• Food Engineering Progress
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• v.13 no.4
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• pp.335-340
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• 2009

This study was performed to analyze changes in the molecular structural and physical properties of modified corn starch, in which particle structure was broken using high impact planetary mill and ultra fine pulverizing techniques. The average diameter and specific surface area of the modditied corn starch after pulverization decreased 50% and increased 567%, respectively. Content of low molecular substances mersured using gel permeation chromatography (GPC) increased from 21.0% to 86.5% after pulverizing corn starch. Damaged starch content also increased from 9.63% to 83.57% after pulverizing corn starch. After pulverization, gel formation capacity corn starch was reduced compared to that of control by structure breakdown.

• Korean Journal of Food Science and Technology
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• v.27 no.5
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• pp.757-761
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• 1995

The relationship between the molecular structure of rice starch and the texture of cooked rice was investigated using hot-water soluble rice starch. The structure of hot-water soluble starch bound amylose which was composed of small molecular weight and amylopectin which was composed of chain length of $\overline{DP}\;10{\sim}20$, and the average composition of amylose : amylopectin was 7 : 3. The molecular weight of amylose was the smaller and super long chain of amylopectin was the fewer, the extractable ratio of hot-water soluble rice starch was the higher. And hot-water solubility of rice starch be responsible for molecular structure of starch. On the texture of cooked rice, the extractable ratio of hot-water soluble rice starch was the higher, the hardness was the lower and the adhesiveness was the higher. The results suggest that the molecular structure of rice starch could be responsible for the texture of cooked rice.

• Journal of Biosystems Engineering
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• v.22 no.4
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• pp.439-450
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• 1997

Most of Korean feed mill has a pregrind system which was suitable for the processing of less number of ingredients and finished products, and good for the mash type feed product. But industries has been changed in production volume and cost, and also from mash to further processed products such as pelleted and extruded. Therefore, Korea feed industries now should change the process, especially the grinding system from the current pregrind to other grind system, but this change will cost a lot of investment and also loosing current grinding system, and should have production shut down during the construction period. To solve these problems, combined grinding system based on a new model mill has been developed. The combined grind system is combination of pregrind and postgrind system, which has the advantages of those two grind systems, and also which can allow to utilize existing pregrind system continuously without any production interruption due to new postgrind system construction. This newly developed model has been applied to the feed mill expansion project of `B`feed company in 1994, and it was very successful application and showed excellent results as we intended. The new model mill, combined grind system applied can save fixed asset investment because old pregrind system can be used as is, and also can reduce production cost and improve product quality. And the possibility of critical production shut down can be much lowered. Within this new grinding model development, multi-screen combination system has been developed for the better grinding texture quality and safer operation. This new model mill with combined grind system will be applied by most feed manufacturing plant and may enhance their production competitiveness, and the further study and development should be continued.

• Korean Journal of Food Science and Technology
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• v.53 no.6
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• pp.749-755
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• 2021

The objective of this study was to investigate the physicochemical properties of rice starch extracted from stale rice using alkaline steeping (AKL) and improved enzymatic digestion (iENZ) methods. The crude protein content (0.5-0.7%) of stale rice starch (SRS) was less than 1% by iENZ, but not so when measured by the existing ENZ methods. SRS is an intermediate amylose rice starch. AKL-SRS and iENZ-SRS exhibited typical A-type crystal packing arrangements with similar relative crystallinities. iENZ-SRS showed higher gelatinization onset and peak temperatures with a narrower gelatinization temperature range, compared to those of AKL-SRS, indicating that iENZ annealed SRS. Thus, iENZ-SRS exhibited lower swelling power and solubility, and higher pasting viscosities with delayed viscosity development. Overall, the use of stale rice as a rice starch source could make economical production of rice starch possible, and iENZ may diversify rice starch characteristics, which expands the utilization of rice starch in food and non-food industries.

• Korean Journal of Food Science and Technology
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• v.53 no.6
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• pp.731-738
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• 2021

This study investigated the physicochemical properties of rice starch isolated from broken rice using alkaline steeping (AKL) and enzymatic digestion (ENZ) methods. Broken rice starch (BRS) by AKL and ENZ possessed crude protein contents (0.6-1.4%) acceptable to commercial products of native starch and belonged to an intermediate amylose rice starch. AKL-BRS and ENZ-BRS showed a typical A-type crystal packing arrangement with small variations in their relative crystallinity. ENZ-BRS exhibited higher gelatinization onset and peak temperatures, and a narrower gelatinization temperature range than AKL-BRS, indicating that annealing occurred in ENZ-BRS. Lower swelling power and solubility were generally observed in the ENZ-BRS. ENZ-BRS also showed slower viscosity development, higher peak and trough viscosities, and lower breakdown, final, and setback viscosities, compared to those in AKL-BRS. These results are ascribed to the annealing phenomenon in ENZ-BRS. Overall, BRS from cheap broken rice using AKL and ENZ could contribute to the expansion of rice starch utilization in food and non-food industries.

• Korean Journal of Food Science and Technology
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• v.27 no.1
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• pp.105-111
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• 1995

The relationship betwwen the molecular structure of amylopectin and the texture of cooked rice was investigated using Korean rice [3 varieties of Japonica type and 3 varieties of Tongil type(Japonica-Indica breeding type)]. The molecular structure of rice amylopectin was polymodal and distributed A chain of $\overline{DP}$ 12.4, short B chain of $\overline{DP}$ 20.6, B chain of $\overline{DP}$ 26.3, long B chain of $\overline{DP}$ 45 and super long chain of above $\overline{DP}$ 55. The super long chain of amylopectin was composed of long linear chain with poorly branched chain. Also, the super long chain of amylopectin showed positive correlated with average chain length, inherent viscosity and ${\beta}-amyloysis$ limit$({\%})$, but negative correlated with ${\lambda}max$ of iodine reaction of amylopectin. The structural properties of amylopectin in Japonica type were different from those of amylopectin in Tongil type. In relationship between molecular structure of amylopectin and texture of cooked rice, the average chain length, inherent viscosity, ${\beta}-amyloysis$ limit and super long chain of amylopectin was showed a positive correlation with hardness, but a negative correlation with adhesiveness of cooked rice. The long chain of rice amylopectin is the less, the eating quality of cooled rice was the better. These results suggest that the molecular structure of rice amylopectin could be responsible for the texture of cooked rice.

