• Journal of Life Science
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• v.6 no.1
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• pp.14-26
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• 1996

In order to effectively utilize fish(Cod, Gadus macrocephalus) bone obtained as fish waste in fish manufactory, the preparation of the fish bone gelatin were attempted by heat extracting method from collagen protein contained in the fish bone. The methods of two kinds pretreatments (the B-type by alkali pretreatment and the E-type by enzyme pretreatment) for fish bone and the optimal extraction conditions to prepare gelatin from pretreated fish bone were investigated. Physical properties and functionalities of the two type fish bone gelatins obtained were compared with the commercial gelatin and the fish skin gelatin. The optimal extraction conditions of the B-type and the E-type gelatins were 5 folds of added water with material(w/w), pH 5.0, 3 hrs of extraction time and 60$\circ$C of extraction temperature. The yield of the B-type and the E-type gelatins were 32.6% and 28.1 %, respectively. The B-type gelatin was superior to the E-type un all physical properties. Molecular weight of the B-type was larger than that of the E-type due to its pretreatment method. Among the composition of amino acids, the amino acids such as glycine, alanine, glutamic acid and imino acids(proline and hydroxyproline) were responsible for 68$\sim$70% of the total amino acids. Functionalities of the fish bone gelatin were almost similar to commercial gelatin.

• KSBB Journal
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• v.15 no.6
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• pp.635-643
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• 2000

To compare the antioxidative activities of fish skin and bovine skin gelatin hydrolysate, gelatin hydrolysates from Alaska pollack and bovine skin were prepared by various enzymatic hydrolysis methods (1st step, Alcalase; 2nd step, pronase E; 3rd step, collagenase) using a continuous three-step membrane reactor. The molecular weight distributions of the 1st, 2nd and 3rd step hydrolysates were 7∼10 kDa, 2∼5 kDa and 0.7∼0.9 kDa, respectively. The antioxidative activity of fish skin gelatin hydrolysate was stronger than that of bovine skin gelatin hydrolysate, and in particular, both of 2nd step hydrolysates showed more antioxidative activity than hydrolysates of any other step. The optimum antioxidative activity concentration of the 2nd step hydeolysates of fish and boving skin were 1% (w/w) in a linoleic acid water-alcohol emulsion. In cultured cells exposed to t-butyl hydroperoxide (t-BHP), the 2nd step hydrolysate of fish skin gelatin delayed cell death most. These results suggest that the antioxidative activity of fish skin gelatin hydrolysate is higher than that of bovine skin gelatin hydrolysate because of their different amino acid contents.

• Korean Journal of Food Science and Technology
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• v.26 no.6
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• pp.683-689
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• 1994

With a view to utilizing effectively fish skin wastes from marine manufactory, a gelatin solution extracted from yellowfin sole skin was fractionated by precipitation with ethanol, and then the functional and physico-chemical properties for the fractionated gelatin were determined. Ethanol was added up to 50% of ethanol content to a gelatin solution extracted from yellowfin sole skin, then the mixture was left to stand at $0^{\circ}C$ for 12 hours. Finally, the precipitates were dried by hot-air ($40^{\circ}C$). The gel strength and melting point of a 10% gel of gelatin prepared from yellowfin sole skin by precipitation with ethanol has 322.4g and $23.3^{\circ}C$, respectively. The physico-chemical properties of the ethanol treated fish skin gelatin were superior to those of fish skin gelatin prepared without ethanol treatment. Besides, the functional properties of the ethanol treated gelatin were lower in solubility and higher in water holding capacity, oil binding capacity, emulsifying activity, emulsifying stability, foam expansion and foam stability than those of pork skin gelatin sold on market as well as gelatin prepared without ethanol treatment. It may be concluded, from these results, that the fish skin gelatin prepared by precipitation with ethanol can be effectively utilized as a human food by improving the functional properties.

• The Korean Journal of Food And Nutrition
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• v.30 no.4
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• pp.681-688
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• 2017

This study was conducted to investigate the effect of gelatin concentration and storage on color and texture of puffer fish stock jelly. Puffer fish stock jelly was prepared by adding various amounts (2.5~10 percent) of gelatin to puffer fish stock. Color changes of puffer fish sstock jelly were also investigated during storage at $4^{\circ}C$ and $25^{\circ}C$ with varying amount of gelatin (2.5~10.0 percent). Regardless of storage temperature, the L values of puffer fish stock jelly were slightly increased, while a values of the stock jelly were negatively decreased during storage. However, L and negative b values were decreased with increasing gelatin concentration, whereas a values were increased negatively with increasing gelatin concentration. The texture profiles of puffer fish stock jelly such as hardness, springiness, cohesiveness adhesiveness, chewiness and brittleness were determined during storage at $25^{\circ}C$ and $4^{\circ}C$ at various intervals. The hardness, chewiness and brittleness were increased during storage at $25^{\circ}C$ for four days, while those of springiness and cohesiveness were decreased during storage. However, the values of all textural parameters were increased with increasing gelatin concentration in puffer fish stock jelly. Patterns of textural parameters of puffer fish stock jelly stored at $4^{\circ}C$ were practically identical to those stored at $25^{\circ}C$.

