• Korean Journal of Food Science and Technology
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• v.26 no.2
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• pp.117-122
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• 1994

The characteristics of amylose-lipid complex(AL-complex) and cyclodextirn-lipid complex(CL-complex) were investigated by using Differential Scanning Calorimetry(DSC). The enzymatic hydrolysis of amylose which was liberated from AL-complex by the addtion of ${\beta}-cyclodextrin({\beta}-CD)$was also studied. The melting temperatures of AL-complex in corn, wheat, and rice starch were above $100^{\circ}C$ and there were no differences among them. In the presence of lysolecithin, the melting enthalpy and temperature of AL-complex were increased and lysolecithin was very effective in the formation of AL-complex. When ${\beta}-CD$ was added to AL-complex, the endothermic peak of AL-complex at $100^{\circ}C$ decreased and that of CL-complex at $70^{\circ}C$ appeared. These results indicated that the amylose was released from AL-complex by substituting ${\beta}-CD$ for amylose, then by forming CL-complex. As the added amount of ${\beta}-CD$ increased, the peak of AL-complex decreased whereas that of CL-complex increased. Enzymatic hydrolysis rate of AL-complex increased in the presence of ${\beta}-CD$, suggesting that amylose was dissociated from AL-complex and hydrolyzed by amylase.

• 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.

• 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.

• Korean Journal of Food Science and Technology
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• v.20 no.3
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• pp.331-337
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• 1988

The thermal properties of typical five Indica and five Japonica rice varieties were investigated by Differential Scanning Calorimetry (DSC). There was no significant difference in gelatinization temperature between Indica and Japonica varieties, but the average enthalpy of gelatinization was larger in Indica types than that in Japonica. However, the enthalpy of melting of amylose-lipid complex was larger in Japonica types than that in Indica types. The DSC thermogram of hydrolyzed rice residue included a smaller peak of gelatinization with narrow range of temperature. Retrogradation of gelatinized rice kernel was also determined with DSC theremograms. The endothermic peak areas clearly increased with increasing storage time at $4^{\circ}C$ so that the area could be used as a measure of the relative degree of retrogradation. The results indicated that Samgang variety(Indica) retrograded more rapidly than Chuncheong variety(Japonica).

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

• Food Science and Biotechnology
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• v.16 no.6
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• pp.902-909
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• 2007

Granular maize starch was treated with Thermus scotoductus 4-${\alpha}$-glucanotransferase (${\alpha}$-GTase), and its physicochemical properties were determined. The gelatinization and pasting temperatures of ${\alpha}$-GTase-modified starch were decreased by higher enzyme concentrations. ${\alpha}$-GTase treatment lowered the peak, setback, and [mal viscosity of the starch. At a higher level of enzyme treatment, the melting peak of the amylose-lipid complex was undetectable on the DSC thermogram. Also, ${\alpha}$-GTase-modified starch showed a slower retrogradation rate. The enzyme treatment changed the dynamic rheological properties of the starch, leading to decreases in its elastic (G') and viscous (G") moduli. ${\alpha}$-GTase-modified starch showed more liquid-like characteristics, whereas normal maize starch was more elastic and solid-like. Gel permeation chromatography of modified starch showed that amylose was degraded, and a low molecular-weight fraction with $M_w$ of $1.1{\times}10^5$ was produced. Branch chain-length (BCL) distribution of modified starch showed increases in BCL (DP>20), which could result from the glucans degraded from amylose molecules transferred to the branch chains of amylopectin by inter-/intra-molecular transglycosylation of ${\alpha}$-GTase. These new physicochemical functionalities of the modified starch produced by ${\alpha}$-GTase treatment are applicable to starch-based products in various industries.

• Korean journal of food and cookery science
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• v.32 no.1
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• pp.9-15
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• 2016

The changes of resistant starch (RS) contents of cooked rice with soybean and coconut oils under different storage conditions were investigated and RS contents were compared between the rice and cooker types. The japonica (Hopyeong) and the indica (Thailand) type rice were cooked (washed rice: water = 100: 130) using an electric cooker and a saucepan. The coconut oil and soybean oil (3%, based on rice, w/w) were added into cooking water before heating. The RS contents of freeze-dried cooked rice powders (newly-cooked rice, stored for 12 h in the refrigerator, microwave heating after storage for 12 h in the refrigerator) were measured by the AOAC method. The RS contents of cooked rice using a saucepan were higher than those using an electric cooker. The indica type cooked rice had a higher RS content than the japonica type cooked rice, regardless of storage conditions. However, addition of oil before cooking rice resulted in increased RS content on storage in the refrigerator. The highest RS content of the cooked indica type rice with soybean oil ($5.89{\pm}0.22%$) that was stored for 12 h in the refrigerator was analyzed. The results suggested that the cooked rice formed retrograded (RS3) and amylose-lipid complex (RS5) type RS; furthermore, the RS content is affected by storage conditions, rice, cooker and oil types.

