• Korean Journal of Fisheries and Aquatic Sciences
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• v.47 no.2
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• pp.135-143
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• 2014

Exopeptidase active fractions from the hepatopancreas of the Argentina shortfin squid Illex argentinus, were obtained with acetone (AC 30-40%), ammonium sulfate (AS 60-70% saturation), anion exchange chromatography (AE-II, 0.2 M NaCl) and gel filtration chromatography (GF-I, 30-50 kDa) fractionation methods. A bitter peptide solution that has a bitterness equivalent to that of 2% glycylphenylalanine and prepared by tryptic hydrolysis of milk casein, was treated with the exopeptidase active fractions. The GF-I fraction was the best based on aminopeptidase activity (35.3 U/mg), percentage of recovery (30.7%) and a sensory evaluation (1.7). The amount of released amino acids increased as incubation time increased, and the bitterness of the enzyme reaction mixtures decreased. Incubation with the GF-I fraction for 24 h resulted in the hydrolysis of several peptides as revealed by the reverse-phase high performance liguid chromatography profile, with three peaks (3, 5 and 6) decreasing in area (%) and three peaks (1, 2 and 4) increasing in area (%). Therefore, the GF-I fraction appeared to be ideally suited to reduce bitterness in protein hydrolysates by catalyzing the hydrolysis of bitter peptides.

• Korean Journal of Food Science and Technology
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• v.33 no.6
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• pp.769-773
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• 2001

Protein content of okara and soybean were found to be 37.3% and 42.5%, respectively by micro-Kjeldahl analysis. Solubility of okara protein in phosphate buffer (pH 8) was 10% versus soy protein of 68.4%. Insolubilization of okara protein was mostly due to disulfide bonding between cysteine residues caused by excessive heat treatment during soymilk processing: hydrophobic interactions and hydrogen bondings were involved to lesser extent. Optimum extraction temperature and time were $60^{\circ}C$ and 40 min. Typical solubility profile of soy protein disappeared for okara protein though minimum solubility of the protein was around pH 3.0. Treating okara with protease was effective in solubilizing okara protein and solubility increased to 19.2%. Optimum reaction temperature and time were $80^{\circ}C$ and 50 min, respectively. Cell wall degrading enzyme did not increase solubility of the protein, however. Through enzymatic reaction okara protein could be effectively solubilized for uses as food ingredient.

• Journal of the East Asian Society of Dietary Life
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• v.26 no.6
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• pp.498-506
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• 2016

A croquette added with heat-treated kimchi at 20% showing higher sensory preferences was analyzed for its physicochemical properties and antioxidant activity using a croquette without kimchi as a control. Compared with the control, kimchi-added croquette had 3.3-fold higher organic acids content (p<0.001), resulting in a significant reduction of pH (p<0.001) and higher metal chelating activity (p<0.001). Upon addition of kimchi, total reducing capacity increased from 109.4 to $139.4{\mu}g/g$ gallic acid equivalents (p<0.01), and DPPH radical scavenging activity also increased 2-fold, which corresponded to 54% of the electron-donating ability of 0.35 mM gallic acid. In addition, contents of free amino acids and ${\gamma}-aminobutyric$ acid (GABA) appreciably increased by 1.6-fold (p<0.01) and 10-fold (p<0.001), respectively. This could be attributed to the ingredients of kimchi and/or enzymatic transformation of precursors by microorganisms during kimchi fermentation. Kimchi-added croquette was determined to be a good source of dietary fiber relative to its calorie content. Texture profile analysis showed no significant differences in hardness, springiness, cohesiveness, gumminess, and chewiness between the two croquettes with or without kimchi. Taken together, this study shows that utilization of heat-treated kimchi as a filling for croquette could be a good strategy to improve both the nutritional quality and antioxidant activity of croquette.

• Mycobiology
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• v.43 no.3
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• pp.184-194
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• 2015

A compressive description of tropical milky white mushroom (Calocybe indica P&C var. APK2) is provided in this review. This mushroom variety was first identified in the eastern Indian state of West Bengal and can be cultivated on a wide variety of substrates, at a high temperature range ($30{\sim}38^{\circ}C$). However, no commercial cultivation was made until 1998. Krishnamoorthy 1997 rediscovered the fungus from Tamil Nadu, India and standardized the commercial production techniques for the first time in the world. This edible mushroom has a long shelf life (5~7 days) compared to other commercially available counterparts. A comprehensive and critical review on physiological and nutritional requirements viz., pH, temperature, carbon to nitrogen ratio, best carbon source, best nitrogen source, growth period, growth promoters for mycelia biomass production; substrate preparation; spawn inoculation; different supplementation and casing requirements to increase the yield of mushrooms has been outlined. Innovative and inexpensive methods developed to commercially cultivate milky white mushrooms on different lignocellulosic biomass is also described in this review. The composition profiles of milky white mushroom, its mineral contents and non-enzymatic antioxidants are provided in comparison with button mushroom (Agaricus bisporus) and oyster mushroom (Pleurotus ostreatus). Antioxidant assay results using methanol extract of milky white mushroom has been provided along with the information about the compounds that are responsible for flavor profile both in fresh and dry mushrooms. Milky white mushroom extracts are known to have anti-hyperglycemic effect and anti-lipid peroxidation effect. The advantage of growing at elevated temperature creates newer avenues to explore milky white mushroom cultivation economically around the world, especially, in humid tropical and sub-tropical zones. Because of its incomparable productivity and shelf life to any other cultivated mushrooms in the world, milky white mushroom could play an important role in satisfying the growing market demands for edible mushrooms in the near future.

