• KOREAN JOURNAL OF CROP SCIENCE
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• v.58 no.4
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• pp.424-431
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• 2013

Consumption of waxy corn is steadily increasing due to consumer preference for natural food. However, availability of waxy corn is limited because most of them are used for steamed waxy corn. It is therefore important to create new demands of waxy corn using food processing technology. There is little prior research about characteristics of milled kernel in waxy corn. This study examined the physicochemical and cooking properties of milled kernel using nine waxy corn hybrids. Colored hybrids (Heukjinju, Miheukchal, and Eolrukchal1) showed high milling yield and low change of grain length after milling process compared to other hybrids. The total starch content ranged from 62.1 to 68.4% and the gelatinization temperature of starch was lowest in Yeonnong1 ($69.9^{\circ}C$). The breakdown viscosity of Yeonnong1, Miheukchal and Heukjinju was higher than those of tested hybrids, whereas setback viscosity of those hybrids was lower. In cooking properties of milled waxy corn, water absorption and volume expansion rate were high in Yeonnong2 (84.9, 219.3%), Miheukchal (85.9, 211.4%), and Heukjinju (80.9, 203.7%). In the sensory test, the overall preference was significantly higher in Heukjinju and Miheukchal. Thus, Heukjinju, Yeonnong2, and Miheukchal showed good scores in milling yield, cooking properties, and the preference of sensory test. These results will provide fundamental information to extend milled waxy corns usage.

• Proceedings of the Korean Journal of Food and Nutrition Conference
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• 2001.12a
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• pp.39-74
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• 2001

The endeavors enhancing the grain quality of high-yielding japonica rice were steadily continued during 1980s∼1990s along with the self-sufficiency of rice production and the increasing demands of high-quality rices. During this time, considerably great, progress and success was obtained in development of high-quality japonica cultivars and qualify evaluation techniques including the elucidation of interrelationship between the physicochemical properties of rice grain and the physical or palatability components of cooked rice. In 1990s, some high-quality japonica rice caltivars and special rices adaptable for food processing such as large kernel, chalky endosperm aromatic and colored rices were developed and its objective preference and utility was also examined by a palatability meter, rapid-visco analyzer and texture analyzer. The water uptake rate and the maximum water absorption ratio showed significantly negative correlations with the K/Mg ratio and alkali digestion value(ADV) of milled rice. The rice materials showing the higher amount of hot water absorption exhibited the larger volume expansion of cooked rice. The harder rices with lower moisture content revealed the higher rate of water uptake at twenty minutes after soaking and the higher ratio of maximum water uptake under the room temperature condition. These water uptake characteristics were not associated with the protein and amylose contents of milled rice and the palatability of cooked rice. The water/rice ratio (in w/w basis) for optimum cooking was averaged to 1.52 in dry milled rices (12% wet basis) with varietal range from 1.45 to 1.61 and the expansion ratio of milled rice after proper boiling was average to 2.63(in v/v basis). The major physicochemical components of rice grain associated with the palatability of cooked rice were examined using japonica rice materials showing narrow varietal variation in grain size and shape, alkali digestibility, gel consistency, amylose and protein contents, but considerable difference in appearance and torture of cooked rice. The glossiness or gross palatability score of cooked rice were closely associated with the peak. hot paste and consistency viscosities of viscogram with year difference. The high-quality rice variety “Ilpumbyeo” showed less portion of amylose on the outer layer of milled rice grain and less and slower change in iodine blue value of extracted paste during twenty minutes of boiling. This highly palatable rice also exhibited very fine net structure in outer layer and fine-spongy and well-swollen shape of gelatinized starch granules in inner layer and core of cooked rice kernel compared with the poor palatable rice through image of scanning electronic mcroscope. Gross sensory score of cooked rice could be estimated by multiple linear regression formula, deduced from relationship between rice quality components mentioned above and eating quality of cooked rice, with high Probability of determination. The ${\alpha}$ -amylose-iodine method was adopted for checking the varietal difference in retrogradation of cooked rice. The rice cultivars revealing the relatively slow retrogradation in aged cooked rice were Ilpumbyeo, Chucheongbyeo, Sasanishiki, Jinbubyeo and Koshihikari. A Tongil-type rice, Taebaegbyeo, and a japonica cultivar, Seomjinbyeo, shelved the relatively fast deterioration of cooked rice. Generally, the better rice cultivars in eating quality of cooked rice showed less retrogiadation and much sponginess in cooled cooked rice. Also, the rice varieties exhibiting less retrogradation in cooled cooked rice revealed higher hot viscosity and lower cool viscosity of rice flour in amylogram. The sponginess of cooled cooked rice was closely associated with magnesium content and volume expansion of cooked rice. The hardness-changed ratio of cooked rice by cooling was negatively correlated with solids amount extracted during boiling and volume expansion of cooked rice. The major physicochemical properties of rice grain closely related to the palatability of cooked rice may be directly or indirectly associated with the retrogradation characteristics of cooked rice. The softer gel consistency and lower amylose content in milled rice revealed the higher ratio of popped rice and larger bulk density of popping. The stronger hardness of rice grain showed relatively higher ratio of popping and the more chalky or less translucent rice exhibited the lower ratio of intact popped brown rice. The potassium and magnesium contents of milled rice were negatively associated with gross score of noodle making mixed with wheat flour in half and the better rice for noodle making revealed relatively less amount of solid extraction during boiling. The more volume expansion of batters for making brown rice bread resulted the better loaf formation and more springiness in rice bread. The higher protein rices produced relatively the more moist white rice bread. The springiness of rice bread was also significantly correlated with high amylose content and hard gel consistency. The completely chalky and large gram rices showed better suitability for fermentation and brewing. Our breeding efforts on rice quality improvement for the future should focus on enhancement of palatability of cooked rice and marketing qualify as well as the diversification in morphological and physicochemical characteristics of rice grain for various value-added rice food processings.

