• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.6
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• pp.895-900
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• 1998

In order to the effective utility of marine by-product, crude lecithin was isolated from skipjack viscera oil and the lecithin was refined by bleaching and deodorization. Crude lecithin was separated from the skipjack viscera oil degummed with 0.4 ml of citric acid per 100 ml of the oil. Bleaching was effected by adding $5\%$ activated clay and treating for $40^{\circ}C$ for 90 min under vacuum, and deodorization was effectively conducted by steam distillation at $130^{\circ}C$ for 60 min under 4 ton of vacuum. The major fatty acids of the skipjack viscera oil. were 16:0. 18:1 (n-9), 22:6 (n-3), 18:0, and 16:1 (n-7). Crude and refined lecithins contained more aproximately $7\~18\%$ of 22:6 (n-3) than raw oil, the skipjack viscera oil.

• Korean Journal of Food Science and Technology
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• v.23 no.3
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• pp.251-255
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• 1991

The antioxidative effects of the six commercial lecithins, tocopherols, citric acid and ascorbyl palmitate on refined perilla oil were inverstigated by active oxygen method ($AOM,\;hrs\;at\;97.8^{\circ}C$) and oven test. Except for the lecithin I (aceton insoluble content 55%), the induction time on perilla oil treated with commercial lecithins at 5% level was longer than that of refined soybean oil. When the concentration of lecithin (0.5, 1, 2.5, 4 and 5%) in perilla oil was increased, enhanced the antioxidative effect at AOM and oven test. Lecithin also showed synergistic effect with the mixtures of tocopherol, citric acid and ascorbyl palmitate. The antioxidative effect of ${\gamma}-rich-tocopherol$ on perilla was higher than that of ${\dalta}-rich-tocopherol$ or mixed tocopherol.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.6
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• pp.901-907
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• 1998

The refined lecithin derived from skipjack viscera oil was added to fish sausage and then the quality stability of the fish sausage during storage was studied. The fish sausages with the lecithin (lecithin $0\%$, A; $2\%$, B: $4\%$, C; $6\%$, D) were shown low level for peroxide value, carbonyl value and acid value compared to that without the lecithin, when they were stored for 40 days at $5^{\circ}C$. The fish sausage with the lecithin was also almost unchanged in polyunsaturated fatty acid compositions such as 22:6 (n-3) and 20:5 (n-3) during storage. Before storage, both the sausages with and without the lecithin were almost unchanged in their sensory score, but the sensory scores were decreased with storage. As a result from sensory score, the sausage contained $2\%$ of lecithin (B) was similar to that of $0\%$ lecithin (A). However, all the samples were kept their oxidative stabilities for 40 days at $5^{\circ}C$.

• Food Science and Biotechnology
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• v.15 no.2
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• pp.202-206
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• 2006

The oxidation stability of fish oil containing omega-3 polyunsaturated fatty acids (PUFAs), which is very susceptible to oxidative deterioration, needs to be improved before it can be successfully applied to functional foods. The antioxidant activities of 17 species of materials in anchovy oil (AO) were compared and a potent antioxidant was determined to improve the shelf-life of refined AO. Antioxidant activities of the 0.05% (w/w) materials in AO were compared against control during storage at $30^{\circ}C$ for 10 days. While no antioxidant effect was shown in alpha tocopherol against control, 3 species of grapefruit seed extracts (GSEs), astaxanthin (AX), soybean lecithin, and green tea extract showed good antioxidant activities. Especially, GSE B, GSE C, and AX showed significantly high peroxide inhibitory activities (PIAs) of $16.2{\pm}2.1$, $20.{\pm}3.5$, and $17.7{\pm}3.5%$, respectively, after the 4th day (p<0.01). Radical scavenging activities (RSAs) of GSE B, GSE C, and AX were $85.1{\pm}0.8$, $95.3{\pm}0.3$, and $85.9{\pm}0.8%$, respectively. Correlation between PIAs and RSAs was high ($R^2=0.926$) in GSE B, GSE C, and AX. Therefore, we concluded that one of the main antioxidative mechanisms of GSEs and AX must operate through an RSA pathway. The $RC_{50}$ (concentration required for 50% reduction of 1,1-diphenyl-2-picryl-hydrazyl, DPPH) of GSE C was $258\;{\mu}g/mL$.

• Fisheries and Aquatic Sciences
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• v.26 no.3
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• pp.204-215
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• 2023

The thermolabile haemolysin (tlh) of Vibrio parahaemolyticus (Vptlh) from V. parahaemolyticus is a multiple-function enzyme, initially describes as a haemolytic factor activated by lecithin and phospholipase A2 enzymatic activity (Shinoda, 1991; Vazquez-Morado, 2021; Yanagase et al., 1970). Until now, the tlh structure has hypothesized including N-terminal and C-terminal domain, but what domain of the Vptlh structure does the haemolytic activity has not been refined yet. In this study, a 450-bp VpTLH nucleotide sequence of the entire Vptlh gene encoded the C-terminal domain cloned firstly to examine its responsibility in the activity of the Vptlh. The C-terminal domain fused with a 6-His-tag named the His-tag-VpC-terminal domain was expressed successfully in soluble form in the BL21 (DE3) PlysS cell. Remarkably, both expression and purification results confirmed a high agreement in the molecular weight of the His-tag-VpC-terminal domain was 47 kDa. This work showed the His-tag-VpC-terminal domain lysed the erythrocyte membranes in the blood agar and the phosphate buffered saline (0.9%) media without adding the lecithin substrate of the phospholipase enzyme. Haemolysis occurred at all tested diluted concentrations of His-tag-VpC-terminal domain (p < 0.05), providing evidence for the independent haemolytic activity of the His-tag-VpC-terminal domain. The content of 100 ㎍ of the His-tag-VpC-terminal domain brought the highest haemolytic activity of 80% compared to that in the three remaining contents. Significantly, the His-tag-VpC-terminal domain demonstrated not to involve the phospholipase activity in Luria-Bertani agar supplemented with 1% (vol/vol) egg yolk emulsion. All results proved the vital responsibility of the His-tag-VpC-terminal domain in causing the haemolytic activity without the required activation by the phospholipase enzyme. Raw extracts of Phellinus igniarus and Phellinus pipi at 10^-1 mg/mL inhibited the haemolytic activity of the His-tag-VpC-terminal domain from 67.7% to 87.42%, respectively. Hence applying the His-tag-VpC-terminal domain as a simple biological material to evaluate quickly potential derivatives against the Vptlh in vivo conditions will accessible and more advantageous than using the whole of the Vptlh.