• Korean Journal of Food Science and Technology
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• v.30 no.3
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• pp.590-595
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• 1998

Seven varieties (Suweonjo, Suweon232, BG276-5, IR44, IR41999-139, Suweon230 and Yongjubyeo) of rice were used to study for making rice bread by amylose content. Suweonjo had the highest amylose content (27.07%) and Yongjubyeo had the lowest one (17.17%). Suweonjo showed the highest volume after baking, while Yongjubyeo the lowest volume one. Volume and hardness of the rice bread decreased as amylose content decreased. The amylose content was not associated with hardness and color values of rice bread after baking. Sensory evaluation for internal parts of rice bread showed that score of air cell, color of crumb, aroma, taste, chewability and texture decreased as amylose content increased, while volume of rice bread increased. The low-amylose rice cultivar revealeded better suitability for rice bread.

• Korean Journal of Food Science and Technology
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• v.21 no.4
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• pp.556-561
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• 1989

Thermal properties of amylose-lysolecithin (AL) complex, amylose content and effect of lysolecithin on the gelatinization of rice starch were investigated by Differential Scanning Calorimetry (DSC). The melting temperature of AL complex was near to $108.5^{\circ}C$ and the melting enthalpy was about 1.0cal/g. The gelatinization temperature of rice starch was not affected by adding lysolecithin. However, the enthalpy of gelatinization was decreased. The amylose contents in rice varieties were calculated from melting enthalpy of AL complex. The amylose contents for Indica and Japonica types of rice were in the range of 16-19%, which were in good agreement with those determined by iodine binding method. Significant differences were not observed in the amylose contents between Indica and Japonica varieties.

• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.5
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• pp.653-658
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• 2017

To evaluate the effects of amylose content and dissolution media on the molecular structure of maize starch, changes in the hydrodynamic diameter of starch molecules were assessed via dynamic light scattering depending on amylose content and dissolution media. As the amylose content of starch increased, the hydrodynamic diameter of starch molecules proportionally decreased from 204 to 92 nm. To alter ionic strength, hydrogen bonding, or polarity of dissolution media, various contents of NaCl (1, 2, or 3 M), urea (1, 2, or 3 M), or 1-butanol (0.1, 0.5, or 1.0%) were added to media, respectively, resulting in increased hydrodynamic diameter of starch. However, the degree of expansion was dependent on amylose content and the concentration and/or type of additive. The hydrodynamic diameter of starch molecules exhibited significant correlation with amylose content obtained by size exclusion chromatography, regardless of dissolution conditions.

• Korean Journal of Food Science and Technology
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• v.31 no.5
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• pp.1171-1177
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• 1999

The changes on microstucture of recombinated gels with different ratio of amylose(A) and amylopectin(AP) which were isolated from nonwaxy rice starch were investigated by scanning electron microscope(SEM) and X-ray diffractometer. As the concentration of amylose was above 3%(1.08% of soluble amylose) in the amylose suspension, gel matrix became like a three-dimensional network. The microstructure of amylose gels showed a network including macroporous structure, but the higher the ratio of amylopectin content were, the firmer network were formed. In case of A/AP mixed gels(15%) with different amylose/amylopectin percent ratios ; 0/5, 5/10, 10/5, 15/0%, as the storage time of gels and the percent ratio of amylose content were increased, network was formed harder with thick films. While X-ray diffractograms of waxy rice starch which contained 100% amylopectin showed A type, those of purified amylose and amylopectin showed V type and amorphous patterns, respectively. Amylose(3%) gels added $2{\sim}3%$ amylopectin and A/AP mixed gels(15%) showed peak at $2{\theta}\;=\;17.0^{\circ}$which were shown B type crystallinity similar af retrograded starches. Also as the percent ratio of amylose content in mixed gels was increased, peak intensity wat increased.

