• Title/Summary/Keyword: degree of retrogradation

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Gelatinization and Retrogradation Properties of Modified Starch by Steeping Sweet Potato (고구마 수침에 의한 변성 전분의 호화와 노화 특성)

  • Lee, Shin-Kyung;Shin, Mal-Shick
    • Korean Journal of Food Science and Technology
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    • v.26 no.5
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    • pp.638-643
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    • 1994
  • Gelatinization and retrogradation properties of modified starches which were prepared by steeping sweet potato at $40^{\circ}C$ for 2, 4, 7 and 10 days were investigated. The peak temperature of gelatinization and enthalpy of untreated starch by DSC were $53.9^{\circ}C\;and\;1.32\;cal/g$, respectively, but those of modified starch were increased by steeping. In gelatinization by alkali, starches with 2, 4 and 7 day steeping showed higher viscosities than untreated starch, whereas the viscosities of starches with 10 day steeping decreased. The clarities in paste decreased during storage in all starches and decreased in starches with steeping. The degrees of retrogradation by ${\alpha}-amylase-iodine$ method were higher in starches with steeping than untreated starch. The enthalpy of retrograded starches by DSC increased by steeping except 4 day steeping starch. The sweet potato extract containing sugar inhibited the retrogradation of starch paste and the degree were higher in residual starches than in untreated starch.

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Retrogradaion of Rice Flour Gels with Different Storage Temperature (저장온도에 따른 쌀가루 겔의 노화)

  • Kim, Jeong-Ok;Shin, Mal-Shick
    • Applied Biological Chemistry
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    • v.39 no.1
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    • pp.44-48
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    • 1996
  • Effects of storage temperature on the retrogradation of 50% nonwaxy rice flour gels stored at $20^{\circ}C,\;4^{\circ}C\;and\;-18^{\circ}C$ for 6 days were investigated by ${\alpha}-amylase-iodine$ method, differential scanning calorimetry(DSC) and x-ray diffractometry. The retrogradation of gels increased with increasing storage time and the initial retrogradation rate was higher. The degree of retrogradation gels stored at different temperature increased as following order, $-18^{\circ}C>20^{\circ}C>4^{\circ}C$. The enthalpy of retrograded rice flour by DSC showed similar as the degree of retrogradation by ${\alpha}-amylase-iodine$ method, but the differences between storage temperatures were clear in using ${\alpha}-amylase-iodine$ method. X-ray diffraction patterns of gels stored at $4^{\circ}C\;and\;20^{\circ}C$ showed small peaks at $2{\theta}=17^{\circ}\;and\;20^{\circ}$, but the difference was not detected.

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Effects of Emulsifier and Enzyme on the Quality Characteristics or Seolgiddeok during Storage (유화제와 효소 첨가가 설기떡의 저장 중 품질특성에 미치는 영향)

  • 최미용;조정순;장윤희
    • Journal of the East Asian Society of Dietary Life
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    • v.13 no.3
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    • pp.197-215
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    • 2003
  • This study was carried out to investigate the effects of added emulsifier and enzyme on the quality characteristics of Seolgiddeok with black rice powder, green tea powder, Lentines edodes powder, pumpkin powder during storage. Samlpes were divided into two groups, the emulsifier-enzyme added group and the control, and stored fur 4 days at 2$0^{\circ}C$. Moisture content was measured by the air oven method; the Hunter's cole. values by Lightness (L), redness (a), yellowness (b) value; the degree of gelatinization by the enzyme digestion method, and expressed as glucose content by Somogi-Nelson method. The degree of retrogradation was calculated as the retrogradation rate using the degree of gelatinization value, and total cell and mold counts were also measured. Texture and sensory characteristics were also investigated. The results are as follows: The emulsifier-enzyme group was significantly different from the control from each examination and the retrogradation of pumpkin Seolgiddeok with emulsifier-enzyme was delayed the most among samples tested.

