The effect of round shrimp post-catch age on the frozen shelf-life characteristics of processed cooked meat was evaluated. Refrigerated shrimp, one, three, and five days post-catch, were cooked, mechanically peeled, frozen at -29°C and held for a period of twelve months at -18°C. At three month intervals, samples were subjected to chemical and sensory evaluation. Levels of trimethylamine oxide (TMAO), trimethylamine (TMA), dimethylamine (DMA), formaldehyde (FA), inosine monophosphate (IMP) and hypoxanthine (Hx) were determined. Sensory evaluations included judgements for texture, juiciness, flavor, and overall desirability. The degradation of frozen cooked meat quality was directly related to round shrimp age. Flavor panel scores for meat from one day old shrimp decreased in a linear manner with regard to texture (r= -.933, P .005), juiciness (r= -.795, P .005), flavor (r= -.861, P .005) and overall desirability (r= -.919, P .005). The change in the quality of the meat from three and five day old shrimp with respect to storage time was largely non-linear and after an initial quality reduction during the first three months flavor panel scores were relatively stable. Scores for frozen meat during the first six months were equal, but the more rapid deterioration of meat from one day old shrimp yielded scores inferior to those for meat derived from three and five day old shrimp after twelve months. Initial levels of TMAO, TMA, IMP and Hx in cooked meat reflected the age of round shrimp. Differences in levels were related to chemical decomposition, drip loss and/or bacterial out growth. DMA and FA levels were low and not related to round shrimp age. No Hx was detected in meat from one day old shrimp and only low levels were detected in meat from three and five day old shrimp. TMAO decomposed during storage to yield DMA and FA. TMAO levels decreased in a roughly linear manner. DMA formation was neglegible during the first six months, but increased during the latter six months of storage in a manner inversely related to round shrimp age. The rates of DMA formation did not show a direct inverse proportionality. Formaldehyde was formed during the first three months of storage, but determined levels between three and twelve months were constant, probably reflecting its high reactivity with protein. Determined IMP and Hx levels were relatively constant. Levels of TMA were stable for the first nine months, but decreased during the last three months, concurrent with the rapid formation of DMA. The degree of quality deterioration during storage was closely associated with the decomposition of TMAO. . The regression of TMAO and DMA levels on scores for meat from one day old shrimp yielded significant positive and negative correlations, respectively. Levels in meat from three and five day old shrimp were not correlative with the observed non-linear quality degradation. Initial levels of TMAO, while not correlative with initial panel scores, did correlate with scores after twelve months. The regression of initial TMAO levels in meat from one, three and five day old shrimp on scores yielded significant negative correlations for texture (r= -.936, P [greater than or equal to] .005), juiciness (r= -.825,P [greater than or equal to] .01) and flavor (r= -.752, P [greater than or equal to] .025). Similarly, texture (r= -.910, P [greater than or equal to] .005), juiciness (r= -.815, P [greater than or equal to] .01), flavor (r= -.670, P [greater than or equal to] .05) and overall desirability (r= -.783, P [greater than or equal to] .025) scores correlated in a significant manner with DMA levels determined for meat stored twelve months. The findings of this investigation support the involvement of TMAO and its decomposition products in mediating the frozen shelf-life of Pacific shrimp. / Graduation date: 1978