• Food Science and Biotechnology
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• v.18 no.1
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• pp.118-123
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• 2009

In order to find out the effect of low level of starch acetylation on physicochemical properties of potato starch, amylose content, digestibility of raw and gelatinized starch, thermal properties, pasting properties, and the swelling power of native and acetylated potato starches were measured. The amylose content was significantly lower in acetylated starch than in their counterpart native starches. Though a tendency in the decrease in digestibility of raw starch was observed with starch acetylation, acetylation did not alter the proportion of readily digestible starch (RDS), slowly digestible starch (SDS), and resistant starch (RS) of both raw and gelatinized potato starches. No clear increase in the swelling power was observed, however, the peak and onset gelatinization temperatures and the enthalpy required for starch gelatinization decreased with starch acetylation. Peak and breakdown viscosities were reduced due to acetylation of potato starch while final viscosity and set back were increased.

• Korean Journal of Food Science and Technology
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• v.23 no.1
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• pp.116-121
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• 1991

The effects of water contents and surfactants, sodium stearoyl-lactylate, sucrose ester and distilled monoglyceride(Dimodan) on wheat starch gelatinization and retrogradation were studied by differential scanning calorimetry. The endothermic peak patterns of starch varied with water content of starch. When water content was less than 30%, gelatinization did not occur. The onset temperature of gelatinization peak of native starch was $59{\sim}60^{\circ}C$ and that of endothermal peak of retrograded starch was $50{\sim}55^{\circ}C$. The enthalpy value of retrograded starch were greatest in the $40{\sim}50%$ water content. In the presence of surfactants, gelatinization temperatures shifted slightly to higher temperatures. DSC endothermal enthalpies of the amylose-lipid complex increased. The degree of retrogradation in starch was lower with surfactant than without surfactant, but enthalpy of amylose-lipid complex did not change during storage.

• Journal of the Korean Society of Food Science and Nutrition
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• v.27 no.5
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• pp.897-902
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• 1998

This study was conducted to develop the standard recipe of Dopyun according to the various content of mung bean starch and sugar. The effects of mung bean starch(10%, 15%, 20%) and sugar(20%, 30%) were evaluated on textural and sensory properties of Dopyun through the mechanical properties using texture analizer and sensory evaluation. Color was tested by color and color difference meter. For sensory evaluation, higher content of sugar and lower content of mung been starch(sugar 30%, mungbean starch 10%) showed advantages in acceptance fo taste and overall quality. Mechanical properties of hardness, cohesiveness and chewiness of Dopyun were increased significantly in Dopyun with higher content of mung bean starch and sugar. The values of Hunter color system indicated that "L" and "b" values tended to decrease and "a" value increase, as the mung bean starch and sugar proportion increased. In the analysis of correlation between sensory evaluation and acceptance test, it was found that they were highly related. In view of the above results, it came to the conclusion that Dopyun with the addition of 30% sugar and 10% mung bean starch could give the best result among the groups studied.sult among the groups studied.

• Journal of the Korean Society of Food Culture
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• v.21 no.2
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• pp.171-178
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• 2006