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Relationship between Molecular Structure of Acid-Hydrolyzed Rich Starch and Retrogradation (산처리 쌀전분의 분자구조와 노화속도)

  • Kang, Kil-Jin;Kim, Kwan;Lee, Sang-Kyu;Kim, Sung-Kon
    • Korean Journal of Food Science and Technology
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    • v.29 no.5
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    • pp.876-881
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    • 1997
  • The relationship between the molecular structure of acid-hydrolyzed rice starch and the retrogradation rate of starch gel was investigated. The molecular structure of starch was modified by acid hydrolysis with 1 N HCl at $35^{\circ}C$. The molecular weight of starch decreased as acid hydrolysis time was increased. At the early stage of hydrolysis up to 3 hr, the branching point of amylopectin was degraded and thereafter both ${\alpha}-1,4\;and\;{\alpha}-1,6$ linkages were hydrolyzed. The starch gel (50%) stored at $20^{\circ}C$ revealed that the rapid retrogradation occurred during 4 hr of storage which was more pronounced as the hydrolysis time increased. The degree of retrogradation of starch gels after 4 hr storage showed a linear relationship with the yield of hydrolyzate. These results suggested that the retrogradation of starch gel was accelerated by degradation of ${\alpha}-1,6$ linkages with acid.

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Suppression Effect of Maltitol on Retrogradation of Korean Rice Cake (Karedduk) (Maltitol 첨가와 가래떡의 노화억제)

  • 박정욱;박현정;송재철
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.32 no.2
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    • pp.175-180
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    • 2003
  • Effect of the addition of maltitol to Korean rice cake (Karedduk) on its retrogradation was examined. Degree of retrogradation was also examined in terms of recrystallinity of starch and color change with a differential scanning calorimeter. As a result, retrogradation was suppressed by the increasing addition of maltitol. In particular, enthalpy showed a tendency to decrease at $25^{\circ}C$ rather than at 4$^{\circ}C$ during 4 days. In the gelatinization properties using DSC, onset temperature (To) was shown to increase slightly according to storage time. Maximum peak temperature (Tp) was shown to decrease by the addition of maltitol during 4 days. Melting enthalpy was decreased at $25^{\circ}C$ and 4$^{\circ}C$ by the addition of maltitol. The analysis X-ray diffraction also revealed that retrogradation of the Korean rice cake was suppressed by the addition of maltitol because crystalline region did not appear. The addition of maltitol into the Korean rice cake was found to result in an increase of its qualify or color stability.

Influence of Water and Surfactants on Wheat Starch Gelatinization and Retrogradation (수분과 계면활성제가 밀전분의 호화와 노화에 미치는 영향)

  • Shin, Mal-Shick
    • Korean Journal of Food Science and Technology
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    • v.23 no.1
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    • pp.116-121
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    • 1991
  • The effects of water contents and surfactants, sodium stearoyl-lactylate, sucrose ester and distilled monoglyceride(Dimodan) on wheat starch gelatinization and retrogradation were studied by differential scanning calorimetry. The endothermic peak patterns of starch varied with water content of starch. When water content was less than 30%, gelatinization did not occur. The onset temperature of gelatinization peak of native starch was $59{\sim}60^{\circ}C$ and that of endothermal peak of retrograded starch was $50{\sim}55^{\circ}C$. The enthalpy value of retrograded starch were greatest in the $40{\sim}50%$ water content. In the presence of surfactants, gelatinization temperatures shifted slightly to higher temperatures. DSC endothermal enthalpies of the amylose-lipid complex increased. The degree of retrogradation in starch was lower with surfactant than without surfactant, but enthalpy of amylose-lipid complex did not change during storage.

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Effects of Freezing Rate and Storage Temperature on the Degree of Retrogradation, Texture and Microstructure of Cooked Rice (동결속도 및 저장온도가 취반된 쌀의 노화도, 조직감 및 미세구조에 미치는 영향)

  • Choi, Sung-Gil;Rhee, Chul
    • Korean Journal of Food Science and Technology
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    • v.27 no.5
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    • pp.783-788
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    • 1995
  • Cooked rices were frozen at four different rates(3, 5, 7 and 12 hr) of maximum ice crystal formation zone and stored at $-20^{\circ}C\;and\;-70^{\circ}C$ for 3 months. Freezing rate, storage temperature and storage period all affected the degree of retrogradation of cooked rice. As the maximum ice crystal formation zone increased from 3 hrs to 12 hrs, the degree of retrogradation of cooked rice increased from 14.9% to 40.0%. Further retrogradation occurred during the freezing storage and cooked rice stored at $-20^{\circ}C$ retrograded faster than that held at $-70^{\circ}C$. The hardness and adhesiveness of frozen cooked rice thawed in $40^{\circ}C$ water were measured. Hardness of the frozen cooked rice was higher than that of non-frozen sample and was higher at lower freezing rate. However, the hardness of cooked rice decreased after 3 months of storage. On the other hand, the adhesiveness decreased during the freezing processing, and adhesiveness decreased more rapidly at a higher freezing rate. However, the adhesiveness of cooked rice increased after 3 months of the storage, and the level of decrease was higher at $-70^{\circ}C$ than at $-20^{\circ}C$. After 3 months of storage, ice crystal size of frozen cooked rice became larger by recrystalization than that of frozen sample prior to storage. Microstructure of cooked rice was damaged by ice crystal formation and its growth when observed by scanning electron microscope.

