• Food Science and Preservation
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• v.20 no.4
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• pp.539-545
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• 2013

Effects of RS4 type resistant corn starch on the quality characteristics of cookies were investigated by physicochemical, instrumental and sensory evaluation. The resistant starch was made by cross-linking of corn starch as following; corn starch slurry was annealed at pH 2.0 and $50^{\circ}C$ for 2 h followed by the cross-linking reaction. The cross-linking reaction was performed at $50^{\circ}C$ for 12 h in the presence of 1.2%/st.ds NaOH, 10%/st.ds sodium sulfate and 10%/st.ds of sodium trimetaphosphate (STMP)/sodium tripolyphosphate (STPP) mixture. Dietary fiber content of the resistant starch was estimated to be 73.8% by the AOAC method. For quality characteristics, dough pH decreased with the increase of the resistant starch content and spread factor decreased a little at 20% of the resistant starch. The moisture content and L value of cookies increased with the increase of the resistant starch content. However, the hardness and fracturability decreased with the increase of the resistant starch content. In the sensory evaluation, no significant differences were observed between the two cookies with or without the resistant starch. The results of this study suggest that the RS4 type resistant corn starch can be a good ingredient to increase dietary fiber content in cookies without changes of their qualities.

• Journal of the Korean Society of Food Science and Nutrition
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• v.32 no.8
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• pp.1193-1199
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• 2003

As a result of resistant starch yield depending on heating temperature, moisture content, storage temperature and heating-cooling cycle with RSM (response surface methodology), high amylose corn starch (46%) was appeared higher than normal corn starch in the yield (22%). At the high amylose corn starch, optimum conditions for resistant starch formation were 6 times of heating-cooling cycle, 108$^{\circ}C$ heating temperature and 67% moisture content at the 2$0^{\circ}C$ storage temperature, which resulted in 25% yield with these experiment conditions. Affecting factor for the resistant starch formation was arranged according to heating -cooling cycle, moisture content, heating temperature and storage temperature. Raw corn starch granule was destructive and appeared a porous reticular structure by the resistant starch formation. Color became dark and increased yellowness by caramelization during heating processing. Heating-cooling processing was the result of decreased hardness, cohesiveness, springiness and gumminess.

• Preventive Nutrition and Food Science
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• v.4 no.4
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• pp.215-220
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• 1999

The Physical properties of corn starch were investigated by scanning electron microscopy, X-ray diffractometry and differential scanning calorimetry during the formation of enzyme-resistant starch(RS). Samples were studied in their native states and after annealing at 50, 55, 60 and 65℃ in excess water(starch : water=1:3) for 48hr. Starch granules became smaller and more rounded after annealing than in their native state. Annealing did not change the X-ray profile of native corn starch. After autoclaving-cooling cycles, native starch lost most of its crystallinity but annealed ones showed some of their crystallinity left as diffuse or poor B-type, which didn't relate to increasing Rs yields. During formation of RS, however, both native and annealed starches changed their X-ray profile from A-type to poor B-type of retrograded amylose. Annealing caused an increase in gelatinization temperature and enthalpy, but a narrowing of gelatinization temperature range. Only starch annealed at 65℃, however, showed a decrease in enthalpy even though its gelatinization temperature increased, which appeared to be due to the partial gelatinization in the amorphous region during annealing. Peak height index(PHI), the ratio of ΔH to Ti-To, increased by annealing. PHI values, therefore, showed the possibility as an indicator to predict RS yield which cannot be differentiated by differential scanning calorimetry and X-ray diffraction data.

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

• Preventive Nutrition and Food Science
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• v.3 no.4
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• pp.303-308
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• 1998

