• Title, Summary, Keyword: gelatinization

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Kinetic Study on the Gelatinization of Barley Starch (보리전분의 호화에 관한 속도론적 연구)

  • Mok, Chul-Kyoon;Lee, Sang-Hyo;Nam, Young-Jung;Min, Byong-Yong
    • Korean Journal of Food Science and Technology
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    • v.17 no.6
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    • pp.409-414
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    • 1985
  • The gelatinization kinetics of barley starch in dilute system (1% w/v concn.) at the temperature range of $60{\sim}95^{\circ}C$ was investigated. The gelatinization rate was extremely temperature dependent. The gelatinization at the temperature above $90^{\circ}C$ was an one step 1st order reaction throughout the gelatinization time, but that below $85^{\circ}C$ consisted of two stages which showed different reaction rates. The reaction rate of the 1 st stage was greater than that of the 2nd stage. The activation energy of the 1 st stage was 31.93 Kcal/g mole and those of the 2nd stage were 78.49 and 23.41 Kcal/g mole above and below $75^{\circ}C$, respectively.

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Gelatinization Characteristics of Nonwaxy Rice Starches (멥쌀 전분의 호화특성)

  • Kim, Nam-Soo;Sog, Ho-Moon;Nam, Young-Jung;Min, Byong-Yong
    • Applied Biological Chemistry
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    • v.30 no.1
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    • pp.24-30
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    • 1987
  • starches, isolated from Japonica and nonwaxy rites, were analyzed fur gelatinization characteristics. Amylose contents of Taebaeg and Sangpung starch were 16 and 17%, respectively. The portion of large-sized particles was more pronounced in the case of Sangpung starch. Swelling power and solubility increased according to the rise in gelatinization temperature. The decrease of pasting temperature according to the incense in starch concentration in Sangpung starch was higher than that of Taebaeg starch. Most of the increase in light penetration was accomplished between 85 and $90^{\circ}C$. Gelatinization reactions of Taebaeg and Sangpung starch appeared as 2 different stages up to the gelatinization temperature of $90^{\circ}C$.

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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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Correlation of morphological changes of rice starch granules with rheological properties during heating In excess water (가열 조리시 쌀 전분 입자들의 형태학적 변화와 리올로지 특성과의 관계)

  • Lee, Young-Eun;Osman, Elizabeth M.
    • Applied Biological Chemistry
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    • v.34 no.4
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    • pp.379-385
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    • 1991
  • Morphological changes of starch granules from 12 different varieties of rice were examined by scanning electron microscopy during heating at 2.5% (w/v) concentration. Rice starch granules proceeded through a similar pattern of progressive morphological changes daring heating, regardless of variety. Rice starch granules began to swell radially in the initial stage of gelatinization and then undergo radial contraction and random tangential expansion to form complex structures in the latter stage of gelatinization temperature range. At higher temperatures, starch granules softened and melted into thin flat discs, and then stretched into thin filaments to form three-dimensional networks. These progressive morphological changes were reflected in the changes of swelling power, solubility and amylograph viscosity of starch. During the transition of melting or softening, swelling power, solubility and amylograph viscosity increased rapidly. The time of loss of granular structure of starch depended on gelatinization temperature range. The ratio of amylose to amylopectin was largely responsible fur the rate of melting or softening and the fineness of a three-dimensional filamentous network above the gelatinization temperature range. Therefore, both the gelatinization temperature range and amylose content of starch affect the rate of cooking, and amylose content of starch affects the final texture of cooked starch paste.

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Effect of Heating Temperature on the Rheological Properties of Com Starch (열처리 온도가 옥수수 전분의 리올로지에 미치는 영향)

  • Kim, Sung-Kon;Suh, Chung-Sik
    • Applied Biological Chemistry
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    • v.38 no.4
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    • pp.353-358
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    • 1995
  • The influence of dry-heat treatment($130{\sim}220^{\circ}C$) on the gelatinization and rheological properties of corn starch(11.4% moisture) was examined. The enthalpy of gelatinization measured by differential scanning calorimetry decreased above $190^{\circ}C$. The viscosity of starch by alkali gelatinization increased as the heating temperature rised. All the values including peak viscosity on amylograms and shear stress, apparent viscosity, consistency index and yield stress of thermal-gelatinized starch dispersion showed decreasing tendencies with increasing of heating temperature from above $170^{\circ}C$ compared with those of raw starch. The apparent viscosity and yield stress of all the samples thermal-gelatinized at $90^{\circ}C$ were increased considerably with process of gelatinization time and especially their rapid increase at the early stage was observed in the $190^{\circ}C$ sample. But all the rheological parameters of $220^{\circ}C$ sample recorded very low values compared with those of the others.

