• The Korean Journal of Food And Nutrition
• /
• v.25 no.4
• /
• pp.1068-1074
• /
• 2012

Ohmic heating uses electric resistance heat which occurs equally and rapidly inside of food when electrical current is flown into. In other study, we researched about soybean protein's characteristic changes by ohmic heating. Nevertheless treated same temperature, denaturation of soybean protein were accelerated by ohmic heating than conventional heating. In this time, we studied thermal property change of potato starch by ohmic heating besides conventional heating. For this purpose, potato starch was heated at same subgelatinization temperature by ohmic and conventional heating. And thermal properties were tested using DSC. Annealing of starch is heat treatment method that heated at 3~4% below the gelatinization point. DSC analysis results of this study, the $T_o$, $T_p$, $T_c$ of potato starch levels were increased, whereas $T_c{\sim}T_o$ was narrowed. This thermal property changes appear similar to annealing's result. It is thought the results shown in this study, because the heating from below the gelatinization point. 6, 12, 24, 72, and 120 hours heating at $55^{\circ}C$ for potato starch, $T_o$, $T_p$, $T_c$ values continue to increased with heating time increase. The gelatinization temperature of raw potato starch was $65.9^{\circ}C$ and the treated starch by conventional heating at $55^{\circ}C$ for 120 hr was $72^{\circ}C$, ohmic was $76^{\circ}C$. The gelatinization range of conventional (72 hr) was $10^{\circ}C$, ohmic was $8^{\circ}C$. In case of 24 hours heating at 45, 50, 55, 60, $65^{\circ}C$ for potato starch, the result was similar to before. $T_o$, $T_p$, $T_c$ values continue to increased and gelatinization range narrowed with heating temperature increase. In case of conventional heating at $60^{\circ}C$, the results of gelatinization temperature and range were $70.1^{\circ}C$ and $9.1^{\circ}C$. And ohmic were $74.4^{\circ}C$ and $7.5^{\circ}C$. When viewed through the results of the above, the internal structure of starch heated by ohmic heating was found that the shift to a more stable form and to increase the homology of the starch internal structure.

• Korean Journal of Food Science and Technology
• /
• v.34 no.1
• /
• pp.24-29
• /
• 2002

The study was performed to investigate the degrees of gelatinization at various processing steps during the preparation of Dangmyuns using sweet potato, potato, corn and tapioca starches, and also determined the rehydration of the freeze dried sweet potato Dangmyun. The degrees of gelatinization after extrusion cooking showed higher value than other processing steps. The degrees of gelatinization after extrusion cooking were 63.5% in sweet potato, 80.0% in potato, 82.3% in corn, and 86.5% in tapioca Dangmyuns. The degree of gelatinization in Dangmyuns after extrusion cooking step decreased as the processing steps, such as cold storage, freezing, thawing, and sun drying, progressed. L values of color in Dangmyuns decreased in the order of corn>tapioca>potato>sweet potato Dangmyuns. The cooking loss decreased in the order of tapioca>corn>potato>sweet potato Dangmyuns. The percentage of weight gain was the highest in sweet potato Dangmyun followed by corn, potato, and tapioca Dangmyuns. The water absorption rate constant was the highest in sweet potato Dangmyun followed by corn, potato, and tapioca Dangmyuns. In the rehydration of freeze dried Dangmyuns, freeze dried sweet potato Dangmyun showed better than the others. An increase from 60% to 70% of the added amount of water in the mixing step resulted in an increase of the degrees of gelatinization after extrusion cooking from $63.4{\sim}70.7%$ to $73.8{\sim}75.0%$. An increase of the added water in the mixing step and a decrease of diameter in the extrusion cooking step slightly improved the rehydration in the boiled water of freeze dried sweet potato Dangmyun.

• Proceedings of the Korean Society of Crop Science Conference
• /
• 2004.04a
• /
• pp.172-173
• /
• 2004

• Proceedings of the Korean Society of Crop Science Conference
• /
• 2022.04a
• /
• pp.141-141
• /
• 2022

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.28 no.5
• /
• pp.1034-1043
• /
• 1999

Rheological properties of dough made from waxy barley(Iri28) flour wheat flour mixtures with additives were investigated for the preparation of waxy barley bread using farinograph, extensograph and amy lograph. The water absorption, development time and dough weakness increased as the waxy barley flour level increased in all blends; however, dough stability decreased. Farinogram properties of 10% waxy barley flour added mixture were similar to those of 100% wheat flour. The addition of A.A(ascorbic acid), gluten, HPMC(hydroxy propyl methyl cellulose) improved rheological properties of dough with 30% waxy barley flour added mixture. In particular, stability and weakness of the dough showed greater dough improving effect by addition of A.A. For the extensograph data, strength, resistance and extensibility of dough decreased with increasing level of waxy barley flour. With the addition of additives, extensogram properties were variable for 30% waxy barley flour mixture. Of these additives, gluten had highest value in strength of dough. Addition of A.A and HPMC to 30% waxy barley flour added mixture resulted in an increase in the resistance and a decrease in the extensibility. Waxy barley flour added mixtures showed little higher gelatinization temperature on amylograph data than control. Maximum viscosity reduced as the waxy barley flour level increased. Also 30% waxy barley flour added mixture containing A.A and HPMC showed a decrease in maximum viscosity. But addition of gluten to 30% waxy barley flour mixture resulted an increase in the maximum viscosity. All of 30% waxy barley flour added mixture with additives had lower gelatinization temperature than those without additives. In the SEM images, starch granules were dispersed in a protein matrix. A non continuous, loose protein starch matrix was observed in all waxy barley flour mixture by SEM. Addition of additives gave the dough a more continuous structure with interactions between the starch granule and protein component.

