• Title, Summary, Keyword: amylograph

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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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Physicochemical Characteristics and Cookie Potentialities of Korean Wheat Cultivars (국내산 밀의 품종별 이화학적 특성과 쿠키 제조 적성)

  • Choi, Young-Sim;Lee, Myung-Ho
    • Culinary science and hospitality research
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    • v.15 no.1
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    • pp.202-208
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    • 2009
  • This study was conducted to investigate the differences on physicochemical properties and cookie potentialities of Korean wheat cultivars. The protein contents of the wheat cultivars ranged from 8.80$\pm$0.76% to 11.19$\pm$0.25%. Korean wheat cultivars had sedimentation values of 19.82 mL to 35.54 mL. Their peak viscosity range measured by Amylograph was from 60 BU to 640 BU. Diameter of cookies for soft wheat was 8.28 cm and Korean wheat cultivars ranged from 7.63 cm to 8.55 cm. Olgeunmil resulted in a higher cookie diameter and top grain score than the soft wheat. Protein content had significantly negative correlations with the coefficient of cookie diameter(r=-0.838$^*$) and with the top grain score(r=-0.751$^*$). There was a significant correlation between protein content and sedimentation value(r=0.762$^*$).

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Rheological Properties of Bread Dough Added with Flour Ferments by Seed Mash and Lactic Acid Bacteria (Seed Mash와 유산균 발효액을 첨가한 밀가루 반죽의 물성학적 특성)

  • Lee, Myung-Ku;Lee, Jeong-Hoon;Lee, Si-Kyung
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.38 no.3
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    • pp.346-351
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    • 2009
  • This study was carried out to determine the rheological properties of bread doughs containing flour-ferments prepared with seed mash obtained by Koji incubation, yeast, and lactic acid bacteria, using farinograph, extensograph, amylograph, and large scale-dough mixer. According to farinograph, the addition of the flour-ferments did not influence the water-absorption rate of doughs, regardless of the kinds of flour-ferments, however, it increased development time and decreased stability of doughs. According to extensograph, both dough resistance and resistance-to-extensibility ratio increased with the addition of flour-ferments. Especially the dough containing the flour-ferments prepared with seed mash, S. cerervisiae, and L. brevis showed the highest resistance-to-extensibility ratio. According to amylograph, although the doughs containing the flour-ferments did not show the differences in gelatinization temperature and temperature at maximum viscosity with the control which does not contain the flour-ferments, they showed lower maximum viscosity than the control. They also showed lower development value and faster development time.

Effects of Low-temperature Blanching on Physical Properties of Chestnut Powder (Low-temperature Blanching 처리가 밤가루의 물리적 특성에 미치는 영향)

  • Lim, Jeong-Ho;Kim, Jun-Han;Seo, Young-Ho;Moon, Kwang-Deog
    • Korean Journal of Food Science and Technology
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    • v.31 no.5
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    • pp.1216-1220
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    • 1999
  • The effects of low-temperature blanching on the physical properties of chestnut powder were studied. Chestnuts were blanched in water for 15, 30 and 60 min., each at three temperatures viz. $45^{\circ}C,\;55^{\circ}C$ and $65^{\circ}C$. The particle size of chestnut powder was prepared smaller than 60 mesh$(250\;{\mu}m)$. Higher blanching time and temperature increased water binding capacity(WBC) of chestnut powder. Water soluble index(WSI) was the highest for chestnuts blanched at $65^{\circ}C$ for 30 min. As with water binding capacity(WBC), swelling power of chestnut powder increased with increasing blanching time and temperature but solubility showed an reduction by increasing blanching temperature. In Brabender amylographic examination, peak viscosity of chestnut powder showed great change, but the gelatinization temperature showed no significant differences by blanching conditions.

