• Korean Journal of Food Science and Technology
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• v.39 no.6
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• pp.652-657
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• 2007

This study was performed to evaluate the physicochemical and quality characteristics of bread with Enteromorpha intenstinalis added. In order to compare the physical and organoleptic properties, 1 to 4% of E. intenstinalis powder was mixed with the flour. Among the physical characteristics of the dough, the absorption ratio in the farinogram and the degree of attenuation increased with increasing amounts of E. intenstinalis powder, whereas the development time, dough stability, the degree of extension, the degree of resistance, and R/E became reduced. In the amylogram, there was no difference in the gelatinization starting temperature among the samples, but the maximum viscosity gradually increased according to increasing amounts of E. intenstinalis powder. Also, a sensory evaluation was carried out in terms of acceptability (color, flavor, moistness, tenderness, mouth feel, and overall acceptability). Taken together, the 2% treatment showed the highest evaluation values, as compared to the other treatments.

• Korean Journal of Food Science and Technology
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• v.46 no.6
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• pp.682-688
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• 2014

The in vitro digestibility and molecular and crystalline structures of rice starches (Seilmi, Dasan1, and Segoami) with differing amylose content were investigated. Segoami had the highest amylose content (30.9%), whereas Dasan1 had the lowest amylose content (21.2%). The molecular weight ($\bar{M}_w$) of amylose and amylopectin in Segoami was much lower than that of the other two rice starches. Segoami had the highest proportion (8.7%) of amylopectin short branch chains (DP 6-12) and the lowest proportion of B1 chains (DP 13-24). The relative crystallinity, intensity ratio of $1047-1022cm^{-1}$ (1047/1022) and gelatinization enthalpy followed the order: Segoami>Seilmi~Dasan1. Segoami showed substantially low pasting viscosity. Rapidly digestible starch (RDS), slowly digestible starch (SDS), and resistant starch (RS) contents showed the highest value in Seilmi, Dasan1, and Segoami, respectively. The expected glycemic index (eGI) of Segoami was lower than that of the other two rice starches. Overall results suggested that the digestibility of rice starch could be highly influenced by their molecular and crystalline structure.

• Korean Journal of Food Science and Technology
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• v.46 no.2
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• pp.135-142
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• 2014

Physicochemical, pasting, and digestion properties of sweet potato starches from 11 Korean cultivars were investigated. Starch granules were variably oval, round, polygonal, spherical, and bell-shaped, and of 10.2-15.3 ${\mu}m$ in mean particle diameter. Amylose contents varied from 12.3 to 17.4%. A similar chain length distribution of amylopectin was found in each of the cultivars. The portion of $B_3$ correlated with the degree of amylose leaching. Thermal properties determined by differential scanning calorimetry showed high values of gelatinization temperatures in Shinyulmi and Jeungmi starches, but a relatively low value in Daeyumi starch. All starches exhibited a Ca-type diffraction pattern. Differing patterns were observed in swelling factors, depending on temperature. The contents of rapidly digestible starch, slowly digestible starch, and resistant starch ranged from 9.6-17.4, 31.4-45.6, and 35.7-62.8%, respectively. In Rapid Visco Analyser profiles, differences were observed in pasting parameters such as pasting temperature, peak viscosity, final viscosity, and breakdown.

• Korean Journal of Food Science and Technology
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• v.43 no.6
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• pp.696-701
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• 2011

To evaluate the processing adaptability of taro flours, the physicochemical properties of taro flour with different drying, roasting and steaming conditions were investigated. The moisture content and total dietary fiber were decreased as temperature increased with hot-air drying. Freeze-dried taro flours showed the highest vitamin C contents. Taro flours made by freeze-drying and hot-air drying showed significantly higher total dietary fiber content than those with roasting and steaming process. Steamed taro flours had the highest water absorption index, while hot-air dried and freeze dried taro flours had the highest water solubility index. No differences were displayed in the differential scanning calorimetry (DSC) thermal characteristics among hot-air dried and freeze dried taro flours. Roasted taro displayed decreased onset temperature and peak temperature as roasting temperature increased. Using a rapid visco-analyzer, the peak viscosity, through viscosity, and final viscosity of dried and steamed taro flours were higher than roasted taro flours, whereas the set back value, which is a prediction of retrogradation, decreased with steaming processing. From those results, it could be concluded that hotair dried taro flours, which have high gelatinization viscosity, are beneficial in imparting viscosity to dough products and hot-air drying after steaming taro flours, which retard retrogradation, is good for porridge and flake base products.

