• Journal of the Korean Society of Food Science and Nutrition
• /
• v.35 no.7
• /
• pp.919-925
• /
• 2006

The study was carried out to prepare oyster hydrolysates by using Alcalase, Flavourzyme, Neutrase, Protamex, pepsin and trypsin, and to investigate its functional properties. The ACE inhibitory activity and antioxidant activity of enzymatic oyster hydrolysates did not increase with hydrolysis time. Among enzymatic oyster hydrolysates, oyster hydrolysates incubated with Protamex for 1 hr (OHP) showed the most excellent ACE inhibitory activity and antioxidant activity, and their $IC_{50}$ values were 1.16 mg/mL and 1.49 mg/mL, respectively. However, all enzymatic oyster hydrolysates were not detected in antimicrobial activity.

• Journal of fish pathology
• /
• v.17 no.2
• /
• pp.131-137
• /
• 2004

In the present study, phosphatidylcholine (PC) hydrolyzing enzyme had been isolated from membrane of flounder liver. PC hydrolyzing enzyme solubilized in 1% Triton X -100 from membrane was partially purified by sequential chromatography on Heparin Sepharose CL-6B and Heparin-5PW columns. The products by membrane-bound hydrolyzing enzyme were identified as phosphatidic acid and choline, but in the presence of primary alcohol, phosphatidylethanol was produced at the expense of phosphatidic acid. These data suggest that membrane-bound enzyme may be a PC-phosphoipase D (PLD) type. The enzyme had pH optimum at below 6.0 and temperature optimum at $37^\circ{C}$. The activity of PC-PLD was dose-dependently increased by $Ca^{2+}$ but not $Mg^{2+}$. The activity of PC-PLD was stimulate by PC, PIP2 and PE.

• Applied Biological Chemistry
• /
• v.40 no.5
• /
• pp.404-408
• /
• 1997

Enzymatically hydrolyzed vegetable protein (eHVP) was produced from soy protein using proteases, and the physicochemical properties were examined. Soy protein hydrolysate of 6% protein and 50% degree of hydrolysis was useful for the base of savory ingredients. The Maillard-reacted and flavoring compound-added hydrolysate had improved flavor. It was for enzymatically hydrolyzed soy sauces and dehydrated seasonings. ISP hydrolysate of low molecular weight $(MW{\sim}250)$ and high protein content (85%) was suitable for special uses such as infant diets, sports nutrition, and medical diets. The eHVP gave no limitation of dosage in the formulation as a flavor enhancer. The byproduct of protein hydrolysis was found to have high content of fiber (21%) and to have potential for the use as dietary fiber or bulking agents.

• Korean Journal of Food Science and Technology
• /
• v.41 no.6
• /
• pp.622-627
• /
• 2009

The objectives of this study were to evaluate a protease suitable for the enzymatic hydrolysis of a snow crab processing by-product (SPB) and to optimize the hydrolysis conditions using response surface methodology (RSM). The SPB was hydrolyzed at $50^{\circ}C$ and pH 7.0-7.2 to obtain various degree of hydrolysis (DH) using Flavourzyme at an enzyme/substrate (E/S) ratio of 3.0%. The reaction progress curve exhibited an initial fast reaction rate followed by a slowing of the rate. The DH was increased to 30% at 90 min with a final DH 32 to 36%. A central composite experimental design having three independent variables (reaction temperature, reaction time, and E/S ratio) with five levels was used to optimize the enzymatic hydrolysis conditions. Based on the DH data, the optimum reaction conditions for the enzymatic hydrolysis of the SPB were a temperature of $51.8^{\circ}C$, reaction time of 4 hr 45 min, and an E/S ratio of 3.8%. It was demonstrated that the enzymatic hydrolysate of SPB could be used as a flavoring agent or a source of precursors for the production of reaction flavors.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.32 no.5
• /
• pp.745-751
• /
• 2003

This study was carried out to investigate whether peptide produced from wheat protein by enzyme hydrolysis can be used as a natural antimicrobial agent. Antimicrobial peptide was obtained from wheat protein hydrolyzed by 7 of pretense. The produced antimicrobial peptide was purified through ultrafiltration, membrane filtration and HPLC and molecular weight and amino acid sequence of the purified antimicrobial peptide were determined. Among hydrolysate produced from wheat protein by 7 of protease, antimicrobial activity was observed for the peptide obtained from Asp. saito protease. The Asp. saito protease did produce antimicrobial hydrolysate showing the highest antimicrobial activity at reaction condition of 37$^{\circ}C$ and pH 6.0, but not at reaction condition above 5$0^{\circ}C$. Wheat protein hydrolysate was fractionated by membrane filtration and showed antimicrobial activity between molecular weight 1,000~3,000. The antimicrobial activity fraction obtained by membrane filtration was separated through HPLC and showed antimicrobial activity in the peak of retention time 31.1~31.8 min. We could convince this hydrolysate as heat-stable peptide since antimicrobial activity was maintained after treated with heat for 15 min at 121$^{\circ}C$. Molecular weight of antimicrobial peptide identified by MALDI-mass was 1,633. Amino acid sequence of antimicrobial peptide was cysteine, glycine, prolin, prolin, prolin, valine, valine, alanine, alanine and arginine.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.32 no.2
• /
• pp.127-133
• /
• 1999

