• Journal of the Korean Home Economics Association
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• v.23 no.1
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• pp.33-47
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• 1985

The rheological properties of acorn starch gel were investigated in region of small and large deformation. The properties were compared with those of potato and wheat starch gel. On the physical characteristics and the effect of tannin contents of acorn starch were examined. RESULTS : 1. X-ray diffractogram of acorn starch showed C-type and its granules swelled gradully with heating. 2. Hardness, brittleness and both small and large deformation of the acorn starch gel were remarkably large, also the concentration dependence of the acorn starch gel could be recognized in small deformation and hardness. 3. The Young's modulus of Hookean body in small deformation and the rupture stress in large deformation differed obviously from the parameters of rheological properties in various gels. 4. It was found that the selling power, viscosity and rhelogical properties were affected obviously by the tannin.

• Korean journal of food and cookery science
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• v.8 no.1
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• pp.9-14
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• 1992

The morphological properties of acorn starch granules and starch gels were examined with scanning electron microscope and X-ray diffractometer. The shape of acorn starch granule was rounded triangular and some elliptical. The size distribution of starch granule was also analyzed. The mean value of minor axis, major axis and the ratio of those were 4.785 $\mu\textrm{m}$, 7.30 $\mu\textrm{m}$ and 0.68, respectively. The surface micro-structure of acorn starch gels were investigated by SEM. Acorn crude and refined starch gel were very different in surface micro-structure. X-ray diffraction pattern of acorn starch was C-type, and the pattern of acorn starch gels were extremely different because of disintegration of starch granules by gelatinization. The diffraction intensity of acorn refined starch gel was slightly higher than crude starch gel.

• Journal of the Korean Society of Food Science and Nutrition
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• v.20 no.2
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• pp.173-178
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• 1991

The rheological properties of acorn crude starch gel and refined starch gel were investigated by puncture test, back-extrusion test and retrogradation test. Puncture test was a useful method to compare the different gel type and concentration, and to calculate the compression and shear coefficient. Maximum extrustion force and adhesiveness were also examined by performing back-extrustion test. The retrogradation rate was analysed by Avrami equation in retrogradation test.

• Korean Journal of Food Science and Technology
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• v.30 no.4
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• pp.803-810
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• 1998

The mechanical and thermal properties of solutions of acorn starch were investigated, to determine the effect of sucrose on the retrogradation. The contents of moisture and amylose of purified acorn starch was 9.35, 27% respectively. From the moecular weight distribution, Mw and Mn of acorn starch were 1,220,432 and 137,201 relatively and the polydispersity of acorn starch was 8.8952. The creep compliance of acorn starch with and without sucrose were decreased with increasing sucrose concentration in the short term. The temperatures of DSC curve of 15% acorn starch solution containg sucrose shifted slightly to higher temperatures with increasing sucrose content. The enthalpy change associated with the gelatinization was increased with increasing sucrose content. After 7 days storage, the creep compliance of acorn starch gel with sucrose were shown higher than acorn starch gel. Regelatinization enthalpy of acorn starch/sucrose/water system was decreased with increasing sucrose content and increased with storage time. In addition, the characteristic temperatures such as onset temperature, peak temperature and conclusion temperature was increased by sucrose addition. Retrogradation ratio decreased with increasing sucrose content, thus sucrose inhibit retrogradation in the long term. Sucrose acts as an antistaling reagents and retatards the retrogradation.

• Korean journal of food and cookery science
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• v.5 no.1
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• pp.49-52
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• 1989

Stress relaxation tests with different percent deformation were performed for crude and refined starch gels of acorn. With no relation to percent deformation, refined starch gel had higher initial stress ($\sigma_e$) and lower equilibrium stress ($\sigma_e$) than crude starch gel. But the ratio of equilibrium stress to initial stress ($\sigma_e$/$\sigma_o$) was minimum at 60 percent deformation. The analysis of relaxation curves by successive residual method revealed that the rheological behavior of acorn starch gels could be expressed by generalized Maxwell model. The element numbers of models for crude and refined starch gel were 7-element and 5-element at 60 percent deformation, and 5-element and 3-element at 45 percent deformation, respectively.

• Korean Journal of Food Science and Technology
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• v.32 no.6
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• pp.1291-1297
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• 2000

Particle size distribution, pasting properties by Rapid Visco Analyser, and textural properties of acorn, mungbean and buckwheat starches, which are the basic raw materials for mook, are compared. The major particle size of mungbean starch was $10{\sim}30$ micron, whereas acorn and buckwheat starches were $5{\sim}20$ micron. At the same starch concentration, mungbean starch had the highest peak viscosity, breakdown and setback. Acorn starch showed the lowest peak viscosity and breakdown. The peak viscosity of buckwheat starch was close to that of mungbean, however the trough and final viscosity were comparable to those of acorn starch. At the same peak viscosity, mungbean starch showed the lowest trough and final viscosity and the highest breakdown and setback. Acorn starch was differentiated from buckwheat starch in that the former had the higher value of setback. The textural properties of mungbean starch gel were significantly different from others. The texture of gels from acorn and buckwheat starches revealed that only the hardness and gumminess were different each other. The hardness of starch gels were negatively correlated with trough and final viscosity, and positively correlated with setback.