• Korean Journal of Food Science and Technology
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• v.49 no.5
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• pp.513-518
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• 2017

The quality and physicochemical characteristics of newly developed Sunsik products were investigated. Sunsik A, B, and C were prepared under different roasting temperatures and times (A: $220^{\circ}C$, 15 min; B: $220^{\circ}C$, 25 min; C, D, E: $230^{\circ}C$, 15 min). Sunsik D was prepared using grain flours passed through a 100 mesh screen, whereas the other products were passed through a 140 mesh screen. Sunsik E was prepared by the addition of germinated grains. The moisture content of Sunsik products ranged from 3.24-7.10%. The viscosity and sugar content ranged from 57-74 cP and $1.5-1.7^{\circ}Bx$, respectively. The pH values were similar among the samples. Sunsik D had the highest gelatinization enthalpy, whereas Sunsik C had the lowest. The viable cell counts were in the range from 3-4 log CFU/g and coliform groups were not detected. Sunsik B and E had higher scores for savory flavor and sweet taste than other Sunsik products.

• Korean Journal of Food Science and Technology
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• v.30 no.1
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• pp.42-48
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• 1998

Physicochemical properties of waxy maize starch and oxidized waxy maize starch with sodium hypochlorite $(0{\sim}60\;mg\;CL_2/g\;starch,40^{\circ}C,\;pH\;10,\;3.0\;hr)$ were studied. As sodium hypochlorite concentration was increased, the content of crude lipid and crude protein of the oxidized starch were decreased. And crude protein content and whiteness was considered to show negative regression. However, the crude ash content of the oxidized starch increased significantly with oxidation and bore a positive regression to the chlorine content. There was a progressive increase in the carboxyl content with increasing oxidant level. After pasting in hot water and cooling, viscosity of the oxidized starches were drastically lower than that of native starch . As carboxyl contents of the oxidized starch increased, the solubility and swelling power was increased. When waxy maize starch treated with 0, 1.5, 3.0 and 6.0% sodium hypochlorite, temperature of initial gelatinization of oxidized starch was shown to 65, 65, 60 and $50^{\circ}C$, respectively. The oxidized waxy maize starches also form clearer pastes. Water binding capacity of the oxidized starch decreased as the degree of carboxyl group substitution increased. Waxy maize starch has polygonal and some round granules which range from about 3.7 to $20\;{\mu}m$ in diameter. Surface appearance of the waxy maize starch became rough when oxidized with sodium hypochlorite. When homogenate of the oxidized waxy maize starch solution and corn germ oil was stored under room temperature for 24 hours, the emulsion stability was considered to depend on starch concentration and degree of substitution.

• Korean Journal of Food Science and Technology
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• v.33 no.3
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• pp.313-318
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• 2001

