• Culinary science and hospitality research
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• v.11 no.2
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• pp.110-124
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• 2005

This study was conducted to investigate the proteolytic properties of Sarcodon aspratus on meat proteins. The analytical condition for the measurement of enzyme activity was determined and the effect of Sarcodon aspratus on beef protein and its fractions were determined by SDS-PAGE and the spectrophotometric method respectively. Optimum temperature and pH of Sarcodon aspratus were $73~78^{\circ}C$ and pH 8 respectively. However, enzyme tended to be denatured at $50^{\circ}C$ for 10 min incubation. Proteolytic activity of Sarcodon aspratus was higher than of kiwi and pear 66 and 990 times by dry weight respectively. It appeared that proteolytic activity of Sarcodon aspratus toward beef protein by SDS-PAGE was prominent when compared to that of kiwi and bromelain. Furthermore, Sarcodon aspratus showed the highest proteolytic activity toward all the beef protein fractions, which was followed by collagenase and bovine protease. Transmission electron microscopy showed the muscle fiber started to be degraded when treated with Sarcodon aspratus(1,000 unit) for 10min at $25^{\circ}C$. No distinct sarcomere, A-band, or z-line was observed when treated with Sarcodon aspratus for 60min at the same condition.

• Food Science of Animal Resources
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• v.42 no.3
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• pp.441-454
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• 2022

This study aimed to determine the effect of enzyme, guar gum, and pressure processing on the digestibility and physicochemical properties of age-friendly liver sausages. Liver sausages were manufactured by adding proteolytic enzyme (Bromelain) and guar gum, and pressure-cooking (0.06 MPa), with the following treatments: control, without proteolytic enzyme; T1, proteolytic enzyme; T2, proteolytic enzyme and guar gum; T3, pressure-cooking; T4, proteolytic enzyme and pressure-cooking; T5, proteolytic enzyme, guar gum, and pressure-cooking. The pH was high in the enzyme- and pressure-processed groups. The pressure-processed groups had lower apparent viscosity than other cooking groups, and it decreased during enzyme treatment. Hardness was lower in the enzyme- and pressure-processed groups than in the control, and the T4 was the lowest. Digestibility was the highest in T4 at 82.58%, and there was no significant difference with that in T5. The general cooking group with enzyme and guar gum also showed higher digestibility than the control (77.50%). As a result of the sodium dodecyl sulfate-polyacrylamide gel electrophoresis, the enzyme- and pressure-treated groups (T4, T5) were degraded more into low-molecular-weight peptides (≤37 kDa) than the control and other treatments. Viscoelasticity showed similar trends for viscous and elastic moduli. Similarly, combined pressure processing and enzymatic treatment decreased viscoelasticity, while guar gum increased elasticity but decreased viscosity. Therefore, the tenderized physical properties and improved digestibility by enzyme and pressurization treatment could be used to produce age-friendly spreadable liver sausages.

• Proceedings of the Culinary Society of Korean Academy Conference
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• 2005.04a
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• pp.19-42
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• 2005

This study was conducted to investigate the proteolytic properties of Sarcodon aspratus on meat proteins. The analytical condition for the measurement of enzyme activity was determined and the effect of Sarcodon aspratus on beef protein and its fractions were determined by SDS-PAGE and spectrophotometric method, respectively. Optimum temperature and pH of Sarcodon aspratus was $73-78^{\circ}C$,pH 8, respectively. However, the enzyme tended to be denatured at $50^{\circ}C$ for 10min incubation. Proteolytic activity of Sarcodon aspratus was higher than those of kiwi and pear by 66 and 990 times by dry weight, respectively. It was appeared that proteolytic activity of Sarcodon aspratus toward beef protein by SDS-PAGE was prominent when compared to those of kiwi and bromelain. Furthermore, Sarcodon aspratus showed highest proteolytic activity toward all the beef protein fractions, which was followed by collagenase and bovine protease. Transmission electron microscopy showed the muscle fiber started to be degraded when treated with Sarcodon aspratus(1,000 unit) for 10min at $25^{\circ}C$. No distinct sarcomere, A-band, and z-line was observed when treated with Sarcodon aspratus for 60min at same condition.

• Korean Journal of Food Science and Technology
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• v.24 no.3
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• pp.294-299
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• 1992

This study was to examine the effect of functional properties of soy protein isolate(SPI) and qualities of soybean curd upon proteolytic hydrolysis. SPI was hydrolyzed using proteolytic enzyme, bromelain. The protein content of SPI by microkjeldahl method was 84% and the degree of hydrolysis in modified soy protein isolate(MSPI) was 2.7%. The solubility of MSPI was higher than that of control at various pH tested and proteolytic hydrolysis was increased emulsion formation and foam expansion while decreased emulsion stability, foam stability and calcium precipitation. Modified soybean curdI, standard soybean milk: Modified soybean milk=3:1, was soft and springy soybean curd when the texture properties of soybean curd were tested by texture profile analysis using Instron and sensory evaluation. The rheological model of soybean curds was investigated by stress relaxation test. The analysis of relaxation curve revealed that the rheological behavior of soybean curds could be expressed by 7-element generalized Maxwell model. The equilibrium modulus and modulus of elasticity decreased as the ratio of modified soybean milk was increased.

