• Korean Journal of Food Science and Technology
• /
• v.30 no.1
• /
• pp.42-48
• /
• 1998

Physicochemical properties of waxy maize starch and oxidized waxy maize starch with sodium hypochlorite $(0{\sim}60\;mg\;CL_2/g\;starch,40^{\circ}C,\;pH\;10,\;3.0\;hr)$ were studied. As sodium hypochlorite concentration was increased, the content of crude lipid and crude protein of the oxidized starch were decreased. And crude protein content and whiteness was considered to show negative regression. However, the crude ash content of the oxidized starch increased significantly with oxidation and bore a positive regression to the chlorine content. There was a progressive increase in the carboxyl content with increasing oxidant level. After pasting in hot water and cooling, viscosity of the oxidized starches were drastically lower than that of native starch . As carboxyl contents of the oxidized starch increased, the solubility and swelling power was increased. When waxy maize starch treated with 0, 1.5, 3.0 and 6.0% sodium hypochlorite, temperature of initial gelatinization of oxidized starch was shown to 65, 65, 60 and $50^{\circ}C$, respectively. The oxidized waxy maize starches also form clearer pastes. Water binding capacity of the oxidized starch decreased as the degree of carboxyl group substitution increased. Waxy maize starch has polygonal and some round granules which range from about 3.7 to $20\;{\mu}m$ in diameter. Surface appearance of the waxy maize starch became rough when oxidized with sodium hypochlorite. When homogenate of the oxidized waxy maize starch solution and corn germ oil was stored under room temperature for 24 hours, the emulsion stability was considered to depend on starch concentration and degree of substitution.

• Korean journal of food and cookery science
• /
• v.12 no.2
• /
• pp.207-213
• /
• 1996

Effects of replacement of corn starch with Amylomaize Vll starch and addition of enzyme-resistant starch on texture characteristics of com bread (CON) were investigated. Amylomaize-substituted corn bread (AMZ) was made by replacing corn starch with Amylomaize Vll starch. 15% (RSl5) and 30％ (RS30) of butter, was replaced with enzyme-resistant starch (RS) from Amylomaife Vll starch, respectively. Textu,e describing terms were classified according to their physical properties. Result of sensory evaluation characteristics showed that the size of air cells increased as butter replacement level decreased and that hardness increased but springiness decreased as com starch was replaced with Amylomaize Vll starch. The results of Texture Profile Analysis with deformation of 30% and 50% showed that hardness inclosed but cohesiveness decreased as cooling time increased.

• Membrane Journal
• /
• v.29 no.3
• /
• pp.164-172
• /
• 2019

In this work, we demonstrate a facile process to prepare an electrolyte membrane for the supercapacitor based on a graft copolymer consisting of starch and poly(acrylonitrile) (PAN). The graft copolymer (starch-g-PAN) was synthesized via free radical polymerization initiated by ceric ions. The starch-g-PAN was dissolved in ionic liquid, i.e. 1-ethyl-3-methylimidazolium dicyanamide (EMIM DCA) without any organic solvents at room temperature. The gelation of polymer electrolyte membranes occurred by applying high temperature, i.e. $100^{\circ}C$ for 1 hour. The resultant electrolyte membrane was flexible and thus applied to flexible solid supercapacitors. The performance of the supercapacitor based on starch-g-PAN graft copolymer electrolyte reached 21 F/g at a current density of 0.5 A/g. The cell also showed high cyclic stability with 86% of retention rate within 10,000 cycles. The preparation of starch-g-PAN based polymer electrolyte membrane provides opportunities for facile fabrication of flexible solid supercapacitors with good performance.

• Korean Journal of Food Science and Technology
• /
• v.20 no.3
• /
• pp.412-418
• /
• 1988

Granular shapes and sizes, physicochemical priperties and gelatinization patterns of sweet potato starches from Wonki(the dry type) and Chunmi(the moist type) were investigated. Starch granules of sweet potatoes were round. Granule sizes of Wonki starch were mainly $11{\mu}m$ and those of Chunmi starch were $12{\mu}m\;and\;17{\mu}m$. Wonki starch had lower water binding capacity and swelling power than Chunmi starch. But Wonki starch had higher amylose content, gelatinization temperature, miture content for gelatinization and temperature for gelatinization than Chunmi starch.

