Masters Theses

Date of Award

12-1994

Degree Type

Thesis

Degree Name

Master of Science

Major

Food Science and Technology

Major Professor

Ruthann B. Swanson

Committee Members

Marjorie Penfield, John Mount

Abstract

Flavor is a primary determinant of red meat acceptability. Although fishmeals have successfully replaced plant protein in animal diets, fishy off-flavors may result, with off-flavor intensity increasing with increased levels of dietary fishmeals. By-products from Alaska's fish processing industry are not currently being used to their fullest extent; increased use of fishmeals as a protein supplement would decrease environmental impacts associated with fish processing. Quality attributes of fresh and cured muscles from 21 Yorkshire X Hampshire and 4 Yorkshire X Duroc X Hampshire cross hogs fed salmon meal as a replacer for soybean meal on a 0, 25, 50, 75 and 100% crude-protein basis were assessed. Pigs were randomly assigned within sex, weight and litter to diet treatments. Pigs were raised at UAF Agriculture and Forestry Experiment Station, slaughtered and processed (hams were injected with brine) at Mount McKinley Meat and Sausage Co.. Palmer, AK, frozen and air freighted (~20 hr) to Knoxville, TN under frozen conditions. An experienced, orient sensory panel (n=23) evaluated fresh loins and cured hams roasted at 5 wk post-mortem to an endpoint temperature of 70°C on 150-mm line scales; sensory attributes were: moisture release, tenderness, flavor intensity, rancidity, off-flavors (other than rancidity), fatty-mouth coating, fat character (oiliness/greasy) and overall quality. The following chemical analyses were performed on muscle tissue: moisture, crude fat and fatty acid profile. Subcutaneous fat was analyzed for fatty acid profile and free fatty acid content. The following physical analyses were performed: cooking losses, Warner-Bratzler shear and expressible moisture index (EM). Data were analyzed with ANOVA and PROC GLM; means were separated with Student-Newman-Keuls or PDIFF, where appropriate. Correlation between sensory attributes and fatty acid profiles of muscle and subcutaneous fat were determined using Pearson Product Moment Correlation. Chemical analyses revealed salmon meal quality was acceptable. Diet treatment did not affect carcass characteristics. Loin pork flavor intensity decreased whereas off-flavors and rancidity increased when salmon meal levels exceeded 25%; significant positive correlations between PUFA-LC (long chain-polyunsaturated fatty acids) and detrimental sensory effects were found. Variation in fatty-mouth coating, fat character (oily vs. greasy) and moisture release was limited; tenderness increased with increased percentages of salmon meal. Few differences among samples were identified in physical tests. Overall quality of the control and 25% loin did not differ; remaining loin samples were rated below the midpoint. Among ham samples, few differences were noted in moisture release, tenderness, fatty-mouth coating, fat character, off-flavor intensity and rancidity. Significant differences found were unlikely to be of practical importance. Similarly, the relationship between PUFA-LC and ham sensory attributes was not notable. Ham flavor intensity did not differ. Overall quality of the 25% ham was rated significantly higher than all other treatments. Incorporation of 25% salmon meal did not impair fresh loin or cured ham quality. However, hams were significantly less rancid, with fewer other off-flavors. Fat character was greasy rather than oily and overall quality of the hams was more desirable.

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