• Culinary science and hospitality research
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• v.23 no.7
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• pp.63-70
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• 2017

The purpose of this study was to investigate the effects of proteolytic enzymes in Letinus edodes powder which has the ratio of 0%, 2%, 4%, and 8% on the tenderness and sensory characteristics of beef. Beef eye of rounds were marinated in distilled water (Control), 2% L. edodes (L2), 4% L. edodes (L4), and 8% L. edodes (L8). As a result, the enzyme activities have shown to have higher activity (p<0.001) as the amount of freeze-dried Letinus edodes powder increased. The pH and color of the meat were slightly different between the C (control) group and the sample groups. The cooking loss showed the lowest value of control (p<0.01), and water holding capacity showed the highest value of L8. Furthermore, the sample groups exhibited lower shear force values compared with the control (p<0.05). L4 and L8 showed muscle proteolytic effects compared with the control. In case of sensory evaluation, L4 showed significantly higher values in terms of color (p<0.05), flavor (p<0.01), taste (p<0.01), tenderness (p<0.01), juiciness (p<0.01), and overall acceptance (p<0.01). Based on the results, this study conclude that adding of 4% around freeze-dried Letinus edodes powder may be the best optimization ratio for sensory character and tenderization of the beef.

• The Korean Journal of Zoology
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• v.31 no.3
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• pp.185-190
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• 1988

To investigate whether malignant behavior of skin tumor correlates with changes in the level of proteolytic activities in skin tumors, rats were treated with 7,12-dimethylbenzanthracene followed by photbor ester. Tumors induced upon the treatrnents exhibited more than 20-fold increase in the activity of plasminogen activator and about 3-fold of plasmin-like activity. as compared to those in treated controls. Furthermore, the former activity was raised to about 6-fold even in the preneoplastic dssues of the skin tissues. On the other hand, the proteolytic activity against casein and insulin decreased to several-fold in the tumor tissues while antitrvpsin activity remained similar in both tumor and controls. Thus, the increase in the activities of plasmInogen activator and plasminlike enzyme appears to occur as a charaderistic to skin cancer and may involve in invasion and metsstasis of the tumor.

• Korean Journal of Food Science and Technology
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• v.21 no.5
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• pp.639-648
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• 1989

The possibility of the use of soy sauce koji and commercial proteolytic enzyme for the acceleration of fish fermentation without affecting its characteristic flavor and nutritional quality inherent to the final products was investigated. Fish sauces were prepared experimentally from small horse mackerel under sixteen kinds of conditions and the chemical composition of those were examined, individually. The amino type nitrogen content, ration of amino type nitrogen to total nitrogen and protein conversion ratio were the highest in the fish sauce product treated with soy sauce koji, of which 10% salt was added to the minced raw fish at the start and additional 10% salt was added to the mixture after 48hrs, incubation.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.37 no.4
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• pp.259-268
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• 2004

Keeping qualities of crude proteases (CP) and fractionated proteases (FP) sedimenting with $30\~80{\%}$ ammonium sulfate from four kinds of fish viscera as a seafood processing waste were examined. Azocaseinolytic activlties (pH 6 and 8) of CP from anchovy (Engraulis japonica), mackerel (Scomber japonicus), bastard flatfish (Pararlichthys olivaceus) and red sea bream (Chysorphys major) were stable without activity loss at $4^{\circ}C$ for 7 months. Activities of NaCP (CP containing $30{\%}$ sodium chloride) on azocasein were approximately $30{\%}$ lower than those of CP. FP activities Increased 3.4-16.1 folds compared to those of CP and NaCP Powdered crude protease (PCP) and fractionated and powdered protease (FPP) containing various sugars (lactose, sucrose, glucose and dextrin) were prepared by freeze drying. Activities of PCP and FPP containing sucrose were higher and more stable than those of PCP and FPP containing other sugars at $30^{\circ}C$ for whole keeping periods. PCP and FPP from mackerel viscera showed the highest proteolytic activity among four kind of fish vlsceras. The Optimum conditions and stabilities of FPP from mackerel viscera were pH 9 and $50^{\circ}C$, and pH 5-10 and $20-45^{\circ}C$, respectively. The results of this study suggest that FPP from seafood processing waste may be used as processing aids.

