• KOREAN JOURNAL OF CROP SCIENCE
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• v.32 no.1
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• pp.86-91
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• 1987

Changes in the contents of sugars and soluble solids and flavor rate of cooked kernels of three sweet com hybrids (Great Bell, Danok 1, and Golden Cross Bantam) and a super sweet corn hybrid (Crisp Super Sweet 720) were observed from 15 days after silking (DAS) to 27 or 33 DAS in 1985 and 1986 to determine the optimum harvest time. Sucrose content in all hybrids and fructose and glucose contents of Crisp Super Sweet 720 increased from 15 DAS to 21 or 24 DAS and then decreased. However, in the three sweet corn hybrids both fructose and glucose contents were highest at 15 DAS and then continuously decreased with maturity. At harvest time the major sugar component was sucrose and the highest total sugar content of Crisp Super Sweet 720 was 2-3 times higher than that of three sweet corn hybrids. Soluble solids were continuously increased with maturity in three sweet com varieties, but that of Crisp Super Sweet 720 increased up to 24 DAS, maintained the level through 30 DAS and then decreased. At harvest time soluble solids of three sweet com varieties were much higher than that of Crisp Super Sweet 720. The optimum harvest time seems to be about 27 DAS considering flavor rate and marketing conditions although the total sugar content was lower than those of earlier harvests. Soluble solids but not total sugars were positively correlated with the flavor of cooke6 com harvested at different growth stages in the same variety. Total sugars were not correlated with soluble solids or negatively correlated depending on hybrids.

• Journal of Life Science
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• v.28 no.8
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• pp.969-976
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• 2018

In this study, transglucosidase (TG), an enzyme produced by Aspergillus niger, synthesized isomaltooligosaccharide from ${\alpha}-(1{\rightarrow}4)$ linked substrates. The highest TG-producing A. niger KCTC6913 was selected from six kinds of species, and optimized TG producing conditions were established. Five different carbon sources (potato starch, sweet potato starch, corn starch, wheat starch, and dextrin) and three different nitrogen sources (yeast extract, malt extract, and beef extract) were tested to establish the carbon and nitrogen sources favorable for TG production. Measurements of TG activity after an initial culture at pH 5.0 for 15 days revealed that potato starch and yeast extract, which are basic culture media, resulted in the highest TG activity. In addition, A. niger KCTC6913 increased TG production under aerobic conditions and a controlled carbon/nitrogen ratio. In conclusion, to evaluate TG activity in the established optimal medium, it is confirmed that the basal and potato dextrose broth medium were used as a control, and the highest TG production was measured, which was highlighted in the established optimal medium.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.45 no.3
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• pp.176-180
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• 2000

The higher sugar and lower starch in super sweet corn may be due to modified endosperm genes sh, bt series, but its seeds have major limiting factors causing low germination and low seedling vigor, This study was conducted to determine what measurable kernel characteristics during the grain tiling period might be more useful as a guide to optimize harvest date for good seed quality in hybrid super sweet corn production. Artificial crossing in super sweet corn hybrid (Chodangok 1) was made on the same day, and ears were harvested from 18 days to 53 days after pollination at weekly intervals. Kernel weight, moisture content, hardness, endosperm rate, seedling height and storage nutrients such as sugars, protein, starch, and germination rate were measured for the kernels at each harvest. Super sweet corn hybrid, Chodangok 1 presented satisfactory germination rate above 70% when harvested on 39 to 46 days after pollination. Its storage nutrients at that time were 23.7-24.2% in starch content 5.5-5.9% in total sugars, 38.9-46.6% in kernel moisture, and 62.7-64.2% in endosperm rate. Germination rate was extremely high when harvested on 39 days after pollination. The black layer of Chodangok 1 could not be used as an indicator for seed harvest. These results suggested that optimum harvest date seems to be 39 days, and kernel moisture and starch content could be used as indications of kernel maturity in deciding when to harvest fer good seed quality in super sweet corn.

