• Korean journal of food and cookery science
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• v.18 no.2
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• pp.157-163
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• 2002

The gelatinization and retrogradation properties of rice starch added with dietary fibers from sikhe were investigated. The pasting temperature and setback of starch measured by using a rapid visco analyzer were increased by the addition of the fiber, whereas the peak viscosity, trough viscosity, end viscosity, breakdown and consistency were lowered. The onset temperature of starch measured by a DSC was increased, but the enthalpy of gelatinization of the starch was decreased as the addition of fiber increased. The melting peak temperature of the retrograded starch gels was 41∼46$\^{C}$ as measured by a DSC. The melting enthalpy of the control retrograded starch gel was increased while storing for 1, 3 and 7 days at 4$\^{C}$, but that of containing sikhe fiber showed no differences.

• Journal of the Korean Society of Food Culture
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• v.24 no.2
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• pp.191-198
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• 2009

The objective of this study was to investigate the effects of different amounts of pumpkin powder on the quality characteristics of hobakpyeon using physicochemical and sensory properties, as well as on its retrogradation rate during storage. As the amount of pumpkin powder increased, the following effects on the quality characteristics were observed: moisture and amylose contents decreased while protein content increased (p<0.05), and in vitro protein digestibility (IVPD) decreased (p<0.05). Levels of slowly digestible starch and resistant starch fractions increased, while the content of rapidly digestible starch decreased. The starch digestion index and rapidly available glucose content also decreased. Among the physical properties, the L-value decreased while the b-value increased (p<0.05). Texture profile analysis revealed that all textural properties except adhesiveness decreased, and presented significant differences in hardness and chewiness (p<0.05). Sensory properties such as color, flavor, and sweetness increased while others such as wetness and chewiness decreased (p<0.05). Effects on the physicochemical properties during refrigerated storage were also compared between the control and 9% hobakpyeon (9%HP). According to the results, moisture content gradually decreased in the 9%HP compared to the control. Amylose content significantly increased in 9%HP whereas no significant changes were observed in the control. In both types of hobakpyeon, IVSD decreased significantly, showing higher values in 9%HP, whereas mechanical hardness increased, showing lower values in 9%HP. The L-value decreased significantly in the 9%HP whereas no significant changes were observed in the control. In conclusion, the above results suggest that hobakpyeon with low IVSD may be obtained by the addition of 9% pumpkin powder, and also showed that pumpkin powder delayed the rate of retrogradation in 9%HP during storage.

• The Korean Journal of Food And Nutrition
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• v.20 no.4
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• pp.427-432
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• 2007

The texture and descriptive sensory characteristics of a Korean rice cake(Karedduk) with added emulsifier were investigated after 2 and 24 hrs of storage at $5^{\circ}C$. The emulsifier, SP, was added at 0, 0.1, 0.5 and 1% levels to the dry rice flour. In the amylogram, the peak viscosity(P), hot paste viscosity(H) and cold paste viscosity(C) of the rice flour with added emulsifier were higher than those of the control. The texture property analysis by a Texture Analyzer revealed that the springiness, cohesiveness and adhesiveness of the Korean rice cake(Karedduk) with added emulsifier were similar to those of the control, while chewiness, gumminess and hardness were lower compared to the control. Also, the hardness by sensory characteristics was significantly different as compared to the control. Lastly, adding emulsifier to the Korean rice cake(Karedduk) was effective at retarding retrogradation.

• The Korean Journal of Food And Nutrition
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• v.20 no.2
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• pp.185-194
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• 2007

This study was performed to evaluate the physicochemical, sensory evaluation of Backsulgi changed with germinated brown rice flour(GBRF) at different ratio. Moisture content decreased gently during storage and the decrease was less in GBRF-added groups than the control group. The color L value decreased significantly by with increasing the GBRF, wherease the redness(a) and yellowness(b) were both increased. As the result of measurement with texture analyzer, hardness, gumminess, chewiness, adhesiveness and fracturability of Backsulgi tended to decrease in proportion to the amount of GBRF in the formula. The thermal properties of Backsulgi were investigated by differential scanning calorimetry(DSC). Onset temperature and peak temperature of gelatinizatino in thermal characteristics showed low in case of addition of GBRF into Backsulgi. All samples changed with GBRF had low values in change of melting enthalphy. In the sensory evaluation, Backsulgi with GBRF were superior in flavor, cohesiveness, hardness, chewiness and moistureness than that of control. And Backsulgi with 20% GBRF showed the highest score in overall acceptability. Therefore we concluded that the addition of GBRF on Backsulgi improve the sensory characteristics as well as delay the retrogradation.

