| Summary: | 碩士 === 國立中興大學 === 畜產學系 === 87 === The main purpose of this study was to investigate effects of four food binders─carrageenan(carr), corn syrup solids(CSS), whey protein concentrate(WPC), and soy protein isolate(SPI),on
the quality of smoked-cooked chicken liver sausage. At first, dependind on the results of evaluation of the cooking loss, rheological properties, and sensory panel scores of chicken liver sausage products with these four binders by different levels, we tried to seekout a suitable level for products. Then, liver sausages were made with these four binders by a suitable level, respectively, and stored at the temperatures of 4℃ and -20℃ for understanding the changes of quality and optimum shelf life of the products during storage.
The results were as followings：in rheological properties, a level of 0.2, 0.5, 0.8% carr, 1.0, 2.0, 3.0% CSS, 1.0, 2.0, 3.0% WPC, and 1.0, 2.0, 3.0% SPI were added with chicken liver sausage, respectively, can improve the gel strength and breaking strength. The improved effeciency of WPC and SPI on the rheological properties of liver sausage were more remarkable than the others, while CSS had the least effect. In sensory properties, the addition of SPI reduced the flavor and overall acceptance of the products, and the overall acceptance scores of products decreased by the increasing levels of four binders. The suitable level of these four binders were carr 0.2%, CSS 1.0%, WPC 1.0%, and SPI 1.0%, individually, in this study depending on the sensory properties, binding ability and slicing.
The higher moisture and lower fat contents were found in chicken liver sausages with these four binders. The total cholesterol, heme iron, and non-heme iron contents of all samples were 292.60~340.31 mg/100g, 2.37~3.20 mg/100g, and 3.30~3.97 mg/100g, respectively.
During cold storage at 4℃, the total plate counts(TPC) and anaerobic plate counts(APC) of all samples increased with storage time increasing. At the 28th day, the TPC and APC of all samples were lower than 6 log CFU/g, but a off-flavor be smelled. The pH values of all samples decreased gradually with storage time increasing, while the TBA(2-thiobarbituric acid) values were unstable during storage. The VBN(volatile basic nitrogen) values of all samples increased with storage time increasing. At the end of storage, the VBN values of products were 34.37~38.63 mg %. The nitrite residues of all samples were 41.73~48.37 ppm at the initial and down to 22.95~27.19 ppm at the 28th day. In the color of products, the L-value and b-value of all samples increased with storage time increasing, but no differences for a-value were observed during storage. The gel strength of all samples at the 28th day were higher than at the 0 day’s. In sensory properties, the color scores of all samples decreased gradually after the 7th day during storage. At the 21th day, the product of SPI treatment had significantly lowest panel scores among all treatments.
During frozen storage at -20℃, the TPC and APC of all samples decreased gradually with storage time. The TBA and VBN values of all samples maintained stable during storage. At the 90th day, the nitrite residues of all samples were 35.56~38.35 ppm. The L-value and b-value decreased while a-value increased at the end of storage. The gel strength of all samples increased singnificantly at the 90th day. No differences were found in sensory properties of all samples during frozen storage.
In conclusion, chicken liver sausage products with 0.2% carrageenan, 1.0% corn syrup solids,1.0% whey protein concentrate and 1.0% soy protein isolate, respectively, had the shelf life of 28 days during cold storage at 4℃ and at least 3 months during frozen storage at -20℃.
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