• Korean Journal of Food Science and Technology
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• v.23 no.3
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• pp.317-324
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• 1991

Gelatinization behaviours and gel properties of hydroxypropylated corn starches (HPCS) were investigated with differential scanning calorimeter, amylograph and rheometer. Gelatinization temperature of HPCS decreased as degree of substitution increased. The retrogradation of corn starch was greatly reduced by hydroxypropylation, indicating that the association of starch molecules was sterically hindered by hydroxypropyl groups. In HPCS, gel was formed slowly and gel strength decreased resulting in soft and sticky texture. Texture profiles of HPCS gels were similar to those of tapioca and waxy corn starch. HPCS has shown a remarkable increase of paste transparency compared to native corn starch.

• Korean Journal of Food Science and Technology
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• v.15 no.4
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• pp.333-341
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• 1983

Tannase of Aspergillus sp. AN-11 isolated from contaminated acorns was purified by a procedure involving ammonium sulfate precipitation, DEAE-cellulose column chromatography and Sephadex G-200 gel filtration. Physiochemical properties of the purified tannase was investigated. Tannase was purified about 37 folds with the yield of 49% from the culture broth of Aspergillus sp. AN-11. The purified tannase was homogeneous on polyacrylamide gel disc electrophoresis and was dissociable into two identical subunits on SDS-polyacrylamide gel electrophoresis. The molecular weight of the tannase was determined to be 200,000 by gel filtration on Sephadex G-200. The purified tannase showed a typical protein ultraviolet spectrum. The enzyme had a optimum pH 5.5 and optimum temperature at 30 to $40^{\circ}C$. The enzyme was stable at a pH range from 5.0 to 6.5 and at the temperature below $30^{\circ}C$. The enzyme was inactivated remarkably by $CuCl_2$ and $ZnCl_2. The Km value of the enzyme was $7.58{\times}10^{-4}\;M$.

• Journal of the Korean Society of Food Science and Nutrition
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• v.21 no.1
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• pp.76-83
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• 1992

Enterotoxigenic E. coli is one of the major causative agents of the infantile diarrhea and traveler's diarrhea. The heat-stable enterotoxin (ST) is thought to be a virulence factor in the pathogenesis of the diarrhea and to be a maker for identification of the enterotoxigenic E. coli from non pathogenic E. coli. ST producing E. coli KM-7 strain was isolated from the swine and molecular cloning of ST gene of KM-7 strain. Transformant eKT-53 $(ST^+,\;LT^-)$ was selected by infant mouse assay (IMA). The culture supernatant of eKT-53 strain was performed purification by multipled steps. The culture supernatant (crude ST) was purified by sequentially applying batch adsorption chromatography on Amberlite XAD-2 resin, ion exchange chromatography on DEAE-Sephacel anion exchanger, gel filtration chromatography on Bio-Gel P-6 and preparative polyacrylamide slab gel electrophoresis. About 113-fold purification was achieved with a yield of about 11% of crude ST and the minimum effective dose(MED) of this purified ST was about 2.8ng in IMA. Homogeneity of purified ST was demonstrated by showing a single band in analytical SDS polyacrylamide disc gel electrophoresis.

• Korean Journal of Food Science and Technology
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• v.17 no.5
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• pp.340-344
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• 1985

In this study, an effective method for purifying of crude agar was attempted, and at the same time, the effect of crude protein and ash contained in impurified agar on the gel strength of the agar were investigated. In order to reduce the content of protein of crude agar, the agar extract was treated with a protein precipitant such as tricholoroacetic acid(TCA) or perchloric acid(PCA), whereas washing with deionized water was applied to decrease the ash content of agar extract. Among the protein precipitants used in the experiment PCA reduced the crude proteins of crude agar most efficiently; addition of 0.01% PCA resulted in the reduction of crude protein content by 3%, and the gel strength of agar thereby increased from 220g/$cm^{2}$ to 402g/$cm^{2}$. High ash content of crude agar was removed by means of washing treatment and it decreased from 8.1% to 2.7%, leading to the gel strength of 530g/$cm^{2}4$.

• Preventive Nutrition and Food Science
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• v.7 no.4
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• pp.373-377
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• 2002

Allergens in processed foods may place persons with food allergies at significant risk when the labels do not Provide sufficient warnings or identification of high-risk ingredients. Because egg proteins are common food allergens, this study was carried out to identify hen's egg albumin (ovalbumin, OVA) in five commercially processed foods containing egg (custayd, cookie and pasta), and chicken meat (sausage and meatball) by immunological methods using commercially produced murine monoclonal immunoglobulin G (M-IgG), immunoblotting and enzyme linked immunosorbent assay (ELISA). Sample buffer with chelating and reducing agents was prepared and used for the preparation of the protein fractions from the foods. Most bands in sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) profile (5~15% gradient gel) presented at 75 kDa below. OVA (43 kDa) in the sample lanes could not be visually observed on the gel. However, OVA in solutions prepared from custard and cookie could be detected by M-IgG, but were not detected in sausage and pasta. OVA in all samples could be quantitatively determined by the equation obtained from the standard curve by ELISA. Cookie and custard containing egg white and egg, respectively, contained very high concentrations of OVA. OVA in the other products were present in relatively low concentrations, but sufficiently high to pose possible risk of allergy, ELISA is a very sensitive and precise method for the identification and quantification of allergens in food products including allergy-inducible materials.

