• Korean journal of food and cookery science
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• v.6 no.3 s.12
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• pp.9-15
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• 1990

Peanut prptein isolate was tested for the purpose of finding out the effect of pH, Sodium Chloride concentration and heat treatment on the solubility, surface hydrophobicity, foam expansion and foam stability. The solubility of peanut protein isolate was affected by pH and showed the lowest value at pH 4.5. When the peanut protein isolate was heated, the solubility decreased at pH 3 and pH 7 but at pH 9 solubility increased. At all pH range, solubility decreased as NaCl was added. The surface hydrophobicity of peanut protein isolate showed the highest value at pH 1.5. Generally, at acidic pH range the surface hydrophobicity was high, but at alkaline region, the surface hydrophobicity increased as the temperature increased. And when NaCl was added, the surface hydrophobicity was also increased. Foam expansion of peanut protein isolate was no significant difference among the values about pH. When the peanut protein was heated and NaCl was added, foam expansion was increased at pH 7. Foam stability was significantly low at pH 4.5 and foam stability was increased at acidic pH region below pH 4.5. At pH 7 and pH 9, heat treatment above $60^{\circ}C$ increased foam stability. When NaCl was added, foam stability was significantly increased at pH 3 and pH 7.

• Food Science of Animal Resources
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• v.34 no.3
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• pp.362-371
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• 2014

This study utilized commercially available proteolytic enzymes to prepare egg-white protein hydrolysates (EPHs) with different degrees of hydrolysis. The antioxidant effect and functionalities of the resultant products were then investigated. Treatment with Neutrase yielded the most ${\alpha}$-amino groups (6.52 mg/mL). Alcalase, Flavourzyme, Protamex, and Ficin showed similar degrees of ${\alpha}$-amino group liberation (3.19-3.62 mg/mL). Neutrase treatment also resulted in the highest degree of hydrolysis (23.4%). Alcalase and Ficin treatment resulted in similar degrees of hydrolysis. All hydrolysates, except for the Flavourzyme hydrolysate, had greater radical scavenging activity than the control. The Neutrase hydrolysate showed the highest 2,2-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging activity ($IC_{50}=3.6mg/mL$). Therefore, Neutrase was identified as the optimal enzyme for hydrolyzing egg-white protein to yield antioxidant peptides. During Neutrase hydrolysis, the reaction rate was rapid over the first 4 h, and then subsequently declined. The $IC_{50}$ value was lowest after the first hour (2.99 mg/mL). The emulsifying activity index (EAI) of EPH treated with Neutrase decreased, as the pH decreased. The EPH foaming capacity was maximal at pH 3.6, and decreased at an alkaline pH. Digestion resulted in significantly higher 1,1-diphenyl-2-picrylhydrazyl (DPPH) and ABTS radical scavenging activity. The active peptides released from egg-white protein showed antioxidative activities on ABTS and DHHP radical. Thus, this approach may be useful for the preparation of potent antioxidant products.

• Food Science of Animal Resources
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• v.39 no.4
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• pp.643-654
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• 2019

The amino acid composition, protein quality, and protein functionality of protein solution extracted from three edible insect species were investigated. We used 0.02% ascorbic acid and 0.58 M saline solution to extract water-soluble and salt-soluble proteins from the three insect species. Extracted protein solutions of Tenebrio molitor (TM), Allomyrina dichotoma (AD), and Protaetia brevitarsis seulensis (PB) were divided into six groups, according to species and solubility: WTM, WAD, WPB (water-soluble), and STM, SAD, and SPB (salt-soluble). Defatted TM had the highest protein content, but its protein solubility was the lowest, for both water and saline solutions. Amino acid composition differed by edible insect species and buffer type; SPB had the highest protein quality, followed by WPB. PB had a higher pH than the other species. Color values also differed among species. SPB had abundant high molecular weight proteins, compared with other treatments; and also had the highest foaming capacity, foam stability, and emulsifying capacity. In conclusion, PB is a good source of functional protein compared with the other studied species. Additionally, protein extraction using saline solution is promising as a useful method for improving edible insect protein functionality.