• Food Science of Animal Resources
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• v.41 no.5
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• pp.869-882
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• 2021

Sodium chloride (NaCl) replacement with calcium chloride (CaCl₂) effect on protein solubility, proteolytic enzyme and quality characteristics of a chicken soup prepared from spent hen (SH) chicken were investigated. By means of immerse marination prior to cooking, a total of 60 skinless SH breast meat were randomly allocated into ten groups admitted to treatments with marinade solution containing sodium tripolyphosphate (STPP) and reduced percentage of NaCl with CaCl₂ at 0%, 25%, 50%, 75%, and 100% at 4±2℃ for 20 h. STPP was adjusted to 0.5% for all treatments and NaCl replacement at 0% was used as control. The different methods, particularly boiling at 100℃ and retorting at 121℃, 1.5 kgf/cm² for 60 minutes, were applied following marination. An upregulation of cathepsin-B and caspase-3 enzymes were a consequences from a higher percentage of CaCl₂ within meat environment. Accordingly, modified the protein solubility in particular the myofibrillar and total protein solubility. In addition, a significant increase in water holding capacity (WHC), pH value, myofibril fragmentation index (MFI), and moisture content was obtained due to salt replacement (p<0.05). Limited effect was observed for shear force value, collagen content and cooking yield. Eventually, this study implied that although protelytic enzyme and protein solubility was upregulated by the replacement of NaCl with CaCl₂ at >75%, extensive effect on texture properties was not observed. Therefore, NaCl replacement at 75% could be a promising strategy for quality improvement of SH chicken soup.

• Food Science of Animal Resources
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• v.42 no.1
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• pp.46-60
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• 2022

In this study, angiotensin-I-converting enzyme inhibitory (ACEI) activity was evaluated in fermented goat milk fermented by lactic acid bacteria (LAB) from fermented foods and breast milk. Furthermore, the potential for ACEI peptides was identified in fermented goat milk with the highest ACEI activity. The proteolytic specificity of LAB was also evaluated. The 2% isolate was inoculated into reconstituted goat milk (11%, w/v), then incubated at 37℃ until pH 4.6 was reached. The supernatant produced by centrifugation was analyzed for ACEI activity and total peptide. Viable cell counts of LAB and titratable acidity were also evaluated after fermentation. Peptide identification was carried out using nano liquid chromatography mass spectrometry (LC-MS/MS), and potential as an ACEI peptide was carried out based on a literature review. The result revealed that ACEI activity was produced in all samples (20.44%-60.33%). Fermented goat milk of Lc. lactis ssp. lactis BD17 produced the highest ACEI activity (60.33%; IC₅₀ 0.297±0.10 mg/mL) after 48 h incubation, viable cell counts >8 Log CFU/mL, and peptide content of 4.037±0.27/mL. A total of 261 peptides were released, predominantly derived from casein (93%). The proteolytic specificity of Lc. lactis ssp. lactis BD17 through cleavage on the amino acid tyrosine, leucine, glutamic acid, and proline. A total of 21 peptides were identified as ACEI peptides. This study showed that one of the isolates from fermented food, namely Lc. lactis ssp. lactis BD17, has the potential as a starter culture for the production of fermented goat milk which has functional properties as a source of antihypertensive peptides.

• Food Science of Animal Resources
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• v.43 no.1
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• pp.46-60
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• 2023

