Animal Science Department


Date of this Version



A THESIS Presented to the Faculty of The Graduate College at the University of Nebraska In Partial Fulfillment of the Requirements For the Degree of Master of Science, Major: Animal Science, Under the Supervision of Professor Roger W. Mandigo. Lincoln, Nebraska: May, 2004
Copyright 2004 Carmina C. Robles.


The objective of the study was to evaluate the impact of fresh vs. frozen bellies on bacon parameters. Differences among bellies from pigs of different genetic lines and sexes were evaluated. A population of 578 pork bellies from barrows and gilts of Berkshire, Chester White, Duroc, Landrace, Poland China and Yorkshire lines were processed to sliced bacon and cooked bacon to be evaluated. Bellies were divided into two storage treatments: fresh (stored at 3°C) or frozen (held at -15°C). Fat samples were collected from each belly to establish a fatty acid profile. Differences in percent pump, smokehouse yield, slicing yield and total yield were evaluated. The bacon slabs were sliced and cooked to evaluate differences in fatty acid content, slicing yield, shattering, cooking yield, distortion and proximate composition. Fresh bellies had bacon slicing yields 1.74 percent higher (P<0.05) than frozen bellies. Total yield was not different (P>0.05) for fresh and frozen bellies. No differences (P>0.05) were found in the saturated and unsaturated fatty acid profile of the bellies due to storage treatment. Gilts had a profile with a 1.08 percent higher (P<0.05) unsaturated fatty acid (palmitoleic, oleic, linoleic, linolenic and 11-eicosenoatic) when compared to barrows. In the center of the slab (locations B, C and D,) frozen bellies had a higher total shatter mark length (P<0.05). Genetic lines with higher fat content had lower (P<0.05) cooking yields. Frozen bellies had higher (P<0.05) distortion scores of the cooked bacon slice than fresh bellies. Distortion was affected by an interaction (P<0.05) among line and sex. Higher yields were associated with sex and lines containing higher percentage of fat in the bellies. Overall, fresh and frozen bellies had similar characteristics when processed. Although statistical difference among treatments existed, the practical advantages of these values may be slight. Considering that bellies were stored frozen for 15 d, it is not known if longer periods of storage could result in lower yields and significant processing and cooking differences.