Masters Theses

Date of Award

12-1988

Degree Type

Thesis

Degree Name

Master of Science

Major

Food Science and Technology

Major Professor

H. Dwight Loveday

Committee Members

M. James Riemann, Sharon L. Melton, William R. Backus

Abstract

The objective of this research was to study the effect of realimentation on the physical, chemical and sensory characteristics of cull ewes. Twenty-six cull ewes were fed a 15% protein, corn and soybean ration while 8 ewes remained on fescue-orchardgrass pasture to serve as controls. This ration was administered to ewes for periods of 21, 42 and 63 days on feed (DOF). Ewes were assigned an initial condition score (Engle, 1983) to remove variation in fatness when assigning ewes to DOF group. Ewes were placed on feed and slaughtered in a manner that minimized freezer storage variation for sensory evaluation. The carcasses were physically separated into bone, lean and fat. An approximately 2.54 centimeter thick slice was removed from the longissimus and evaluated for color by a sensory panel and the Hunter Color Lab Meter. Proximate analysis was performed on the subcutaneous fat, inside leg cushion and total lean of the carcass. Fatty acid analysis by gas chromatography was performed on the subcutaneous fat and inside leg cushion. An experienced sensory panel (n=8) evaluated the mutton roasts and a lamb reference for flavor, tenderness and juiciness. A consumer panel (n=26) evaluated mutton roasts and lamb roasts for flavor intensity and overall acceptability.

Yield grade and quality grade factors were not different across DOF (P>.05). The yield grades for ewes ranged from 2.5 to 6.7 and quality grades from utility to choice. Longissimus color scores were not different (P>.05) when evaluated by a sensory panel and Hunter Color Lab Meter. In the subcutaneous fat, the fatty acids I18:IT, 18:2W6, 18:3W6 and 20:2W6T decreased Linearly as DOF increased while 20:1 exhibited a quadratic effect (P>.05). When fatty acids were grouped by saturation, polyunsaturated omega 6 groups (PUFA 6) decreased linearly across DOF. The fatty acid 4M14:0 decreased linearly across DOF for the inside leg cushion.

An experienced sensory panel found 42 DOF mutton roasts had lower flavor scores (P>.05) than lamb, but were not different (P>.05) from other mutton roasts. Sensory tenderness scores found 63 DOF roasts were not different from lamb (P>.05), but lamb was more tender than 0, 21 and 42 DOF roasts (P<.05). However, the Warner-Bratzler shear force values did not differ (P>.05) among lamb and DOF treatment roasts. For juiciness, sensory evaluators found no difference (P>.05) among lamb and DOF mutton roasts. The consumer panel found no difference (P>.05) among lamb and mutton DOF roasts for flavor intensity and overall acceptability.

The grain feeding of mutton at the maintenance level did not affect the carcass traits and had only slight effect on fatty acid profile and sensory characteristics. The sensory results indicate that the use of mutton roasts could possibly be expanded especially into the food service area.

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