• Title/Summary/Keyword: Gelatinization

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Physicochemical Factors Affecting Cooking and Eating Qualities of Rice and the Ultrastructural Changes of Rice during Cooking (쌀의 취반 및 식미특성에 영향을 주는 요인들과 취반 시 쌀의 배유 조직의 변화)

  • 이영은;오스만엘리자베쓰엠
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.20 no.6
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    • pp.637-645
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    • 1991
  • Physicochemical factors affecting cooking and eating quality of rice and their mechanisms were investigated. The stickiness of cooked rice was negatively correlated with amylose content(r=0.58, p<0.05) and protein content(r=-0.72, p<0.01), but not affected by crude fat content of rice. The ultrastructure of cooked rice grain showed the progressive gelatinization of starch from the periphery toward the center of the endosperm as water and heat energy diffused into. The rate of water diffusion appears to be dependent on the cell arrangement in the endosperm and the protein content of milled rice. Once water and heat reach the starch granules, the rate of in situ gelatinization of starches appears to be dependent on their own gelatinization temperature range and amylose content. Protein acts as a barrier for the swelling of starch and water diffusion in two ways : 1) by encasing starch granules in the starchy endosperm, and 2) by forming a barrier between the subaleurone layer and the starchy endosperm. Therefore, the separation and fragmentation of the outermost layers of the endosperm occurred more easily in the low-protein content rices, and was associated with increases of solids lost in cooking-water at 95$^{\circ}C$ and stickiness of cooked rice.

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Factors Affecting Gelatinization Temperature of Rice Starch (쌀 전분의 호화온도에 영향을 주는 요인들)

  • 이영은;오스만엘리자베쓰엠
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.20 no.6
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    • pp.646-652
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    • 1991
  • Factors affecting gelatinization temperature of rice starches from different varieties were investigated. Birefringence end-point temperature(BEPT), amylose content, granule size distribution and degree of crystallinity of rice starches showed the significant varietal differences at ${\alpha}\;=0.01$. Susceptibility of the granule to gelatininzation was dependent mainly on the degree of crystallinity, as indicated by the significant positive correlation between BEPT and the relative crystallinity(r=0.67, p<0.01). However, granule size distribution did not affect the GT(gelatinization temperature) range, nor did amylose electron microscopy (SEM). SEM also confirmed that there is no relationship between the size and the shape and the amylose content of the rice starch.

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Comparative Degree of Gelatinization and Retrogradation on Gamkugsulgie with Added of Gamkug (감국 첨가에 의한 감국설기의 호화 및 노화도 비교)

  • 박금순;최미애;임정교
    • Journal of the East Asian Society of Dietary Life
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    • v.10 no.6
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    • pp.514-521
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    • 2000
  • This study was induced to compare retrogradation and gelatinization in sulgie with added powder and flower of gamkug, which had been stored in 4$^{\circ}C$, 1$0^{\circ}C$ and 3$0^{\circ}C$, respectively. The addition of 5% powdered gamkug showed the highest degree of gelatinization while the control did the lowest. The degree of hardness of gamkugsulgie was lower than control and the following order 4$^{\circ}C$>1$0^{\circ}C$>3$0^{\circ}C$. Gamkugsulgie showed a little lower degree of retrogradation than control group. The degree of retrogradation at 4$^{\circ}C$ was far greater comparing with the other group. The degree of retrogradation were delayed as the storing temperature rose tran 4$^{\circ}C$ to 3$0^{\circ}C$, temperature namely, gamkugsulgie retrogradation time constant of the test group was slower 1.18 times at 4$^{\circ}C$. 1.24 times at 1$0^{\circ}C$ and 2.58 times at 3$0^{\circ}C$ than that of the control group.

