• Journal of the Korean Applied Science and Technology
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• v.36 no.3
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• pp.1018-1027
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• 2019

Natural-derived protein-derived low molecular weight peptides have been known to have physiological activities such as antioxidant, hypertension relief, immunomodulation, pain relief and antimicrobial activity. In this study, the low-molecular peptides were produced using commercial proteases (alcalase, bromelain, flavourzyme, neutrase, papain, protamex), and the antioxidant activity (DPPH scavenging activity, superoxide radical scavenging activity, hydroxy radical scavenging activity, and metals chelation capacity), constituent amino acid and molecular weight of the peptide were analyzed. Enzyme reaction was performed by adding 50 g of chopped Ogae meat slurry and 2%(w/v) protein enzyme into the enzyme reactor for 2 h at a pH of 6 and a temperature of $60^{\circ}C$. The degree of hydrolysis(%) after the reaction ranged from $36.65{\pm}4.10%$ to $70.75{\pm}5.29%$. The highest degree of hydrolysis of protamex was 46.3%, and the highest value of papain hydrolysate was $70.75{\pm}5.29%$. On the other hand, alcalase hydrolysate showed the lowest value of $36.65{\pm}4.10%$. Bromelain-treated low molecular weight peptides showed the highest DPPH radical scavenging activity and the lowest scavenging activity of alcalase-treated peptides. Superoxide radical scavenging activity showed that bromelain treated low molecular peptide showed the highest radical scavenging activity of 50% or more. Hydroxyl radical scavenging activity ranged from about 16.73 to 69.16%, the highest among bromelain-treated low molecular peptides. $Fe^{2+}$ chelation abilities showed a distribution between about 17.85 to 47.84%. The chelation capacity of the hydrolysates was not significantly different without any difference to the enzymes used. The results of amino acid analysis showed differences between hydrolysates of alcalase, bromelain, flavourzyme, neutrase, papain, and protamex enzymes. The most amino acid was glutamic acid. The molecular weight distribution of the enzyme hydrolyzates was in the range of 300-2,000 Da, although the molecular weight distribution differed according to the treated enzymes.

• Journal of the Korean Chemical Society
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• v.45 no.6
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• pp.555-561
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• 2001

Vinyl acetate usually used in PVA resin preparation was converted to PVAc by bulk polymerization using AIBN as a initiator and PVA was synthesized by changing the concentration of NaOH added for saponification subsequently. As a result of estimating molecular weight using GPC, molecular weight increased as the NaOH concentration increased to 2.5 N, 5.0 N, 7.5 N and 10.0 N and polydispersity had similar values of 2.1~2.3, however, showed slightly decreasing tendency. In addition, PVA saponificated by 10.0 N-NaOH showed high syndiotacticity in observation of tacticity using NMR spectroscopy. From this fact, the degree of tacticity was predicted to be high and it was in good agreement with the tendency of polydispersity by GPC. Also, from the result of FT-IR spectroscopy, it might be known that hydrolysis was more promoted in the PVA with 10.0 N-NaOH than other NaOH concentration. Intrinsic viscosity measured using Ubbelohde viscometer, which increased as the concentration of NaOH added for saponification increased. The change of shear strength with the change of shear rate was investigated using Brookfield viscometer, in consequence, viscosity of PVA synthesized decreased as shear rate increased. PVA solution confirmed to show the shear thining behavior by Casson plot and PVA with 10.0 N-NaOH had the largest yield value. DSC measurement was performed to know the thermal properties of PVA. Tp had nearly constant value of 214$^{\circ}C$ in all cases except for adding 2.5 N-NaOH and $\Delta$H was increased as the concentration of NaOH increased. From this properties, it was concluded that the degree of hydrogen bonding was proportional to the added concentration of NaOH and the increase of the degree of hydrogen bonding and hydrophobic interaction could affect the rheological and thermal properties of title compound.

• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.4
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• pp.435-441
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• 2017

The present study was carried out to evaluate the applicability of Tenebrio molitor larvae (mealworm) as a health functional food material in order to contribute to the development of the domestic insect industry and health functional food industry. Protein hydrolysates were prepared from mealworm powder by enzymatic hydrolysis using five different proteases (alcalase, bromelain, flavourzyme, neutrase, and papain), and the hydrolysates were then tested for their antioxidant activities. Based on available amino group contents and sodium dodecyl sulphate-polyacrylamide gel electrophoresis analyses, mealworms treated with alcalase ($4,781.39{\mu}g/mL$), flavourzyme ($5,429.35{\mu}g/mL$), or neutrase ($3,155.55{\mu}g/mL$) for 24 h showed high degree of hydrolysis (HD) value, whereas HD values of bromelain ($1,800{\mu}g/mL$) and papain-treated ($1,782.61{\mu}g/mL$) mealworms were much lower. Protein hydrolysates showing high HD values were further separated into > 3 kDa and ${\leq}3kDa$ fractions by a centrifugal filter system and then lyophilized, and the production yields of the low molecular weight protein hydrolysates (${\leq}3kDa$) by alcalase, flavourzyme, and neutrase were 42.05%, 26.27%, and 30.01%, respectively. According to the RC_{50} values of the protein hydrolysates (${\leq}3kDa$) obtained from three different antioxidant analyses, all three hydrolysates showed similar antioxidant activities. Thus, alcalase hydrolysates showing the highest production yield of low molecular weight protein hydrolysates were further tested for their inhibitory effects on peroxidation of linoleic acid by measuring thiobarbituric acid values, and the results show that peroxidation of untreated linoleic acid increased dramatically during 6 days of incubation. However, pretreatment with the hydrolysates ($100{\sim}800{\mu}g/mL$) significantly inhibited linoleic acid peroxidation in a dose-dependent manner over 6 days.

• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.10
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• pp.1164-1170
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• 2017

Protaetia brevitarsis larvae (PBL) has recently been registered as a temporary food in Korea, and this study evaluated the application potential of PBL proteins as health functional food materials. Protein hydrolysates were prepared from PBL powder by enzymatic hydrolysis using five different proteases (alcalase, bromelain, flavourzyme, neutrase, and papain), and based on the results from the peptide content and SDS-PAGE analyses, PBL treated with alcalase or flavourzyme showed a high degree of hydrolysis (HD) value, whereas the HD value of those treated with neutrase, bromelain, or papain was minimal. The protein hydrolysates showing a high HD value were separated further into the fractions of >3 kDa and <3 kDa by a centrifugal filter system and then lyophilized, and according to the $RC_{50}$ values of the protein hydrolysates (<3 kDa) obtained from three different antioxidant analyses; the alcalase hydrolysates showed the highest antioxidant activity. Therefore, the alcalase hydrolysates were tested further for their inhibitory effects on the peroxidation of linoleic acid by measuring the thiobarbituric acid values. The results showed that the peroxidation of untreated linoleic acid increased dramatically during 6 days of incubation, but a pretreatment with the hydrolysates ($100{\sim}800{\mu}g/mL$) significantly inhibited the linoleic acid peroxidation in a dose-dependent manner for 6 days. Our current studies are focused on the identification of active peptide sequences from alcalase hydrolysates.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.11 no.2
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• pp.118-125
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• 2001

Recently, biochemical analysis using hemoglobin adduct is frequently performed to evaluate the exposure to chemical carcinogens. However, data on the effect of co-exposure with other chemicals on hemoglobin adduct formation are seldom provided. The objective of this study is to evaluate the effects of pretreatment of ethanol(EtOH) and phenobarbital(PB), which are known to affect metabolism of xenobiotics, on the formation of hemoglobin adducts in the rats(Sprague-Dawley) administered benzidine(BZ). The experimental rats were divided into control, EtOH, and P8 groups. Rats were pretreated with EtOH or PB 24 hours before the oral administration of BZ. Blood sampling was taken before the administration of the chemicals and 0.5, 3, 6, 9, 12, 24, 48, 72, 96, and 144 hours after the administration of the BZ in 5 rats each. The blood was separated into hemoglobin and plasma immediately after taking the blood samples, and the adducts were undergone basic hydrolysis to convert them into aromatic amines. Hydrolyzed BZ, monoacetylbenzidine (MABZ), and 4-aminobiphenyl(4ABP) were separated by reversed-phase liquid chromatography without derivatization, and quantitative analyses of them were performed by a highperformance liquid chromatograph equipped with electrochemical detector. The quantitative amount of the metabolites was expressed by hemoglobin binding index(HBI), BZ-, MABZ-, and 4ABP-HBI of EtOH and PB groups were increased more than those of control group. These results are attributable to the fact that EtOH and PB induced N-hydroxylation related to the hemoglobin adduct formation. The ratio of N-acetylation (viz, MABZ-HBI/BZ-HBI) showed no significant difference between EtOH group and control group. It means that EtOH increased N-hydroxylation and N-acetylation in a similar degree. The N-acetylation ratio of PB group was relatively lower than control group because the PB increased N-hydroxylation induction. The N-acetylation ratios of all groups were higher than 1 during the entire experimental period. This result suggests that the effects of EtOH or PB need to be considered in the biochemical monitoring for the assessment of intermittent exposure of benzidine.

• Journal of the Korean Applied Science and Technology
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• v.33 no.3
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• pp.549-559
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• 2016

Korean Black body fowl (Gallus gallus domesticus; Ogae) designated as a natural monument (registration number 265) has been known as a superb traditional Korean medicine. In this study, The production of peptide from the Viscera Waste of Yeonsan Ogae was optimized using commercial protease (bromelain) by response surface methodology under high pressure process. The range of processes was pressure (30 to 100 MPa), reaction time (1 to 5 h), and substrate concentration (10 to 30%, w/v). After reaction, the degree of hydrolysis, distribution of amino acids, and molecular weight of peptides were investigated. As a results, the optimization conditions were pressure 90 MPa, reaction time 3 to 4 h, and the amount of viscera meat 20% (w/v), respectively. The molecular weight of protein hydrolysates was distributed 400 to 1,000 Da. Accordingly we presumed that most products were peptides. Of those peptides, nonpolar or hydrophobic, polar but uncharged, positively charged, and negatively charged amino acids were 42.03, 26.0, 13.3, and 18.6%, respectively. Because higher amount of hydrophobic amino acids, we expected that those products would be able to utilize as the functional food ingredients.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.30 no.1
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• pp.1-7
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• 1997