• Journal of the Korean Applied Science and Technology
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• v.35 no.1
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• pp.173-185
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• 2018

Effects of three different types of dispersions and flow improving additives composed with fatty acid esters, fatty acid metal salts and amide compound on the vulcanization and the mechanical properties properties of rubber compounds of EPDM and carbon black as fillers. were investigated using Mooney viscometer, moving die rheometer, hardness tester, and universal test machine. The aging characteristics of vulcanized EPDM compounds were also investigated. The Mooney viscosity measured at $125^{\circ}C$ showed a tendency to decrease in the order of amide type> metal salt type > ester type additive. Scorch time showed little or no difference with the addition of ester or metal salt type additives, but the amide type additive shortened a scorch time more than one minute. Rheological measurement data obtained at $160^{\circ}C$ showed that the vulcanization time was faster for metal salt type and amide type additive systems. Delta torque values of EPDM compound increased with metal salt type and amide type additives, but slightly decreased with ester type additive. The tensile strength of the EPDM compound was greatly improved when an ester type additive was added, but the amide type or metal salt type additive had no significant effect. The elongation was significantly improved for metal salt type additive, while the rest were not significantly affected. The tear strength of the EPDM compounds increased with the addition of all kinds of additives, and it increased remarkably in the case of metal salt type additive. Hardness of the EPDM compounds was nearly same value regardless of additive types. The thermal aging of the EPDM blend at $100^{\circ}C$ for 24 h showed little change in the case of metal salt type or amide type additive, but the elongation tends to decrease by 10-20% for all EPDM compounds containing additives.

• Journal of the Korean Applied Science and Technology
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• v.35 no.1
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• pp.99-110
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• 2018

In this study, oil of Platycodon grandiflorum seeds was prepared using supercritical carbon dioxide extraction (SCE) and its physicochemical indices as a new edible oil were investigated. Compared to Soxhlet solvent extraction, SCE under the condition of 6,000 psi at $40^{\circ}C$ produced more oil, especially from the roasted seeds to 32.7%. TLC analysis showed triacylglycerols accounted for most of the oil obtained from roasted Platycodon grandiflorum seeds by SCE similarly to commercial soybean oil or perilla seeds oil. The oil had highly unsaturated lipid with considerable amount of linoleic acid(73.27%) much more than two commercial oils followed by oleic acid(13.16%). Physicochemical properties of the oil were as follows; specific gravity, 0.92; dynamic viscosity, 45.37 cP; refractive index, 1.48; color, L=47.30, a=-3.69, b=25.72; iodine value, 141.57 g $I_2/100g$ oil; saponification value, 191.21 mg of KOH/g of oil; acid value, 2.60 mg of KOH/g of oil. Among those, refractive index, viscosity and iodine value, which were related to unsaturation degree of lipid, were ranged between those of two commercial oils. The oxidation stability of oil(2.03 hr) was also ranged between less stable perilla seeds oil(1.79 hr) and more stable soybean oil(2.94 hr) based on the induction time measured by Rancimat assay. In addition to extraction yield increase, seeds roasting provided further benefits such as reductions of cholesterol ester content and acid value without change in fatty acid composition. In conclusion, oil was extracted from the roasted Platycodon grandiflorum seeds at high yield by supercritical carbon dioxide and it seemed to have proper characteristics as a edible oil.

