• Title/Summary/Keyword: gelatinization temperature

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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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Comparison of Gelatinization Properties of Japonica and Tongil Brown Rice Starches (일반계와 통일계 현미전분의 호화성질 비교)

  • 변기원
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.21 no.4
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    • pp.428-435
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    • 1992
  • Intrinsic viscosity and gelatinization properties of brown rice starches of Japonica and Tonsil type cultivars were investigated. The intrinsic viscosity was similar between the two cultivars. The gelatinization temperature of Japonica brown rice starch determined by differential scanning calorimetry was higher than that of Tonsil brown rice starch. However, the range of gelatinization temperature, gelatinization enthalpy and the water content for gelatinization were similar between the two starches. The treatment of starch at 6$0^{\circ}C$ for 24hr increased the gelatinization temperature and gelatinization enthalpy and decreased the range of geltinization temperature. The water content for gelatinization was negatively correlated with the range of gelatinization temperature in case of Japonica starch and with the intrinsic viscosity in case of Tonsil one. The in-trinsic viscosities of both Japonica and Tonsil starches were positively correlated with gelatinization enthalpy.

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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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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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The Effects of Blending Starches on the Development of Plybond Strength of Two-ply Linerboard (삼성분 전분혼합에 의한 이겹지의 층간결합강도 개선)

  • Lee, Hak-Lae;Ryu, Jeong-Yong
    • Journal of Korea Technical Association of The Pulp and Paper Industry
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    • v.39 no.4
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    • pp.14-20
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    • 2007
  • The effects of blending starches with different gelatinization temperatures on the development of ply-bond strength were systematically investigated using a three component mixture design technique. Oxidized corn starches with different gelatinization temperatures were blended with natural corn starch and sprayed for plybonding. Optimum blend ratio for maximizing plybond strength improvement for the starch blends was 40% of natural starch, 27% of oxidized starch with low gelatinization temperature and 33% of oxidized starch with high gelatinization temperature. Starch granules with the lowest gelatinization temperature gelatinizes at the lowest temperature, while the natural corn starch gelatinizes at later stage of drying. The improvement of plybond strength with starch blends were verified on machine trial as well. Plybond strength improvement obtained from the machine trial was lower than that achievable with handsheets, which was attributed to the lower internal bond strength of the linerboards made from recycled fibers.

Noodle Making Characteristics of Buckwheat Composite Flours (메밀복합분을 이용한 제면 특성)

  • 김복란;최용순;김종대;이상영
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.28 no.2
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    • pp.383-389
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    • 1999
  • To determine the optimum condition for buckwheat noodle making, we prepared noodle from com posite flours of buckwheat, wheat and corn starch, and those physical properties and sensory evalua tion were investigated. The weights of cooked noodle became lower with increasing buckwheat content level indicating that elution of its components to soup was high. Wheat flour in the composite flours probably caused to drop gelatinization temperature and maximum viscosity compared to buck wheat flours. Corn starch in the composite flours increase gelatinization temperature and maximum viscosity compared to buckwheat flours. From the result of farinogram, buckwheat flour lower water absorption ability, and increased dough development time compared to composite flours. Adhesiveness of the cooked noodle with wheat flour was decreased. Cohesiveness of the cooked noodle was decrea sed with increasing buckwheat flour level. In sensory evaluation, chewing and softness of noodle with 100% buckwheat flour was evaluated the best. In taste, BW1 and BSW1 noodles showed slightly higher preference although there was no significant differences.

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Studies on the Properties of Barley and Naked Barley Starch Part II. On the Gelatinization Temperature and Alkali Number of Starch (보리전분(澱粉)의 특성(特性)에 관한 연구(硏究) 제2보 보리 전분(澱粉)의 호화온도(糊化溫度) 및 Alkali 수(數)에 대하여)

  • Kim, Yong-Hui;Kim, Hyong-Soo
    • Korean Journal of Food Science and Technology
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    • v.8 no.1
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    • pp.42-46
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    • 1976
  • In order to compare the quality of starches, isolated from the various barley and naked barley species, the gelatinization-temperature and alkali number were determined for 11 species of barley and 13 species of naked barley. The results are as follows; 1. Gelatinizations start at $51-59^{\circ}C$ and complete at $58-64^{\circ}C$ in range. Average gelatinization temperature of the starches from naked barley showed $3^{\circ}C$ lower than those from barley while small differences were observed between species for both barleys. 2. Alkali number varies between 8.0 to 9.5. No significant changes of alkali number were observed between both barleys (8.8 for naked barley and 8.7 for barley in average).

