• 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.

• Food Science of Animal Resources
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• v.34 no.2
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• pp.207-213
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• 2014

This study investigated the effects of microbial transglutaminase (MTGase) and pH-shift processing on the functional properties of porcine myofibrillar proteins (MP). The pH-shift processing was carried out by decreasing the pH of MP suspension to 3.0, followed by re-adjustment to pH 6.2. The native (CM) and pH-shifted MP (PM) was reacted with and without MTGase, and the gelling and emulsion characteristics were compared. To compare the pH-shifted MTGase-treated MP (PT), deamidation (DM) was conducted by reacting MTGase with MP at pH 3.0. Rigid thermal gel was produced by MTGase-treated native MP (CT) and PT. PM and DM showed the lowest storage modulus (G') at the end of thermal scanning. Both MTGase and pH-shifting produced harder MP gel, and the highest gel strength was obtained in PT. All treatments yielded lower than CM, and CT showed significantly higher yield than PM and DM treatments. For emulsion characteristics, pH-shifting improved the emulsifying ability of MP-stabilized emulsion, while the treatments had lower emulsion stability. PM-stabilized emulsion exhibited the lowest creaming stability among all treatments. The emulsion stability could be improved by the usage of MTGase. The results indicated that pH-shifting combined with MTGase had a potential application to modify or improve functional properties of MP in manufacturing of meat products.

• Food Science of Animal Resources
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• v.33 no.2
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• pp.221-228
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• 2013

This study was performed to evaluate the effects of various levels of mungbean flour (MF) (0-2.4%) on the quality characteristics of pork model sausages (PMS) in experiment 1 and also select the optimum level of MF to enhance the water retention and gelling properties of low-salt PMS (LSPMS) with or without microbial transglutaminase (MTGase) in experiment 2. In experiment 1, the addition of MF did not affect pH, chemical compositions (fat and moisture contents), color values, and functional properties (expressible moisture, EM (%) and cooking yield, CY (%)) of PMS. However, the addition of MF increased the chewiness of PMS and hardness if the mungbean flour at the level of more than 1.2% was incorporated. Since the interaction between the microbial transglutaminase (MTGase) treatment and MF level was not significant (p>0.05), data were pooled by different factors (MTGase treatment and MF level) in experiment 2. MF improved the water binding ability and textural springiness of LSPMS. On the other hand, MTGase treatment decreased the pH and cooking yield (%) of LSPMS, but increased most textural properties. In conclusion, the addition of MF could enhance the water retention and textural properties of PMS and LSPMS, regardless of MTGase, when it was added to over 1.2%. Based on these results, mungbean protein may interact with MTGase on the low-salt comminuted meat systems. Therefore, further study might be needed to understand the mechanisms of interaction between MTGase and functional components induced from MF.

• Bulletin of the Korean Chemical Society
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• v.30 no.7
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• pp.1547-1552
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• 2009

Sphingomonas chungbukensis DJ77 has the ability to produce large quantities of an extracellular polysaccharide that can be used as a gelling agent in the food and pharmaceutical industries. We identified, cloned and expressed the UDP-glucose dehydrogenase gene of S. chungbukensis DJ77, and characterized the resulting protein. The purified UDP-glucose dehydrogenase (UGDH), which catalyzes the reversible conversion of UDP-glucose to UDPglucuronic acid, formed a homodimer and the mass of the monomer was estimated to be 46 kDa. Kinetic analysis at the optimal pH of 8.5 indicated that the $K_m\;and\;V_{max}$ for UDP-glucose were 0.18 mM and 1.59 mM/min/mg, respectively. Inhibition assays showed that UDP-glucuronic acid strongly inhibits UGDH. Site-directed mutagenesis was performed on Gly9, Gly12 Thr127, Cys264, and Lys267. Substitutions of Cys264 with Ala and of Lys267 with Asp resulted in complete loss of enzymatic activity, suggesting that Cys264 and Lys267 are essential for the catalytic activity of UGDH.

• Journal of the Korean Society of Food Science and Nutrition
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• v.35 no.7
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• pp.903-907
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• 2006

Frozen stability of proteins recovered from white croaker and jack mackerel have been tested by measuring oxidation of residual lipid, browning, total plate count, and texture of gel during storage at $-20^{\circ}C$. The oxidation of residual lipid in recovered protein from Jack mackerel increased up to 60 days, and then decreased. Both browning values significantly was increased after 90 days. Total plate count was $1.2{\times}10^4\;CPU/g$ for proteins recovered from white croaker and $3.2{\times}10^4\;CPU/g$ for proteins recovered from jack mackerel in 60 days. The breaking force, deformation, and whiteness of gel formed from proteins recovered from white croaker did not change up th 120 days significantly, while proteins recovered from jack mackerel did not form heat-induced gel in 120 day. Frozen storage of the recovered protein was limited to 90 days for white croaker and to 60 days for jack mackerel considering the gelling ability and textural properties.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.5
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• pp.673-676
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• 1998

Preparative conditions of high-gel strength agar from Gelidium amansii have been studied, The effect of NaOH pretreatment on the quality and yields of agar extracted from Gelidium amansli was examined. The Bel strength of agar extracted from C. amansii pretreated with NaOH was higher than that of agar extracted from G. amansii non-pretreated with NaOH. The gel strength of agar extracted from G. amansii was influenced by concentration, temperature and time of pretreatment with NaOH. It was found that the proper concentration, temperature and time of NaOH pretreatment to produce high-gel strength agar was $6\%$ NaOH, $80^{\circ}C$ and 2$\~$3 hrs. The principal sugars of agar extracted from G. amansli were galactose and 3,6-anhydrogalactose.

• Journal of the Korean Geosynthetics Society
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• v.19 no.1
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• pp.25-33
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• 2020

To improvement the swelling characteristics of the existing cutoff wall against the moisture, the permeability of the sand, calcium bentonite and solidifier mixture according to the contact with trichloroethylene (TCE) was evaluated. Characteristics analysis and the permeability test of the research materials were performed. The permeability was decreased as the mixing ratio of the calcium bentonite was increased and it was increased as the mixing ratio of the solidifier was increased. In conclusion, when mixing 15% of calcium bentonite and more than 30% of solidifier, the permeability coefficient in the underground water movement was analyzed as more than α × 10^-4 cm/sec showing that it does not block the underground water movement. In addition, as the permeability coefficient of mixtures after TCE reaction was analyzed as less than α ×10^-7 cm/sec, it satisfied the condition of blocking layer (less than 1.0 × 10^-6 cm/sec). Therefore, the calcium bentonite and solidifier can be utilized as barrier that showing the characteristic of percolation ability conversion in soil and underground water contaminated with TCE.