• Korean Journal of Food Science and Technology
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• v.20 no.1
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• pp.13-18
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• 1988

Retrogradation characteristics of 1% dilute rice starch dispersion were analyzed. The retrogradation was increased with prolonged storage, however, the trend in increase was more conspicuous during the initial phase of retrogradation period. The Avrami exponent, rate constant, and time constant of 1% dilute Chuchong starch dispersion were 0.96, 0.21 $days^{-1}$, and 4.77 days, respectively As the Avrami exponent approaches unity (n=1), it is confirmed that the dilute rice starch dispersion retrogrades following the formation of a rod-like growth of crystals from instantaneous nuclei. When the retrogradation process of dilute rice starch dispersion was traced, the three-dimensional structure of crystals which had different contour from native stach was formed.

• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.10
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• pp.1320-1325
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• 2007

Retarding retrogradation of a Korean rice cake (Karedduk) added with carbohydrate materials after $0{\sim}30hrs$ of storage at $5^{\circ}C$ were investigated by Avrami equation using textural characteristics. Carbohydrate materials such as powdered sugar, trehalose, fructooligosaccharide (95%), isomalto, healtholigo, and galactooligo-saccharide (50%) were added in 0, 1, 5 or 10% levels on dry rice flour. In the amylogram, the breakdown (P-H) and consistency (C-H) for Karedduk added with carbohydrate materials were lower than those of the control. Decrease in the Avrami exponent (n) and increase in the time constant (1/k) of Karedduuk added with carbohydrate materials during storage determined by Avrami equation were important comparison factors to the control in terms of retrogradation rate analysis. The Aurami exponent (n) for control, fructooligosaccharide (95%) 10% and healtholigo 1% addition were 2.415, 1.977 and 3.297, respectively. The time constant (1/k) for fructooligosaccharide (95%) 5% and healtholigo 1% addition were lower than thecontrol. Lastly, Karedduk added with carbohydrate materials, except for fructooligosaccharide (95%) 5% and healtholigo 1% addition, was effective in retarding retrogradation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.7 no.4
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• pp.559-566
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• 2006

The isothermal crystallization behavior of blends of poly(ethylene terephthalate) and liquid crystalline polymers(LCP) was studied. The Avrami analyses were applied to obtain the information on the crystal growth geometry and factors controlling the rate of crystallization. The crystallization kinetics for the blends followed the classical Avrami equation up to a high degree of crystallization regardless of crystallization temperature, The values of Avrami exponent, n, for PET in the blends were estimated to be around 2, which indicate that the polymer crystals grow into one-dimensional linear or fiber-like crystallization mode. The crystallization rate, as expected, decreases with increasing the crystallization temperature.

• The Korean Journal of Food And Nutrition
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• v.23 no.1
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• pp.39-44
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• 2010

Retarding retrogradation of Korean rice cakes(Karedduk) with a mixture of trehalose and Sun-Tender added, after 0, 24, and 48 hr of storage at $5^{\circ}C$, was analyzed by Avrami kinetics. A central composite design was used for arrangement of treatment. The two independent variables selected for retarding retrogradation analysis were amounts of trehalose(x) and Sun-Tender(y). Trehalose was added at 0, 3, 6, 9, and 12% levels, and Sun-Tender added at 0, 0.3, 0.6, 0.9, and 1.2% levels, to dry rice flour. The Avrami exponent(n) for the mixtures of 9% trehalose and 0.3% Sun-Tender, and 9% trehalose and 0.9% Sun-Tender were lower than in the control. The time constant(1/k) for the mixture of trehalose and Sun-Tender was higher than in the control. The effect of retarding retrogradation of Korean rice cakes with added mixtures of trehalose and Sun-Tender showed an increasing trend as the amount of trehalose increased. These results suggest that adding a mixture of 9% trehalose and 0.3% Sun-Tender, or 9% trehalose and 0.9% Sun-Tender to Korean rice cakes(Karedduk) is effective for retarding retrogradation.