In order to utilize fish by-products from the skipjack tuna (Katsuwonus pelamis) canning manufactures Lactobacillus buigaricus KCTC 3188 and L. piantarum KCTC 1048 were used as a starter culture for the preparation of fermented fish silage with skipjark tuna viscera. The optimum temperature and pH on barterial growth and lactic acid production of L. bulgaricus and L. plantarum in MRS broth were $35^{\circ}C$ and around pH 6.0, respectively. And the optimum concentrations of the carbohydrate sources added to the broths were $7\%$ for dextrose and $10\%$ for molasses on the basis of total weights of skipjack tuna viscera. The pH of acid treated skipjack tuna viscera silage (ASS) slightly increased from 4.0 to 4.5, while that of fermented skipjack tuna viscera silages by the use of lactic acid bacterias (FSS) was significantly declined from 5.9 to about 40 after 42 days of storage at $35^{\circ}C$. Though the content of volatile basie nitrogen (VBN) in ASS was lower than those of FSS after 42 days of storage at $35^{\circ}C$, VBN content in silages slightly increased from an initial value of $62\~65{\cdot}mg/100g$ to final value of $113\~155\;mg/100g$ over 42 days. The fermented silage by L. piantarum reached a maximum concentration of amino nitrogen and showed $81\%$ of hydrolysis degree after 4 days of storage at $35^{\circ}C$.

• Korean Chemical Engineering Research
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• v.54 no.3
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• pp.431-435
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• 2016

The aim of this study was to investigate the effect of gamma irradiation on the pretreatment of wood chips with NaOH solution. The degree of saccharification was quantified by measuring reducing sugar and glucose concentrations after enzymatic hydrolysis. After pretreatment with 10 g/L NaOH, the wood chips were irradiated at the doses of 0, 50, 100, and 200 kGy, respectively. Among the irradiated samples, wood chips irradiated at the dose of 200 kGy had the highest reducing sugar concentration of 12.2 g/L. Also, to define the effect of irradiation before pretreatment, the wood chips were first gamma-irradiated and then pretreated with NaOH. When the NaOH treatment was conducted after irradiation at 200 kGy, the reducing sugar content was further increased to 13.4 g/L and glucose content of the wood chip was as high as 7.9 g/L. These results suggest that gamma irradiation may be the promising method for pretreatment of cellulose biomass.

• Korean Journal of Agricultural Science
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• v.25 no.1
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• pp.107-117
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• 1998

Ths studies was carried out to investigate the processing possibility of pheasant meat extracts treated with proteases. The crude protein, aminonitrogen, degree of hydrolysis, yield and amino acid composition of pheasant meat extracts when it was treated with proteases at various temperature and reaction time were analyzed. The crude protein contents of pheasant meat extracts processed in $130^{\circ}C$ were more than when it was done in $100^{\circ}C$, but the contents of aminonitrogen were not quite different between two processing temperature. The content of crude protein and aminonitrogen when pheasant meat was hydrolyzed with protease NP and prozyme A. The yields of pheasant meat extracts, when pheasant meat were treated at $100^{\circ}C$ and $130^{\circ}C$, were from 2.24 to 7.10% and from 5.51 to 10.45%, respectively. And the yield of extraction depended on extraction temperature, kinds of enzyme, amount of enzyme, extraction time. The content of aminonitrogen in pheasant meat extracts treated with enzyme was much higher than any other treatments. And it depended on amount of enzyme, extraction time and temperature. The amount of the amino acids in pheasant meat extracts treated by protease NP were eminently higher than by heat at $100^{\circ}C$ or $130^{\circ}C$.

• Korean Journal of Food Science and Technology
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• v.28 no.4
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• pp.696-701
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• 1996

For effective utilization of skipjack (Katsuwonus pelamis) cooking juice (SCJ), the SCJ was hydrolyzed with 0.5% neutrase at $50^{\circ}C$ for 1 hr, and the degree of hydrolysis was estimated to be 66.0% at this reaction condition. The hydrolysate was treated with charcoal and filtered under reduced pressure. The extract powder was prepared from the filtrate in a spray-dryer. The major free amino acids of the extract Powder were taurine (526.3 mg/100 g), glutamic acid (375.8 mg/100 g), phenylalanine (315.9 mg/100 g), and alanine (283.6 mg/100 g), and their content accounted for 55.4% of the total free amino acids (2,711.5 mg/100 g). Among the nucleotides and their related compounds, inosine was the major component with 76.29 mole/g. The content of betaine-N, total ceatinine-N, TMAO-N, and TMA-N were 72.2, 51.2, 10.3, and 6.9 mg/100 g, respectively. From the omission test, it was concluded that the major taste compounds of the extract powder were believed to be free amino acids such as glutamic acid and alanine. Organic acids and nucleotides and their related compounds acted an auxiliary role in the taste of the extract powder.