• Korean Journal of Food Science and Technology
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• v.22 no.1
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• pp.99-104
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• 1990

The effects of concentrations of sulfur dioxide (0.16-0.20%) and steeping times (25-50hr) at $52^{\circ}C$ on the changes in pH of steep water and weight and volume of corn and starch properties were investigated. The pH of steep water increased and remained constant after steeping time of 20 hours. The degree of weight or volume gain decreased as the concentration of sulfur dioxide increased. The protein content of starch increased as the concentration of sulfur dioxide increased. Water·binding capacity of starch showed the highest value at the steeping time of 35 hours. Swell ins power and solubility decreased as cocentration of sulfur dioxide and steeping time increased. The initial pasting temperature and peak viscosity were increased and decreased, respectively, as the concentration of sulfur dioxide increased. At the same concentration of sulfur dioxide, the peak viscosity was increased and then decreased. Viscosity of starch in sodium hydroxide solution tended to decrease as the concentration of sulfur dioxide and sleeping time increased. The gel volume of starch in 3M KSCN solution was not affected by concentration of sulfur dioxide and steeping time.

• Korean Journal of Food Science and Technology
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• v.27 no.1
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• pp.30-35
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• 1995

Gamma irradiation was applied to non-glutinous and glutinous corns for improving starch isolation process. No significant changes in proximate composition of corn grains were observed by gamma irradiation. Irradiation at 1 and 5 kGy was effective for sterilizing all contaminated microorganisms of non-glutinous and glutinous corns, respectively. The moisture-uptake rate constants were increased in proportional to the steeping temperature and applied irradiation dose level. The irradiation efficacy on water absorption properties was also recognized in the corns stored for six months at room temperature. The combined use of gamma irradiation with sulfur dioxide solution was very effective for reducing steeping time. The starch yield gradually increased as irradiation dose levels increased. At 2 kGy, the sarch yield of non-glutinous and glutinous corns increased by 38% and 27%, respectively. No significant difference in Hunter's color value was observed between the starches isolated from nonirradiated and irradiated corn grains.

• Korean journal of food and cookery science
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• v.15 no.2
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• pp.185-190
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• 1999

In order to develop the techniques for isolation and production of barley starch from Youngsan variety, optimum conditions of isolation processes of barley starch was investigated. The effect of steeping temperature and time in wet-milling process was examined and the results showed that optimal steeping temperature and time were 30$^{\circ}C$ and 12 hr. The barley starch isolated under these conditions contained 5.7% crude protein, 69% starch content and 83% white value by 100 mesh process. The optimum condition of alkali treatment was showed that concentration of NaOH and treating time were 0.2% and 6 hr, respectively. To remove the fat content of barley starch, after alkali process obtained barley starch with the addition of 10% (v/v) EtOH was attempted. As the result, the barley starch contained 0.1% of crude fat. Under the optimized isolation conditions, the barley starch finally contained 0.1% protein and 95% starch content. The isolated barley starch were superior to commercial corn starch in purity and white value.