• The Korean Journal of Food And Nutrition
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• v.17 no.2
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• pp.193-198
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• 2004

This study was carried out to develop the intermediate material for its processing product of sea tangle by investigating softening stability of softened sea tangle for storage. The change of softening stability, Avrami (equation) exponent, color and sensory characteristics was examined during storage when hydrophilic softening agent was added to the softened sea tangle. Inclination of the sample added with isomalto oligosaccharide showed the lowest value in relation of ln(E$\_$L/- Et) vs t for four days of storage. Exponent range of Avrami equation was 1.00-1.67 and isomalto oligosaccharide having 1.0 of exponent exhibited the most stable effect in softerness. The sample formulated with isomalto oligosaccharide indicated the lowest value in rate constant and its rigidity was progressed very slowly during storage. The L, a and b value of softened sea tangle during storage was relatively decreased. Color preference, odor, cohesiveness, softerness, process compatibility were revealed to be in best when isomalto oligosaccharide was added. When softening agent was added to the softened sea tangle it showed the positive result in processing compatibility and the available value in intermediate material for its processing product. It was relatively effective on softening stability when isomalto oligosaccharide was added to the softened sea tangle.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.4
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• pp.533-538
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• 2012

The retrogradation properties of a Korean rice cake ($Karedduk$) added with oligosaccharides after 0~30 hr of storage at $5^{\circ}C$ were examined by texture profile analysis and the Avrami equation using textural characteristics. Oligosaccharides, such as galactooligosaccharide (50%) and maltooligosaccharide, were added to dry rice flour at levels of 10%. In the amylogram, the breakdown (P-H) and consistency (C-H) of the Korean rice cake (Karedduk) added with oligosaccharides were lower than those of the control. Texture profile analysis using a Texture Analyzer revealed that the hardness of the Korean rice cake ($Karedduk$) added with oligosaccharides was lower than the control. The Avrami exponent ($n$) for the control, galactooligosaccharide (50%) 10% and maltooligosaccharide 10% addition was 2.415, 2.771 and 2.683, respectively. The time constant (1/$k$) for galactooligosaccharide (50%) 10% or maltooligosaccharide 10% addition was higher than the control. Overall, adding galactooligosaccharide (50%) 10% or maltooligosaccharide 10% to a Korean rice cake ($Karedduk$) is effective in retarding retrogradation.

• Fibers and Polymers
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• v.1 no.2
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• pp.76-82
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• 2000

A series of random copolyesters having various compositions were synthesized by bulk copolymerization of bishydroxyethyl terephthalate (BHET) with 1,4-cyclohexane dimethanol (CHDM) or dimethyl isophthalate (DMI). CHDM and DMI content was less than 10 wt%. For the synthesized copolyesters, isothermal crystallization rate, melting behavior, and equilibrium temperature were investigated by calorimetry and by Avrami and Hoffman-Weeks equation. Crystalline lattice and morphology were studied by WAXD and SEM. Regardless of the composition, the value of the Avrami exponent was about 3, which indicates that crystallization mechanism of the copolyester was similar to those of PET homopolymer. Incoporation of CHDM or DMI units in PET backbone decreased the crystallization rate of the copolyesters. Surface free energy of copolyesters was evaluated using the newly proposed equation. The value of surface free energy was about 189$\times$$10^{-6}$/$J^{2}$/$m^{4}$ regardless of comonomer contents. This result is in good agreement with that of PET homopolymer.

• Polymer(Korea)
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• v.36 no.2
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• pp.245-250
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• 2012

Branched polypropylenes (PP) with long chain branch were prepared by solid state reaction with three different branching agent of 0.3 wt% content. The chemical structures, non-isothermal crystallization behavior and complex viscosity of the branched PP were investigated by FTIR, DSC, optical microscope, and dynamic rheological measurement. The chemical structure of the branched PP was confirmed by the existence of =C-H stretching peak of the branching agent at 3100 $cm^{-1}$. There was no distinct change in melting temperature in case of PP-D-0-3 and PP-F-0-3, but PP-H-0-3 indicated a decrease in melting temperature. The decrease in melting temperature was interpreted by the fact that the degradation reaction of PP was more dominant than branched reaction, and confirmed by a decrease in complex viscosity. The non-isothermal crystallization behavior of the branched PP was analyzed using by Avrami equation. The Avrami exponent of PP was 3, and the values of the branched PP with DVB and FS were below 3. The activation energy of PP calculated by Kissinger method was 25 kJ/mol, and there were no big difference in activation energies of the branched PPs compared to PP.

