• Korean journal of food and cookery science
• /
• v.7 no.3
• /
• pp.53-59
• /
• 1991

This study was carried out in order to investigate the change of protein functionalities such as foaming and emulsifying properties by succinylation of protein isolates. Succinylated and unsuccinylated munghean protein isolates were tested for finding out the effects of pH, heat treatment and sodium chloride concentration on the solubility, emulsion capacity, emulsion stability, foaming capacity, and foam stability. The results are summarized as follows: 1. Succinylation enhanced the solubility of MPI except at pH 4.5. When heated, succinylation greatly increased the solubility of succinylated MPI above $60^{\circ}C$. With the addition of NaCl, succinylation increased the solubility of MPI at acidic condition. 2. Emulsion capacity of succinylated MPI showed the lowest value at pH 7 and higher values at acidic and alkaine condition. when succinylated MPI was heated, emulsion capacity showed the highest at $80^{\circ}C$. With NaCl was added, emulsion capacity of succinylated MPI lincreased at pH 7, 9 or 11 decreased at pH 3 except addition of 1.0M NaCl. 3. Emulsion stability of MPI and succinylated MPI showed the highest at pH 4.5. Succinylation enhanced the emulsion stability of MPI at acidic condition. 4. The foaming capacity of MPI was increased at pH 3, 7 or 9 by succinylation. 5. When heated, foam stability of MPI and succinylated MPI showed the highest at pH 4.5 and at pH 11, respectively. When heated, both proteins showed the highest stability at $100^{\circ}C$.

• Korean Journal of Food Science and Technology
• /
• v.38 no.4
• /
• pp.488-494
• /
• 2006

This study was carried out in order to investigate the feasibility of utilizing concentrated sunmul (soybean curd whey), which is a waste by-product of soybean curd processing, as a functional food ingredient. Sunmul Powder was concentrated by ultrafiltration and spray dried with or without dextrin. Oil adsorption capacity of UF retentate powder was similar to that of ISP (Isolated Soy Protein) and higher than that of sunmul powder, whereas water holding capacity of UF retentate powder was lower than that of ISP. Protein solubility of all types of UF retentate powder was significantly higher than that of ISP at pH 2.0-10.0 with the lowest protein solubility seen at pH 4.0 and solubility increasing as the conditions became more acidic or alkaline. Emulsifying activity indexes of UF retentate powder at pH 2.0-10.0 were not influenced by pH. Emulsion stability of 4% sunmul solution was lowest at pH 4.0, but that of UF retentate powder was higher at acidic pH values and decreased with increasing pH. Foaming capacities of sunmul and UF retentate powder were high at pH 4.0-6.0, but the foam of UF retentate powder disappeared within 20 minutes in all conditions of pH.

• Korean Journal of Food Science and Technology
• /
• v.23 no.4
• /
• pp.428-432
• /
• 1991

This study was carried out to investigate the effect of NaCl, pH and phosphate on the functional properties of a mixed system of plasma protein and myofibrillar proteins. The solubility of plasma protein, myofibrillar protein and the mixture (plasma+myofibrillar protein) increased according to the increase of NaCl concentration ($0{\sim}4%$) and pH $pH4{\sim}8$). The solubility, emulsifying activity and capacity of the mixture were lower than those of plasma protein, whereas higher than those of myofibrillar protein. The gel strength of the mixture and myofibrillar protein showed a significant increase when NaCl concentration was increased from 2 to 3%. The gel strength of myofibrillar protein increased about four times when 0.3% polyphosphate added to the sample containing 2% NaCl, whereas the moisture loss of the mixture and myofibrillar protein decreased significantly. The gel strength of plasma protein, myofibrillar protein and the mixture increased slightly at $3{\sim}5%$ protein concentration, whereas the gel strength of those increased significantly as the protein concentration increased from 5 to 9%.