• Applied Biological Chemistry
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• v.43 no.4
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• pp.241-246
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• 2000

In order to investigate structural properties of Chindo black rice(grown in Chindo, Chonnam) starch and its amylopectin, Chindo black rice was investigated in comparison to Shinsun waxy rice. The maximum absorbance wave and intrinsic viscosity of Chindo black rice starch and Shinsun waxy rice starch were 523 nm, 521 nm and 183 ml/g, 178 ml/g, respectively. ${\beta}-amylolysis$ limit(%) of Chindo black rice and Shinsun waxy rice starch were 62.8% and 60.3%, respectively. Chindo black rice was determined to be a waxy rice due to the results of iodine reaction and elution profile on Sephroce CL-2B. The chain of amylopectins in Chindo black rice distributed fraction 1$(F_1)$ of above degree of polymerization$({\overline{DP}})$ 55, fraction 2$(F_2)$ of ${\overline{DP}} $40{\sim}50$ and fraction 3$(F_3)$ of ${\overline{DP}} $15{\sim}20$, and the ratio of $F_3$ to $F_2$ for Chindo black rice was higher than that for Shinsun waxy rice. The super long chain of amylopectin in Chindo black rice was consisted much more than that of Shinsun waxy rice. ${\beta}-limit$ dextrins in Chindo black rice amylopectin distributed $F_1$ of above ${\overline{DP}} 55, $F_2$ of ${\overline{DP}} $30{\sim}45$ and $F_3$ of ${\overline{DP}} $10{\sim}20$. Little difference was shown between elution patterns of the pullulanase treated ${\beta}-limit$ dextrins of Chindo black rice amylopectin and Shinsun waxy rice amylopectin. These results suggest that Chindo black rice starch was similar to Shinsun waxy rice starch.

• Korean journal of food and cookery science
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• v.17 no.4
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• pp.391-398
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• 2001

This study was carried out to investigate the effects of storage temperature(5$\^{C}$ and 25$\^{C}$) and time(1, 24, 48 and 72hours) on the retrogradation characteristics of mungbean starch gels by using differential scanning calorimeter, rapid visco-analyzer, $\beta$-amylase method, X-ray diffractometer and scanning electron microscope. Endothermic peaks of gels stored at 5$\^{C}$ were shifted to the lower temperature than those stored at 25$\^{C}$ and endothermic enthalpy of gels stored at 5$\^{C}$ was greater than that stored at 25$\^{C}$. DSC thermograms showed that the retrogradation rate of gels stored at 5$\^{C}$ was higher than that shored at 25$\^{C}$. The pasting properties of the gels such as peak viscosity and final viscosity increased with increasing storage time except the gels stored at 25$\^{C}$ for 72 hours and this trend was more apparent at the storage temperature of 5$\^{C}$. The digestibility measured by $\beta$-amylase method decreased with increasing storage time and this trend was more apparent at the storage temperature of 5$\^{C}$. X-ray diffraction patterns of the gels stored at 5$\^{C}$ showed more distinct peak than those stored at 25$\^{C}$, but no difference was detected by the storage time. The microstucture of all the gels showed a well developed three dimensional network The network structure of the gels stored at 25$\^{C}$ formed a thick matrix after 72 hours and those stored at 5$\^{C}$ from the early stage of storage.

• Korean Journal of Food Science and Technology
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• v.30 no.1
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• pp.118-124
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• 1998

Dehulled cowpea was microparticulated and coarse fractions and fine fractions were collected by air classification at air classifying wheel speed (ACWS) of 15,000 rpm, 12,000 rpm and 9,000 rpm, respectively. Protein content in fine fraction after air classification was 2 times higher than that of microparticulated cowpea, emulsion capacity was about 3 times than coarse fraction. The coarse fraction of the highest viscosity on the gelatinization properties were detected by amylograph, was C-3 (9,000 rpm coarse)fraction. The majority of microparticulated cowpea particles were oval shaped starch and the rest of them were indeterminate minute particles which had some sharp corners. As an application test, microparticulated cowpea and coarse fraction (C-3) were used for mook (Korea traditional starch jelly) preparation and the wet milled cowpea starch was compared as a control. Some impurities induced discoloring was detected by sensory evaluation but after washing, it made no difference in sensory scores between washed starch and the control cowpea mook. And also syneresis of washed cowpea was less than control. At the above result, it can be to recovery about 85% of cowpea starch using microparticulation/air classification technology.

• Korean Journal of Food Science and Technology
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• v.31 no.2
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• pp.380-384
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• 1999

For the effective utilization of anchovy as a food source, processing conditions of expanded anchovy snack and monolayer moisture content of the products were investigated. Ground anchovy was mixed with 50% of wheat flour, 2.5% of NaCl and 3.0% of onion. The mixture were rolled, cut, dried and finally deep-fried with soybean oil. When 50% of wheat flour was mixed with ground anchovy, expansion rate showed the highest value among the treatments and organoleptic quality of the product was also high. Dried base with 6.4% of moisture content showed the maximum expansion rate and good crispness and brittleness when fried at $200^{\circ}C$. Monolayer moisture content of the expanded products was calculated as 2.77% by BET equation.