• Food Science and Biotechnology
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• v.15 no.2
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• pp.196-201
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• 2006

Freeze concentration of milk was carried out thorough the controlled recrystallization of ice in a multi-stage freeze concentrator. Artificial temperature control was used to induce ice recrystallization via a heat and cold shock process. In each stage of freeze concentration, the recrystallization time was fixed at 1, 2, 4, and 8 hr to compare the solute concentrate, yield, Brix, ice crystal size, and freezing point at each experimental condition. Higher concentrations of milk solids were seen with increased durations of recrystallization time, and a maximum total solids in the final product of 32.7% was obtained with a ripening time of 8 hr in a second stage process. Milk solid yield decreased according to the solute concentration and recrystallization time. The results of Brix and ice crystal size showed a positive correlation with recrystallizaiton time. These results suggest the possibility of freeze concentration being of practical use in the dairy industry.

• Journal of Advanced Marine Engineering and Technology
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• v.26 no.2
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• pp.240-247
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• 2002

Recently, a thermal energy storage system has been developed actively fur the purpose of saving energy and reducing the peak electrical demand. Especially, ice slurry is a promising working fluid for low temperature energy storage systems. A flow of ice crystals has a large cooling capacity as a result of the involvement of latent heat. However, there are still problems related to the recrystallization of ice crystals for realizing long term storage and long distance transportation. To find improvements fur this, a method for the creation of ice crystals resistant to recrystallization has been proposed and researched by the use of an antifreeze protein (AFP) solution etc. In the present study, it has been investigated the growth of ice crystal in several kinds of water solution added non-ionic surfactant. The results shows that size of ice crystal was smaller with increasing in added surfactant. And ice crystal was not increased with added surfactant.

• Food Science of Animal Resources
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• v.32 no.5
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• pp.627-634
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• 2012

This study was carried out to investigate the physical and thermal properties of ${\kappa}$-carrageenan (${\kappa}$-car) gel added whey protein isolate (WPI) as a cryoprotectant. The concentration of ${\kappa}$-carrageenan was fixed at 0.2 wt%. The mean ice crystal size of the WPI/${\kappa}$-car was decreased according to increasing whey protein isolate concentration. The temperature of gel-sol (Tg-s) and sol-gel (Ts-g) transition of WPI/${\kappa}$-car maxtrix was represented in the order of 3.0, 0.2, 5.0 and 1.0 wt%. In addition, the transition temperature of gel-sol of WPI in sucrose solution were showed in order of 1.0, 5.0, 0.2 and 3.0 wt% depending on whey protein isolate concentration. The shape of ice crystal was divided largely into two types, round and rectangular form. 1.0 wt% WPI/${\kappa}$-car matrix at pH 7 and 9 showed minute and rectangular formation of ice crystals and whey protein isolate in sucrose solution at a concentration of 1.0 wt% WPI/${\kappa}$-car matrix at pH 3 and 5 showed relatively large size and round ice crystals. The ice recrystallization characteristics and cryprotective effect of ${\kappa}$-carrageenan changed through the addition of different concentrations of whey protein isolate. It seems that the conformational changes induced interactions between whey protein isolate and ${\kappa}$-carrageenan affected ice recrystallization.

• Food Science and Biotechnology
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• v.15 no.5
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• pp.756-762
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• 2006

Freeze concentration of milk was carried out through the controlled recrystallization of ice in a multi-stage freeze concentrator. Rheological characteristics of ice slurries were analyzed to determine efficient concentration levels for the freeze concentration process. It was determined that efficient concentration level was 17% of total solids in the first and 27% in the second stage. Physicochemical properties were compared between freeze concentrated and evaporated milk. Freeze concentrated milk was more similar in color appearance to control milk than was evaporated milk. pH significantly decreased in evaporated milk than in freeze concentrated milk. pH of freeze concentrated milk resulted in similar value to control. These results indicated the advantages of freeze concentration as a non-thermal milk processing technology in terms of physicochemical properties. Consequently, we investigated the influence of ice recrystallization on the rheological characteristics of ice slurries and physicochemical properties of freeze concentrated milk.

• Fisheries and Aquatic Sciences
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• v.18 no.2
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• pp.137-142
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• 2015

Antifreeze proteins and glycoproteins [AF(G)Ps] constitute a group of proteins that lower the freezing but not the melting points of aqueous solutions, enabling polar and north-temperate fish to survive in ice-laden environments. However, little is known about antifreeze activity in temperate fish; such work would extend our knowledge on the functions and evolution of AF(G)Ps. In the present study, we screened for antifreeze activity in temperate fish caught off the coast of Jumunjin ($37.89^{\circ}N$), Gangneung, Korea. Thermal hysteresis (TH) and the ability to inhibit ice recrystallization (IR) in blood, liver, and muscle samples from nine fish were examined to assess antifreeze activity. As the East Sea off the coast of Jumunjin is ice-free year round, we thought it most unlikely that the fish would express antifreeze proteins. Surprisingly, the blood of Pleurogrammus azonus and three types of tissue from Gymnocanthus herzensteini, Zoarces gilli and Kareius bicoloratus exhibited measurable TH values together with the ability to trigger characteristic morphological changes in ice crystals. Blood samples from the three species also evidenced ice recrystallization (IR) inhibition. This implies that AF(G)Ps or other antifreeze-like substances are present in temperate fish even under nonfreezing conditions. These results contribute to our understanding of the functions and origins of antifreeze activity in fish.

