• Korean Journal of Fisheries and Aquatic Sciences
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• v.35 no.1
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• pp.97-104
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• 2002

Protein hydrolysate was prepared as a natural flavor stock from the sharp toothed eel (Muraenesox cinereus) mince using com-mercially available proteolytic enzymes, Alcalase, Neutrase, Protamex, and Flavourzyme. A 6 hr hydrolysis of mince, to which water of the equal weight of the mince was added, with $2\%$ (w/w, protein weight) Elavourzyme at $50^{\circ}$ yielded a hydrolysate of the highest acceptability. Removing the access lipid in liquified hydrolysate (not dehydrated) after enzyme hydrolysis, five times repetitive extraction using n-hexane (liquified hydrolysate : n-hexane=4 : 1, v/v) was effective, resulting in less than $1\%$ lipid content of the dehydrated-hydrolysate. The amino acid composition of the hydrolysate (prepared with Flavourzyme) was similar to that of the starting material. Hydrolysis led to an increase in concentration of not only total free amino acid but also free amino acid such as serine, glutamic acid, alanine, and methionine responsible for umami taste, especially up to about 40 times for methionine. Major free amino acids in amount were leucine, phenylalanine, valine, alanine, and isoleucine and they comprised about half of the total free amino acids, Moisture adsorption, fat adsorption, emulsifying capacity, and foaming capacity of the hydrolysate were 870.1 $\pm$ $7.9\%$, 352.0$\pm$ $5.3\%$, 50.3 $\pm$ $1.2\%$, and $87.5\pm$ $2.5\%$, respectively, and solubility was 83$\~$$84\%$ at acid pH range of 2$\~$4.

• Journal of the Korean Society of Food Science and Nutrition
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• v.35 no.3
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• pp.307-314
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• 2006

This study was conducted to screen in vitro angiotensin converting enzyme (ACE) inhibitory activities of methanol (MeOH) and aqueous extracts which were prepared by four different extractions-80% methanol extracts(ME) at $20^{\circ}C\;and\;70^{\circ}C$, respectively and aqueous extracts (AE) at both temperatures with the residue of the MEs-of ten marine green algae and nineteen brown algae collected along Jeju coast of Korea. Most marine brown algae extracts showed higher capacities than those of marine green algae in ACE inhibitory activity. Particularly, $70^{\circ}C$ MeOH extract (70ME) of Hizikia fusiforme showed the strongest inhibition activity (about 87%) among all the extracts. Also, 70 MEs of Enteromorpha linza, Ishige sinicola, Laminaria ochotensis, Petrospongium rugosum, Sagrassum horneri, Undaria pinnatifida and $20^{\circ}C$ MeOH extracts (20ME) of Myagropsis myagroides, Petrospongium rugosum, $20^{\circ}C$ aqueous extracts (20AE) of Codium contractum, Enteromorpha compressa, and $70^{\circ}C$ aqueous extracts (70AE) of Ecklonia cava, Petrospongium rugosum showed moderate ACE inhibitory activities more than 50% and the other extracts exhibited weak activities. On tile other hand, E. cava had the best ACE inhibitory activity among 70AEs. This indicates that 70AE of E. cava contains potential anti-ACE macromolecular. We tried to proteolytic digest 70AE of E. cava to induce production of anti-ACE peptides from E. cava 70AE. The enzymes used are five pretenses including Kojizyme, Flavourzyme, Neutrase, Alcalase, and Protamex, which are food grade-commercial enzymes from Novo Co. Flavourzyme-digest of E. cava 70AE showed the highest inhibitory activity about 90%. And the five different enzymatic digests of the E. cava 70AE ranged from 2.33 to 3.56 ${\mu}g/mL$, respectively in $IC_{50}$ values of anti-ACE activity.

• Journal of the Korean Society of Food Science and Nutrition
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• v.35 no.7
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• pp.926-934
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• 2006

The base for preparing oyster hydrolysate-added yogurt was consisted of whole milk (1,000 mL), skim milk (44.05 to 42.05 g), enzymatic oyster hydrolysates powder (OHP, 0 to 2.0 g) and pectin. The yogurt base was fermented with 7 kinds of starter cultures (3% based on yogurt volume), such as Lactobacillus acidophilus, lactobacillus bulgaricus, lactobacillus casei, Lactobacillus fermentum, Lactobacillus pentosus, Streptcoccus thermophilus and the mixed starters (L. bulgaricus and S. thermophilus) at optimal temperature. Processing condition and quality characteristics of the yogurt were evaluated by analyzing pH, titratable acidity, viscosity, viable cell count, functional properties and sensory evaluation. The results suggested that the optimal conditions for preparing the good quality yogurt revealed the mixed starters (L. bulgaricus and S. thermophilus) for starter culture, 1.0 g of 3 kDa hydrolysate for amount, and 5.5 hrs for fermentation time. The good quality yogurt showed 4.31 for pH, 1.07% for titratable acidity, 469 cps for viscosity and $4.9{\times}10^8\;CFU/mL$ for viable cell count. The hydrolysate-added yogurt was 2 times higher in ACE inhibitory and antioxidant activities than commercial yogurt, and kept good quality during storage of 15 days at $5^{\circ}C$.

• Journal of the Korean Society of Food Science and Nutrition
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• v.35 no.9
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• pp.1139-1145
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• 2006

In this study, antioxidant activities of enzymatic and methanolic extracts from E. cava stem and leave were evaluated by measuring the scavenging activities on 1,1 diphenyl 2 picrylhydrazyl (DPPH), hydroxyl radical, hydrogen peroxide and the inhibitory effects on DNA damage induced by oxidative stress of cells. Enzymatic extracts were prepared by enzymatic hydrolysis of both stem and leave using food grade five different carbohydrases (Viscozyme, Celluclast, AMG, Termamyl, Ultraflo) and five proteases (Protamex, Kojizyme, Neutrase, Flavourzyme, Alcalase). The enzymatic extracts were lower than methanolic extracts in polyphenol contents, but higher in extraction yield by approximately 30%. The enzymatic extracts were superior to methanolic extracts in DPPH and H2O2 scavenging activities and DNA damage protective effect. There were no significant antioxidant activity difference between stem and leave, but the extracts of leave were relatively better than those of stem. In this study it is suggested that E. cava stem as well as its leave would be a good raw materials for antioxidants compound extraction and enzymatic hydrolysis would be a good strategy to prepare antioxidant extracts from seaweeds.