Physicochemical properties of starch vermicelli (Dangmyun) made with different starches in laboratory were determined to develop a modified corn starch comparable to sweet potato starch which is highly expensive than corn starch but commonly used for starch vermicelli in Korea. Initial temperatures (Ti) of gelatinization of starch vermicelli made in laboratory measured by differential scanning calorimeter, which were above $60^{\circ}C$, were higher than those of starch vermicelli in the market. Their X-ray diffraction peaks were relatively sharp compared with those of starch vermicelli in the market, which showed that starches were not completely gelatinized during the process of starch vermicelli preparation in laboratory. Initial temperature (Ti) of corn starch vermicelli was decreased by $3^{\circ}C$ by hydroxypropylation but increased by $2.5^{\circ}C$ by oxidation. Hardness and compression slope of sweet potato starch vermicelli and mungbean starch vermicelli, which were $11,726{\sim}12,555\;g/cm^2$ and $29,914{\sim}30,604\;g/cm^2$, respectively, were the highest in the samples and those of waxy corn starch were lowest. Hardness and compression slope of starch vermicelli made with corn starch slightly oxidized in the concentration of 0.5% NaOCl at pH 9.0, $40^{\circ}C$ for 30 min. increased and found to be comparable to those of sweet potato starch vermicelli.

• Korean Journal of Food Science and Technology
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• v.32 no.3
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• pp.604-609
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• 2000

This study was carried out to investigate the possibilities of adopting xanthangum, guargum and ${\kappa}-carrageenan$ as cryprotectant by examining the rheological and structural properties of dough. Results of farinography showed that water absorption, development time and mechanical tolerance index in dough with the gums increased more than those of the control. It was also found that resistance in dough with the gums increased greatly, but extensibilities were similar to that of the control, resulting in increasing R/E values in the dough with the gums through extensograph. According to amylogram, gelatinization temperature of dough was $59.5^{circ}C$ and those of the dough with the gums were $58^{circ}C$. Even though maximum viscosity of the dough was 550 B.U in the control, those were 690 B.U, 780 B.U and 760 B.U in the dough with xanthangum, guargum, and ${\kappa}-carrageenan$, respectively. The control deeply increased the pH during frozen storage but the addition of ${\kappa}-carrageenan$ and xanthangum increased the pH slightly. The dough with the gums had more stable spaces than control in the microstructure through SEM.

• Korean Journal of Food Science and Technology
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• v.22 no.3
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• pp.272-277
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• 1990

Some additives were applied to improve Yukwa(Popped rice snack) quality and process modifications were tested for cutting down soaking time and application of rice flour. Addition of soaked soybean (3%, w/w) to dough showed higher expansion rate and better physical properties with more acceptable quality by sensory evaluation of Yukwa. Baking powder, modified starch and alcoholic liquor, Mackeali(rice wine, turbid). Soju(distilled liquor) and Yakju(rice wine, clear), were no positive effect on quality of Yukwa but alcoholic liquor gave more fine texture than others. High temprature soaking $(60^{\circ}C)$ of rice for 3 hours which is near gelatinization temperature of rice starch. gave same quality of Yukwa comparing with long time soaking (12 hours) at room temperature. Extention of high temperature soaking (12 hours) did not improve the quality of Yukwa. The 100 mesh of rice flour by dry milling method was better in expansion rate and hardness than 40 and 80mesh but it was worse than ordinary wet milling. It was notified that milling method and milling mechines for Yukwa preparation should be studied in more detail.

• Korean Journal of Food Science and Technology
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• v.20 no.4
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• pp.504-510
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• 1988

The physicochemical properties of rice flours which were obtained by dry milling(blade, hammer, test and micro mill) and wet & dry milling (roller & micro mill) were investigated. The resulting flour particle sizes were reduced in the order that of blade, hammer, test, micro and roller & micro mill. Scanning electron microscopic examination showed that the starch granules were freed from the imbedding matrix as the particles became finer. The test-milled flour had the hightest levels of starch damage, maltose value and hot-water soluble amylose content, and the blade-milled flour showed the lowest levels. Amylograph viscosity and gelatinization temperature of the flours decreased as the particles became finer, and the addition of $Hg^{+2}$ increased the peak viscosity of the dry-milled flour pastes, whereas the wet & dry-milled flour did not show any changes. The blue values and ${\lambda}$max values of the iodine complex of the cold-water extractable ${\alpha}-D-glucan$ from flours were in the range of 0.023-0.029 and 518-522nm, respectively, indicating these materials were shown to be mainly composed of amylopectin-like polymer.