• KOREAN JOURNAL OF CROP SCIENCE
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• v.44 no.3
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• pp.267-272
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• 1999

In order to determine the optimum harvest time of vegetable corns, the changes in sugars, soluble solids, and flavor of kernels of sweet (cv. ‘Golden Cross Bantam 70’), super sweet (cv. ‘Cocktail E-51’), and waxy corns (cv. ‘Chalok 2’) were observed at different ripening stages. Sucrose was a major sugar in the sweet and super sweet corns and the content increased from 15 to 21 and 27 days after silking (DAS), respectively and then decreased. Glucose and fructose contents of sweet and super sweet corns tended to decrease with kernel maturity. Total sugar content of the sweet corn analyzed by the anthrone method increased rapidly from 15 to 21 DAS, while that of the super sweet and the waxy corns increased slowly up to 24 and 26 DAS, respectively and decreased thereafter. The content of soluble solids in sweet corn was much higher than that of super sweet corn. Starch content of the sweet corn increased slowly from 15 to 33 DAS, while that of the super sweet corn increased a little rapidly from 15 to 21 DAS and then leveled off to 33 DAS. Starch content of the waxy corn increased continuously from 21 to 38 DAS. There was a positive correlation between the sum of individual sugars (sucrose, glucose, and fructose) and soluble solids in both sweet and super sweet corns, while the content of soluble solids was not related to the sum of individual sugars or total sugars. The flavor rate of sweet and super sweet corns maintained high between 21 and 27 DAS and that of waxy corn decreased from 24 to 33 DAS. The optimum harvest time for sweet, super sweet, and waxy corns was thought to be 21 to 24 DAS considering sugar and starch contents, flavor, and marketing.

• Korean Journal of Food Science and Technology
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• v.24 no.2
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• pp.160-164
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• 1992

Cooking, texture and sensory properties of sweet potato Tangmyon (starch noodle), common Tangmyon (50% sweet potato starch+50% corn starch) and corn Tangmyon were evaluated. The weight gain of Tangmyon showed a linear relationship with the square root of cooking time, in which the common Tangmyon showed the highest value. The solid loss during cooking was the highest in common Tangmyon followed by corn Tangmyon. The sweet potato Tangmyon showed the highest value for compression strength and stretching ratio, but lowest value for elongation elastic modulus. At the same compression strength, corn Tangmyon had the highest tensile strength and sweet potato Tangmyon the lowest value. Sweet potato Tangmyon showed the highest sensory scores of gloss, clarity, adhesiveness, gumminess, extensibility and overall desirability, and corn Tangmyon the lowest scores. Except adhesiveness (by appearance) and the gumminess of common and corn Tangmyon, significant differences (p<0.05) were observed for other sensory properties among samples.

• Korean Journal of Food Science and Technology
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• v.27 no.4
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• pp.593-597
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• 1995

To measure theological properties of the starch dough, an Extrusion Capillary Viscometer(ECV) cell was self-made and attached to Instron machine(Model 1140). Apparent viscosities of corn and waxy corn starch doughs were measured and their gelatinization degrees were determined by enzymatic analysis. The effects of heating temperature on the viscosity of starch dough with $36{\sim}52%$ moisture contents were examined in terms of Arrhenius equation. The activation emergy(Ea) of the dough viscosity from the effect of heating temperatures changed from negative(-) to positive(+), as the moisture content increased from 44% to 48% in the corn starch dough and from 44% to 44% in the waxy corn starch dough.

• 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).

• Korean Journal of Food Science and Technology
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• v.22 no.4
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• pp.473-478
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• 1990

A computer-aided simulation technique was selected to predict the gain or loss of moisture in corn starch packaged with gas and moisture permeable materials under various conditions. Water activity and moisture content of corn starch was predicted by computer program at various conditions. A linear relationship was showed between water activity and equilibrium moisture content at the range of $A_w$ 0.332 to 0.90 and simulated values obtained by the proposed model was given to a dose approximation with the observed values.