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Retrogradation of Rice Starch Gels by Additives (첨가물이 쌀전분겔의 노화에 미치는 영향)

  • Song, Ji-Young;Kim, Jeong-Ok;Kim, Sung-Kon;Kim, Kwang-Joong;Shin, Mal-Shick
    • Applied Biological Chemistry
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    • v.40 no.4
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    • pp.289-293
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    • 1997
  • The effects of different types of additives(sucrose fatty acid ester(SE), oligosaccharide and alum) on 40% nonwaxy rice starch gels stored at $20{\pm}1^{\circ}C$ were investigated by ${\alpha}-amylase-iodine$ method, X-ray diffractometry and differential scanning calorimetry. The addition of SE retarded the retrogradation of gels throughout storage period and the antistaling effect of SE was increased with increasing concentration. Oligosaccharide(0.1%) inhibited the retrogradation, but oligosaccharide(0.1% or 0.5%) retarded the retrogradation at early stage of storage, and stimulated the retrogradation after 3 days. Alum of 0.1% level retarded the retrogradation, but 0.3% level activated the retrogradation after 24 hours and 0.5% level did after 12 hours. The effect of additives on the retrogradation of rice starch gels showed the different tendencies at the level of additives. On 0.1% level, the effect of those was similar but on 0.5%, the degree of retardation increased in order of oligosaccharide, SE1170, alum, no addition for up to 2 days of storage and SE1170, no addition, oligosaccharide, alum for 3 days of storage.

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Effect of Surfactants on the Characteristics of Cooked Rice During Storage (계면활성제가 저장 중의 밥의 특성에 미치는 영향)

  • 김수경;이신경;신말식
    • Korean journal of food and cookery science
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    • v.13 no.3
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    • pp.278-285
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    • 1997
  • The effects of three surfactants (SSL, Dimodan, and SE1670) on the properties of cooked nonwaxy and waxy rice during storage were investigated by sensory evaluation, instrumental test, and measurement of retrogradation degree. The results of sensory evaluation revealed that the overall quality of cooked rice was affected by textural characteristics. The addition of surfactant decreased the roughness and hardness of cooked rice, however, increased the stickiness and moistness during the storage in the order of SE, SSL, and Dimodan. In instron test, the hardness of surfactant-added cooked rice was significant lower than that of control. The addition of surfactant decreased the degree of retrogradation both in cooked nonwaxy and waxy rices.

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Effect of Added Trehalose and Enzymes on the Qualities of Backsulgie (트레할로스 및 효소제 첨가가 백설기 품질에 미치는 영향)

  • Oh, Moon-Hun;Shin, Hyung-Chan;Park, Jong-Dae;Lee, Hyun-Yu;Kim, Keun-Sung;Kum, Jun-Seok
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.39 no.7
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    • pp.992-998
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    • 2010
  • This study investigated changes of quality during storage period with 6 types of Backsulgie manufactured by adding enzyme (BS-300 0.3%) and trehalose (3%, 6%) to minimize the changes of quality and tried to determine their optimal combination ratio. When Rapid Visco Analyzer (RVA) gelatinization properties of rice powder were examined, adding both of enzyme and trehalose to the powder increased stability of process and reduced retrogradation. In comparison of the degree of retrogradation of Backsulgie by using Differential Scanning Calorimetry (DSC), the sample with enzymes and trehalose suppressed retrogradation. Moreover, the retrogradation effect became larger by using both of enzyme and trehalose and it was the largest in the sample with 0.3% enzyme and 6% trehalose. Enzyme and trehalose added to Backsulgie were found to improve water retention, to minimize changes of texture and color during storage of Backsulgie. Therefore, optimal combination ratio of Backsulgie is 0.3% enzyme with 6% trehalose added Backsulgie.