Slaughterhouse blood is a by-product of animal slaughter that can be a good source of animal protein. This research purposed to examine the functional qualities of the blood plasma from Hanwoo cattle, black goat, and their hydrolysates. Part of the plasma was hydrolyzed with proteolytic enzymes (Bacillus protease, papain, thermolysin, elastase, and α-chymotrypsin) to yield bioactive peptides under optimum conditions. The levels of hydrolysates were evaluated by 15% sodium dodecyl sulfate polyacrylamide gel electrophoresis. The antioxidant, metal-chelating, and angiotensin I-converting enzyme (ACE) inhibitory properties of intact blood plasma and selected hydrolysates were investigated. Accordingly, two plasma hydrolysates by protease (pH 6.5/55℃/3 h) and thermolysin (pH 7.5/37℃/3-6 h) were selected for analysis of their functional properties. In the oil model system, only goat blood plasma had lower levels of thiobarbituric acid reactive substances than the control. The diphenyl picrylhydrazyl radical scavenging activity was higher in cattle and goat plasma than in proteolytic hydrolysates. Ironchelating activities increased after proteolytic degradation except for protease-treated cattle blood. Copper-chelating activity was excellent in all test samples except for the original bovine plasma. As for ACE inhibition, only non-hydrolyzed goat plasma and its hydrolysates by thermolysin showed ACE inhibitory activity (9.86±5.03% and 21.77±3.74%). In conclusion, goat plasma without hydrolyzation and its hydrolysates can be a good source of bioactive compounds with functional characteristics, whereas cattle plasma has a relatively low value. Further studies on the molecular structure of these compounds are needed with more suitable enzyme combinations.

• 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.

• Korean journal of food and cookery science
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• v.16 no.4
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• pp.363-366
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• 2000

This study was attempted to compare the properties of proteolytic enzymes in fruits(Pear, Kiwifruit, Fig, Pineapple and Papaya) for the application of scientific information to cooking. The results were as follows: 1. The optimum temperature of crude proteolytic enzymes in pear, fig and pineapple is 60$^{\circ}C$ and it was relatively active in 40-70$^{\circ}C$; papaya showed max. activity in 60$^{\circ}C$ and highly stable activity in 40-80$^{\circ}C$, but kiwifruit showed max. activity in 40$^{\circ}C$ and it maintained to 70$^{\circ}C$. 2.. The crude proteolytic enzymes of pear, fig, pineapple and papaya showed opt. pH at pH 7.0 and maintained at pH 5.0-8.0, but max. activity of kiwifruit observed in pH 3.0 and pH 5.0-8.0. 3. As a result of comparison of total activities of fruits per kg unit, the order of activities was pineapple > kiwifruit > papaya > fig > pear.

• Biomolecules & Therapeutics
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• v.15 no.1
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• pp.16-26
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• 2007

Tissue plasminogen activator (tPA) is a serine protease catalyzing the proteolytic conversion of plasminogen into plasmin, which is involved in thrombolysis. During last two decades, the role of tPA in brain physiology and pathology has been extensively investigated. tPA is expressed in brain regions such as cortex, hippocampus, amygdala and cerebellum, and major neural cell types such as neuron, astrocyte, microglia and endothelial cells express tPA in basal status. After strong neural stimulation such as seizure, tPA behaves as an immediate early gene increasing the expression level within an hour. Neural activity and/or postsynaptic stimulation increased the release of tPA from axonal terminal and presumably from dendritic compartment. Neuronal tPA regulates plastic changes in neuronal function and structure mediating key neurologic processes such as visual cortex plasticity, seizure spreading, cerebellar motor learning, long term potentiation and addictive or withdrawal behavior after morphine discontinuance. In addition to these physiological roles, tPA mediates excitotoxicity leading to the neurodegeneration in several pathological conditions including ischemic stroke. Increasing amount of evidence also suggest the role of tPA in neurodegenerative diseases such as Alzheimer's disease and multiple sclerosis even though beneficial effects was also reported in case of Alzheimer's disease based on the observation of tPA-induced degradation of $A{\beta}$ aggregates. Target proteins of tPA action include extracellular matrix protein laminin, proteoglycans and NMDA receptor. In addition, several receptors (or binding partners) for tPA has been reported such as low-density lipoprotein receptor-related protein (LRP) and annexin II, even though intracellular signaling mechanism underlying tPA action is not clear yet. Interestingly, the action of tPA comprises both proteolytic and non-proteolytic mechanism. In case of microglial activation, tPA showed non-proteolytic cytokine-like function. The search for exact target proteins and receptor molecules for tPA along with the identification of the mechanism regulating tPA expression and release in the nervous system will enable us to better understand several key neurological processes like teaming and memory as well as to obtain therapeutic tools against neurodegenerative diseases.