• Journal of Life Science
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• v.11 no.2
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• pp.173-180
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• 2001

This study was conducted to estimate the cultural characteristics, the production of antibiotic, and the selection of optimal media for mass culture of Bacillus licheniformis N1 isolate which was previously reported as an antagonistic bacterium to Botrytis cinerea. We investigated initial pH, temperatures and shaking speed for good cultural conditions and antibiotics production by N1 isolate. According to the results, the optimal conditions of initial pH, temperatures, and shaking speed were determined to be pH 5.0~5.5, 30~35$^{\circ}C$ and 250 rpm, respectively. Also, the optimal conditions for the antagonism by N1 isolate highly appeared in the initial pH as 5.0, and the mycelial growth inhibition was high when the substances used such as glucose or corn starch as carbon sources, and biji(soybean curd residue) flour as a nitrogen source. Furthermore, inhibitory area was significantly expanded, when 3% or 5% of corn starch was added into 5% of Biji flour as nitrogen source, were respectivley selected for mass culture of N1 isolate. Among them, 5% Biji flour medium showed higher cell density more than 10 times that in NB medium after 48 hour incubation. Therefore, the optimal medium was determined as 5% biji flour added 3~5% of corn starch for high density of cells.

• Food Engineering Progress
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• v.15 no.2
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• pp.155-161
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• 2011

The aim of this study was to determine the effects of different extrusion conditions on the saccharification characteristics( initial reaction velocity, reaction rate constant, yield) of extruded corn starch. Extruded corn starch-water slurries were mixed with alpha-amylase for the enzymatic saccharification. The saccharification yield of extruded corn starch was high at lower feed moisture content and higher barrel temperature. The solubility of extrudates increased with increase in the SME input which increased with increase in the feed moisture content. Starch hydrolysates having DE 63.8 was obtained after 2 hr reaction. The initial reaction velocity of the extrudate slurry with alpha-amylase was higher with decrease in the feed moisture content. The initial reaction velocity of extruded corn starch was the highest ($2.26{\times}10^{-3}mmol/mL{\cdot}min$) at 25% feed moisture content and $120^{\circ}C$ barrel temperature, 250 rpm screw speed. The pregelatinized starch was $1.83{\times}10^{-3}mmol/mL{\cdot}min$ as a control. Reaction rate constant was a similar trend to initial reaction velocity.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.34 no.4
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• pp.37-43
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• 2002

In recent years, numerous studies have been carried out to find out the possible substitution of PE-coated paperboards used in packaging of watery or oily foods. Accordingly, this study was carried out to obtain the basic data for producing higher functional coating agents for pulp mold by evaluating various kinds of synthetic and natural coating agents on the market. Physical properties of coated paperboards were tested. Conclusions obtained from this study were as follows. AKD and PVA showed higher functions than the other synthetic coating agents, while functions of CMC, Com starch and Oxidized starch were higher than those of other natural coating agents. Based on concentrations, AKD 0.5%, PVA 10%, CMC 1.5%, corn starch 6% and oxidized starch 8% were appeared as the proper concentrations. W3 consider that AKD may be suitable for the storage of higher moisture vegetables and other food, and PVA may be suitable for higher oily fried food.

• Korean Journal of Food Science and Technology
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• v.18 no.2
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• pp.82-87
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• 1986

The water sorption isotherms of binary mixtures, prepared by corn starch and isolated soybean protein (ISP) or casein, were measured and analyzed. Simple equations to predict moisture content from knowledge of composition and water activity of the mixture were derived by applying Response Surface Analysis. Comparison between predicted and experimental moisture content for 13 combinations of corn starch-lSP mixture at the range of $a_w$ 0.25-0.87 resulted in a maximum error of only 6.06% and an absolute mean error of 2.60%, and for the mixture of corn starch-casein the error was -4.39% and 2.12%, respectively. The agreement between experimental and predicted water sorption isotherms was shown to be 'highly acceptable' for the binary mixtures of 50% corn starch-50% ISP and 50% corn starch -50% casein.

• Korean Journal of Food Science and Technology
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• v.18 no.2
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• pp.77-81
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• 1986

The water sorption isotherms of individual insoluble components of corn starch, isolated soybean protein (ISP) and casein and their binary mixtures of corn starch-lSP and corn starch-casein were measured and analyzed. BET monolayer values and Smith plot parameters from the results of sorption isotherms were calculated by mass balance concept . The comparisons between experimental and predicted values resulted in an error of 2.29% for equilibrium moisture content and an error of 2.95% in monolayer value for the mixture 50% corn starch-50% ISP. On the other hand , for the mixture 50% corn starch-50% casein the errors were 2.66% and-5.34%, respectively.