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.10
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• pp.1278-1286
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• 2008

The effect of Tween 20 addition on changes in the stability of methylcellulose (MC) emulsions (1 wt% MC, 10 wt% n-tetradecane, 20 mM bis-tris buffer, pH 7) was investigated by creaming stability and orthokinetic stability measurements. In the case of MC emulsions containing varying amounts of oil (1$\sim$30 wt%) and no Tween 20 added, creaming stability, judged by mean migration velocity of fat globules ($V_m$), was found to depend on droplet size: the larger the droplet size, the worse the stability [$V_m$: 0.326 $\mu$m $min^{-1}$ ($d_{32}$: 0.32 $\mu$m) ${\rightarrow}V_m$: 0.551 $\mu$m $min^{-1}$ ($d_{32}$: 0.53 $\mu$m)]. With Tween 20, creaming stability was found to be worse than the one without Tween 20, except for MC emulsion containing 0.2 wt% Tween 20. In addition, cream stability was the lowest with the lowest concentration of Tween 20 and a tendency to recover with increasing Tween 20 concentration [$V_m$: 0.598 $\mu$m $min^{-1}$ (0.01 wt%)${\rightarrow}V_m$: 0.389 $\mu$m $min^{-1}$ (0.2 wt%)] was found. From viscosity measurement for aqueous bulk phase of MC emulsions, such a change in the creaming stability was found to coincide well with the results of viscosity measurement. Therefore, it was reasonable to say that creaming stability of MC emulsions containing Tween 20 depended on MC concentration in aqueous bulk phase, which was in turn varied by competitive adsorption between MC and Tween 20 at the oil droplet surface. In case of orthokinetic stability, judged by destabilization time ($t_d$), it was found that the addition of Tween 20 resulted in lowered stability with more pronounce tendency at higher concentrations [$t_d$: 160 min (0.03 wt%)${\rightarrow}t_d$: 100 min (0.2 wt%)]. Moreover, combined with previous results, the orthokinetic stability of MC emulsions containing Tween 20 was found to be exponentially proportional to MC load. In conclusion, competitive adsorption between MC and Tween 20 may affect the stability properties of MC emulsion to varying extents, depending on the concentration of Tween 20.

• Microbiology and Biotechnology Letters
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• v.13 no.3
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• pp.191-198
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• 1985

Seven different strains of lactic bacteria and 13 combinations of these microorganisms were tested for their acid forming capacity on a vegetable milk made from lupinseed protein concentrate(LPC). L acidophilus, L casei, S. lactis, L. mesenteroides, mixed culture of L. acidophilus and S. thermophilus, and mixed culture of S. lactis and L. mesenteroides were selected and further tested for their growth pattern and acid forming property on lupinseed milk both untreated and partly hydrolized one with carbohydrate decomposing enzymes. The enzyme hydrolized lupinseed milk had 1.5 folds of total free sugar, 8.2 folds of fructose, 3 folds glucose, 2.3 folds maltose, compared to the untreated lupinseed milk. For the untreated lupinseed milk, L. mesenteroides was appeared to be most suitable microorganism having the maximum cell concentration of 1.0 $\times$ 10$^{9}$ $m\ell$ and the final pH 4.40 with the acidity 0.46％. For the enzyme treated lupinseed milk, mixed culture of L. acidophilus and S. thermophilus showed the best performance having 1.9$\times$10$^{9}$ $m\ell$ maximum cell number and the final pH and acidity were 3.69 and 1.13％, respectively. Lactic acid fermentation altered the physical property of lupinseed milk; by fermentation the viscosity generally increased with untreated lupinseed milk, but decreased with enzyme hydrolized one. The viscosity change and sedimentation rate of fermented milk varied with the type of lactic bacteria. The results of sensory evaluation indicated that S. lactis, L. casei, mixed culture of S. lactis and L. mesenteroides, and mixed culture of L. acidophilus and S. thermophilus, grown on enzyme hydrolized lupinseed milk, could produce acceptable lactic beverage.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.62 no.3
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• pp.172-183
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• 2017

Germinated brown rice (GBR) has received considerable attention over the last decade as a means of enhancing the nutritional value and health-promoting functions of rice. The effect of germination on the physicochemical and textural properties of brown rice (BR) was investigated in different rice varieties (Samkwang, Misomi, Chindeul, and Hyeonpum). Cooking properties, such as water absorption, expanded volume, and soluble solids were significantly increased by germination in all rice varieties. Textural properties (hardness, toughness, adhesiveness, and stickiness) of cooked samples were determined using a texture analyzer. Hardness and toughness were decreased by germination, whereas stickiness and adhesiveness increased significantly. These results revealed that germination leads to improvements in the cooking and eating properties of BR. In Rapid Visco Analyzer (RVA), significant reductions were observed for peak viscosity, break down, set back, and final viscosity after germination. Although the amylose content of Misomi was slightly decreased by germination, that of other varieties increased significantly. Germination induced no noticeable change in the average chain length of amylopectin in Misomi, Chindeul and Hyeonpum, but led to a significant increase in Samkwang.

