• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.5
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• pp.616-621
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• 2017

The objective of this study was to investigate the physicochemical properties of domestic strong wheat flour (DSWF). Three commercial DSWFs (D1, D2, and D3) were compared with imported strong wheat flour (ISWF). DSWFs had higher moisture content, crude protein content, lightness, and whiteness than ISWF. DSWFs showed lower solvent retention capacity and water absorption index than ISWF. DSWFs also showed significantly higher water solubility index than ISWF (P<0.05). Setback values by rapid visco analysis were significantly higher in D1 and D2 than in ISWF and D3, which means ISWF and D3 were better in retarding retrogradation. Differential scanning calorimetry results showed that ISWF required 6.2 J/g of energy for phase transition, whereas DSWFs needed 6.67~7.13 J/g. The farinograph results showed that ISWF had higher water absorption, longer dough stability time, and significantly higher softening of dough at 20 min than DSWF (P<0.05). Dough resistance and extensibility were higher in ISWF than in DSWFs.

• Applied Biological Chemistry
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• v.37 no.3
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• pp.154-160
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• 1994

Pregelitinized rice (PR), pregelitinized waxy rice (PWR), and pregelitinized rice flour (PRF) were evaluated for physico-chemical properties comparing with rice starch and acetylated potato starch. L value was decreased during drum drying. PFR had the highest value (P<0.05) for water absorption index and PWR had the highest value for water solubility index. Transmittance of gelitinized samples had drastically increased at $80{\sim}90^{\circ}C$. PWR had the highest value for apparent viscosity and rice samples had a steady apparent viscosity during heating at $90^{\circ}C$. Viscosity was decreased as pH decreased at room temperature and drastically decreased below pH 2. Rice starch and PR had no significant effect for change of pH. Change of viscosity had more effect for hot temp. than room temp.. Pregelitinized samples showed only second peak for DSC. PWR had the lowest value for degree of retrogradation and acetylated potato starch had the highest value for freeze-thaw-stability.

• 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.