• Food Science and Biotechnology
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• v.16 no.3
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• pp.477-481
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• 2007

Fourier transform near-infrared (FT-NIR) spectroscopy and partial least squares (PLS) regression were used to predict the amylose content of polished rice. Spectral reflectance data in a wavelength range of 1,000 to 2,500 nm were obtained with a commercial spectrophotometer for 60 different varieties of Korean rice. For a comparison of this spectroscopic method to a standard chemical analysis, the amylose contents of the tested rice samples were determined by the iodine-blue colorimetric method. The highest correlation for the rice amylose ($R^2=0.94$, standard error of prediction=0.20% amylose content) was obtained when using the FT-NIR spectrum data pre-treated with normalization, the first derivative, smoothing, and scattering correction.

• Preventive Nutrition and Food Science
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• v.10 no.3
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• pp.207-213
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• 2005

Molecular structures and functional properties of starches isolated from normal, waxy, and zero amylose barleys were examined. Amylopectins from zero amylose starch had the largest molecular weight $(M_w)$, whereas those from high amylose starch, the smallest. A good correlation between the $(M_w)$ and the radius of gyration $(R_g)$ was observed among amylopectins from various starches, indicating similar polymeric conformation in solution even with the differences in the $(M_w)$. The debranched amylopectin molecules from different types of barley starches exhibited similar profiles, implying that the packing geometry of double helices in the different types of barley starches may be similar. Zero amylose starch showed the highest peak viscosity (326 RVU) in RV A viscograms at lower pasting temperature $(67.6^{\circ}C)$, compared to normal and high amylose starches. Relationship between RVA peak viscosity and amylose content suggested that the presence of amylose inhibited the development of granular swelling of barley starches during cooking. A rapid retrogradation, traced by differential scanning calorimetry (DSC) and strain-controlled rheometry, occurred in the high amylose starch sample during storage, while zero amylose starch showed a very good resistance to retrogradation, indicating excellent storage stability.

• 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.

• 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.21 no.6
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• pp.766-771
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• 1989

physicochemical properties of rice starch isolated from eight varieties were examined to evaluate the rice processing suitability The amylose contents of rice starch were varied with 16.7-29.7%, and IR 30, Godael, Aguja and Lengkwang varieties showed higher amylose content than the other varieties. The water binding capacity and blue value were in the range of 87.0 103.0 and 0.178-0.305, respectively. As the amylose content increased, the amylogram pasting temperature and the break down ratio increased, while the peak viscosity did not show any significant difference. The transmittance of 0.1% starch suspension slowly increased at $50^{\circ}C$ in the low-amylose content rice group, and rapidly increased at $65^{\circ}C$ in the high-amylose content rice group, but there were no differences above $75^{\circ}C$ among varieties. Also the low-amylose rice starch showed higher values in the swelling power and solubility. The hardness of the 30% rice starch gels was low in low-amylose one. During storage at $20^{\circ}C$ for 14 days, the increment of hardness was more slow in high-amylose one. The retrogradation velocity constant of rice starch gel by Avrami equation was the highest as 0.219 in Aguja variety.

• Korean Journal of Food Science and Technology
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• v.29 no.3
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• pp.516-521
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• 1997

Effect of amylose content on the physical properties of resistant starches (RS) from autoclaved maize starches (with starch:water=1:3.5, at $121^{\circ}C$) which were repeated up to 4 times heating-cooling cycles, were investigated by water uptake, scanning electron microscope (SEM) and differential scanning calorimetry (DSC). Amylose content of waxy maize starch (Amioca), common maize starch (PFP), high amylose starch(Amaizo, Amylomaize VII) were 0%, 29%, 50%, and 72%, respectively. Yield of RS increased as amylose content increased. Water uptake of all kinds of native starch was higher than that of RS, but lower than that of autoclaved starch. By SEM, RS showed some small particles on surface but the size of particles was different with amylose content. Single endothermic transition peak exhibited at $40{\sim}70^{\circ}C$ in autoclaved Amioca and PFP (crystalline melting of amylopectin) and at $132{\sim}169^{\circ}C$ in autoclaved Amaizo and Amylomaize VII(crystalline melting of amylose) by DSC. RS from all kinds of autoclaved starches except Amioca showed single endothermic peak over $155^{\circ}C$ but the enthalpy was not related to amylose content.