• Korean journal of food and cookery science
• /
• v.15 no.1
• /
• pp.73-80
• /
• 1999

This study was carried out to investigate the effects of enzyme treatments on the functional properties of soy protein isolate (SPI) and to examine the quality attributes of soy yogurt prepared by different enzyme treatments, sweeteners and starter cultures. Enzyme treatment increased the solubility and emulsifying capacity of soy proteins, but decreased the emulsifying stability; the enzymatic activity of ${\alpha}$-chymotrypsin was higher than that of trypsin. Enzyme treatments decreased the pH of soy yogurts prepared by both culture methods, the culture of L. bulgaricus and S. thermophilus and the culture of L. bulgaricus and K. fragilis, but increased the titratable acidity, total numbers of lactic acid bacteria and yeast. Trypsin was more effective than ${\alpha}$-chymotrypsin in decreasing pH and increasing titratable acidity and total numbers of lactic acid bacteria and yeast. Fructose decreased the pH of soy yogurts more than sucrose in the culture of L. bulgaricus and S. thermophilus, and vice versa in the culture of L. bulgaricus and K. fragilis. Fructooligosaccharides were more effective in the culture of L. bulgaricus and K. fragilis than in the culture of L. bulgaricus and S. thermophilus in increasing the titratable acidity, total count of lactic acid bacteria and yeast. In sensory evaluation, soy yogurts containing trypsin treated SPI, fructose and fructooligosaccharides (75%:25%) were more acceptable than those containing untreated or trypsin treated SPI and fructose. This was because of more smooth and less sour, in which the values of pH, titratable acidity, microbial growth, and viscosity were in the range of commercial yogurts. Soy yogurts fermented by L. bulgaricus and K. fragilis showed more smooth mouthfeel than those fermented by L. bulgaricus and S. thermophilus.

• Korean Journal of Agricultural Science
• /
• v.37 no.1
• /
• pp.61-68
• /
• 2010

Rice bran proteins from different cultivars(Youngan, Sindongjin, Suwon 511) were extracted with Xylanase using orthogonal analysis method and their functional properties were investigated. The optimum extraction conditions, based on protein content in the extract found to be at 1 wt% xylanase, pH 7 and 50:1, solvent to rice bran ratio(v/w %). Nitrogen solubility indices(NSI) of rice bran protein concentrates were shown a minimum value at pH 4 ranged 2~23%, varied with different cultivars and a maximum (NSI${\geq}$90% for all cultivars) at pH 10. As for water adsorption and fat adsorption capacity, rice bran protein concentrates were shown to be better than Na-caseinate and isolated soy protein, respectively. Emulsifying activities were observed high in order of Na-caseinate>Youngan rice bran protein>Shindongjin rice bran protein>Suwon 511 rice bran protein>isolated soy protein. In general, the surface tension of rice bran protein solution($10^{-3}$ wt%, 5 mM bis-tris, pH 7) was increased with increasing concentrations and found a minimum value near pI. On heating, it was decreased slightly with increasing temperatures up to $70^{\circ}C$ and then increased above $80^{\circ}C$. Addition of sodium chloride was made the surface tension decrease. In conclusion, with Xylanase, rice bran protein concentrate can be successfully extracted from the rice bran of different cultivars and the Youngan rice bran protein was thought to have best functionality among rice cultivars tested. It might be used as a milk protein substitute.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.18 no.4
• /
• pp.410-422
• /
• 1989

Soybean protein isolates were acylated with succinic anhydride and partially hydrolyzed with trypsin. Chemical modification decreased protein contents of samples and, in amino acid composition, tyrosine was increased comparatively. And lysine was increased remarkably by partial proteolysis. Succinylation and trypsin treatment increased the aqueous solubility and shifted the isoelectric potint that showed high pH-dependence of protein solubility. Protein solubility was influenced by salt concentration such as $NaCl,\;CaCl_2,\;NaNO_3$ and $NaH_2PO_4$. Chemical modification increased the absorption of oil and water, emulsification properties and foam capacity, but decreased foam stability, ultraviolet absorbance and bulk density. Protein-protein Interaction between soybean protein isolates and beef protein increased the emulsifying activity, emulsifying activity index and foaming properties, but it didn't have any influence on emulsion stability.