• Korean Journal of Food Science and Technology
• /
• v.23 no.1
• /
• pp.116-121
• /
• 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
• /
• v.28 no.1
• /
• pp.1-8
• /
• 1999

Starch was isolated from nine Korean sweet potato varieties(Shinmi, Seangmi, Yulmi, Shinyulmi, Sunmi, Jeungmi, Mokpo 26, Mokpo 29, and Mokpo 30) and analysed in its physicochemical properties in comparison with a commercial sweet potato starch(Kumokanyu) imported from China. Protein content in the isolated starch was highest(1.1%) in Mokpo 29 and lowest(0.3%) in Kumokanyu, whereas lipid content was equally less than 0.2%. Pasting analysis by Rapid Viscoanalyser(RVA) showed that Yulmi starch had the lowest pasting temperature(70.2oC) whereas Kumokanyu did the highest one (74.3oC). Under a differential scanning calorimetry(DSC), however, Kumokanyu showed the lowest onset temperature(61.8oC) and enthalpy(42.0 J/g) for crystal melting. Shinyulmi showed the highest peak viscosity of the starch paste, but shear thinning was significant like commercial potato starch. Kumokanyu, however, displayed the least peak visicosity but good shear stability. With the starch gels prepared at 4oC, Mokpo 29 showed the highest hardness, whereas Shinyulmi did the lowest one. Against repeated freeze thawing treatments, the starch gel of Kumokanyu was most stable, and among the Korean varieties, Yulmi, Shinyulmi, Jeungmi and Mokpo 26 had good stability. According to the chain distribution analysis, Shinyulmi and Mokpo 29 consisted of larger quanitites of shorter amylopectin chains than Kumokanyu, potato and corn starches.

• The Korean Journal of Food And Nutrition
• /
• v.30 no.4
• /
• pp.689-695
• /
• 2017

Ohmic heating is an internal heating method based on the principle that when an electrical current passes through food, electric resistance heat is uniformly generated internally by food resistance. Previous studies indicate that the thermal properties, external structure, internal structure, and swelling power of ohmic heat treated starch of various starches, such as potato, wheat, corn, and sweet potato, differed from those of conventional heating at the same temperature. In this study, the pasting property of starch, treated with ohmic and conventional heating, were measured by RVA (Rapid Visco-Analyzer). Our results show that as the ohmic heating temperature increased, the PV (Paste Viscosity) of the starch decreased significantly, and the PT (Pasting Temperature) increased. Changes in PV and PT indicate that the swelling of starch remains unchanged by ohm heating. The HPV (Hot Paste Viscosity), CPV (Cold Paste Viscosity) and SV (Setback Viscosity) of ohmic heated starch also differed from the conventional heated starch. The pasting property is similar to the viscosity curve of common cross-linked modified starch. In this experiment, we further confirm the similarity with modified starch and its usability.

• Food Science and Preservation
• /
• v.21 no.2
• /
• pp.286-293
• /
• 2014

In this study, one GRAS strain was screened from doenjang, a traditional Korean fermented food, as a microorganism producing amylase due to the formation of a clear zone on the medium including soluble starch. From the analysis of the gene sequence of 16S ribosomal RNA, the strain was identified as Bacillus subtilis and was therefore named Bacillus subtilis CBD2. When the nutrient broth medium was prepared with 3% NaCl, 5% glucose, and the initial medium pH 7.0, the B. subtilis CBD2 showed maximum growth. Among soluble starch, corn starch, maize amylopectin, and wheat starch, soluble starch was the most effective carbon source in the production of amylase by B. subtilis CBD2. The amylase from B. subtilis CBD2 showed the highest activities at pH 8.0 and $50^{\circ}C$, and corn starch was the most proper substrate for the enzyme activity. When corn starch was used as a substrate, the production of sugars through enzyme activity increased for 24 h, and then the enzyme activity became constant.

• Applied Biological Chemistry
• /
• v.50 no.3
• /
• pp.160-166
• /
• 2007

This study was performed to analyze the molecular structural and physical properties changes of modified rice starch, which particle structure was broken using high impact planetary mill and ultra fine pulverizing techniques. The average diameter and specific surface area of rice starch after pulverization decreased 20% and increased 25%, respectively. Low molecular substances content in rice starch using GPC (gel permeation chromatography) increased from 36.5% to 59.5% after pulverizing of rice starch. Damaged starch contents in rice starch also increased from 16.4% to 99.2% after pulverizing of rice starch. Water holding capacity, solubility and transmittance of rice starch after pulverization increased compared to those of control. Apparent viscosity value of rice starch after pulverization decreased to 7% in control based on $30^{\circ}C$ and 20 RPM conditions.

• Korean journal of food and cookery science
• /
• v.19 no.1
• /
• pp.65-71
• /
• 2003

The objective of this study was to compare the textural properties and sensory evaluation of Injulmi, a traditional Korean waxy rice cake, added with 10, 20 and 30% of RS3-type resistant starch. RS3-type resistant starch was prepared from nonwaxy rice(Odaebyeo) starch by autoclaving-cooling cycle. The RS yield of RS3-type resistant starch was 9.10%. By increasing the addition level of RS3-type resistant starch, the hardness and adhesiveness of Injulmi increased as measured by using a rheometer. Hunter color L and a values of Injulmi added with RS3-type resistant starch were increased, but b value was decreased. In case of sensory evaluation, the hardness of Injulmi added with RS3-type resistant starch was higher than that of non-added Injulmi. The overall duality of Injulmi added with RS3-type resistant starch by sensory evaluation was negatively correlated with the hardness measured by rheometer(p＜.0.05).