• Journal of the Korean Society of Food Science and Nutrition
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• v.32 no.1
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• pp.89-95
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• 2003

Four-dimensional response surface methodology was used for monitoring the manufacturing characteristics of aloe gel-state food. The optimum conditions predicted for each corresponding sensory properties of aloe gel-state food were 87.38 mL (content of aloe juice), 0.16 g (content of konjac) and 0.19 g (content of carrageenan) in coloror of gel-state food, 83.84 mL, 0.17 g and 0.20 g in aroma of aloe gel-state food, 83.20 mL.0.15 g and 0.27 g taste of aloe gel-state food and 98.95 mL, 0.10 g and 0.23 g in texture of aloe gel-state food. Maximum chewiness of aloe gel-state food was in 113.05 mL aloe juice, 0.27 g konjac and 0.21 g carrageenan. The optimum conditions, which satisfied all sensory properties of gel-state food, were 88.23 mL, 0.15 g and 0.49 g in content of aloe juice, content of konjac and content of carrageenan, respectively.

• Food Science and Biotechnology
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• v.15 no.6
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• pp.856-859
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• 2006

The effects of moisture content on non-fracture dynamic properties and fracture gel quality of Pacific whiting surimi were investigated to determine their relationships. Surimi samples were tested at various moisture contents (75, 78, and 81 %). Torsion test showed that shear stress decreased rapidly and strain values decreased gradually as moisture concentration increased. Dynamic storage modulus (G') also decreased as moisture content increased. A strong positive correlation ($R^2=0.90$ to 0.99) was found between the G' measured at temperatures between 10 and $45^{\circ}C$ and fracture stress values. The results indicate that dynamic rheological measurements could be used as a tool for early gel quality assessment.

• Preventive Nutrition and Food Science
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• v.2 no.4
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• pp.281-284
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• 1997

Heat-induced gelation is an important functional property of whey proteins. Preheating of calcium reduced whey was reported to increase gel strength. 5% whey-protein solutions were preheated at pH7 and at various temperatures(60~8$0^{\circ}C$) for 15 minutes. The amount of soluble aggregates and denaturation enthalpy of preheated whey proteins were measured. Preheating temperature was negatively correlated with denaturation enthalpy($R^2$=0.857, P=0.08) and positive with the amount of soluble aggregates($R^2$=0.921, P=0.002). Denaturation enthalpy was negatively correlated with gel strength($R^2$=0.93, P=0.002). Soluble aggregates and gel strength were positively correlated($R^2$=0.972, P=0.0003). The formation of three dimensional gel network requires controlled protein denaturation and aggregation. Since preheating leads to the partial denaturation of proteins and the formation of soluble aggregates, preheated whey proteins have a higher gel strength than non-preheated one.

• Korean Journal of Food Science and Technology
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• v.20 no.4
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• pp.594-599
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• 1988

Methods by which liquid egg could be stored in liquid state at frozen storage temperature$(-15^{\circ}C)$ with selected cryoprotectants and enzyme treatment were investiated, and quality changes in samples during storage were examined. The concentration of cryoprotectants (45% fructose and 55% glucose) to be added to egg yolk and whole egg to store them at $-15^{\circ}C$ in unfrozen state were 45.2% and 70.3%, respectively. Changes in consistency, precipitation of protein and microstructure of egg samples during storage indicated that adding cryoprotectants to liquid egg could effectively inhibit development of gelation during storage at $-15^{\circ}C$. Treating liquid egg with 0.15% papain could inhibit gelation during storage to some extent.

• Korea-Australia Rheology Journal
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• v.11 no.4
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• pp.275-278
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• 1999

Soft polymeric materials have gained importance in recent years, namely in food, pharmaceuticals, photographic media, adhesives, vibration dampeners and superabsorbers (to name a few), but also as inter-mediates for selforganization of molecules or supramolecules into long range order. Many of these soft materials are close to their gel point, i.e. they are liquids just before reaching their gel point or they are solids which have barely passed the gel point. New rheological methods need to be developed for the understanding of these soft materials; the typical liquid properties (viscosity) and typical solid properties (modulus) are not applicable since they diverge at the gel point. This will be discussed in the following. Fortunately, chemical gelation experiments with model polymers has given insight into the behavior at the gel point (Winter and Mours, 1997). This knowledge of the critical gel provides us with a reference state when working with soft polymeric materials. Chemical gels will serve as model materials for the exploration of physical gels. A novel method for detecting the gel point has been proposed: the instant of liquid-to-solid transition(gel point) is marked by the crossover of the normalized dynamic moduli G'/cos($n_c$$\pi$/2) and G"/sin($n_c$$\pi$/2).>/2).