• KSBB Journal
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• v.10 no.5
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• pp.540-546
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• 1995

Dry corn gluten meal of 70% protein content was enzymatically hydrolyzed by alkaline protease in a pH-state reactor. Such process variables as temperature, pH, and enzyme-to-substrate ratio were varied, and at each condition degree of hydrolysis was monitored and calculated. The ultimate degree of hydrolysis, which ranged between 25 and 28% based on gluten protein mass, was not significantly affected by the process variables. However, $50^{\circ}C$ and pH 9-10 appeared optimum. Kinetic analysis indicated enzyme deactivation was negligible during the hydrolysis, and the experimental data were near perfectly fitted to the model kinetic equation which was modified after neglecting enzyme deactivation term. The enzyme reaction was 1$100\times$ scaled up and basically the same hydrolysis performance was resulted. Amino acid analysis showed the hydrolyzate was relatively rich in glutamine/glutamic acid, leucine, and alanine at 19.6, 16.1, and 12.3 mole %, respectively.

• Preventive Nutrition and Food Science
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• v.18 no.4
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• pp.273-279
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• 2013

Protease widely exists in the digestive tract of animals and humans, playing a very important role in protein digestion and absorption. In this study, a high protease-producing strain Planomicrobium sp. L-2 was isolated and identified from the digestive tract of Octopus variabilis. The strain was identified by physiological and biochemical experiments and 16S rDNA sequences analysis. A protease was obtained from the strain Planomicrobium sp. L-2 through ammonium sulfate precipitation, dialysis and enrichment, DEAE-Sephadex A50 anion-exchange chromatography, and Sephadex G-100 gel chromatography. The molecular weight and properties of the protease were characterized, including optimum temperature and pH, thermal stability, protease inhibitions and metal ions. According to our results, the protease from Planomicrobium sp. L-2 strain designated as F1-1 was obtained by three-step separation and purification from crude enzyme. The molecular weight of the protease was 61.4 kDa and its optimum temperature was $40^{\circ}C$. The protease F1-1 showed a broad pH profile for casein hydrolysis between 5.0~11.0. No residual activity was observed after incubation for 40 min at $60^{\circ}C$ and 60 min at $50^{\circ}C$. F1-1 protease was inhibited by $Mn^{2+}$, $Hg^{2+}$, $Pb^{2+}$, $Zn^{2+}$, and $Cu^{2+}$ ions, as well as PMSF, indicating that the protease F1-1 was a serine protease. Additionally, research basis provided by this study could be considered for industrial application of octopus intestinal proteases.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.157-157
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• 2022

Plants being sessile are prone to various abiotic challenges, including salinity. Plants generally cope with salt stress by regulating their endogenous NO levels. NO exogenously applied in various forms also successfully impedes the salt stress, but its small size, short half life, and high volatility rate hamper its application in agriculture. NO application via CS as a nanocarrier is an alternate option to ensure the optimal kinetic release of NO for a long period compared to the free NO form. Herein, we synthesized and characterized GSNO-CS NP by ionic gelation of TPP with CS and then reacting with GSH, followed by reaction with NaNO₂ suspension. The synthesized NPs were characterized using non-destructive analytical techniques such as DLS, FTIR, and SEM to ensure their synthesis and surface morphology. NO-release profile confirmed optimal kinetic NO release for 24 h from NO-CS NP as compared to free NO form. The efficiency of NO-CS NP was checked on Arabidopsis plants under salinity stress by gauging the morphological, physiological, and enzymatic antioxidant system and SOS pathway gene expression levels. Overall, the results revealed that NO-CS NP successfully mitigates salinity stress compared to free GSNO. Concluding, the findings provide sufficient experimental evidence for the application of nanotechnology to enhance NO delivery, thus inducing more benefits for the plants under stress conditions by mitigating the deleterious impacts of salt stress on the morphological and physiological status of the plants, and regulating the ions exchange by overexpression of SOS pathway candidate genes.

