Influence of feeding thermally peroxidized soybean oil to finishing barrows on processing characteristics and shelf-life of commercially manufactured bacon

Authors: OVERHOLT, MARTIN - University Of Illinois; LOWELL, JESSICA - University Of Illinois; KIM, GAP-DON - University Of Illinois; BOLER, DUSTIN - University Of Illinois; Kerr, Brian; DILGER, ANNA - University Of Illinois

Submitted to: Journal of Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/9/2018
Publication Date: 7/10/2018
Citation: Overholt, M.F., Lowell, J., Kim, G., Boler, D., Kerr, B.J., Dilger, A. 2018. Influence of feeding thermally peroxidized soybean oil to finishing barrows on processing characteristics and shelf-life of commercially manufactured bacon. Journal of Animal Science. 96:2723-2733.

Interpretive Summary: Research on lipid quality has typically focused on the role of dietary fatty acid profile, commonly measured by its iodine value, on the quality of adipose tissue in pork products. Recently however, knowledge of an oils’ peroxidation status, commonly measured by its thiobarbituric acid reactive substances concentration, is also being considered for its impact on adipose tissue quality. The current study was conducted to determine the effects of feeding thermally processed soybean oil on the iodine value and peroxidation status of pork bellies, and how this may affect fresh belly characteristics, processing yields, and shelf-life of commercially manufactured bacon stored under food-service style conditions. Data from this experiment indicated that feeding highly peroxidized soybean oil reduced belly adipose tissue iodine value, but feeding peroxidized soybean oil did not affect peroxidation status of pork bellies, processing yields, or shelf-life characteristics of commercially manufactured bacon. This information is important for nutritionists at universities, feed companies, and pork processors showing that finishing pigs fed peroxided soybean oil have only minor effects on belly adipose tissue iodine value, and did not affect the peroxidation status, processing yield, or shelf-life characteristics of commercially manufactured bacon.

Technical Abstract: Objectives were to evaluate effects of feeding soybean oil (SO) with varying levels of peroxidation on fresh belly characteristics, processing yields, and shelf-life of commercially manufactured bacon stored under food-service style conditions. Fifty-six barrows were randomly assigned to 1 of 4 diets containing 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 air at a rate of 15L/min. Individually housed pigs were provided ad libitum access to feed for 81 d. On d 82 pigs were slaughtered and on d 83 carcasses were fabricated and bellies collected for recording of weight, dimensions, and flop distance. Belly adipose tissue cores were collected for analysis of iodine value (IV) by near-infrared spectroscopy (NIR-IV). Bacon was manufactured at a commercial processing facility and sliced bacon was subsequently transferred to food-service style packaging and subjected to 0, 30, 60, or 90 d storage at -20°C. Stored bacon was evaluated for thiobarbituric acid reactive substances (TBARS) and trained sensory evaluation of oxidized odor and flavor. Fresh belly and bacon processing traits were analyzed as a one-way ANOVA with the fixed effect of SO; whereas, shelf-life traits were analyzed as a one-way ANOVA repeated in time. There was no effect (P = 0.30) of SO on belly weight, length, width, or thickness; but bellies of pigs fed 90°C SO had greater (P = 0.04) flop distance (more firm) than all other SO treatments. Belly fat NIR-IV of pigs fed 90°C SO were 10.22 units less (P < 0.0001) than pigs fed 180°C SO, which were 2.99 and 3.29 units less than belly adipose tissue of pigs fed 22.5°C and 45°C SO, respectively. There was no effect of SO on brine uptake or cooking yield of commercially manufactured bacon. There was a trend (P = 0.09) for bacon manufactured from bellies of pigs fed 45°C and 90°C SO to have greater slicing yields than those from pigs fed 22.5°C and 180°C SO. There were no SO × storage time interactions (P = 0.27) for any shelf-life trait. There was no difference in TBARS, oxidized odor, or oxidized flavor among the four SO treatments, though all three shelf-life metrics increased (P < 0.0001) with storage time. Overall, feeding SO thermally processed at 90°C and 180°C reduced belly adipose tissue IV, but feeding peroxidized SO did not affect processing yields or shelf-life characteristics of commercially manufactured bacon.