• Korean Journal of Agricultural Science
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• v.12 no.2
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• pp.292-308
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• 1985

This study was performed to obtain the basic data which can be applied to the use of foamed mortars using foaming agent of prefoamed type. The data was based on the properties of foamed mortars depending upon various mixing ratios of cement to fine aggregates, flow values and foam-cement ratio to compare those of cement mortar. The results obtained were summarized as follow; 1. At the mixing ratio of 1:0 and the foam-cement ratio of 6.00%, the increasing rate of water-cement ratio was 25% by flow $200{\pm}5mm$, 28% by flow $240{\pm}5mm$ and 32% by flow $280{\pm}5mm$. But it decreased as the mixing ratio gets poorer. The result showed that water amount increased because of the high viscosity caused by the increase of foam-cement ratio. The decrease of water-cement ratio was the greatest when the foam-cement ratio was 1.50%. 2. Absolute aridity bulk density of foamed mortars decreased with the increase of foam-cement ratio and the decrease of flow values. 3. Generally, compressive, tensile and bending strenghs of foamed mortars decreased with the decrease of flow values and the increase of foam-cement ratio. 4. The compressive strength was in proportion to tensile strength. It was estimated that the compressive strength was 8.8 times of tensile strength. The compressive strength was in proportion to bending strength. It was estimated that the compressive strength was 4.0 times of bending strength. The bending strength was in proportion to tensile strength. It was estimated that the bending strength was 2.1 times of tensile strength. 5. At the mixing ratio of 1:1 the lowest absorption rates were showed by foamed mortars, respectively. It was significantly higher at the early stage of immersed water.

• Journal of the Korea Institute of Building Construction
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• v.14 no.4
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• pp.301-307
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• 2014

In order to reduce the emission of carbon dioxide($CO_2$), this research use blast furnace slag in concrete manufacture, as 100% replacement of cement. The aim of this study is to investigate the density and strength properties of alkali-activated lightweight composites with alkali activators of different types and different amounts. The bubble for achieving the lightweight of alkali-activated lightweight composites was generated in the reaction between the paper ash and the alkali activators instead of using a foaming agent. Lightweight formed concrete was conducted basic experimental for determining replacement ratio of paper ash. Then, the density and strength were measured according to the types and the contents of the alkali accelerator that can react with the paper ash. As results, the optimum replacement ratio of the paper ash was 5%. The alkali activator containing NaOH 12.5% obtained the lowest weight of $1.13g/cm^3$. Also, compressive strength were relatively high. Therefore, this study demonstrated that alkali accelerator with a certain amount of NaOH can achieve relatively high strength and lightweight alkali-activated lightweight composites.

• Korean journal of food and cookery science
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• v.7 no.2
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• pp.97-104
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• 1991

This study was carried out in order to study the protein functionality such as foaming and emulsifying properties by succinylation of peanut protein isolates. Succinylated and unsuccinylated peanut protein isolate was tested for to find out the effect of pH, heat treatment and sodium chloride concentration on the solubility, foam expansion, foam stability, emulsion capacity and emulsion stability. The results are summarized as follows; 1. Succinylation enhanced the solubility of peanut protein isotate (PPI). The solubility of succinylated PPI markedly increased at pH 4.5. When the protein solutions was heated, the solubility of succinylated PPI greatly increased than PPI at pH 3. With addition of NaCl, solubility of succinylated PPI increased at pH 7 and pH 9. 2. The foam expansion of PPI and succinylated PPI on pH was no difference between both proteins. Addition of NaCl and heat treatment caused steeply increased in foam expansion at pH 3. 3. The foam stability of PPI and succinylated PPI showed the lowest value at pH 4.5. When PPI and succinylated PPI was heated, foam stability of two proteins incensed at pH 3 and showed similar aspects between PPI and succinylated PPI. However, at pH 9 stability of succinylated PPI decreased by heat treatment over $60^{\circ}C$. 4. Emulsion capacity of succinylated PPI on pH was markedly increased and showed the highest value at pH 11. At pH 4.5 which is isoelectric point of PPI, emulsion capacity of PPI by succinylation improved than that of PPI. When succinylated PPI was heated, emulsion capacity was greatly increased at pH 2 and pH 7. With NaCl was added, emulsion capacity of succinylated PPI increased than that of PPI. 5. Emulsion stability of PPI and succinylated PPI was affected by pH and showed its highest value at pH 11. At pH 4.5, emulsion stability of succinylated PPI increased than that of PPI. Addition of NaCl and heat treatment caused slightly increased in emulsion stability of succinylated PPI.

