| Summary: | 碩士 === 東海大學 === 食品科學系 === 87 === Pig blood was centrifuged to separate the plasma and blood cell . Blood cell was decolorized by treatment with sodium pectate and gave globin that was then modified by heating and treating with pectin . Both the plasma and modified globin were spray dried .
The plasma and modified globin were mix together at different ratio and adjusted to different protein concentration and different pHs before heating into gels . Optimum conditions for obtaining the gel of good hardness were determined . Based on these gelating conditions , other polymer-protein gels were prepared by adding chitosan products of different degree of hydrolyzation or by adding some polysaccharides such as κ-carrageenan , sodium alginate and gellan gum to the protein solution at different concentration before heating . These gels were investigated on the hardness , shear force , scanning electronic micrograph (SEM) and sensory evaluation . A chitosan product and a polysaccharide those gave the gels of good sensory evaluation were chosen and added together at different chitosan product/polysaccharide ratio to the protein solutions before heating , the gels were compared on the physical properties and SEM . On other hand , modelized meat bead was prepared by using the protein as a main material with and without adding some given chitosan products or polysaccharides . Meat bead was also made by the conventional process as reference . The products were also compared on the physical properties and sensory evaluation .
As a result , pH7 was suitable for the gel formation of the plasma and the plasma-modified globin mixes . The lower modified globin/plasma ratio and the higher protein concentration , the higher gel hardness . The gel prepared by only plasma at a protein concentration of 25% showed sensory evaluation better than others .
The gel that was prepared by adding the hydrolyzed chitosan of 20% degree of hydrolyzation to the 25% plasma solution at a concentration of 0.5% showed comparatively good in hardness , shear force , also as in sensory evaluation , gave an internal structure (presented by SEM) more rigid and had a mouth feel nearly that of fish and meat products . The gel prepared by adding κ-carrageenan to the 25% plasma solution at a concentration of 0.25% gave a superior sensory evaluation to gels prepared by adding sodium alginate or gellan gum . Its SEM appeared as same as spongy network that was different from the structures of the plasma gel and the chitosan product-plasma gel .
In comparatively , the scores of total acceptibility in the sensory evaluation of the hydrolyzed chitosan-plasma gel , the κ-carrageenan-plasma gel and the plasma gel were 7.3 , 6.0 and 5.2 , respectively .
If the above hydrolyzed chitosan and κ-carrageenan were mixed together with the 25% plasma solution and heated into gels , it occurred that the hydrolyzed chitosan/κ-carrageenan ratio was higher , the values of hardness and shear force of the gel was nearer to those of the hydrolyzed chitosan-plasma gel , and the spongy network of the gel was finer and more completely .
To the modelized meat bead , the product that was prepared by using the 25% plasma as a main material with adding the hydrolyzed chitosan of 20% degree of hydrolyzation at a concentration of 0.5% or with adding 0.25% κ-carrageenan showed a total acceptibility value higher than that without adding these polymers . It was also notable that , the scores of all items in the sensery evaluation of the above modelized meat beads were closer to those of the product prepared by the conventional process .
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