• Bulletin of the Korean Chemical Society
• /
• v.24 no.2
• /
• pp.239-242
• /
• 2003

• Korean journal of food and cookery science
• /
• v.29 no.6
• /
• pp.833-839
• /
• 2013

Separated normal and waxy rice starches were pulverized, and the physicochemical and digestive properties of the starches were determined. The size of both starch granules significantly decreased (less than $8{\mu}m$) after pulverization. For pasting properties, significant decreases of peak and setback viscosity were observed in both of pulverized starches than in native ones. The lower pasting temperature as well as increased solubility and water binding capacity of pulverized starches imply molecular degradation of starch by pulverization. For thermal properties, onset temperature and melting enthalpy significantly decreased after pulverization, especially in normal rice starch, however there was no difference in amylose-lipid complex before andafter pulverization. The slowly digestible and resistant starch portion of normal rice starch increased after pulverization, however, in waxy rice starch, the rapidly digestible portion increased.

• Proceedings of the Korean Society of Organic Agriculture Conference
• /
• 2009.12a
• /
• pp.314-314
• /
• 2009

The effects of mixtures of each of rice hull charcoal and wood charcoal with pyroligneous acid on the cultivation and antioxidant activities of rice were investigated. Results of the total phenolic compounds, DPPH radical electron-donating ability and xanthine oxidase stress activity analyses revealed that the environment-friendly materials increased the total antioxidant capacity in rice. In the case of palatability of rice, total amylose blue value and starch-I2color reaction analyses, data showed that environment-friendly materials generally decreased the amylose content of rice. Also, the environment-friendly materials improved the rice endosperm quality.

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

• Applied Biological Chemistry
• /
• v.28 no.4
• /
• pp.239-244
• /
• 1985

Physicochcmical properties of the Lotus root starch wert investigated. The shape of starch granules was elliptical with the average size of $20{\sim}35{\mu}$. Starch showed B-type X-ray pattern. The content of amylose was 22.1%. The blue value for starch and amylose were 0.280 and 0.692, respectively. The alkali number was 4.74. By X-ray diffraction examination, gelatinization began at $55^{\circ}C{\sim}60^{\circ}C$ and almost completed at $65^{\circ}C{\sim}70^{\circ}C$.

• Bulletin of the Korean Chemical Society
• /
• v.20 no.10
• /
• pp.1153-1158
• /
• 1999

β-Cyclodextrin, amylose, and cellulose were partially methylated and acetylated in order to examine the relative reactivities of 2-, 3-, and 6-OH groups to alkylation and acylation. The partially methylated samples of the polysaccharides were treated with excess of ethyl iodide and sodium hydroxide in dimethyl sulfoxide to convert all of the free hydroxyl groups to ethyl ether groups. The partially O-ethylated and O-methylated polysaccharides were reductively cleaved with triethylsilane in the presence of trimethylsilyl methanesulfonate and borontrifluoride etherate (5 : 1 by mole) and the resulting 4-OH group was acetylated and benzoylated to form mixtures of eight 4-O-acyl-1,5-anhydroalditols. The relative ratio of the alditol esters were analyzed by gas chromatography to determine the degree of substitution at each position. A similar sequence of reactions was carried out with partially acetylated polysaccharides. The results indicated that the order of relative reactivities for methylation are 2-OH > 6-OH > 3-OH and for acylation are 6-OH > 2-OH > 3-OH regardless of the anomeric configuration.

• Proceedings of the Korean Society of Crop Science Conference
• /
• 2022.10a
• /
• pp.173-173
• /
• 2022

In this study, we investigated whether there is another amaranth GBSS isoform in an attempt to characterize the synthesis of amylose in the pericarp. We used I2/KI staining to analyze the temporal and spatial starch accumulation patterns during seed development. The spatiotemporal starch accumulation patterns in developing seeds were observed by staining with I2/KI. Starch granules were observed in the pericarp in the initial developmental stage (3 DAP). A few starch granules were detected in the perisperm in the early-late developmental stage (8 DAP), during which the pericarp starch contents rapidly decreased. Starch granules were distributed throughout the perisperm in the mid-late developmental stage (15 DAP). Similar results were reported for other cereal crops, including barley, rice, and sorghum. Starch granules in the pericarp are synthesized during the early seed developmental stages but are absent in mature seeds. We recently reported that starch deposits in the perisperm of developing amaranth seeds are detectable only after the initial developmental stage. Prior to this stage, the pericarp is the major site of starch deposition. A recent study suggested that GBSSII isoforms are responsible for amylose synthesis in pericarps.

• Proceedings of the Korean Society of Crop Science Conference
• /
• 2020.11a
• /
• pp.107-107
• /
• 2020

• Korean Journal of Food Science and Technology
• /
• v.41 no.6
• /
• pp.668-672
• /
• 2009

Cookies containing wheat flour mixed with 10, 30 or 50% esterified with octenylsuccinic anhydride (OSA, 3%) and dry-heated ($130^{\circ}C$, 2 hr) high amylose rice (Goami 2) starch (DH-OSAR) were prepared and then their physical and digestive properties were evaluated. When the amount of added DH-OSAR increased, the hardness and brittleness of the cookies decreased, and L (brightness) value increased. For the digestive properties, the cookies containing 50% DH-OSAR significantly increased the amount of slowly digestible starch (SDS), and decreased the amount of rapidly digestible starch (RDS), resulting in the lowest expected Glycemic Index (eGI) among tested cookies. Although the cookies containing DHOSAR were inferior to the control, the addition of xanthan gum (0.5% based on total powder amount) significantly improved their textural and sensory properties. Specially, the cookies containing 50% DH-OSAR and the addition of 0.5% xanthan gum showed the lowest eGI value, maintaining the improved textural and sensory properties.

• The Korean Journal of Food And Nutrition
• /
• v.25 no.4
• /
• pp.762-769
• /
• 2012

In order to study the cooking characteristics of four rice cultivars of Seolhyangchal, Baegjinju, Ilpum and Haiami, we investigated the relationship between the textures of cooked rice and their physicochemical properties. Different levels in grain weight. length/width ratio and amylose content were observed among the four rice cultivars. There was no significant difference in the amylopectin chain length distribution among the cultivars. Water absorptions of rice grains during soaking were completed between 30 and 40 min, with Haiami showing the slowest absorption. Significant differences in the viscosity properties of rice flour were found by a Rapid Visco Analyser. Baegjinju with low amylose content had the highest viscosity in paste breakdown. According to the DSC results of rice starches, there were significant differences in the onset, peak and conclusion temperatures of the endothermic peak. Gelatinization enthalpy showed energy content changes between 4.20 and 6.97 J/g, with the lowest change in Haiami. Texture properties of cooked rice were assessed using a Texture Analyzer, which showed that the hardness of cooked rice was decreased with soaking than without soaking. However, this finding was not applicable for Haiami rice.