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Studies on the Change of Components with Long-Term Storage of paddy (장기저장 미곡의 성분변화 특성)

  • 김영수
    • The Korean Journal of Food And Nutrition
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    • v.12 no.4
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    • pp.409-414
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    • 1999
  • In order to investigate the changes of rice qualities during 4 years storage of paddy stored in ware-house of normal temperature condition. Temperature in warehouse was changed more than 3$0^{\circ}C$ under the influence of average temperature outside of a warehouse. Water content of paddy was not increased over 15% But as average temperature in warehouse was gone up 18$^{\circ}C$ from June to September every years it was supposed that these periods were to be deterioration of rice quality. On investigation of change in paddy it was supposed that these periods were to be deterioration of rice quality. On investigation of change in paddy components during the long term storage, reducing, sugar, amylose, crude protein were increased 0.24%, 19.23%, 7.02% at enterance time to 0.5%, 20.31% 7.46% 4 years later respectively. Max viscosity final visocity and set back value by amylograph were increased 449B,U 610B.U, 161B.U to 493B.U, 715B,U 222B.U but breakdown was decreased 125B.U to 76B.U with the increase of storage period. Gel consistency of rice stored was decreased 44.7mm at enterance time to 39,9mm 4years later. Fatty acid was increased remarkably 4.5KOHmg/100g to 24.4KOHmg/100g. Germination ratio and germ activity of paddy during long-term storage were decreased 97%, 100% to 0%, 0.4% respectively, With the increase of storage period contaminated paddy by molds increased and its by bacteria decreas-ed.

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Quality of Wet Noodle Prepared with Wheat Flour and Mushroom Powder (버섯분말을 첨가한 생면의 품질특성)

  • Kim, Young-Soo
    • Korean Journal of Food Science and Technology
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    • v.30 no.6
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    • pp.1373-1380
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    • 1998
  • Wet noodles were prepared with wheat flour and mushroom powder (oyster and oak mushrooms), and effects of added mushroom powders on dough rheology and wet noodle quality were examined. Particle size distribution of mushroom powder ranged from 0.04 to $500\;{\mu}m$, which was different from that of wheat flour. The initial pasting temperature in amylograph, and the water absorption and the dough development time in farinograph increased with the increase of mushroom powder. The peak and final viscosities in amylograph, and dough stability in farinograph decreased with the increase of mushroom powder. Decrease of L value and increase of a and b values were shown with the increase of mushroom powder in wheat flour-mushroom powder composite as well as wet noodles. The cooked weight and volume of cooked noodles were decreased, but the turbidity of soup were increased with the addition of mushroom powder. Most of texture parameters (hardness, cohesiveness, chewiness and cutting force) of cooked noodles decreased with the addition of oyster mushroom powder, but increased with the addition of oak mushroom powder. From the result of sensory evaluation, wet noodles containing 3% oyster mushroom powder and 5% oak mushroom powder were rated as high quality wet noodles.

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Quality Characteristics of Fresh Pasta Noodle Added with Red Hot Pepper Juice (홍고추액을 첨가한 생면 파스타의 품질특성)

  • Kim, Jung-Soo;Hong, Jin-Sook
    • Korean journal of food and cookery science
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    • v.24 no.6
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    • pp.882-890
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    • 2008
  • The present study investigated the influence of different volumes of red hot pepper juice on the quality characteristics of fresh Pasta noodle. Supplementation with 0% (control), 2.5%, 5%, 7.5%, or 10% red hot pepper juice produced similar gelatinization characteristics of peak viscosity, temperature at peak viscosity, hot paste viscosity and numerical value of breakdown. However, increasing concentrations of red hot pepper juice produced progressively and significantly low cold paste viscosity and setback. The chromaticity of wet and cooked noodles was significantly lower in L value and significantly higher in +a and +b values with increasing volumes of red hot pepper juice. The texture of fresh noodles displayed no significant differences in hardness, adhesiveness and chewiness. The springiness and cohesiveness were lower and higher with the increase of added red hot pepper juice, respectively, but the differences just attained significance. For cooked noodles, adhesiveness, springiness, cohesiveness and chewiness tended to be higher with increasing volumes of red hot pepper juice, but again the differences just attained significance. Cooking characteristics of weight, volume, moisture absorptive power and turbidity decreased with increasing volumes of red hot pepper juice. Sensory characteristics of acceptability including appearance, color, flavor, taste, texture and overall-acceptability improved with increasing red hot pepper juice volume, in particular with 5% and 7.5%. Amylograph characteristics for initial paste temperature positively correlated with the texture characteristics for chewiness (p<0.05). Negatively correlated amylograph parameters included texture for springiness with for peak viscosity (p<0.01), texture for adhesiveness with hot paste viscosity (p<0.01) and breakdown with texture for adhesiveness, cohesiveness and chewiness (p<0.05).