• Korean Journal of Agricultural Science
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• v.23 no.1
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• pp.120-130
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• 1996

Concrete is the most commonly used structural materials, but in concrete construction, its self-weight represents a very large proportion of the total load on the structure, and there are clearly considerable advantages in reducing the density of concrete. This study was carried out to investigate the stress-strain properties of no-fines synthetic lightweight concrete with synthetic lightweight coarse aggregates. The used synthetic lightweight coarse aggregate were two types, one was expanded clay with grading 3~8mm, the other is pumice stone with grading 4.75~10mm. The results of this study were summarized as follows ; The static modulus of elasticity of the synthetic lightweight concrete was $1.8{\times}10^5kg/cm^2$ at type CE using the expanded clay and $1.6{\times}10^5kg/cm^2$ at type CL using the pumice stone. The dynamic modulus of elasticity was $1.9{\times}10^5kg/cm^2$(CE) and $2.0{\times}10^5kg/cm^2$(CL). The dynamic modulus of elasticity was 10~30% larger than that of the static modulus of elasticity. The load-time curves of synthetic lightweight concrete were shown approximately similar to each other type except for added foaming agent. The stress-strain curves in uniaxial compressive of synthetic lightweight concrete were similar to each other.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.27 no.6
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• pp.319-326
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• 2017

In this study, a lightweight geopolymer was prepared using by slag discharged from IGCC (Integrated Gasification Combined Cycle) power plant and its physical properties, the density and compressive strength, were analyzed as a function of the concentration of alkali activators, W/S ratio and aging times. Also the possibility of applying it to lightweight materials by adding Si sludge as a foaming agent to the geopolymerg was investigated. In particular, a complex composition of alkali activator and a pre-curing process were applied to improve the strength properties of lightweight geopolymers. While the compressive strength of the lightweight geopolymer using a single activator was 9.5 MPa, the specimen made with a complex composition of alkali activator had compressive strength of 2~5 times higher. In addition, the lightweight geopolymer with pre-curing process showed a compressive strength value of 18~48 % higher than that of specimen made with no precuring process. In this study, by using a complex activator and a pre-curing process. the maximum compressive strength of lightweight geopolymer was obtained as 40 MPa (The specimen was aged for 3 days and had density of $1.83g/cm^3$), which is comparable to cement concrete. By analyzing the crystal phase and microstructure of geopolymers obtained in this study using by XRD and SEM, respectively, it was confirmed that the flower-bud-like zeolite crystal was homogeneously distributed on the surface of the C-S-H gel (sodium silicate hydrate gel) in the geopolymer.

• Korean Journal of Food Science and Technology
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• v.19 no.6
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• pp.499-505
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• 1987

The functional properties of lupin seed protein concentrate (LPC) were examined and compared to those of soybean protein isolate (SPI) and Na-caseinate. LPC-50, of which protein level was 50%, was prepared by a two phase solvent (hexane: alcohol: water= 10:7:3) extraction method. LPC-70 was made from LPC-50 by removing the fractions solubilized by carbohydrate decomposing enzymes. The solubilities of LPC-50 and LPC-70 were similar to that of of SPI but slightly higher at pH 4-5, and less susceptible to the added salt. The apparent viscosity of LPC increased exponentially as the concentration increased over 6% level, and the change was similar to that of Na-caseinate. LPC showed strong pseudoplastic non-Newtonean flow behavior, which was similar to that of SPI The emulsifying capasity of LPC-70 was similar to that of SPI when salt was added. The foaming capacity of LPC was comparable to that of SPI. LPC showed high oil and water absorption capacities, which increased as the protein level was elevated. LPC-70 showed the highest oil absorption capacity of all the samples tested.

• Resources Recycling
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• v.14 no.2
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• pp.19-27
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• 2005

The recycling possibility of aluminum waste dross(AWD) as a ceramic raw material of porous light-weight material was examined. A aluminum waste dross was washed 4-7 consecutive times and roasted at 900$^{\circ}% for 1hour as pre-treatments. The properties of the pre-treatment of aluminum waste dross was investigated. It was conformed by XRD result that the spinel crystalline was grown in AWD, after roasting. After the roasted AWD was ground in aqueous state, the sodium hexaphosphate(SHP) as a dispersant which is used for stabilizing the concentrated slurry was added to the AWD slurry. The porous material was prepared by slurry foaming method with surfactant at room temperature. The foamed slurry volumes were 2 and 3 times of the original slurry volume. The properties of porous material with extended volume of 3 times was following: the porosity was about 84%, bulk density was 0.59 g/cm$^3$, the range of pore was from 50 ${\mu}m$ to 500 ${\mu}m$ and mean pore size was about 200 ${\mu}m$. AWD porous material was sintered at 1150$^{\circ}C-1250$^{\circ}C. It was colcluded that AWD was sintered well at 1200$^{\circ}C from material surface observation by SEM.