• Applied Biological Chemistry
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• v.38 no.2
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• pp.129-134
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• 1995

With a view to utilizing effectively fish skin wasted from marine manufactory, an extracted dover sole skin gelatin was fractionated by further ethanol fractional precipitation method, and then the functional and physicochemical properties for the modified gelatin were determined. Ethanol was added to the concentration of 30% in an extracted dover sole skin gelatin solution, and then the mixture was left to stand at $0^{\circ}C$ for 12 hours. Finally, the precipitates were dried by hot-air$(40^{\circ}C)$ blast. The yellowfin sole skin gelatin prepared by further ethanol fractional precipitation has 223.0 g in gel strength, $17.7^{\circ}C$ in the melting point, and $12.0^{\circ}C$ in the gelling point. The physicochemical properties of the ethanol treated fish skin gelatin were superior to those of fish skin gelatin prepared without ethanol adding, whereas inferior to those of animal skin gelatin. The functional properties of the ethanol treated fish skin gelatin were superior to those of fish skin gelatin prepared without ethanol adding, and were more similar to animal skin gelatin. It may be concluded, from these results, that the dover sole skin gelatin prepared by further ethanol fractional precipitation can be effectively utilized as a human food by improving the functional properties.

• Applied Biological Chemistry
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• v.39 no.4
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• pp.282-286
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• 1996

To effectively utilize fish skin gelatin as a material for quality improvement in surimi gel from fish with a red muscle, conger eel skin gelatin was modified with succinic anhydride, and funtional properties such as emulsifying activity and emulsifying stability were determined. The degree of chemical modification incresed up to 0.3 g of succinic anhydride/g of gelatin, above this adding ratio a nearly constant value was reached. The maximum amount of modification was about 90%. The emulsifying activity and emulsifying stability of gelatin gradually increased up to 89.8% of succinylation extent, little changed above of succinylation extent. The other functional properties as solubility, water holding capacity, foam expansion and foam stability were improved following succinylation with 0.3 g of succinic anhydride/g of gelatin. Amino acid composition of succinylated gelatin was similar to that of unmodified gelatin. Heavy metal contents such as cadmium, lead, copper and zinc of succinylated gelatin were lower than those of unmodified gelatin.

• Fisheries and Aquatic Sciences
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• v.12 no.2
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• pp.79-85
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• 2009

Gelatin hydrolysates with a high inhibitory activity against angiotensin I-converting enzyme (ACE) were fractionated from Alaska pollock surimi refiner discharge. The ACE-inhibitory activity, expressed as $IC_{50}$ (mg/mL), was highest (0.49 mg/mL) in gelatin hydrolysates formed by sequential 2-hr treatments of Pronase and Flavourzyme. After fractionation through four different membrane filters with molecular weight cut-offs of 3, 5, 10, and 30 kDa, the highest ACE-inhibitory activity (0.21 mg/mL) was observed with the 3-kDa filtrate.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.41 no.6
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• pp.419-426
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• 2008

Physicochemical characteristics of gelatin extracted from abdominal skin of yellowfin tuna (Thunnus albacares), were investigated by comparing its proximate composition, pH, amino acid composition, viscoelastic properties, gel strength and SDS-PAGE patterns, with those of bovine and porcine gelatins. The effects of gelatin concentration, maturation time, heat and freeze treatments on the gel strength of yellowfin tuna abdominal skin gelatin were studied. Amounts of $\alpha$-chains, $\beta$- and $\gamma$-components of yellowfin tuna abdominal skin gelatin were higher than those of the two mammailan gelatins. Yellowfin tuna abdominal skin gelatin had the lowest imino acids (proline and hydroxyproline) content, which was consistent with that of other fishes. However, yellowfin tuna abdominal skin gelatin was highest in glycine, alanine, and lysine. The gel strengths of all gelatins were proportional to the concentration of gelatin, but yellowfin tuna abdominal skin gelatin exhibited the greatest gel strength at each concentration. Yellowfin tuna abdominal skin gelatin required a longer maturation time than the two mammalian gelatins to form a firm gel. Higher heating temperature decreased the gel strength of yellow fin tuna abdominal skin gelatin more than in the two mammalian gelatins. Freezing decreased the gel strength of bovine gelatin only slightly, but longer freezing times resulted in greater reductions in gel strength in the yellowfin tuna abdominal skin and porcine gelatins.

• Fisheries and Aquatic Sciences
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• v.12 no.3
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• pp.163-170
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• 2009

This study was conducted to obtain the gelatin fraction with a high anti oxidative activity from Alaska pollock surimi by-products using a two-step enzymatic hydrolysis and ultrafiltration. Among gelatin hydrolysates from refiner discharge of Alaska Pollock surimi, the highest antioxidative activity (81.5%) resulted from gelatin hydrolysate sequentially treated with Pronase E and Flavourzyme each for 2 hr. However, no difference was seen in the anti oxidative activity of the second hydrolysate (Pronase E-/Flavourzyme-treated hydrolysate) when compared to the permeate fractionated through a 10-kDa membrane. The results suggest that the Pronase E-/Flavourzyme-treated hydrolysate from refiner discharge gelatin of Alaska pollock surimi can be used as a supplementary raw material for improving health functionality.

• 한국생물공학회:학술대회논문집
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• 2000.11a
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• pp.769-772
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• 2000

Fish oil has abundant highlly unsaturated fatty acids such as EPA and DHA. Therefore, fish oil is very susceptible to peroxidation. Adding any antioxidants to fish oil is acceptable to prevent the peroxidation. However, nontoxic and strong naturally occurring antioxidants for fish oil was not developed. ${\alpha}-tocopherol$ is one of useful natural antioxidants, but it is not good to prevent the fish oil peroxidation. In this study, we examined the development of microencapsulated squid liver oil product to prevent effectively peroxidation of the fish oil. The acceptable materials for encapsuling the squid liver oil were gum arabic and gelatin. The ultimate encapsulation rate of squid liver oil was 45.5%.