• Korean Journal of Food Science and Technology
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• v.32 no.3
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• pp.500-506
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• 2000

The effects of sodium stearoyl lactylate(SSL) on the thermal properties of wheat starch and amylopectin, and the crystallinity properties of amylopectin were investigated using differential scanning calorimetry(DSC) and X-ray diffractometer. On the rescan(second heating), amylopectin produced the featureless thermogram shown at the second heating, and SSL alone melted at $40{\sim}55^{\circ}C$, while the mixture of amylopectin containing 8% water and SSL(10:1), presenting the evidence of AP-SSL complex, showed differentiate melting temperature(other crystallinity) from SSL alone. Also, the melting enthalpy of AP and SSL mixture by subsequent heating and cooling were continuously increased. Further, the mixtures of wheat starch: SSL (5:1, w/w) and amylopectin: SSL(5:1, w/w), indicated AP-SSL complex, showed the reversible melting peak at temperature range of $60{\sim}70^{\circ}C$ together with melting peak of SSL observed at temperature range of $40{\sim}55^{\circ}C$. AP-SSL complex in the X-ray diffraction, compared V-form of amylose-lipid complex, exhibited characteristic peaks($2{\theta}$, 5.57, 20.903, 23.227). The gelatinization enthalpy value of wheat starch in the presence of SSL, observed at temperature range of $50{\sim}70^{\circ}C$, was decreased at total water content 60%, whearas had no significant effect at total water content 40, 50%, and also, SSL increased melting enthalpy of amylose-lipid complex. The extent of AP and wheat starch retrogradation wasreduced significantly by SSL.

• Korean Journal of Food Science and Technology
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• v.52 no.6
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• pp.655-660
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• 2020

High amylose corn starch and dextrin (acid-treated at 30, 40 and 50℃ denominated as Dextrin30, Dextrin40 and Dextrin50) were added to non-fried instant noodles. X-ray diffraction pattern, water absorption, cooking loss, microstructure, and textural properties of non-fried instant noodles were investigated. The addition of high amylose corn starch/dextrin induced a slight peak intensity at 20o in the X-ray pattern indicating the insignificant formation of amylose-lipid complex. Non-fried instant noodles including high amylose corn starch/dextrin showed lower water absorption than the control. Dense microstructure in transverse section of noodles was observed in non-fried instant noodles including high amylose corn starch/dextrin except Dextrin50. Also, the addition of high amylose corn starch/dextrin induced low tensile strength, high firmness, and high stickiness. However, non-fried instant noodles containing Dextrin50 showed a loose microstructure and high cooking loss (3.98%), which might be associated with the textural properties such as the lowest tensile strength (0.17 N), lowest increase in firmness (46.77 N) and highest stickiness (18.43 N).

• Applied Biological Chemistry
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• v.40 no.6
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• pp.508-513
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• 1997

Thermal characteristics and granular morphology on enzyme-resistant starches (RS) formed during heat-moisture treatment (HMT) and retrogradation were investigated in high amylose corn starches, Hylon V and Hylon VII. With each treatment, both starches showed a similar trend in the increase of RS, but RS yield of Hylon VII is higher than that of Hylon V. Specially, RS was increased remarkably by HMT. It was more than doubled from 11.4% to 26.6% for Hylon V and from 15.9% to 32.8% for Hylon VII. A small increase of RS resulted from retrogradation. HMT on starch increased gelatinization temperature, decreased enthalpy. Retrograded starch exhibited small three endothermic transitions at $94^{\circ}C$, $110^{\circ}C$ and $140^{\circ}C$ in differential scanning calorimetry (DSC) thermogram due to the remained ungelatinized starch granules, dissociation of amylose-lipid complex and melting of recrystallized amylose, respectively. Enzyme-resistant starches isolated from native and heat-moisture treated starches showed a broad endothermic transition at higher temperature than native starch, while retrograded starch exhibited a very sharp peak at ${\sim}150^{\circ}C$ due to the melting of amylose crystallites. Under microscopy, starch granules with HMT was not changed, but retrograded starches showed the aggregates of starch granules because amylose leached out during gelatinization. Iodine stained RS clearly showed the differences in enzyme hydrolysis on the native, heat-moisture treated and retrograded starches.