Tarakjuk with different amylose content was made up using roasted rice flours that consisted of the highest enzyme-resistant starch (RS), while differential scanning calorimetry (DSC) was also utilized to measure the gelatinization temperature of these roasted rice flours in order to establish cooking temperature of tarakjuk. The following qualities of tarakjuk with different amylose content were studied: color, viscosity, spreadability, starch fractions involving total starch (TS), rapidly digestible starch (RDS), slowly digestible starch (SDS) and RS, in vitro starch digestibility (IVSD) and sensory properties. During experimentation, it was found that as the amylose content of the rice flour decreased, the L value of tarakjuk decreased, whereas a value increased significantly (p<0.05). Also, while viscosity showed to increase significantly (p<0.05), on the opposite end, the property of spreadability decreased. TS ranged from $15.95{\sim}17.31%$, RDS $9.36{\sim}10.16%$, SDS $5.46{\sim}6.91%$ and RS $0.33{\sim}1.07%$, on a dry basis. Although the amylose content of rice flours decreased, IVSD increased, however showing no significant difference. When testing the sensory properties of tarakjuk, color and viscosity increased, whereas clumpiness decreased. Ilpum tarakjuk showed the highest score for nutty taste and overall acceptance levels. In fact a high correlation was shown between nutty taste and overall acceptance level (p<0.01), which leads one to believe that nutty taste is a prime factor that greatly influences overall acceptance. Furthermore, viscosity was positively correlated with both a and b values, however negatively correlated with L value (p<0.05). Moreover, roasted nutty taste and overall acceptance were positively correlated with a value (p<0.05), respectively. In conclusion, the above results suggest that tarakjuk could be made by choosing the appropriate rice flour based on the nutritional or sensory purpose.

• Korean Journal of Food Science and Technology
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• v.9 no.1
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• pp.19-23
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• 1977

The variation of the amount of starch, size and shape of the starch granules, amylose content, and blue value of the starch in the Korean ginseng roots from one year old to five year old cultivated at Kumsan was studied. The results obtained were as follows; 1) The starch content of the ginseng root(dried) was increased with the age of the root; that is, 9.62% for one-year-old roots, 10.35% for two-year-old root, 15.50% for three-year-old root, 17.05% for four-year-old root, and 18.32% for five-year-old root. 2) The shape of the ginseng starch granules was round or short oval, and in the latter case the ratio of minor axis to major axis was 1 to 1.1. Diameter of the starch granules was in the range of $1.48\;{\mu}\;to\;8.14\;{\mu}$ and the most frequent granule size was $3\;{\mu}\;(32.1{\sim}35.7%)$. The number of big size starch granules was increased during the five years of growing, while, the number of small size granules was decreased. 3) The amylose content in the ginseng starch was varied with the age of the root, in the range of $53.6{\sim}70.5%$. 4. The blue value of the ginseng starch was in the range of 0.60 to 0.71.

• Agricultural and Biosystems Engineering
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• v.2 no.2
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• pp.59-62
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• 2001

The starch content of apples, which is related to the maturity and ripeness, was quantified by using a computer vision system. The stained area was measured by image analysis when an apple slice was stained with KI/I$_2$ solution. The ratio of stained area of the apple slice to its whole area, so called the starch index, was defined as an indicator of the starch content. When Tsugaru apples were manually sorted into immature, turing and mature groups, their starch indices were 0.374, 0.312 and 0.129, respectively. The starch index had relationships to various physicochemical properties of Tsugaru apples. At the statistically significant level of 0.1%, it was correlated with the pH value, bio-yield force, rupture force and color of intact and skin-removed apples. At the 1% significant level, it had the correlation with the density and moisture content.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.16 no.3
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• pp.247-254
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• 1983

In previous paper (Lee and Kim, 1983) the effect of moisture level and frequency on dielectric properties of sardine starch paste was mentioned. The effect of temperature and starch content of the paste upon dielectric permittivity and activation energy was discussed in this report. Addition of starch affected on dielectric property. Increases of starch in the mixtures resulted in higher complex permittivity and lower critical moisture content (hc) as shown in the mixtures with $20\%$ and $50\%$ starch which were ${\varepsilon}^{\ast}=2.97+j0.36,\;hc=8.0\%;\;{\varepsilon}^{\ast}=3.54+j0.44,\;hc=7.8\%$, respectively while being ${\varepsilon}^{\ast}=2.73+j0.29,\;hc=8.4\%$ for the plain ground sardine meat. When temperature was raised the complex permittivity tended to increase at above the critical moisture content in all cases. The activation energies for plain ground meat and $30\%$ starch added mixture at below the critical moisture of $8.4\%$ were 15.44 kcal/mol and 13.86 kcal/mol while those at the moisture of $12.2\%$ were 10.27 kcal/mol and 9.31 kcal/mol, respectively.