The purpose of this study was to determine the optimum hydrolysis conditions for the production of enzymatic hydrolysate from tuna boiled extract (TBE) using membrane (molecular weight cut off 10,000Da) reator. The tuna pyloric caeca crude enzyme (TPCCE) was identified as the most suitable enzymes for the hydrolysis of TBE. The optimum hydrolysis conditions of TBE in the batch reactor were $40^{\circ}C$, pH 9 and substrate to TPCCE ratio 50 (w/w). For 6hr under the above conditions, $70\%$ of the total amount of initial TBE was hydrolysed. The optimum hydrolysis conditions of TBE in the membrane reactor were $40^{\circ}C$, pH 9, enzyme 0,1 g/$\ell$, volume 1$\ell$ and substrate to enzyme ratio 100(w/w). The degree of hydrolysis of TBE was above $60\%$ for 3 hr. The TBE hydrolysate were prepared with $5\%$ TBE solution under the optimum hydrolytic conditions in the membrane reactor

• Journal of the Korean Applied Science and Technology
• /
• v.33 no.2
• /
• pp.293-303
• /
• 2016

Protein hydrolysate that shows physiological function such as antioxidant, suppression of hypertension, immunodulatory, alleviation of pain, and antimicrobial activity has been known as playing important role like hormone. This study was performed to optimize the hydrolysis of the wing's meat of Yosan-Ogae by a commercial protease. The ranges of processes were the reaction temperature of 40 to $60^{\circ}C$, pH 6 to 8, and enzyme concentration 1 to 3%(w/v). As a result, the optimization of process was determined at temperature of $48-50^{\circ}C$, pH of 7.0-7.2, and enzyme concentration of 3%(w/v), and degree of hydrolysis was 68 to 69% at above conditions. The molecular weight of hydrolysate was distributed to 500-1,200 Da and showed typical peptides. The amino acids of peptides showing presumably antioxidant activity such as histidine, proline, methionine, cystein, tyrosine, tryptophan, phenylalanine comprised about 43.07%. The glutamic acid was 13.6%. Therefore, we expect that those products are useful as functional food ingredients.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.30 no.5
• /
• pp.842-849
• /
• 1997

This study was designed to investigate the antioxidative activity of enzymatic hydrolysates prepared from defatted anchor muscle by various pretenses. In these hydrolysates, the hydrolysates derived from pepsin and Protamex showed the strongest antioxidative activity. Enzymatic hydrolysates also showed the synergistic effects on antioxidative activity of $\alpha-tocopherol$, and almost no change in butylated hydroxytoluene (BHT). Peroxidation of metal ions $(Fe^{3+},\;Cu^{2+})$ was inhibited by enzymatic hydrolysates. Ten fractions (P-1 to P-10) were fractionated from the peptic hydrolysates by Amberlite IR-120 and Bio-gel P-2 column chromatography. The maximum antioxidative activity was observed in the traction P-2 (fraction No. $26\~31$). In amino acid composition of before and after hydrolysis of defatted anchovy muscle and the active fractions (P-2), contents of aspartic arid and glutamic acid were increased, but alanine, cysteine, tyrosine and phenylalanine were decreased.

• Journal of the Korean Wood Science and Technology
• /
• v.40 no.4
• /
• pp.294-301
• /
• 2012

In this study, we investigated the features of bioethanol fermentation of corncob biomass after oxalic acid pretreatment as well as enzymatic hydrolysis. The enzymatic hydrolysis was performed with Accellerase 1000 and the highest yield of monomeric sugars ($64.8g/{\ell}$) was obtained at $50^{\circ}C$ and pH 4.5 for 96 hrs hydrolysis period. For the ethanol fermentation the monomeric sugars obtained from pretreated corncob were subjected to the biological treatment using Pichia stipitis CBS 6054. It was turned out that ethanol production from oxalic acid pretreated corncob was the most feasible at 10~14% of biomass loading as well as 15 FPU enzyme amount. Under these fermentation condition, the ethanol yield was approached to 0.47 after 24 hrs fermentation period, which was corresponded to 92.2% of conversion rate.

• Journal of the Korean Chemical Society
• /
• v.22 no.3
• /
• pp.164-172
• /
• 1978

Carboxypeptidase A-catalyzed hydrolysis of ester substrates was carried out at room temperature in the presence of a number of external reagents. If the acyl-enzyme intermediate, an anhydride, is attacked by the external reagents, products formed by trapping at the acyl portion or at the enzyme portion of the anhydride group can be obtained. Examination of the uv/vis spectral properties of the reaction products and of changes in enzyme activity indicated that such trapping reactions did not occur. Also performed was evaluation of enzymatic rate parameters for the the hydrolysis of O-(o-hydroxyphenylacetyl)-L-${\beta}$-phenyllactate. Detection of 2-coumaranone possibly formed by attack of the o-hydroxy group as an intramolecular trapping group at the acyl-enzyme intermediate was tried, but no evidences for the intramolecular trapping reaction were obtained. Failure to trap the intermediate was discussed in terms of steric hindrance imposed on the approach of the trapping reagents to the anhydride group of the acyl-enzyme intermediate and of the fast enzymatic breakdown of the intermediate.