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Gelatinization Properties of Heat-Moisture Treated Potato and Sweetpotato Starches (수분 열처리한 감자 및 고구마전분의 호화 특성)

  • Kim, Sung-Kon;Lee, Shin-Young;Park, Yong-Kon
    • Korean Journal of Food Science and Technology
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    • v.19 no.5
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    • pp.435-440
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    • 1987
  • Gelatinization properties of heat-mositure treated potato and sweet potato starches were investigated. Water-binding capacity of starch was increased by heat-mositure treatment, which was more pronounced in sweet potato starch. Blue value was not affected by the treatment. Amylograph viscosities were decreased by heat-mositure treatment, which was more pronounced in potato starch. Critical concentration of NaOH for gelatinization of starch increased as moisture level increased. Gel volume of starch upon KSCN gelatinization was higher in potato starch. Gelatinized starches showed Binghamapseudoplastic behavior. Consistency index and yield stress were drastically decreased upon heat-moisture treatment.

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The Influence of the Annealing of Corn Starch on the formation and Characteristics of Enzyme-resistant Starch

  • Yoon, Ji-Young;Lee, Young-Eun
    • Preventive Nutrition and Food Science
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    • v.4 no.4
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    • pp.215-220
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    • 1999
  • The Physical properties of corn starch were investigated by scanning electron microscopy, X-ray diffractometry and differential scanning calorimetry during the formation of enzyme-resistant starch(RS). Samples were studied in their native states and after annealing at 50, 55, 60 and 65℃ in excess water(starch : water=1:3) for 48hr. Starch granules became smaller and more rounded after annealing than in their native state. Annealing did not change the X-ray profile of native corn starch. After autoclaving-cooling cycles, native starch lost most of its crystallinity but annealed ones showed some of their crystallinity left as diffuse or poor B-type, which didn't relate to increasing Rs yields. During formation of RS, however, both native and annealed starches changed their X-ray profile from A-type to poor B-type of retrograded amylose. Annealing caused an increase in gelatinization temperature and enthalpy, but a narrowing of gelatinization temperature range. Only starch annealed at 65℃, however, showed a decrease in enthalpy even though its gelatinization temperature increased, which appeared to be due to the partial gelatinization in the amorphous region during annealing. Peak height index(PHI), the ratio of ΔH to Ti-To, increased by annealing. PHI values, therefore, showed the possibility as an indicator to predict RS yield which cannot be differentiated by differential scanning calorimetry and X-ray diffraction data.

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A study on Reducing Power, Degree of Gelatinization and Retrogradation Rate of Soybean Jeolpyon (콩절편의 소화율, 호화도 및 노화속도)

  • 정해옥
    • Korean journal of food and cookery science
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    • v.12 no.2
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    • pp.162-165
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    • 1996
  • Various kinds of jeolpyon (cubed rice cake) differing in roasted soybean flour. content (0, 5, 10, 15, 20%) were prepared to study digestibility, degree of gelatinization and retrogradation rate. Digestibility slightly in creased as soybean content increased. Degree of gelatinization also increased as soybean content increased. Retrogradation rate obtained from the changes in hardness of soybean jeolpyon with the control was 0.528 day and time constant (1/k) was 1.89 days.

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Rheological Properties of Gelatinization of Rice Starch (쌀 전분 호화중의 리올로지 특성)

  • Lee, Shin-Young;Cho, Hyung-Yong;Kim, Sung-Kon;Lee, Sang-Kyu;Pyun, Yu-Ryang
    • Korean Journal of Food Science and Technology
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    • v.16 no.3
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    • pp.273-278
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    • 1984
  • Changes in rheological properties of rice starch-water systems during the gelatinization were evaluated with the tube viscometer at temperatures between 50 and $85^{\circ}C$ and for the concentrations ranging from 3-5% rice starch. The flow consistency index increased exponentially with time at a particular temperature while being linearly dependent upon the concentration. The gelatinization rate measured by rheological method followed Arrhenius type equation. The value of activation energy of gelatinization for 5% rice starch was about 25 kcal/g mol.