• Preventive Nutrition and Food Science
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• v.15 no.1
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• pp.74-77
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• 2010

Antibiotic-resistant Staphylococcus aureus is beginning to pose a social issue. Thus, there is an urgent need for the development of effective anti-staphylococcal agents to eradicate antibiotic-resistant S. aureus in food systems and to treat the pathogen in clinical areas. To address this need, lactic acid bacteria (LAB) from kimchi were screened for the production of anti-staphylococcal bacteriocin. From this screening, a bacteriocin generated by the MK3 strain, which was identified by 16S rRNA gene sequence analysis as Enterococcus faecium, demonstrated antimicrobial activity against an S. aureus strain, and was designated enterocin MK3. Enterocin MK3 also demonstrated activity against other gram-positive bacteria, including several LAB and Listeria monocytogenes, but not gram-negative Escherichia coli. The molecular mass of enterocin MK3 was estimated as approximately 6.5 kDa on an SDS-PAGE (sodium dodecyl sulfate-polyacrylamide gel electrophoresis) gel.

• Journal of Life Science
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• v.26 no.8
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• pp.955-962
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• 2016

Fish-meat gel is an intermediate product used in a variety of surimi-based seafood. One of the most-used raw materials of fish-meat gel is Alaska Pollock due to its high-quality meat in terms of gel strength and texture. However, increasing demand for fish-meat gel, along with overexploitation of the wild catch Alaska Pollock, has put the industry in need of low-cost sustainable alternative sources for fish-meat gel. Pagrus major (PM) is a widely aquacultured fish known for having white meat that is low in fat. The current study compares the quality of fish-meat gel prepared from aquacultured PM to that of high and mid-grade Alaska Pollock fish-meat gel. Gels were compared in terms of gel strength, texture, color, and protein pattern. Results indicated that fish-meat gels prepared from PM were superior to Alaska Pollock fish-meat gels with regard to gel strength, hardness, springiness, chewiness, cutting strength, and breaking force. In addition, although not matching in quality, PM exhibited a cohesiveness, whiteness, and expressible moisture content comparable to Alaska Pollock of both grades. Protein pattern analysis also showed that PM and Alaska Pollock fish-meat gels had similar protein profiles before and after gel preparation. Therefore, P. major is suggested as a potential substitute for Alaska Pollock in fish-meat gel production.

• Korean Journal of Food Science and Technology
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• v.16 no.1
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• pp.78-82
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• 1984

Effects of various drying conditions of agar gel on the physico-chemical properties of dried agar were investigated. For drying of the agar gel$(1.0{\times}1.0{\times}34.0cm)$ by means of sun drying, simple solar drying, hot-air drying ($30^{\circ}C$, control, natural convection), hot-air drying ($30^{\circ}C$, pretreatment, natural convection) and freeze drying, it took 96, 75, 67, 50 and 21 hours, respectively. The gel strengths of dried agar gel prepared by sun drying, solar drying, freeze drying and spray drying were320, 370, 270 and $360g/cm^2$, respectively and that of hot air-dried agar gel was influenced by drying temperature, pretreatment an mode of heat transfer. The gel strength, the gelation temperature and other quality index of spray-dried agar were not inferior to those of sun-dried agar, but it was not expected to be economical because of it recovery rate. In case of hot air drying, the gel strength value of agar increased as the drying rate increased. No significant differences among various products were noted in the gelation temperature, the melting temperature, the ash and $SO_3$ content.

• Food Science of Animal Resources
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• v.32 no.3
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• pp.316-322
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• 2012

This study was conducted to evaluate the effects of soaking pH and extraction temperature on the physicochemical properties of chicken skin gelatin. In order to extract gelatin from chicken skin, the chicken skin was soaked at various pH ranges (1-13) and was extracted at 75 and $100^{\circ}C$. For the rate of weight increase, the highest value was obtained from two pH ranges (1-2 and 12-13). In addition, the rate of weight increase was affected by soaking time. The alkali treatments had greater crude protein content as well as total extraction yield compared to the acid process (p<0.05), and the increased extraction temperature resulted in a significant (p<0.05) increase of crude protein content and total extraction yield. All treatments showed ${\alpha}1$ and ${\alpha}2$ chains derived from type I collagen on SDS-PAGE. The pH value and color of gelatin gel (6.67%) were affected by soaking pH and extraction temperature. Chicken skin gelatin gel extracted at $75^{\circ}C$ after soaking at a pH of 2 had the highest melting point (p<0.05) and gel strength among all treatments. Although the chicken skin treated with the alkali process had a higher yield, a lower extraction temperature following the acid process would be better for obtaining superior gelatin from chicken skin.

• Korean journal of food and cookery science
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• v.10 no.4
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• pp.447-459
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• 1994