• Bulletin of the Korean Chemical Society
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• v.33 no.12
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• pp.3931-3932
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• 2012

• Journal of Microbiology and Biotechnology
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• v.25 no.12
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• pp.1989-1996
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• 2015

Ice-binding proteins (IBPs) can inhibit ice recrystallization (IR), a major cause of cell death during cryopreservation. IBPs are hypothesized to improve cell viability after cryopreservation by alleviating the cryoinjury caused by IR. In our previous studies, we showed that supplementation of the freezing medium with the recombinant IBP of the Arctic yeast Glaciozyma sp. (designated as LeIBP) could reduce post-thaw hemolysis of human red blood cells and increase the survival of cryopreserved diatoms. Here, we showed that LeIBP could improve the viability of cryopreserved mammalian cells. Human cervical cancer cells (HeLa), mouse fibroblasts (NIH/3T3), human preosteoblasts (MC3T3-E1), Chinese hamster ovary cells (CHO-K1), and human keratinocytes (HaCaT) were evaluated. These mammalian cells were frozen in dimethyl sulfoxide (DMSO)/fetal bovine serum (FBS) solution with or without 0.1 mg/ml LeIBP at a cooling rate of -1℃/min in a -80℃ freezer overnight. The minimum effective concentration (0.1 mg/ml) of LeIBP was determined, based on the viability of HeLa cells after treatment with LeIBP during cryopreservation and the IR inhibition assay results. The post-thaw viability of mammalian cells was examined. In all cases, cell viability was significantly enhanced by more than 10% by LeIBP supplementation in 5% DMSO/5% FBS: viability increased by 20% for HeLa cells, 28% for NIH/3T3 cells, 21% for MC3T3-E1, 10% for CHO-K1, and 20% for HaCaT. Furthermore, addition of LeIBP reduced the concentrations of toxic DMSO and FBS down to 5%. Therefore, we demonstrated that LeIBP can increase the viability of cryopreserved mammalian cells by inhibiting IR.

• Bulletin of the Korean Chemical Society
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• v.33 no.11
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• pp.3565-3570
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• 2012

Until now, few groups reported the antifreeze activity of cyclic glycopeptides; however, the tedious synthetic procedure is not amenable to study the intensive structure activity relationship. A series of N-linked cyclic glycopeptoids and glycopeptide have been prepared to evaluate antifreeze activity as a function of peptide backbone cyclization and methyl stereochemical effect on the rigid Thr position. This study has combined the cyclization protocol with solid phase peptide synthesis and obtained significant quantities of homogeneous cyclic glycopeptide and glycopeptoids. Analysis of antifreeze activity revealed that our cyclic peptide demonstrated RI activity while cyclic glycopeptoids showed no RI activity. These results suggest that the subtle changes in conformation and Thr orientation dramatically influence RI activity of N-linked glycopeptoids.

• Journal of Applied Biological Chemistry
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• v.58 no.4
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• pp.325-332
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• 2015

Rapeseed (Brassica napus) is now the second largest oilseed crop after soybean. Cold temperature tolerance is an important agronomic trait in winter rapeseed that determines the plant's ability to control below freezing temperatures. To improve cold tolerance of rapeseed plants, an expression vector containing an Barley Ice recrystallization inhibition protein (HvIRIP) cDNA driven by a cauliflower mosaic virus 35S promoter was transferred into rapeseed plants. Transgenic expression of HvIRIP was proved by southern- and northern-blot analyses. The level of freezing tolerance of transgenic $T_3$ plants was found to be significantly greater than that of wild-type rapeseed plants by freezing assay. Proline accumulation during cold stress was also highly induced in the transgenic rapeseed plants. The transgenic plants exhibited considerable tolerance against oxidative damage induced by cold stress. Our results indicated that heterologous HvIRIP expression in transgenic rapeseed plants may induce several oxidative-stress responsive genes to protect from cold stress.

• Korean Journal of Food Science and Technology
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• v.29 no.5
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• pp.939-946
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• 1997

Effects of moisture content on the gelatinization and recrystallization of non-waxy and waxy rice starch gels were investigated by differential scanning calorimetry (DSC). The recrystallization rates of the starch gels containing various moisture contents $(40{\sim}70%)$ were analyzed by Avrami equation. The waxy rice starch had higher gelatinization temperature and enthalpy than non-waxy one. The highest degrees of recrystallization in both rice starch gels stored at $4^{\circ}C$ were shown at 40%, and recrystallizations above 80% moisture content were not found. The degree of recrystallization of waxy one was higher than that of non-waxy one in the range of 40 to 60% moisture content. The Avrami exponents (n) of both rice starch gels were near to 1.0 and the time constant (1/k) was increased with increasing moisture content in the range of 40 to 70% moisture content. The recrystallization rate of waxy rice starch gel was slower than that of non-waxy one. The recrystallization of rice starch gels could be explained by the change of ice melting enthalpy during storage. The Wg's, represented the maximum practical amount of plasticizing water, were about 29.9% and 28.2% for non-waxy and waxy rice starch gels, respectively.