Thesis (Honors)--College of William and Mary, 2009. / Includes bibliographical references (leaf 25). Also available via the World Wide Web.

Machine separated flesh from American shad (Alosa sapidissima) was evaluated for preparing heat set gel products. Round fish frozen for 15) to 10 months at -18°C served as raw material for processing investigations. The effectiveness of various additives and processing procedures for improving gel strength and sensory characteristics were determined. Addition of 0.5% polyphosphate to sols enhanced the hardness (P [greater than or equal to] .005), cohesiveness (P [greater than or equal to] .01) and springiness (P [greater than or equal to] .001) of heat set gels. Small amounts (0.5 and 1.0%) of dried egg white also improved hardness, cohesiveness and springiness (P [greater than or equal to] .001). Employing a two stage heat setting regime (40°C for 30 min followed by 90°C for 20 min) strengthened (hardness, cohesiveness and springiness) (P [greater than or equal to] .001) gels over a one stage (90°C for 30 min) heat set. Two stage heating improved gel strength when sol fonnulations contained additives that improved, lowered or exerted no effect on gel strength. Concentrations of dried egg white (1.0, 2.0, 3.0 and 4.0%) and potato starch (1.0, 2.0 and 5.0%) did not improve gel strength. Dried egg white (>1%) did not alter (P > .05) any physical parameters of gel texture. Potato starch (>1%) reduced gel hardness (P [greater than or equal to] .001). More basic pH conditions produced by the addition of 0.1 and 0.2% sodium carbonate to sols did not alter gel hardness or springiness (P < .05) and only caused a slight inprovement in cohesiveness (P [greater than or equal to] .001). Ihe cryoprotectants sorbitol, (0.0, 2.0, 4.0, 6.0 and 8.0%) and sucrose (0.0, 2.0, 4.0 and 6.0%), reduced gel strength in a concentration dependent manner. Gel hardness was reduced in a linear manner as fish protein was replaced with sorbitol (r =.976) or sucrose (r =.965) in sols formulated to contain 74 + 1.5% moisture. Cohesiveness was reduced in a similar manner (r = .942) by sorbitol, but not by sucrose. Gel springiness was not altered by additions of sorbitol or sucrose. Incorporation of sucrose into formulations reduced sensory preference for the texture, flavor, appearance and overall desirability of heat set gels. Analysis of covariance of texture preference scores and physical measurements of texture reveal a strong linear correlation with hardness (P =.0004), but not with cohesiveness (P =.6675). Within the range of sucrose levels evaluated, harder gels were preferred. Washing was evaluated for improving the strength and sensory preference for heat set gels containing 0.5% polyphosphate and 0.5% dried egg white. Sols were set by heating for 30 min at 40°C followed by 90°C for 20 min and exposed to wood smoke. Gel hardness and springiness were reduced by washing (P [greater than or equal to] .05), but not cohesiveness (P > .05). This was surprising, since the gel strength enhancing effect of washing is well documented. Sensory preference for the flavor, color, texture or overall desirability of heat set gels was not affected (P > .05) by washing. Mean overall desirability scores for gels prepared from unwashed minced flesh of 5.25 and 5.27 for washed minced flesh were only slightly above a neutral preference (5.0 = neither like nor dislike). Round shad yielded 65.06% planks, 41.20% minced flesh and 40.10% refined flesh. A single exchange wash followed by dewatering yielded 23.02% pressed flesh based upon round weight which was reduced to 20.68% by refining. Processing minced flesh into washed and refined flesh recovered 51.37% of total solids. The yield through refining was 97.33 and 89.83% respectively for unwashed and washed flesh. The protein and lipid content of flesh was not altered (P > .05) by washing, but ash content was reduced (P [less than or equal to] .001). / Graduation date: 1989

Thesis (Ph. D.)--Joint Program in Oceanography/Applied Ocean Science and Engineering (Massachusetts Institute of Technology, Dept. of Biology; and the Woods Hole Oceanographic Institution), 2007. / Includes bibliographical references (p. 188-204).

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Analysis of mitochondrial DNA (mtDNA) sequence variation among 244 American shad (Alosa sapidissima) from 14 rivers spanning the (Florida-Quebec) range of the species revealed several unusual features of shad mtDNA polymorphism. Two types of heteroplasmy, one involving a length polymorphism and the other a restriction site are common in shad. The length polymorphism involves a novel tandem triplication of a 1.5-kb sequence in the D-loop region. Both forms of heteroplasmy stem from multiple mutational events. The mtDNA data indicate that shad populations are reproductively discrete, and suggest that differences in the reproductive traits of northern and southern shad populations have evolved since the Pleistocene. Low mtDNA sequence variation in shad may stem at least in part from Pleistocene population reductions. A fossil calibration supports an mtDNA divergence rate in shad at least one order of magnitude slower than the prevailing estimate for vertebrates.

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Thesis (M.S.)--Oregon State University, 1982. / Typescript (photocopy). Includes bibliographical references (leaves 37-40). Also available on the World Wide Web.