• Food Science and Biotechnology
• /
• v.16 no.5
• /
• pp.836-842
• /
• 2007

In this study, we investigated the effects of heating ($80^{\circ}C$, 30 min) on the physicochemical and functional attributes of acid (cottage) and sweet (Edam and Cheddar) whey powders. The water holding capacity (WHC) of the whey powders was not affected by heating or pH value. The heated Cheddar whey powder had a significantly lower (p<0.05) WHC than that of the other wheys. Heating detrimentally impacted the emulsifying and foaming properties, On the other hand, heating significantly enhanced the heat stabilities (HS) of all powders, This was best demonstrated at the acidic pH values of 3.0 and 4.5, where the HS increased by 57 and 53, 181 and 167, and 31 and 48%, for the cottage, Edam, and Cheddar, respectively. Overall, this data provides useful insights into the manufacture of pasteurization and retort-stable whey powders.

• Korean Journal of Food Science and Technology
• /
• v.19 no.5
• /
• pp.409-413
• /
• 1987

Microcrystalline collagen was manufactured from raw pigskins and its functional properties were measured. It showed a thixotropic behavior. The maximum viscosity was obtained at pH 3.5 and the viscosity increased with the increase of concentration in a nonlinear manner. The increase in temperature decreadsed the viscosity while the effect of temperature was greater at pH below 4.5. Foaming capacity was similar to that of gelatin but superior to that of egg white at 1%. The foam stability was inferior to that of egg white. Emulsifying capacity was lower than that of pork. Values from physical and chemical analysis were somewhat different from those of medical-grade microcrystalline collagen made from bovine cerium collagen.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.17 no.4
• /
• pp.312-319
• /
• 1988

The functional properties of plasteins have been compared with those of sardine protein concentrate and egg albumin. The solubility of plasteins was higher than that of FPG and the glu-plastein had 84% solubility in the range of pH 3-10. The dispersibility of plasteins was lower than that of egg albumin, however those of plasteins was higher than that of sardine protein concentrate. The water holding capacity of plasteins was higher than that of egg albumin. Lipid absorption of leu-papain plastein was the highest, holding 2.2m119, and that of the other plastein was higher than that of egg albumin. The emulsifying activity of leu-papain plastein was the highest, holding 66.4%, and that of glu-papain plastein was the lowest, holding 51.2%, The emulsifying stability of plasteins was similar to that of the emulsifying activity. The foaming capacitt of leu-papain plastein was the highest, holding 460%, and those of the other plasteins was higher than that of egg albumin. The foaming stability of plasteins was superior to that of egg albumin. The viscosity of plasteins was lower than that of see albumin. The in vitro digestibility of plasteins was 67.6-78.0% range. The digestibility by four pretense were somewhat lower in the glu-papain plastein than in the FPG. The digest of plasteins treated with the microbiol pretense such as molsin and pretense(from Streptomyces griceus), which had a storage broth taste.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.25 no.2
• /
• pp.288-293
• /
• 1996

Chitosan의 막형성능을 이용하여 계란의 저장성 증진 효과를 검토하기 위하여 세척란과 미세척란을 chitosan용액 1%와 2%를 이용하여 coating 처리하여 $20^{\circ}C에서$ 저장하면서 난중 감소율, yolk index, Haugh unit 및 유화력 등을 측정하여 대조구와 비교한 결과 난중 감소율은 chitosan 처리에 의해 저장 기간이 경과함에 따라 감소하는 경향을 나타내었다. Yolk index와 Haugh unit 측정결과 chitosan의 처리효과는 p<0.05 수준에서 유의성이 인정되었다. 난황의 유화력은 저장 기간이 경과함에 따라 감소하였으며 chitosan 처리구는 대조구에 비해 완만하게 감소하였다. Chitosan coating의 농도별 처리는 계란의 저장중 무처리구에 비해 품질보존 효과가 점차 뚜렷하였으며, 미세척란 보다 세척란에서 더욱 뚜렷하였다.