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Physicochemical Properties of Japonica Non-Waxy and Waxy Rice during Kernel Development

  • Kim, Sung-Kon;Jung, Sun-Ok
    • Food Science and Biotechnology
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    • v.15 no.2
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    • pp.289-297
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    • 2006
  • In this study we examined the changes in weight and dimension, protein and amylose contents, and pasting properties of brown rice flour, as well as the gelatinization properties of starch, from two non-waxy japonica cultivars and one waxy japonica cultivar planted in an experimental field in 2002 under the same fertilizer conditions. The weight of both rough and brown rice increased consistently up to 42 days after flowering (DAF) for the non-waxy rice and to 35 DAF for the waxy rice. The changes in dimension of the brown rice kernel indicated that the length was maximized first, followed by breadth and then thickness. The protein content of the non-waxy rice remained fairly constant, but that of the waxy rice decreased by about 1% after 14 DAF. The amylose content of the non-waxy brown rice flour increased, but that of the waxy brown rice flour decreased during kernel development. As the kernel developed, the peak viscosity of the non-waxy rice flour increased up to 35 DAF, after which it decreased, whereas that of the waxy brown rice flour increased consistently. The gelatinization temperature of starch also increased in the waxy rice during kernel development up to 21 DAF. The gelatinization enthalpy of starch, however, increased in all rice cultivars throughout the kernel development.

Characteristics of Dry and Moist Type Sweet Potato Starches (분질 및 점질 고구마 전분의 특성)

  • Shin, Mal-Shick;Ahn, Seung-Yo
    • Korean Journal of Food Science and Technology
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    • v.20 no.3
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    • pp.412-418
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    • 1988
  • Granular shapes and sizes, physicochemical priperties and gelatinization patterns of sweet potato starches from Wonki(the dry type) and Chunmi(the moist type) were investigated. Starch granules of sweet potatoes were round. Granule sizes of Wonki starch were mainly $11{\mu}m$ and those of Chunmi starch were $12{\mu}m\;and\;17{\mu}m$. Wonki starch had lower water binding capacity and swelling power than Chunmi starch. But Wonki starch had higher amylose content, gelatinization temperature, miture content for gelatinization and temperature for gelatinization than Chunmi starch.

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Comparison of Cooking Properties between the Functionally Fortified and Regular Rices using Electric and Pressure Cookers (전기솥과 압력솥을 이용한 기능성 강화쌀과 일반쌀의 취반 특성 연구)

  • Kim, Gee-Yeoun;Lee, In-Seon;L.Kim, Hye-Young
    • Journal of the Korean Society of Food Culture
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    • v.19 no.3
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    • pp.359-368
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    • 2004
  • The Physicochemical, sensory and cooking properties of functionally fortified rice with dietary fiber and chitosan were compared with regular rice when the rices were cooked with pressure and electric cookers. Moisture content of functional rice before cooking was 11.11%, which was lower than 13.72% in regular rice. Accordingly, moisture contents of functional rice samples cooked both with pressure and electric cookers were lower than those of regular rice. L value showing the degree of lightness of cooked rice was significantly higher in rice samples cooked with pressure cookers. The ${\alpha}$ value, the degree of redness and the b value, the degree of yellowness, were the highest in the functional rice cooked with an electric rice cookers. Textural measurement of hardness using a rheometer showed the highest value in functional rice cooked with a pressure cooker. The degree of gelatinization measured using differential scanning calorimetry (DSC) before cooking showed higher onset gelatinization temperature ($T_0$) and peak gelatinization temperature ($T_p$) in functional rice compared with those in regular rice. The gelatinization enthalpy (${\Delta}H$) of functional rice was lower than that of regular rice, showing that functional foe had lower gelatinization energy compared with regular rice. When the samples were stored in a refrigerator for one week, the DSC showed faster retrogradation degrees in samples cooked with electric rice cooker, having significantly higher enthalpies of regular and functional rice cooked with electric cooked compared to those cooked with pressure cookers. The functional rice samples cooked with pressure cooker had higher consumer acceptance test values compared to those cooked with electric cookers.