• Journal of the Korean Recycled Construction Resources Institute
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• v.4 no.4
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• pp.388-395
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• 2016

This paper explores the photocatalytic sensitivity of cement mortar incorporated with recycled $TiO_2$ from waste water sludge. Basically, $TiO_2$ cluster sank down slowly to the bottom of cement mortar specimen before setting and hardening process. This leads the mismatch of $TiO_2$ concentration on the top and the bottom faces of a specimen. This poorly dispersed $TiO_2$-cement mortar naturally exhibits poor NOx removal efficiency especially on the top of cementitious structure. In architectural engineering application such as building or housing structures, one can simply filp over from the bottom so that more $TiO_2$ concentrated surface can be placed outward into the air. However, in highway pavement case, this could not be applicable due to in-situ installation of concrete pavement. Hence, the dispersion of $TiO_2$ cluster inside the cementitous material is getting important issue onto road construction application. To elaborate this issue, according to our results, silica fume, high-ranged water reducer, viscosity agent, blast furnace slag were not enhanced much of dispersion characteristics of $TiO_2$ cluster. The combination of foaming agent and accelerator of hardening with viscosity agent and small grain size of fine aggregate may help the dispersion of $TiO_2$ inside cementitious materials. Even though the enhanced dispersion were applied to the specimen, NOx removal efficiency doest not change much for the top surface of the specimen. This concurrently affected by the presence of tiny air voids and the dispersion of $TiO_2$ in that these voids could easily adsorbed NOx gas with the aid of large surface area.

• Korean Journal of Food Science and Technology
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• v.17 no.5
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• pp.389-398
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• 1985

To shorten the processing of cheese slurry, four different slurries, ie, Control, Cheddar 1 and 2, and Italian-type that were made of Na-caseinates, cream, trace elements, lactic culture, and enzymes were fermented at $30^{\circ}C$ for 7days with daily stirring. PH, titratable acidity, soluble nitrogen, viable cell count, active SH groups, total volatile fatty acid, free fatty acid, electrophoretic patterns of degraded caseins, and viscosity were analyzed to investigate physicochemical properties of fermented slurries. Acid production was accelerated in the cheese slurries with protease than that without the enzyme and PH of the former was decreased after three days of fermentation to 4.90. The Change of titratable acidity agreed to PH patterns. Soluble nitrogen of the Control slurry was increased slowly for four days and then rapidly to 40% of total nitrogen while those containing protease to 70%. The protease of lactic cultures used (Streptococcus lactis and Streptococcus cremoris) broke down as-casein more rapidly than $\beta$-casein and most proteins were degraded to peptides and amino acids after three days of fermentation. Total volatile fatty acids were increased by added lipase and free fatty acids composition analyzed by GLC in cheddar slurry with 0.00001% lipase was similar to that of commercial cheddar cheese, while that in Italian-type slurry was a half of that in commercial Italian cheese. Active SH groups were increased in the cheese slurries with glutathione from fourth day of fermentation. The viscosity of slurries decreased very rapidly by addition of protease.

• Journal of the Korea Concrete Institute
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• v.20 no.1
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• pp.67-75
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• 2008

An engineered cementitious composite produced with slag particles (Slag-ECC) had been developed based on micromechanical principle. Base grain ingredients were properly selected, and then the mixture proportion was optimized to be capable of achieving robust tensile ductility in the hardened state. The rheological design is performed in the present study by optimizing the amount of admixtures suitable for self-consolidating casting and shotcreting process in the fresh state. A special focus is placed on the rheological control which is directly applicable to the construction in field, using prepackaged product with all pulverized ingredients. To control the rheological properties of the composite, which possesses different fluid properties to facilitate two types of processing (i.e., self-consolidating and shotcreting processing), the viscosity change of the cement paste suspensions over time was initially investigated, and then the proper dosage of the admixtures in the cement paste was selected. The two types of mixture proportion were then optimized by self-consolidating & shotcreting tests. A series of self-consolidating and shotcreting tests demonstrated excellent self-consolidation property and sprayability of the Slag-ECC. The rheological properties altered through this approach were revealed to be effective in obtaining Slag-ECC hardened properties, represented by pseudo strain-hardening behavior in uniaxial tension, allowing the readily achievement of the desired function of the fresh Slag-ECC. These ductile composites with self-consolidating and shotcreting processing can be broadly utilized for a variety of applications, e.g., in strengthening seismic resistant structures with congested reinforcements, or in repairing deteriorated infrastructures by shotcreting process.