• Korean Chemical Engineering Research
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• v.46 no.1
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• pp.106-111
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• 2008

Polypropylene (PP)/corn starch master batch (starch-MB)/silicate composites with different corn starch compositions of 10, 20, 30, 40 and 50 were prepared by melt compounding at $200^{\circ}C$, using lab scale Brabender mixer. The content of silicate was fixed at 5 wt%. The composition of starch-MB in composites was confirmed by the existence of hydroxy group and peak intensity in fourier-transform-infrared (FT-IR) spectrum. The thermal properties of the PP/starch-MB/silicate composites were investigated by differential scanning calorimetry (DSC), and thermogravimetric analyzer (TGA). There was no district change in melting temperature, and TGA curve indicates a decrease in degradation temperature with the increase of starch-MB content. The silicate dispersion of the composites was measured by X-ray diffraction (XRD) and transmission electron microscope (TEM). The degree of silicate dispersion in PP/starch-MB/silicate composites depended on the content of starch-MB. There was detectable change in d-spacing and peak intensity of the composite when the content of starch-MB was higher than 20 wt%. The rheological behavior of the composites was explained by both shear thinning effect and elastic property with the starch-MB amount. These effects were remarkable when the content of starch-MB was higher than 20 wt%. These were confirmed by an oscillatory viscometer at $200^{\circ}C$.

• Journal of Environmental Science International
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• v.13 no.12
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• pp.1131-1138
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• 2004

The starch-filled waterborne acrylate (SWAC) films were prepared. The structures and properties of SWAC films were investigated by infrared spectroscopy, thermogravimetric analysis, and strength test. The biode­gradability of SWAC film was also studied by determination of reduced sugar products after enzymatic hydrolysis. The surface morphology of the SWAC film was investigated by scanning electron microscopy (SEM). The results showed that the tensile strength and elongation of SWAC film decreased with the increase of starch content. The SWAC film showed significantly higher water absorbed content than waterbonre acrylate film. The biodegradability of SWAC film increased as the content of starch increased. The biodegradation of starch in SWAC film by ${\alpha}-amylase\;was\;about\;77{\%}$ of that of pure starch.

• Journal of Biosystems Engineering
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• v.41 no.4
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• pp.342-356
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• 2016

Purpose: The drying of a thin layer of native cassava starch in a tray dryer was modeled to establish an equation for predicting the drying behavior under given conditions. Methods: Drying tests were performed using samples of native cassava starch over a temperature range of $40-60^{\circ}C$. We investigated the variation in the drying time, dynamic equilibrium moisture content, drying rate period, critical moisture content, and effective diffusivity of the starch with temperature. The starch diffusion coefficient and drying activation energy were determined. A modification of the model developed by Hii et al. was devised and tested alongside fourteen other models. Results: For starch with an initial moisture content of 82% (db), the drying time and dynamic equilibrium moisture content decreased as the temperature increased. The constant drying rate phase preceded the falling rate phase between $40-55^{\circ}C$. Drying at $60^{\circ}C$ occurred only in the falling rate phase. The critical moisture content was observed in the $40-55^{\circ}C$ range and increased with the temperature. The effective diffusivity of the starch increased as the drying temperature increased from 40 to $60^{\circ}C$. The modified Hii et al. model produced randomized residual plots, the highest $R^2$, and the lowest standard error of estimates. Conclusions: Drying time decreased linearly with an increase in the temperature, while the decrease in the moisture content was linear between $40-55^{\circ}C$. The constant drying rate phase occurred without any period of induction over a temperature range of $40-55^{\circ}C$ prior to the falling rate period, while drying at $60^{\circ}C$ took place only in the falling rate phase. The effective diffusivity had an Arrhenius relationship with the temperature. The modified Hii et al. model proved to be optimum for predicting the drying behavior of the starch in the tray dryer.