• Korean journal of food and cookery science
• /
• v.14 no.3
• /
• pp.207-212
• /
• 1998

The changes in physicochemical properties of potato were investigated while steeping in water for 7 days at 30${\pm}$1$^{\circ}C$. The shape of raw starch granules was round or oval, the starch granule showed birefringence distinctly under polarized light and it was kept clearly even after steeping. X-ray diffraction pattern of the starch was B-type and there was no change in the pattern after steeping. However, crystallinity was increased up to the 4th day and then decreased. Amylose contents of raw starch and the starch steeped for 7 days were 19.3% and 13.1%, respectively. When the potato starch was gelatinized in 0.15 N sodium hydroxide solution, the viscosity was decreased until the 3rd day, but increased thereafter. Gel volume of the starch in KSCN solution was decreased during steeping.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.28 no.1
• /
• pp.132-139
• /
• 1999

Physicochemical properties of the crosslinked potato starches of MDC(Molar Degree of Crosslinking) 0.137~3.333 treated with epichlorohydrin were examined. MDC increased proportionally as epichlorohydrin concentration increased. Water binding capacity increased but blue value decreased with increasing MDC. Gelatinization trends obtained from DSC thermograms and transmittance showed that the gelatinization temperature of the crosslinked potato starch was higher than that of native potato starch, but there was no significant difference among the crosslinked potato starches. Solubility and swelling power decreased with increasing MDC. X ray diffraction patterns and scanning electron micrographs showed that the crosslinking of starch did not affect the crystallinity and the granule shape of starch.

• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.38 no.2 s.115
• /
• pp.43-51
• /
• 2006

Starch is widely used as an adhesive material in the paper and corrugated board industry. The adhesion problem of corrugated board is categorized by two main parts called zipper board and white glue line. The object of this research is to investigate the factors affecting the adhesion problem by the gelatinization of various starch solutions and dynamic penetration properties measurements of various commercial base paper and handsheets. Flow property of starch solution is affected by sodium hydroxide addition and reaction level. Absorption property of commercial base papers and handsheets is affected by sizing and stock composition. Optimum bonding between top/bottom liners and corrugated medium is accomplished by acceptable flow viscosity of mixed starch solution and proper adsorption characteristic of base paper.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.44 no.3
• /
• pp.277-281
• /
• 1999

Dull grains segregated from F$_3$ and F$_4$ of the crosses between two dull mutants and a glutinous cultivar were compared with non-glutinous and glutinous segregants for their physicochemical properties. Amylose content of dull rice grain segregated from the dull/glutinous cross showed the intermediate value between glutinous and non-glutinous rice grain, whether it is controlled by the recessive or dominant gene. Alkali digestibility value (ADV) of dull rice grain was lower than that of glutinous or non-glutinous rice. A positive correlation was found between ADV and amylose content of homozygous non-glutinous or dull F$_4$ grains, but a negative relationship was observed in glutinous grains. Protein content of dull grain was significantly higher than that of glutinous or non-glutinous grain segregated from the same cross, while those of glutinous and non-glutinous grains were not different. Among gelatinization characteristics, initial pasting temperature and peak viscosity of dull grains were higher than glutinous rice, and were not different with non-glutinous grain. Hot, cool and consistency viscosities of dull grain were intermediate between glutinous and non-glutinous rices. Dull grains showed the highest breakdown viscosity and the lowest setback viscosity among the three endosperm types.

• Applied Biological Chemistry
• /
• v.30 no.4
• /
• pp.315-322
• /
• 1987

Attempts were made to unravel the differences in the textural properties between a dry type, Wonki and a moist type, Chunmi sweet potato. The changes in the ingredients, cellular shapes, degree of gelatinization and hardness of sweet potatoes during baking were studied. Alcohol insoluble solid, starch and protopectin contents and activities of amylase and polygalacturonase of Wonki sweet potato were higher than those of Chunmi sweet potato. The cell sizes were smaller and the number of starch granules within the cells were higher in Wonki than in Chunmi. Gelatinization occurred in Wonki more lately than in Chunmi during baking. The difference in hardness after baking between Wonki and Chunmi was found distinctively. But both samples were gelatinized completely, the difference in hardness was not found.