• Culinary science and hospitality research
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• v.22 no.3
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• pp.11-21
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• 2016

This study investigated the quality characteristics and retarding retrogradation of sponge cakes made with red yeast rice (RYR) flour. RYR (Monascus nuruk) is known to help digestion, smooth blood flow, and have anti-cancer, anti-microbial, and inhibitory effects against biosynthesis of cholesterol and blood pressure. This studys aim' was to find the optimal proportion of RYR flour in sponge cake. RYR sponge cakes were prepared with various levels (0, 5, 10, 15 and 20%) replacement of wheat flour and were designated as the control (without RYR), RYR5, RYR10, RYR15 and RYR20 respectively. Specific gravity was the lowest in RYR15 at 0.57, and the baking loss rate was not significantly different among the samples (p<0.05). The dough yield was the highest in RYR15 at 96.61. The moisture contents was highest in order, control, RYR5, and RYR15 at 28.67%, 28.18%, and 26.82% respectively. The L-value of crust tended to increase according to the level of RYR, but the L-value of crumb decreased in accorddance with the the content of RYR. The a-value of crust also decreased according to the level of RYR, although the a-value of crumb increased in response to higher levels of RYR. The b-value tended to decrease with increases of RYR (p<0.05). RYR5 exhibited the highest pH at 8.63, compared with RYR15 (8.57). The hardness, which was measured after cooling for 1 hour, was the lowest in RYR15 at $163.33g/cm^2$ and the springiness was not different significantly (p<0.05). Cohesiveness was the highest in RYR10 at 133.06%. The chewiness was the highest in RYR10 at $391.63g{\cdot}cm$ and lowest in RYR15 ast $169.62g{\cdot}cm$. Avrami equation showed that RYR15 and RYR20 had the lowest Avrami exponent (n) at 0.0664 and 0.4983 respectively. Time constant (1/k) was the highest in RYR15 at 200.00. Sensory evaluation revealed that RYR15 was the highest in color (5.50), flavor (4.95), sweetness (4.90), chewiness (4.75), and overall acceptability (4.60).

• Korean Journal of Food Science and Technology
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• v.38 no.6
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• pp.838-842
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• 2006

Gum was added to Jeungpyun (steamed Korean rice cake) to extend the shelf life and prevent retrogradation. The hardness of Jeungpyun was analyzed and the type of retrogradation was calculated by the Avrami equation. Guar gum, xanthan gum and pullulan were added to the steamed Korean rice cake at contents of 0.05%, 0.1% and 0.5% (w/w). The moisture contents of the steamed Korean rice cake stored at $4^{\circ}C$ remained unchanged over the three days. When the concentration of added gums was less than 0.1 %, the hardness was lower than that of the non-added gum. At a gum concentration of 0.5%, the hardness of Jeungpyun with added guar gum and xanthan gum was higher than that of pullulan and non-added Jeungpyun. The types of retrogradation varied according to the amount and the kind of the added gums. The type of retrogradation of pullulan-added rice cake was similar to that of xanthan-added rice cake. The Avrami exponent of pullulan-added and xanthan-added Jeungpyun was 1.4${\sim}$1.49 and 1.25${\sim}$1.43, respectively. As the concentrations of pullulan were increased from 0.05% to 0.5%, the time constant (1/k) increased from 5.37 to 15.65. Pullulan and xanthan gum were confirmed to be more effective than guar gum for preventing the retrogradation of the steamed Korean rice cake known as Jeungpyun.