• Korean journal of food and cookery science
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• v.7 no.1
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• pp.11-14
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• 1991

The physical properties of acorn and chestnut gels by various heating temperature were investigated. In microsturcture analysis by SEM, acorn starch gels of 9$0^{\circ}C$$90^{\circ}C$ showed regular three dimensional network structure and chestnut starch gels had finer porous network from $70^{\circ}C$. X-ray diffraction patterns of two starch gels showed very weak peak at 8~$10^{\circ}C$ and 16~$19^{\circ}C$. Hardness had the highest value at $90^{\circ}C$ and $98^{\circ}C$ for acorn gels, and $80^{\circ}C$ for chestnut gels. But cohesiveness increased with heating temperature in both of two starch gels.

• Korean journal of food and cookery science
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• v.11 no.2
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• pp.158-163
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• 1995

This study was surveyed and compiled the contribution about acorn in korea .the physico-chemical properties of acorn and acorn starch. preparation of acorn starch and elimination of the acorn tannin, the rheological properties of acorn starch gel. Nutrition of acorn and antioxidative activity of tannin in acorn extract. The result obtained were as follow. 1. The chemical compositions of acorn were water 6.5∼13.7%, crude ash 1.9∼3.4%, crude fat 1.1∼5.0%, crude protein 5.8∼7.8%, crude fiber 2.1∼3.6%, N-free extract 71∼77.5%, total tannin 4.6∼9.3%, Ca 92.7∼460.9mg%, p 80.0∼740.9mg%, Na 66.2∼93.9 mg%, and K 867.9∼983.1mg%. 2. The acorn tannin was extracted with water, acetone, and ethanol. The generation method was wash SE settling method with water. 3. The shape of acorn starch granule was rounded triangular and some elliptical, rasing power 12.4∼12.5, Blue value 0.43∼0.47, Alkali number 10.8∼11.3, Amount of Arnylose 28.8∼30.50% Tannin contents on the initial go tim-zation temperature of acorn starch were not influenced but maximum and cooling viscosity o the acorn starch were decreased. 4. Nutritional effect and diet absorption rate were not influence, by rice and 20% T-A(elimination of tannin from the acorn) mixed diet, and the content of lipid in s rum were not influenced by rice 40% and T-A (elimination of tannin from the acorn) mixed diet. 5. jallic acid, digallic acid, gallotannin were contained in acorn powder extract. The main antioxidative : stlvity was speculated due to the gallic acid.

• Korean Journal of Food Science and Technology
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• v.25 no.6
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• pp.649-654
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• 1993

We investigated the texture of the sweet potato starch gels treated with maltogenic amylase. Effects of branched gluco-oligosaccharides and acorn starch on the texture of the sweet potato starch gel were also investigated. Hardness and cohesiveness of gels were measured by using Instron and sensory evaluation on the gel properties was performed. From the results of the instrumental analysis, it was found that the overall textural properties as Mook could be improved by adding branched glucooligosaccharides, maltogenic amylase or acorn starch to the sweet potato starch gel. As a result, there was a decrease in the cohesiveness of gels while the hardness of gels increased. The sensory evaluation study indicated that the sweet potato starch gels treated with 0.02% maltogenic amylase, or added with 12.5% branched gluco-oligosaccharides, or mixed with 50% acorn starch had preferable quality as Mook.

• Food Science and Preservation
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• v.11 no.4
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• pp.496-502
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• 2004

Purified acorn starch was obtained from alkali precipitation method. Acorn amylose and acorn amylopectin were fractionated from purified acorn starch by butanol improvement method. Gel permeation chromatography (GPC) was used to measure molecular weight distribution of acorn starch, acorn amylose, acorn amylopectin and corn starch, corn amylose, corn amylopectin. GPC measurement diagrams were obtained by each retention time. And then, we used DMSO and DMF as solvent, pullulan as standard material. We calculated the Number-average molar mass (Mn), Weight-average molar mass (Mw) and polydispersity from molecular weight distribution of each sample. As a result of estimating molecular weight using GPC, Mw of amylose has small value than Mw of amylopectin. From this fact, the molecular structural aspects of amylose and amylopectin were predicted and it was in good agrement with the tendency of polydispersity by GPC. The polydispersity of starch had big value than amylose and amylopectin, from this result, it might be known that the range of molecular weight appeared broad by heterogeneous properties of two components. The viscosity of purified acorn starch, amylose, amylopectin seperated from acorn starch, was decreased by increasing the shear rate and raising the temperature exponentially. Acorn starch solutions exhibited pseudoplastic power law fluid behavior.