• Animal Bioscience
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• v.37 no.7
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• pp.1277-1288
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• 2024

Objective: This study was aimed to investigate the effect of fresh and dried hydrolyzed Cordyceps militaris (CM) mushroom with proteolytic enzymes; bromelain (CMB), flavorzyme (CMF), and mixture of bromelain: flavorzyme (CMBF) on quality properties of spent hen chicken. Methods: Mushroom extract (CME) were combined with three proteolytic enzyme mixtures that had different peptidase activities; stem bromelain (CMB), flavorzyme (CMF), and mixture of stem bromelain:flavorzyme (CMBF) at (1:1). The effect of these hydrolysates was investigated on spent hen breast meat via dipping marination. Results: Hydrolyzation positively alters functional properties of CM protease. in which bromelain hydrolyzed group (CMB) displayed the highest proteolytic activity at 4.57 unit/mL. The antioxidant activity had a significant increment from 5.32% in CME to 61.79% in CMB. A significantly higher emulsion stability index and emulsification activity index compared to CME were another result from hydrolyzation (p<0.05). Texture properties along with the shear force value and myofibrillar fragmentation index were notably improved under CMB and CMBF in fresh condition. Marination with CM mushroom protease that was previously hydrolyzed with enzymes was proven to also increase the nucleotide compounds, indicated by higher adenosine 5'-monophosphate (AMP) and inosine 5'-monophosphate (IMP) in hydrolysate groups (p<0.05). The concentration of both total and insoluble collagen remained unchanged, meaning less effect from CM protease. Conclusion: This study suggested the hydrolyzation of CM protease with bromelain or a mixture of bromelain:flavourzyme to significantly improve functional properties of protease and escalate the taste-related nucleotide compounds and texture profiles from spent hen breast meat.

• Analytical Science and Technology
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• v.12 no.3
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• pp.190-195
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• 1999

The metabolism of testosterone ($17{\beta}$-hydroxy-androst-4-en-3-one) was confirmed in horse after a single intramuscular administration of testosterone cypionate (750 mg). Solvent extracts of urine obtained with enzymatic hydrolysis and methanolysis were analyzed by GC/MS after oxime t-butyldimethylsilyl (oxime-TBDMS) derivatization. The structures of four urinary metabolite after testosterone administration in horse were determined based on EI mass spectra and $5{\alpha}$-androstane-$3{\beta}$, $17{\alpha}$-diol and $5{\alpha}$-androstane-$3{\beta}$-ol-17-one as major was confirmed with authentic standard. Also the concentrations of $5{\alpha}$-androstane-$3{\beta}$, $17{\alpha}$-diol, $5{\alpha}$-androstane-$3{\beta}$, $17{\beta}$-diol, dehydroepiandrosterone (DHEA), $5{\alpha}$-androstane-$3{\beta}$-ol-17-one and testosterone were determined in the urine of normal subjects and the urine after administration. The recovery and detection limit in the most drugs were 86.3~94.7% and 1~3 ppb, respectively. Correlation coefficients for calibration were in the range of 0.984~0.999. Excretion profile of testosterone presents the rapid and large increasement up to maximum values at days 5 after administration and the slow regression. The relative ratios of testosterone, its metabolites over DHEA were determined for indication of testosterone administration in horse doping.

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.6
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• pp.752-760
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• 2008

Scale-up production of low-trans fat containing conjugated linoleic acid (CLA-TFO) was performed through lipase-catalyzed synthesis. Blend of fully hydrogenated soybean oil, olive oil containing conjugated linoleic acid and palm oil with 1:2:7 ratio was interesterified through Lipozyme RM IM in the 1 L-batch type reactor at $65^{\circ}C$ for 12 hrs, and the physicochemical and melting properties of CLA-TFO were compared with conventional (high trans fat) or commercial low-trans fat shortening. The trans fatty acids content in the conventional shortening (48.8 area%) was much higher than that of low-trans shortening (0.4 area%) and CLA-TFO (0.3 area%+CLA; 7.6 area%). Acid, saponification and iodine values of CLA-TFO were 0.4, 173.9 and 59.0, respectively. Their ${\alpha}$-, ${\gamma}$-tocopherol contents showed 4.7, 1.0 mg/100 g. Differences were observed in the solid fat contents (SFC), melting point of the conventional or low-trans fat and CLA-TFO. Each SFC of conventional, low-trans fat and CLA-TFO was 32.0, 29.3 and 30.4% with melting point of 38.5, 43.0 and $39.5^{\circ}C$ at $35^{\circ}C$, respectively. In texture profile analysis, hardness of conventional, low-trans fat and CLA-TFO was 111.7, 75.2 and 63.8 g.