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Effect of the Energy of Extrusion on the Starch Gelatinization (압출성형 에너지가 녹말의 호화에 미치는 영향)

  • Chung, Moon-Young;Lee, Seung-Ju
    • Korean Journal of Food Science and Technology
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    • v.29 no.1
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    • pp.72-76
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    • 1997
  • The effect of the energy supplied in extrusion on the starch gelatinization was analyzed. The energy needed for extrusion is generated by motor and heater. The motor energy is transformed into a thermal energy by heat dissipation and a mechanical energy, and the heater energy is of a thermal energy. At the low barrel temperature $({\leq}80^{\circ}C)$, it was found out there are two kinds of thermal energy by heat dissipation: one by a powder friction of corn grit with low moisture contents and the other by a viscous dissipation of corn grit with high moisture contents. The dissipated thermal energy by the powder friction was more effective on the starch gelatinization than that by the viscous dissipation. The effect of the mechanical energy was also analyzed in terms of a relative mechanical energy. The gelatinization of corn grit with high moisture contents $({\geq}33%)$ largely depended on the change in the relative mechanical energy, whereas that with low moisture contents $({\leq}30%)$ hardly depended on it.

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Physicochemical and Gelatinization Properties of Glutinous Rice Flour and Starch Steeped at Different Conditions (수침한 찹쌀가루와 전분의 이화학적 및 호화 특성)

  • 최은정;김향숙
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.26 no.1
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    • pp.17-24
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    • 1997
  • The effects of steeping on the physicochemical and gelatinization characteristics of glutinous rice flour and its starch were studied. Steeping conditions were 1 day at 25"C,7 days at 2iC and 7 days at 35"C. Crude protein, lipid and ash content were decreased br steeping. It was observed with scanning electron microscopy that endosperm cell wall of glutinous rice flour was diminished by steeping. Although morphology of the glutinous rice starch granules was not affected, the size was decreased by steeping. Density and water binding capacity(WBC) of glutinous rice flour and its starch were changed by steeping. X-ray diffraction pattern of glutinous rice starch was A type and was not affected by steeping. Swelling power of glutinous rice flour and its starch was increased but solubility was decreased by steeping. In Brabender amylographic examination, peak viscosity of untreated glutinous rice flour was very low and increased enormously by steeping resulting in the similar Brabender viscosity pattern to its starch. The gelatinization temperature examined by X-ray diffractometry was lowered by steeping. And the degree of gelatinization under the conclusion temperature increased with increasing of steeping Period and temperature.mperature.

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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.

Reaction Mechanixm of Cyclodextrin formation from Swollen Extrusion Starch by cyclocextrin Glucanotransferase (팽윤 전분을 기질로 한 Cyclodextrin Glucanotransferase의 Cyclodextrin 생성반응 기작)

  • 이용현;조명진;박동찬
    • Microbiology and Biotechnology Letters
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    • v.23 no.4
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    • pp.416-424
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    • 1995
  • Mechanism of the cyclodextrin (CD) production reaction by cyclodextrin glucanotransferase (CGTase) using swollen extrusion starch as substrate was investigated emphasizing the structural features of starch granule. The degree of gelatinization was identified to be the most representative structural characteristic of swollen starch. The most suitable degree of gelatinization of swollen starch for CD production was around 63.52%. The structural transformation of starch granule during enzyme reaction was also followed by measuring the changes of the degree of gelatinization, microcrystallinity, and accessible and inaccessible portion to CGTase action of residual swollen starch. The adsorption phenomenon of CGTase to swollen starch was also examined under various conditions. The inhibition mechanism of CGTase by various CDs was identified to be competitive, most severely by a-CD. The mechanism elucidated will be used for development of a kinetic model describes CD production reaction in heterogeneous enzyme reaction system utilizing swollen extrusion starch.

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Physiochemical Properties of Purple-Fleshed Sweet Potato Starch (자색고구마 전분의 이화학적 특성)

  • 박양균;최차란;임종환
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.29 no.1
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    • pp.1-5
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    • 2000
  • Physicochemical properties and gelatinization patterns of purple-fleshed sweet potato starch were studied. Shape of starch granule was round and polygonal, X-ray diffraction pattern was Ca-type. Amylose content was 14.4% which was lower than that of other sweet potato starch. Water binding capacity was 82.54%, swelling power and solubility at 8$0^{\circ}C$ were 27.94% and 15.35%, respectively. Initial temperature of gelatinization was 72$^{\circ}C$ using Brabender/Visco/Amylograph, consistency and setback were lower than those of other sweet potato starch. The peak temperature and enthalpy determined by DSC were 68.1$^{\circ}C$, 1.24cal/g, respectively. The transmittance of starch dispersions in alkaline solutions increased with NaOH concentration up to 0.17N, and then changed slowly at 0.19N or above. The apparent viscosities were similar to the transmittance of starch dispersions in alkaline solutions, but drastically increased above 0.21N.

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