• Korean Journal of Food Science and Technology
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• v.23 no.2
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• pp.235-240
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• 1991

Starch phosphates were prepared from the corn starch mixed with 2% sodium tripolyphosphate by twin-screw extruder with a feed rate of 20 kg/hr and an extrusion temperature of $130^{\circ}C$, and the effects of extrusion variables on the physicochemical properties (target parameters) of starch phosphates were investigated. Interrelations of system parameters (specific mechanical energy and extrudate moisture) and rheological properities of starch was analyzed by using the response surface analysis. Degree of substitution (DS) was increased with increasing the feed moisture, and showed the maximum value at the screw of near 250 rpm, Degree of gelatinization was proportionally increased with increasing the screw speed and decreasing the feed moisture. Apparent viscosity of the paste was increased with increasing the feed moisture, but it was not significantly affected by the screw speed. It was found by scanning electron microscopy that the starch microgranules were much more degradaded, and as consequent result, the intrinsic viscosity was decreased, whereas, water solubility index was increased. The rate of retrogradation of the gels was retarded with increasing DS and decreasing viscosity.

• Korean journal of food and cookery science
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• v.16 no.2
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• pp.188-194
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• 2000

Effects of native and RS-3 type resistant starches prepared from autoclaved-cooled amylomaize VII(AVII) and normal maize starches(NMS) on the rheological and baking properties of wheat flour dough and quality of breads were investigated. In farinogram, water absorption and dough development time were increased, but stability was reduced by the addition of RS. The addition of native starches or resistant starch made from AVII to wheat flour improved the total volume and specific loaf volume of bread compared with the control(no addition), but the addition of NMS-RS reduced those. During the storage of bread at room temperature, the moisture content of control was decreased but those of native starch- or RS-added breads remained constantly. AVII-RS- or NMS-RS-added bread was evaluated to have good overall acceptability compared with control by elementary school students. The addition of enzyme-resistant starch to bread regardless of botanical sources of starch not only improved the overall acceptability and nutritional benefits but also improved the sensory acceptability.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.65 no.2
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• pp.93-103
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• 2020

The average growth day of 11 maize varieties from planting to silking in the first cropping (FC) was 89.5 days and in the second cropping (SC) was 46.7 days, which was 43 days faster than in the FC. The average 100-kernel weight (100 KW) in the FC was 28.4 g and 18.3 g in the SC, which was approximately 36.4% lower than that in the FC. The average crude oil content of FC was 3.97% and SC was 3.08%, which was about 0.89% lower than that of FC. The composition of stearic and oleic acid was significantly higher in FC, whereas palmitic and linoleic acid were higher in SC; however, linolenic acid was not statistically different between the two crops. The crude oil content was negatively correlated with linoleic acid (FC -0.264^ns, SC -0.504**) and positively correlated with linolenic acid (0.526**). Unsaturated fatty acid (USFA) composition showed a significant difference between FC (83.48%) and SC (82.96%). Total phytosterol content was 598.3 mg/100 g and 701.9 mg/100 g in FC and SC, respectively, and showed significant difference by planting dates. The β-sitosterol content showed no statistical difference between the planting dates, but campesterol and stigmasterol were significantly higher in SC than in FC. Therefore, it was considered that the temperature condition during the ripening period affects the 100 KW of maize, and this leads to the variation in phytosterol content. However, among phytosterols, β-sitosterol was relatively little affected by the planting dates. USFA composition showed a significantly negative correlation with phytosterol content. Considering the results, the relatively high phytosterol content in SC was mainly because of the delay in progress of starch accumulation as daily air temperature decreased from the middle of the ripening period, whereas progress of phytosterol accumulation in the maize kernel was considered relatively faster than that of starch accumulation.

• Journal of the Korean Society of Food Science and Nutrition
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• v.30 no.6
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• pp.1060-1067
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• 2001

