• KSBB Journal
• /
• v.13 no.5
• /
• pp.621-625
• /
• 1998

The raw starch hydrolysis by amylase prepared from alkaline-tolerant Bacillus sp. were investigated. Degree of hydrolysis(%) of 5%(w/v) raw rice, corn and potato starch by this enzyme were about 40, 25 and 20%, respectively. The hydrolysis action on raw starch by change of blue value was similar to the action pattern of exo ${\beta}$-amylase. The hydrolysis products of rice starch were mainly glucose and maltose. Oligosaccarides were also detected. From the above results, this enzyme was considered as exo type ${\alpha}$-amylase. This enzyme activity on the raw starch and the gelatinized starch were 28.40 and 86.60 IU/mg protein, respectively, and the ratio of raw starch-digesting activity to gelatinized starch-digesting activity (raw starch digestivity) was about 32%. The Km values for the raw and the gelatinized starch were 4.22 and 3.0mg/mL, respectively, and the VmaX values were 0.20 and 0.31mg/mL/min, respectively.

• Korean Journal of Food Science and Technology
• /
• v.16 no.4
• /
• pp.451-456
• /
• 1984

Rheological properties of gelatinized rice starch solutions were investigated with Brookfield rotational viscometer. The 8% starch solution showed thixotropic behavior with yield stress. The alkali gelatinized starch was more thixotropic than the thermal gelatinized one. The time dependent characteristics of starch solutions followed Tiu's model. The value of rate constant $(a_1)$ in Tiu's model increased linearly with shear rate, and was exponentially dependent on concentration and temperature. Temperature dependency of rate constant and apparent viscosity followed Arrhenius type equation and the activation energy were about 14.3 and 6.8 Kcal/g mole, respectively. The $a_1-value$ was found to be useful to evaluate changes in structaral decay on the shearing time of gelatinized rice starch solutions.

• Journal of Nutrition and Health
• /
• v.15 no.2
• /
• pp.83-90
• /
• 1982

This study was attempted to investigate the effects of adding gelatinized waxy rice flour, wheat flour, and Xanthan Gum to rice flour on the preparation and (quality) of dried noodles. 1) Rice flour demonstrated higher maximum viscosity value as determined by Amylograph than wheat flour. Among the composite flour mixture (Rice Flour 85+Gelatinized Waxy Rice Flour 15 + Xanthan Gum 2%) showed the highest viscosity value and (RF 35+ GWRF 15 + Wheat Flour 50) had the lowest. (RF 35 + GWRF 15 +WF 50) demonstrated gelatinization characteristics which is quite similar to that of wheat flour. 2) Forty and 50% replacement of rice flour and gelatinized waxy rice flour (15%) mixture by wheat flour improved significantly noodle making characteristics and cooking quality of noodles. 3) The addition of 2% XG to (RF 45 + GWRF 15 + WF 40) was effective on noodle making properties and on binding properties of cooked noodles. 4) The cooked noodle made of composite flour (RF 45 + GWRF 15 + WF 40 + XG 2%) received the highest total sensory evaluation score among the testing samples, and it was not significantly different from that of wheat flour.

• Korean journal of food and cookery science
• /
• v.14 no.3
• /
• pp.261-265
• /
• 1998

The activity and characteristics of ${\alpha}$-amylase in soy milk as well as in Jeungpyun batters were determined to investigate the enzyme system related to Jeungpyun preparation. ${\alpha}$-Amylase activity was detected in soy milk as well as in Jeungpyun batters. Soy milk had ${\alpha}$-amylase activity of 0.79 units/mg protein for gelatinized starch and 0.036 units/mg protein for raw starch. ${\alpha}$-Amylase in soy milk showed maximum activities at pH 5.92∼6.87 and at 60$^{\circ}C$ for both gelatinized starch and raw starch. ${\alpha}$-Amylase activities of Jeungpyun batters containing soy milk were 25.59 units/mg protein for gelatinized starch and 1.37 units/mg protein for raw starch. Jeungpyun batters without soy milk demonstrated ${\alpha}$-amylase activities of 3.37 units/mg protein for gelatinized starch and 0.49 units/mg protein for raw starch. ${\alpha}$-Amylase of Jeungpyun batters showed an optimal activity at pH 5.25 and at 60$^{\circ}C$ for both gelatinized and raw starch. The results demonstrated that Jeungpyun batters with soy milk showed significantly higher ${\alpha}$-amylase activity than the ones without soy milk.

• Korean Journal of Food Science and Technology
• /
• v.20 no.3
• /
• pp.392-398
• /
• 1988

Gelatinized rice flours were prepared by drum drying at different moisture contents of slurry made from dry milled and wet milled rice flours. Milled rice samples were prepared from the Chuchung and the Samgang varieties. Degree of gelatinization of drum-dried rice flours revealed over 92% at 60% moisture content of wet milled rice flours and 80% moisture content of dry milled ones. With regards to amylogram and rheological properties, drum-dried rice flours prepared from wet milled raw materials showed higher viscosity than from dry milled ones. Increasing water contents in the slurry increased water absorption index(WAI) and decreased water solubility index(WSI). Hunter's color values of drum-dried rice flour at high moisture contents showed higher L values and lower b values. For the preparation of gelatinized rice flours by drum drying process, the higher water content caused more gelatinized network structure of rice starch in scanning electron micrographs. With regards to farinogram properties of dough with drum-dried rice flours and wheat flours in mixing ratio of 1 to 9 by weight, drum-dried rice flours made from wet milled raw rice flours revealed higher MTI than from dry milled ones.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.28 no.6
• /
• pp.1293-1297
• /
• 1999