• Korean Journal of Food Science and Technology
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• v.31 no.5
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• pp.1254-1261
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• 1999

The influence of addition of arrow(Pueraria hirsuta Matsum) root flour and its fractions by ultrafiltration on the flow properties of the rice flour-water systems were investigated. The flow properties of rice flour pastes during cold storage$(5^{\circ}C)$ were measured and the components from arrow root flour responsible for changes of flow properties were screened. Addition of arrow root flour significantly changed the flow properties of rice flour pastes. Permeate fractions by ultrafiltration, representing low molecular weight component fraction, significantly affected the flow property of rice flour paste stored at $5^{\circ}C$. Addition of permeate fraction to rice flour pastes rapidly decreased the consistency index, yield stress and pseudoplasticity, and showed a stability of flow property during storage suggesting the retardation of rice starch retrogradation. Permeate fractions of ultrafiltration were identified as puerarin, daidzein and daidzin known to representive isoflavonoid from arrow root.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.10
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• pp.1517-1524
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• 2015

The purpose of this study was to determine the storage characteristics of Sulgidduk, a kind of rice cake, added with Portulaca oleracea L. The effect of P. oleracea L. paste (0, 1, 3, or 5%) on the storage qualities of Sulgidduk was evaluated during storage period at $20{\pm}2^{\circ}C$ for 3 days. As the amount of P. oleracea L. paste increased, loss of water in P. oleracea L. Sulgidduk decreased. Textural properties by texture profile analysis showed that hardness of Sulgidduk added with 5% P. oleracea L. paste was the lowest among treated samples. However, the hardness of all Sulgidduks increased during storage, regardless of the addition amount of P. oleracea L. paste. In accordance with the texture results, differential scanning calorimetry exhibited that the enthalpy of Sulgidduk with 5% P. oleracea L. addition was the lowest, indicating the delaying effect of P. oleracea L. paste on retrogradation of rice cake. From these results, the addition of P. oleracea L. to Sulgidduk extended shelf-life by delaying retrogradation.

• Food Engineering Progress
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• v.14 no.3
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• pp.235-242
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• 2010

This study was to investigate the combined effect of enzyme and trehalose addition on the retrogradation rate and quality changes in a Korean traditional rice cake, Backsulgi. As for the enzyme, a commercial maltogenic amylase, Novamyl, was used. From texture profile analysis and sensory tests, the optimum enzyme content for the preparation of Backsulgi was determined to be 0.1%. Backsulgi was prepared with the fixed content of Novamyl (0.1%) and different ratios (5, 10, 15%) of trehalose, and physicochemical and sensory properties were examined for 3 days of storage at ${25^{\circ}C}$. As trehalose content increased, the water activity of Backsulgi decreased. In Hunter's color value, L- and a-values of trehalose-added samples were significantly lower than those of control. In texture profile analysis, hardness of Backsulgi decreased with trehalose content. During storage, a increase in hardness and a decrease in cohesiveness were typically observed for all samples. However, those changes were significantly reduced with trehalose content. The retardation of retrogradation with the enzyme and trehalose addition was confirmed using calculated Avrami rate and time constants. These results revealed that combined treatments of 0.1% Novamyl and 10% trehalose could produce Backsulgi of better sensory quality with retarded retrogradation compared to separated treatment.

• Korean Journal of Food Science and Technology
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• v.45 no.4
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• pp.460-465
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• 2013

Garaedduk made with various levels of buckwheat flour (0, 15, 30, and 45%) for rice flour was prepared using retrogradation-retardation technology and their physical and sensory properties were investigated. The moisture content of garaedduk decreased and the color differences increased as the ratio of buckwheat flour to rice flour increased. During storage at $4^{\circ}C$, the hardness values of garaedduk made with 15 and 30% buckwheat flour were maintained for up to three days. Immediately after manufacture, garaedduk made with higher levels of buckwheat flour had reduced overall acceptability. However, there was no significant difference in the overall acceptability of garaedduk made with 0 and 15% of buckwheat flour after storage. Therefore, buckwheat flour can replace rice flour with retrogradation-retardation technology to inhibit the starch retrogradation of garaedduk, which maintained its overall quality at a buckwheat flour level of 15%.

• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.4
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• pp.573-579
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• 2010

This study investigated starch properties of 'Daehak waxy corn (DWC)' with different harvest times. The DWCs were harvested at 4 days before suitable time (BST), suitable time (ST) and 4 days after suitable time (AST). As harvest time was delayed, starch yield and amylopectin content of DWC starch increased from 43.21 to 52.73%, and from 90.79 to 92.83% based on dry weight, respectively. As harvest time was postponed, enzymatic digestibility and water solubility of DWC starch decreased from 81.43 to 80.58%, and from 10.23 to 9.23%. However, water binding capacity and swelling power of DWC starch increased from 227.94 to 244.88%, and from 24.75 to 29.74%, respectively. Retrogradation viscosity of starch was the lowest in DWC harvested at AST. There was a high correlation coefficient among starch properties of DWC, such as starch yield, enzymatic digestibility, water binding capacity, swelling power, water solubility and retrogradation viscosity (p<0.01). As harvest time was deferred, enzymatic digestibility, water solubility and retrogradation viscosity decreased; however, amylopectin content increased, and water binding capacity and swelling power significantly increased with increasing amylopectin content.

• Korean Journal of Food Science and Technology
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• v.20 no.3
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• pp.331-337
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• 1988

The thermal properties of typical five Indica and five Japonica rice varieties were investigated by Differential Scanning Calorimetry (DSC). There was no significant difference in gelatinization temperature between Indica and Japonica varieties, but the average enthalpy of gelatinization was larger in Indica types than that in Japonica. However, the enthalpy of melting of amylose-lipid complex was larger in Japonica types than that in Indica types. The DSC thermogram of hydrolyzed rice residue included a smaller peak of gelatinization with narrow range of temperature. Retrogradation of gelatinized rice kernel was also determined with DSC theremograms. The endothermic peak areas clearly increased with increasing storage time at $4^{\circ}C$ so that the area could be used as a measure of the relative degree of retrogradation. The results indicated that Samgang variety(Indica) retrograded more rapidly than Chuncheong variety(Japonica).