Effect of various thickening agents on kakdugi fermentation was investigated by measuring physicochemical and sensory properties during fermentation at 2$0^{\circ}C$. Paste of seven kinds of thickening agents (wheat flour (WF), waxy rice flour (WR), corn starch (CS), acid modified starch (AM), aretylated distarch adipate (AA), hydroxypropyl distarch phosphate (PP) and xanthan gum (XG) ) at 0.25% concentration was added to kakdugi. Total acidity during fermentation was not different among thickening agents, but slightly lower in XG than control at the 7th day of fermentation. At 0 day of fermentation, free sugar amount were higher in thickening agent addition groups than control, but rapidly decreased to below control at the 7th day of fermentation, except XG. Glucose and fructose which were the major free sugars, decreased rapidly during fermentation, whereas mannitol increased in all samples. Viscosity of kakdugi liquid was much higher in thickening agent addition groups than control at 0 day of fermentation, but rapidly decreased from 1 day of fermentation. However, initial viscosity was maintained only in XG. Hardness at the 7th day of fermentation was higher in WR, PP, XG than control. The result of sensory evaluation shows that there were no significant difference in sour odor, sour taste and savory taste among samples. Moldy odor was higher in WR, WF and AM, but was not significantly different in XG, PP, AA compared to control. Viscosity of XG and PP, and starchy taste of XG were higher than those of control. Overall preference of XG, AM, PP were not significantly different from that of control. Xanthan gum was considered to be a good thickening agent for kakdugi but it is necessary to find a minimum concentration for kakdugi since starch taste of xanthan gum.

• Journal of the Korean Society of Food Science and Nutrition
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• v.32 no.7
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• pp.965-970
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• 2003

This study has been performed to develope a method for the simultaneous determination of 1,4-dioxane (DOX), epichlorohydrin (EPC), propylene chlorohydrin (PCH), ethylene chlorohydrin (ECH) and 1,3-dichloro-2-pro-panol (DCP) in polysorbates, chloline chloride, choline bitartrate, modified starch and spices by purge and trapgas chromatography. Experimental design was used to select a suitable trap by measuring the limit of detection (LOD) and to investigate the effect of temperature and salt of extraction, and the percentage of recovery in various matrix. The LOD of DOX, EPC, PCH, ECH and DCP were 1.38$\mu\textrm{g}$, 0.23$\mu\textrm{g}$, 3.30$\mu\textrm{g}$, 3.97$\mu\textrm{g}$, 20.43$\mu\textrm{g}$ respectively, by means of using Vorcarb 3000 trap with 5$0^{\circ}C$ sample sparger. Excluding EPC, the recoveries of target compounds were above 90% in all matrix. Target compounds in polysorbates (17), choline chloride (5), choline bitartrate (5), modified starch (8) and spices (25) were not detected. But 2.5 ppm of DOX was detected in Tween 80.

• Journal of the East Asian Society of Dietary Life
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• v.10 no.5
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• pp.431-438
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• 2000

The physical and processing properties of acorn jelly were investigated to see the effect of polysaccharides in seaweed extract and corn starch. The yield of acorn jelly added starch concentration was slightly increased when the concentration was added more. However, moisture content and color had no significant changes with concentration. In the case of acorn jelly added sea tangle, color of acorn jelly was darker, but color of the jelly with carrageenan was lighter. According to the concentration of seaweed extract, the hardness was increased as concentration was added. The texture of acorn Jelly added agar had the highest binding. In the case of acorn jelly added corn starch, there were no significant changes, but this binding was stronger than the acorn jelly added extract of marine algae. In the physical and sensory properties of acorn jelly with corn starch, the ideal mixture ratio between the acorn jelly and the corn starch was 6:4.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.15 no.1
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• pp.74-82
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• 1982

In the previous study, we have reported the effect of lowering water activity of sodium chloride, sugars and polyols. In this study, water activity($a_w$)of various model Preparations of Kamaboko was measured and ability of lowering $a_w$ of starch, glycine and sodium lactate was discussed. In addition, the aw measurements were also compared to the predicted values of au which were derived from the equation of Raoult's law and the linear slope method by Sloan ana Labuza. The effect of starch on lowering $a_w$ was very low, and glycine was more effective than starch. Sodium lactate was shown to be the most effective among humectants examined. When it was added by $7.5\%$, the $a_w$ of model Kamaboko A was reduced to 0.93-0.94. Generally, prediction by the equation of Raoult's law turned out to be useful for determining $a_w$ lowering effect of humectants, excepting sodium chloride and sodium lactate. The equation of regression derived from the least squares could be applied to Predicting au in the model Kamaboko.