Effect of rice protein and lipid on rheological properties of gelatinized rice flour solutions(4%) with three rice varieties(Dongjin, Jinmi, Tamjin) known for varying taste of cooked rice was investigated with Haake viscometer. The rheological behaviors of all rice flour solutions were illustrated by Herschel Bulkley equation and exhibited pseudoplastic behavior with yield stress. When rice flour solutions treated with protease and dithiothreitol, there was decreased in flow behavior index value. Flow behavior index was decreased by dealbumin and deglutelin rice flour solutions among deprotein groups. The Jinmi rice flour solutions exhibited slightly lower consistency index than Dongjin and Tamjin. Defatted rice flour solutions exhibited lower consistency index than rice flour solutions, while dealbumin, deglutelin rice flour solutions exhibited high consistency index. Protease treated rice flour solutions exhibited increase in Dongjin and Tamjin. The yield stress was increased in sequence eating quality. Yield stress of defatted rice flour solutions was decreased, while deglutelin and rice starch flour solutions was increased. The time dependent charac teristics of all rice flour solutions appeared forming hysteresis loop and thixotropic behavior showed. The time dependent characteristics was appeared in sequence eating quality. Rice starch and deglutelin flour solutions appeared greatly time dependent characteristics, but defatted rice flour solutions appeared very little.

• Culinary science and hospitality research
• /
• v.18 no.4
• /
• pp.199-208
• /
• 2012

The purpose of this study is to investigate the characteristics of Sansapyun prepared with various amounts of Sansa concentrate(0%, 5%, 10% 20%, 30%) gelatinized with Chinese water chestnut starch. The Moisture contents and pH values decreased with Sansa concentrate increased. The Hunter L value of Sansapyun significantly decreased(p<0.001), but a, b values increased with Sansa concentrate increased. The hardness, springiness, chewiness, gumminess, cohesiveness were the highest in the control sample(0%) and the adhesiveness was the highest in Sansapyun with 30% sansa concentrate. In the sensory evaluation, red color, sour flavor, fruity flavor, Chinese medicine flavor, Sour taste, Chinese medicine taste, brittleness, stickiness increased with Sansa concentrate increased. Sleekness, hardness, springiness, gumminess decreased with Sansa concentrate increased. Sansapyun prepared with 10% Sansa concentrate showed the highest acceptance score(p<0.001). In addition, this study showed the possibility of Chinese water chestnut starch which is less expensive and easily available as a good replacement starch for traditional mung bean starch to prepare Kwapyun.

• Korean journal of food and cookery science
• /
• v.13 no.5
• /
• pp.627-634
• /
• 1997

The purpose of this study is to examine the effect of protein content on the physicochemical properties, gelatinized characteristics and textural properties of cowpea precipitate gels stored for 24 hrs and 48 hrs at room temperature. The contents of protein, total fat, and ash ranged from 0.35%∼1.38%, 0.54%∼0.64%, and 0.21%∼0.25%, respectively. The X-ray diffraction patterns were all Ca-type, showing no difference according to the protein content. Protein content did not make any difference in the blue values of cowpea precipitate. The blue value of cowpea precipitate powder as protein content was decreased. The water-binding capacity of cowpea precipitate powder increased as the protein content increased. Swelling power and solubility of cowpea precipitate powder increased as protein content decreased. The transmittance of cowpea precipitate powder was not different according to the protein content. The initial pasting temperature of cowpea precipitate powder by differential scanning calorimetry (DSC) and rapid visco analyser (RVA) showed no differences according to the protein content. In sensory evaluation, the color and clarity of cowpea precipitate gels stored for 24 hrs and 48 hrs at room temperature as the protein content increased, and the hardness, cohesiveness, springiness, acceptability were greater when the gels were stored for 48 hrs. Instrumental analyses using a rheometer showed that the hardness, gumminess, and chewiness of cowpea precipitate gels stored for 24 hrs, which was increased as the high protein content increased. For the gels stored for 48 hrs, all other factors are significantly different except cohesiveness as the protein content increased.

• Journal of Ginseng Research
• /
• v.5 no.2
• /
• pp.114-121
• /
• 1981

Starch was isolated from 4-year-old and 6-year-old ginseng roots and its physical and chemical characteristics were studied. The results obtained were summarized as follows. 1. The shape of ginseng starch granules was polygonal and rounded with its granule size ranging from 2.0 to 7.5$\mu$. The swelling power of 4-year-old ginseng starch was much greater than that of 6-year old ginseng starch. Gelatinization pattern showed that 6-year-old ginseng starch gelatinized rapidly at $65^{\circ}C$, whereas 4-year-old starch continued to gelatinize, without having a definite gelatinization temperature as temperature increased 3. Amylogram of ginseng starch showed that gelatinization initiated at 61$^{\circ}C$ and was completed at 88$^{\circ}C$ with its viscosity reaching at 810 B.U. 4. The amylose contents were 32% and 9% for 4-year-old and 6-year-old ginseng starch, respectively. 5. X-ray diffraction analyses indicated that there were some structural differences between 4-year-old and 6-year-old ginseng starch.

• Applied Biological Chemistry
• /
• v.33 no.4
• /
• pp.293-300
• /
• 1990

The physical and chemical properties of dry acorn starch(DS), defatted acorn starch (DFS) and reincorporated acorn starch(RIS) were investigated. Swelling power and solubility of all starch sample, were exhibited two stage behavior. It had a little change on the pasting temperature of DS and DFS but the peak viscosity and breakdown value of DFS was somewhat higher than those of DS and RIS. Flow behavior of gelatinized starch pastes showed a pseudoplastic behavior and flow behavior index was lower than unit The consistency coefficient showed concentration and temperature dependency. The activation energies of DS, DFS and RIS were from $1.70Kca1/g\;{\cdot}\;mol$ to $3.75Kca1/g\;{\cdot}\;mol$.