences in oxidized odors or flavors

Boneless loins ( = 286) were selected from a population of pigs of a common genetic line and management strategy to be used in an experiment to determine the effects of instrumental color and extractable lipid content on sensory traits of boneless pork chops cooked to an end point internal temperature of 63°C. Loins were cut into 2.54-cm-thick chops and aged until 14 d postmortem. Chop L* values ranged from 57.60 (light) to 43.11 (dark) and extractable lipid ranged from 0.80 to 5.52%. Using these values, chops were assigned to 5 color and 6 marbling categories using National Pork Producers Council (NPPC) standards, resulting in a 5 × 6 factorial arrangement of treatments. Chops were also assigned a quality grade using a proposed grading system. Low-quality loins ( = 56) had marbling scores < 1.5, regardless of color, or had color scores ≤ 2.5 and marbling scores ≤ 2.0. Medium-quality loins ( = 180) had color scores of 2.0 to 3.5 and marbling scores ≥ 2.5 or loins with color scores of 3.0 through 3.5 and marbling scores ≥ 2.0. High-quality loins ( = 50) had color scores > 4.0 and marbling scores ≥ 2.0. Chops were cooked to a medium-rare degree of doneness (63°C) and evaluated for tenderness, juiciness, and pork flavor by trained panelists. Slice shear force (SSF) and cooking loss were also evaluated. Data were analyzed using the MIXED procedure of SAS as a 1-way ANOVA with the fixed effect of quality grade and using the REG procedure of SAS. Individually, extractable lipid content and instrumental color accounted for no more than 2% ( ≤ 0.02) of the variation in tenderness, juiciness, or pork flavor. High-quality chops had 6.5 and 11.2% less SSF ( ≤ 0.04) than medium- and low-quality chops, respectively, and medium-quality chops had 5.6% less SSF ( < 0.04) than low-quality chops. Trained sensory panelists did not detect differences in tenderness ( = 0.09) or juiciness ( = 0.48) among quality grades, but low- and medium-quality chops were more flavorful ( < 0.01) than high-quality chops. Cooking loss tended ( = 0.06) to decrease from 16.57% to 15.32% as quality grade increased. Neither color nor marbling alone was predictive of sensory quality. But when these were used together, as they were in the proposed grading system, pork sensory flavor ratings were greater for low-quality chops than for high- and medium-quality chops. Also, the proposed grading system was able to discern differences in SSF but not sensory tenderness among the quality grades.

In livestock science and meat science, muscle fiber characteristics have been evaluated based on a cross-sectional area (CSA) of muscle fiber. However, muscle fiber is not planar but cylindrical. Thus, muscle fiber volume and volume-based characteristics were evaluated in this study. In addition, their relationships to pork loin quality was assessed and compared with that of CSA-based muscle fiber characteristics. Muscle fiber type IIB was underestimated by CSA-based evaluations with 1.6 times in fiber size and 2.6 times in relative composition. The pennation angle, which ranged from 48.00° to 83.33°, determined the real CSA and total number of fibers (TNF) on the surface of a loin chop. Significant (P < 0.05) correlation coefficients were found: fiber volume (r = –0.37) and volume % (r = –0.37) of type IIX with loin length; volume % of type IIX with CIE L* (r = 0.40); volume % of types IIX (r = 0.39) and IIB (r = –0.39) with Warner-Bratzler shear force. Although those correlations to loin quality differed from those of CSA-based characteristics, the Z-scores did not show any significance between the 2 correlation coefficients, except for TNF. Therefore, the conventional methodology for muscle fiber characteristics can be used for evaluating the relationship to pork quality; however, the new methodology is more useful in estimating the characteristics of muscle fiber, which is elongated and cylindrical and to correct the underestimated fiber size and composition of type IIB.

The objective was to determine the predictive ability of carcass length for the number of equal-thickness chops obtained from a boneless pork loin. Longer pork carcasses are assumed to yield longer loins and, therefore, an increased number of chops. Loins were collected from pigs (1,238 total) raised under commercial conditions and marketed when the mean pig weight in a pen reached 138 kg. Pigs were slaughtered over 7 wk in a commercial facility. Carcass length was measured at 1 d postmortem on the left side of each carcass from the anterior edge of the symphysis pubis bone to the anterior edge of the first rib. Carcasses were fabricated, and boneless loins (North American Meat Processors number 414) were vacuum packaged and transported to the University of Illinois Meat Science Laboratory. Loins were stored at 4°C for 14 d. At the end of the aging period, loins were weighed, measured for stretched length (stretched to maximum length without distortion) and compressed length (compressed to minimum length without distortion), and sliced into 2.54-cm-thick chops. Boneless chops were counted and weighed. Carcass length ranged from a minimum of 78.2 cm to a maximum of 96.5 cm and the number of boneless chops ranged from a minimum of 13 to a maximum of 20 chops. Data were analyzed using the regression procedure of SAS. The dependent variable was the number of boneless chops. Coefficient of determination () was calculated for carcass length, boneless loin weight, compressed loin length, and stretched loin length. Carcass length explained 15% ( < 0.0001) of the variation in the number of loin chops. Loin weight explained 33% ( < 0.0001) of the variation in the number of loin chops. Compressed loin length and stretched loin length explained 28 and 8% ( < 0.0001), respectively, of the variation in the number of loin chops. Multiple linear regression was used to determine a predictive equation for the number of loin chops using the stepwise selection option of all independent variables. The combination of boneless loin weight, compressed loin length, 10th-rib carcass fat depth, and carcass length explained 45% of the variation ( < 0.0001; C(p) = 16.76) in the number of loin chops using a required statistic at the SLENTRY and SLSTAY level = 0.15. Overall, carcass length is a poor predictor of the number of equal-thickness loin chops that can be derived from a boneless pork loin.