• Food Science and Biotechnology
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• v.18 no.3
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• pp.618-623
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• 2009

Synergistic interactions between xanthan (X) and carob (C) were investigated by studying the linear viscoelastic behavior of X, C, and X/C mixtures at sol and gel states. At the solution state, storage modulus (G') dominates the linear viscoelastic properties of X/C mixtures. The gelation temperature (52 to $57^{\circ}C$) was weakly dependent on the xanthan fraction (${\phi}x$) in the mixture. The ${\phi}x$ also had a strong effect on G' until ${\phi}x=0.5$. The elastic active network concentration (EANC) of X/C gels was estimated from the pseudo-equilibrium modulus. The EANC for systems with ${\phi}x=0.25$, 0.5, 0.75, and 1 at 1% total concentration was 2.3, 4.4, 4.1, and 0.32 (${\times}10^{-3}\;mol/m^3$), respectively. The maximum synergistic effect was observed at about ${\phi}x=0.5$. The G' at the transition state of X/C mixed gel was proportional to ${\omega}^{3/2}$ at ${\omega}$>${\omega}_{tr}$ (the onset transition frequency) compared to the theoretical limit of ${\omega}^{1/2}$.

• The Korean Journal of Food And Nutrition
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• v.1 no.2
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• pp.50-55
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• 1988

B-Amylase was obtained from sweet potato extract in a crystalline state by dialysis against water after precipitated with acetone according to the method reported previously followed by DEAE Sephadex A-50 ion exchange chromatography plus gel chromatography of Sephadex G-200. The purified enzyme was homogeneous by SDS PAGE. The efforts had done to remove the miner bands in SDS PAGE by Sephadex G-200 gel chromatography, DATE Sephadex A-50 ion exchange chromatography. isoelectrophocusing, affinity chromatography, hydroxyapatite chromatography, recrystallizstion and HPLC on a column of TSK gel SW 3000 but have given any result. But, N -terminal amino acid of the enzyme was revealed mainly alanine and trace of glycine and glutamic acid. Therefore, it seems that the miner bands in SDS PAGE have a role of subunit.

• Applied Biological Chemistry
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• v.30 no.4
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• pp.305-310
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• 1987

The enzymatic properties of ${\beta}-amylase$ from soybean and sweet potato were compared. The sweet potato enzyme consists of four identical subsunits whereas soybean enzyme has no subunit $structure^{12,\;15)}$. In the denatured state, both enzymes exhibited the same molecular weight on SDS-gel electrophoresis and on gel-filtration analysis. The spectra of circular dichroism revealed that both enzyme have almost same secondary structure but the environment of aromatic side chains are different. The chemical cleavage of soybean and sweet potato ${\beta}-amylases$ at cysteine residues and methionine residues demonstrated the homology of amino acid sequence between the enzymes. The similarity between soybean and sweet potato ${\beta}-amylase$ was also revealed by immunological method. The antibody for soybean enzyme inhibited the activity of sweet potato enzyme but it did not inhibit the activity of wheat, barley and Japanese-raddish ${\beta}-amylases$.

• Journal of Microbiology and Biotechnology
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• v.5 no.4
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• pp.181-187
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• 1995

The cells of Vibrio vulnificus can be induced to the viable but nonculturable (VBNC) state by natural environmental parameters. The V. vulnificus cells in the VBNC state can not be recovered by ordinary laboratory techniques. This nonculturability could often hamper development of effective processing strategies to minimize the number of V. vulnificus in seafoods. Even with V. vulnificus cells in a culturable state, the length of time required to identify the bacteria in contaminated food by phenotyphic characterization may prevent appropriate in-time responses by public health agencies to infections of the bacteria. In the present study, we used polymerase chain reaction (PCR) to develop a rapid and direct detection method for V. vulnificus in small octopus (Octopus variabilis) which is consumed as a raw food in Korea. The region targeted was a 704-base pair (bp) portion of the hemolysin gene, vvhA, of V. vulnificus. The primers designed for PCR amplification were specific for all V. vulnificus sp. tested. Several methods were examined to extract total DNA directly from V. vulnificus seeded into the octopus homogenate and the guanidine isothiocyanate (CITC) method appeared to be most effective. From the octopus homogenate seeded by V. vulnificus at an initial level of $10^2$ CFU/ml of the homogenate and then incubated for 12 h, the targeted sequence was successfully amplified by PCR and the 704-bp DNA fragment was observed by gel electrophoresis. The total completion of this assay requires less than one day.

• Food Science of Animal Resources
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• v.34 no.2
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• pp.230-237
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• 2014

This study was designed to find the most suitable method and wall material for microencapsulation of the Lactobacillus plantarum to maintain cell viability in different environmental conditions. To improve the stability of L. plantarum, we developed an encapsulation system of L. plantarum, using water-in-oil emulsion system. For the encapsulation of L. plantarum, corn starch and glyceryl monostearate were selected to form gel beads. Then 10% (w/v) of starch was gelatinized by autoclaving to transit gel state, and cooled down at $60^{\circ}C$ and mixed with L. plantarum to encapsulate it. The encapsulated L. plantarum was tested for the tolerance of acidic conditions at different temperatures to investigate the encapsulation ability. The study indicated that the survival rate of the microencapsulated cells in starch matrix was significantly higher than that of free cells in low pH conditions with relatively higher temperature. The results showed that corn starch as a wall material and glycerol monostearate as a gelling agent in encapsulation could play a role in the viability of lactic acid bacteria in extreme conditions. Using the current study, it would be possible to formulate a new water-in-oil system as applied in the protection of L. plantarum from the gastric conditions for the encapsulation system used in chicken feed industry.