Influence of amylose content on formation and characteristics of enzyme-resistant starch (RS) was investigated by scanning electron microscopy, X-ray diffractometry and differential scanning calorimetry. RS yield increased up to 36.1 % as the amylose content of corn starch increased. Starch granules of Amyulomaize V and Ⅶ were more rounded and smaller than those of regular corn ; some were elongated and had appendages. After autoclaving -cooling cycles, the granular structure disappeared and a continous spongy-like porous network was visible in regular corn starch ; the granular structure was stillevident in parts in Amylomaize V and Ⅶ starches. In all isolated RS residues , the porous structures were no longer visible and more compact formations predominated. While regular corn starch showed an A-type X-ray profile, Amylomaize V and Ⅶ starches exhibited a combination of B- and V-types. Regular corn starch lost most of its crystallinity during autoclaving , but the crystallinity was still left in Amylomaize starches as diffuse or poor B-types. All RS residues showed the presence of poor B-type regardless of amylose contents. Transition temperatures and enthalypy of native starches were a little higher in Amylomaize V and Ⅶ starches than those of regular corn starch . Regardless of amylose contents, all RS residues exhibited an endothermic transition over a similar temperature range (135 $^{\circ}C$~169$^{\circ}C$), with a mean peak temperature of ~154$^{\circ}C$, which is generally foud for retrograded amylose crystallities. Higher transition temperature, enthalypy, and RS yield of AMylomaize V and Ⅶ starches were related granular stability shown by the microscopic and crystallographic studies.

• Applied Biological Chemistry
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• v.40 no.3
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• pp.220-224
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• 1997

As corn starches with different amylose content were heated at different temperature $(100^{\circ}C,\;121^{\circ}C)$ with starch / water ratio (1:3.5, 1:9) and heating-cooling treatment was repeated up to 4 times, the yield of RS(resistant starch) from heated corn starches was investigated by the enzymatic-gravimetric method and the ${\alpha}-amylase$ treatment. Compared to ${\alpha}-amylase$ method, enzymatic-gravimetric method was more effective to hydrolyze the amorphous region of heated corn starch. With increasing the amylose content and the number of heating-cooling treatment, the yield of RS increased, regardless of isolation method. Heated corn starches formed at $121^{\circ}C$ provided higher yield of RS than those formed at $100^{\circ}C$. Higher RS yield was also observed in the case of starch/water ratio (1:3.5) compared to the case of ratio (1:9).

• Korean Journal of Food Science and Technology
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• v.38 no.3
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• pp.378-384
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• 2006

Intrinsic viscosity of starch irradiated with Co-60 (0.25-9.1 kGy) significantly decreased, and swelling power and solubility measured at $80^{\circ}C$ linearly increased with increasing irradiated dose. Radiation treatment up to 1 kGy increased amylose content of starch. Water-binding capacity increased rapidly up to 3 kGy. Peak viscosity of irradiated starches by Rapid visco Analyser and Visco/amylo/Graph indicated that the decrease in peak viscosity was dose-dependent. Gamma irradiation showed no effect on endothermic temperatures of irradiated starches, but decreased endothermic enthalpy with increasing dose level. Viscosity of starch autoclaved at $120^{\circ}C$ and air-dried significantly decreased with increasing irradiation dose. Resistant starch content slightly decreased upon irradiation.

• Applied Biological Chemistry
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• v.27 no.3
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• pp.214-216
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• 1984

Alkali gelatinization of rice, corn, arrow root and ginger root starches at various sodium hydroxide concentrations was investigated. Critical concentrations of alkali for starch gelatinization ranged from 2.33 to 3.17 meq NaOH per gram of starch. Ginger root starch was most resistant to alkali gelatinization and arrow root starch was least stable to alkali.

• 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.

• Food Science and Biotechnology
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• v.17 no.4
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• pp.755-760
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• 2008

The aim of this study was to produce resistant starch preparations from acid-modified com starches prepared at various hydrolysis levels (0.5-4.0 hr). Effect of autoclaving cycles on resistant starch (RS) formation was investigated. Molecular weight distribution, pasting and functional properties of acid-modified com starches were determined. For RS formation native and acid-modified starch samples were gelatinized and autoclaved (1 or 2 cycles). While native and acid-modified starches did not contain any RS, the levels increased to 9.0-13.5% as a result of storage at $95^{\circ}C$ after first autoclaving cycle. Second autoclaving cycle together with storage at $95^{\circ}C$ brought final RS contents of the samples incubated at 4 and $95^{\circ}C$ after the first cycle to comparable level. As acid modification level increased, the amount of high molecular weight fractions decreased, resulting in significant decreases in viscosities (p<0.05). The samples produced in this study had low emulsion stability and capacity values.