Effect of Gamma Irradiation on Water Uptake Rate and Gelatinization of Brown Rice (감마선 조사가 현미의 수화속도 및 호화양상에 미치는 영향)

  • Lee, You-Seok;Shu, Chung-Sik;Lee, Ju-Woon;Byun, Myung-Woo
    • Korean Journal of Food Science and Technology
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    • v.36 no.6
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    • pp.900-904
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    • 2004
  • Effects of gamma irradiation on brown rice quality were evaluated. Brown rice was irradiated at absorbed dose of 1, 3 or 5 kGy, and ground. Water uptake, pasting properties, and physicochemical characteristics of flour samples were tested. Water uptake rates of irradiated samples were higher than that of control, and were dose-dependent. Hydration capacity decreased in sample irradiated at 5 kGy due to leaching out of soluble compounds, whereas no differences were observed among other irradiated samples and control. Irradiation significantly decreased pasting properties as determined by amylograph. Gamma irradiation accelerated water evaporation at high temperatures (over $300^{\circ}C$) in test of weight-loss profile with thermogravimetric analyzer.

Effect of Elevated Steeping Temperature on Properties of Wet-milled Rice Flour (가온 수침처리가 습식제분 쌀가루의 특성에 미치는 영향)

  • Kim, Sang-Sook;Kang, Kyung-A;Choi, So-Yeon;Lee, Young-Tack
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.34 no.3
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    • pp.414-419
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    • 2005
  • Newly harvested milled rice and stored milled rice for 2 years were steeped at the elevated temperatures of 40, 50, and 60℃ for 2hr, and physicochemical properties of the wet-milled rice flour were investigated. The lightness of rice flour was slightly higher in the newly harvested milled-rice, while yellowness was higher in the stored milled rice. For both newly harvested and stored milled rice, WAI, WSI, and gel consistency increased as steeping temperature increased. The amylograph pasting properties indicated that increasing steeping temperature increased peak viscosity. The differential scanning calorimetry (DSC) results of the rice flour showed that increasing steeping temperature increased onset and peak temperatures, with reduced gelatinization enthalphy, suggesting partial annealing occured. Particle size of rice flour from newly harvested milled rice was larger than that from stored milled rice.

Rheological Properties of Dough and Quality Characteristics of Bread Added with Silkworm Powder (누에가루 첨가 반죽의 물성 변화 및 빵의 품질 특성)

  • Kim, Young-Ho;Cho, Nam-Ji;Im, Moo-Hyeog
    • Korean Journal of Food Science and Technology
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    • v.37 no.3
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    • pp.377-388
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    • 2005
  • Effects of silkworm powder addition on rheological properties of dough and quality characteristics of bread were investigated. Protein content of silkworm powder was 53,98%, much higher than 12.46% of wheat powder, Crude fiber, fat, and pretense contents of silkworm powder were higher than those of wheat flour, Acid analysis revealed glutamic acid content was highest 4,046.16 mg thus, significant depreciation of breadmaking was expected due to weakened gluten structure or dough. Addition of silkworm powder(optimum at 2%) with pretense inactivated by heat treatment resulted in significant improvement of volume and bread quality, with external and internal scores close to those of the control.