• The Korean Journal of Food And Nutrition
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• v.11 no.5
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• pp.576-579
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• 1998

Water extract of mulberry tree barks(Morus alba Linne) was studied for its proteolytic activity. Protein content of the extract was 1.12mg/ml and its specific activity was 5.14U/ml. The enzyme was active on various proteins : the relative acitities were 100 for casein, 63 for albumin, 58 for collagen, 45 for hemoglobin and 36 gelatin, respectively. There suggested that the ability of the enzyme to hydrolyze meat was relatively high since those are major meat proteins. Optimum pH and temperature for proteolytic activity were : pH 6.0 and 6$0^{\circ}C$. And the enzyme was stable at the pH range of 6.0 to 7.0 and temperature between 50 and 8$0^{\circ}C$. Apparent proteolytic activities could support some scientific grounds of traditional application of mulberry tree barks to home cooking for meat tenderization.

• Journal of Microbiology
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• v.41 no.2
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• pp.73-77
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• 2003

Four proteolytic bacteria were isolated and identified from a rotating biological contactor based on Bacillus. The four isolates, Ni 26, 36, 39 and 49 were identified as B. vallismortis, B. subtilis, Aeromonas hydrophila and B. amyioliquefaciens, respectively, based on their biochemical properties and 16S rDNA sequence analyses. The optimal proteolytic activity was observed in the temperature and pH ranges of 40-70$^{\circ}C$ and 8.0-8.5, respectively. The proteolytic activities of all the isolates were partially inhibited by phenylmethylsulfonylfluoride (PMSF), and the isolates Ni 26, Ni 39 and Ni 49 were inhibited by the metalloprotease inhibitor, 1,10-phenanthroline. Zymographic analyses of the culture supernatants revealed the presence of at least two pretenses in all isolates.

• Journal of the Korean Society of Food Science and Nutrition
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• v.26 no.6
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• pp.1116-1121
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• 1997

Effects of gamma irradiation onf the activity and the properties(amino acid compositions, in vitro digestibility and SDS-PAGE pattern) of proteolytic enzymes were investigated. The proteolytic activity of soluble human serine protease, enzyme in kiwi and pineapple decreased 10% and 30~65% by 5 kGy and 30 kGy, respectively. In dried pancreatin and lysozyme, the proteolytic and antimicrobial activities decreased 6~14% and 10~20% by 5kGy and 40kGy, respectively. The analysis of above 10kGy-irradiated soluble human serine protease by SDS-PAGE revealed radiolysis of the enzyme into protein or peptides of lower molecular weights. The irradiation of skim milk, hammastein casein, and lysozyme up to 40kGy had no deleterious effect on either the in vitro digestibility or amino acid compositions.

• Applied Chemistry for Engineering
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• v.10 no.5
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• pp.635-638
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• 1999

The effect of proteolytic enzyme on the unhairing process has been studied. this enzyme significantly changed the physical properties of pelt for leather shoes. A SEM was used to examine physical properties of the pelt. Even though bio-tech treatment using proteolytic enzyme slightly reduced the degree of unhairing compared to chemical treatment. Physical property of the pelt is better and this method is environmentally favorable. $H_{2}S$ gas produced in the chemical treatment was not detected and the value of COD and BOD for waste water after the unhairing process were reduced to 939 mg/L and 5268 mg/L, respectively. We found that a process with 0.4~0.5% proteolytic enzyme for 20 h at $29{\sim}30^{\circ}C$ is most suitable for the unhairing process.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.6
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• pp.884-888
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• 2003

Proteolytic enzymes are used for meat tenderization, an important process with regard to consumer preference. The proteolytic enzyme, IVRIN was isolated from the plant Cucumis pubescens W and its effect on physico-chemical properties and lipid profile of thigh and breast muscle of culled, desi and broiler birds was studied. Fifty-gram meat was treated with IVRIN containing 32.5 mg enzyme protein at $60^{\circ}C$ for 20 min. The pH of IVRIN treated meat was decreased significantly (p<0.01) and the effect was more pronounced in breast than thigh muscle. The water holding capacity (WHC) was increased significantly (p<0.01) in broiler as compared to desi and culled bird, and in breast compared to thigh muscle. IVRIN failed to produce any impact on muscle fiber diameter (MFD). The MFD of desi was significantly higher (p<0.01) than broiler and culled birds. The total lipid concentration in thigh and breast muscle of desi was lower (p<0.01) than broiler and culled birds, latter being similar in this respect. The cholesterol content was lower (p<0.01) in breast than thigh muscle, in broiler than desi and culled and in IVRIN treated than untreated meat samples. The phospholipid concentration was unaffected by IVRIN. Broiler and culled birds exhibited more phospholipid content than desi birds.

• Korean Journal of Food Science and Technology
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• v.29 no.6
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• pp.1191-1195
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• 1997

This study was conducted to investigate the proteolytic properties of saewoojeot (salted and fermented shrimp) on various meat proteins. NaCl content was decreased less than 2% by electrodialysis. As electrodialysis time was passed, the protease activity was increased. The proteolytic activity of crude protease on muscle proteins of beef, pork, chicken was analyzed by SDS-PAGE. Crude enzyme easily degradated both heat-denatured and native meat proteins. Protein degradation was rapidly occurred within 5 min and most all myofibrilar protein was disappeared. Heat-denatured chicken meat (100%) was most easily degraded than heat-denatured pork meat (47%) and beef meat (31%).