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A Study of Amylose Content, Water Absorption and Gelatinization Characteristics of Barley Varieties. (보리품종의 Amylose함량, 수분흡수율 및 호화조건에 관한 연구)

  • Park, M.W.;Cho, C.H.;Kim, H.B.
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.23 no.2
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    • pp.88-98
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    • 1978
  • Amylose content, water absorption and amylograph characteristics of waxy and nonwaxy barley varieties were studied. Amylose content of nonwaxy varieties ranged from 23.4% to 31. 5% and waxy varieties showed 5.4%-9.5%. Water absorption of waxy varieties was highest among the materials tested. Waxy barley showed lowest gelatinization temperature among the varieties. Gelatinization temperature was positively related with the maximum viscosity in all tested varieties. There was no relationships between amylose content and gelatinization temperature, gelatinization time and viscosity.

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Effect of Ohmic Heating on Thermal and Water Holding Property of Starches (옴가열이 전분의 열적 특성과 흡수력에 미치는 영향)

  • Cha, Yun-Hwan
    • The Korean Journal of Food And Nutrition
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    • v.27 no.1
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    • pp.112-119
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    • 2014
  • Ohmic heating uses electric resistance heat which occurs equally and rapidly inside food when the electrical current is transmitted into. Prior to the study, we have researched the potato starch's thermal property changes during ohmic heating. Comparing with conventional heating, the gelatinization temperature and the range of potato starch treated by ohmic heating are increased and narrowed respectively. Herein, we have studied thermal property changes of wheat, corn, potato and sweet potato starch by ohmic heating as well as conventional heating. And then we measure the water holding capacity of starches. Annealing of starch is a heat treatment method heated at 3~4% below the gelatinization point. This treatment changes the starch's thermal property. In the DSC analysis of this study, the $T_o$, $T_p$, $T_c$ of all starch levels have increased, and the $T_c$-$T_o$ narrowed. In the ohmic heating, the treatment sample is extensively changed but not with the conventional heating. From the ohmic treatment, increases from gelatinization temperature are potato ($8.3^{\circ}C$) > wheat ($5.3^{\circ}C$) > corn ($4.9^{\circ}C$) > sweet potato ($4.5^{\circ}C$), and gelatinization ranges are potato ($7.9^{\circ}C$), wheat ($7.5^{\circ}C$), corn ($6.1^{\circ}C$) and sweet potato ($6.8^{\circ}C$). In the case of conventional treatment, water holding capacity is not changed with increasing temperature but the ohmic heating is increased. Water holding capacity is related to the degree of gelatinization for starch. This result show that when treated with below gelatinization temperature, the starches are partly gelatined by ohmic treatment. When viewing the results of the above, ohmic treatment is enhanced by heating and generating electric currents to the starch structure.

The Effects of Annealing on Resistant Starch Contents of Cross-linked Maize Starches (Annealing 처리가 가교결합 옥수수전분의 저항전분 수율에 미치는 영향)

  • Mun, Sae-Hun;Shin, Mal-Shick
    • Korean Journal of Food Science and Technology
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    • v.34 no.3
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    • pp.431-436
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    • 2002
  • To develop a method for increasing RS level in maize starch, cross-linked resistant starches treated with annealing were prepared. Maize starch and amylomaize VII were used in the study and annealed at $40{\sim}60^{\circ}C$ before cross-linking modification. To compare effect of annealing below gelatinization temperature, starches were heat treated at 70 and $100^{\circ}C$. RS contents were assayed by pancreatin-gravimetric (P/G) method. When maize starch and amylomaize VII were cross-linked at $45^{\circ}C$ and pH 11.0 by slurrying the starch on a solution of STMP(sodium trimetaphosphate), STPP(sodium tripolyphosphate), and sodium sulfate, RS content was 14.7% and 45.3%, respectively. Annealing below gelatinization temperature before cross-linking increased RS contents of prepared cross-linked starches but did not affect the swelling power. Heat treatment above gelatinization temperature increased the swelling power of cross-linked starch prepared from maize starch. The characteristics by X-ray diffractometry and scanning electron microscopy of cross-linked resistant starch were not changed by annealing.