• Journal of Nutrition and Health
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• v.15 no.2
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• pp.119-128
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• 1982

The effect of dietary protein on growth and lipid levels of plasma and liver was studied in weanling male rats fed diets differing protein sources and amino acid balance. Rats were devided into 9 experimental diets which were grouped into 3 categories ; 1) Simple protein category includes gluten-, soy protein isolate-, and casein-containing diet groups, 2) Supplemented category includes casein supplemented with methionine, soy protein isolate supplemented with methionine, and gluten supplemented with lysine and methionine, 3) Mixed protein category includes diet groups containing gluten (2/3), casein (1/3), soy protein isolate (2/3) and casein (1/3), and casein (1/3), soy protein isolate (1/3) and gluten (1/3). The experimental diets composed of 15% protein, 65.8% carbohydrate, 10% fat and 1% cholesterol. The body wt. gain and P.E.R. were greater in rats of supplemented and mixed protein groups than simple protein groups. No statistical differences were found in plasma cholesterol among gluten, soy protein isolate and casein groups. Consumption of diets supplemented with limiting amino acid to gluten or soy protein isolate reduced the plasma cholesterol level by 23.2% and 34.2% respectively. However there was no difference between casein and the supplemented casein groups. The mixed protein groups shows relatively high plasma cholesterol concentration and low liver cholesterol levels. On the other hand gluten group showed low plasma cholesterol and high liver cholesterol levels, which means body cholesterol pool may not have been changed by the dietary protein. Feeding soy protein meal and the supplemented soy protein isolate resulted in lower plasma cholesterol, plasma triglycerides, liver cholesterol and liver triglycerides levels. This hypolipidemic effect is considered to see unique to soy protein isolate. Rats in gluten and the supplemented gluten groups showed lower plasma protein levels and a tendency of fatty liver.

• Food Science of Animal Resources
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• v.32 no.5
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• pp.627-634
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• 2012

This study was carried out to investigate the physical and thermal properties of ${\kappa}$-carrageenan (${\kappa}$-car) gel added whey protein isolate (WPI) as a cryoprotectant. The concentration of ${\kappa}$-carrageenan was fixed at 0.2 wt%. The mean ice crystal size of the WPI/${\kappa}$-car was decreased according to increasing whey protein isolate concentration. The temperature of gel-sol (Tg-s) and sol-gel (Ts-g) transition of WPI/${\kappa}$-car maxtrix was represented in the order of 3.0, 0.2, 5.0 and 1.0 wt%. In addition, the transition temperature of gel-sol of WPI in sucrose solution were showed in order of 1.0, 5.0, 0.2 and 3.0 wt% depending on whey protein isolate concentration. The shape of ice crystal was divided largely into two types, round and rectangular form. 1.0 wt% WPI/${\kappa}$-car matrix at pH 7 and 9 showed minute and rectangular formation of ice crystals and whey protein isolate in sucrose solution at a concentration of 1.0 wt% WPI/${\kappa}$-car matrix at pH 3 and 5 showed relatively large size and round ice crystals. The ice recrystallization characteristics and cryprotective effect of ${\kappa}$-carrageenan changed through the addition of different concentrations of whey protein isolate. It seems that the conformational changes induced interactions between whey protein isolate and ${\kappa}$-carrageenan affected ice recrystallization.

• Journal of the Korean Society of Food Science and Nutrition
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• v.14 no.1
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• pp.51-56
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• 1985

This study was to compare the effects of soy hot water extract, soy slurry, defatted soy flour, soy protein concentration and soy protein isolate on the quality of Busuge Base. In Busuge Base preparation the addition of soy products, in general, showed the improvable effect in the quality of Busuge Base. Among them the soy slurry was especially effective in volume increasing, hardness and panel score, and the soy protein isolate was effective in the protein fortification of Busuge Base. In addition, the qualify of Busuge Base was best when soy slurry and soy protein isolate were jointly used. In this case, the adequate amount of soy protein isolate was about 10%.

• Korean Journal of Food Science and Technology
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• v.24 no.3
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• pp.279-283
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• 1992

This study was undertaken to investigate the effects of added phytate and pH on the solubility and in vitro digestibility of low-phytate rapeseed protein isolate. Phytate content of low-phytate rapeseed protein isolate was 1.5%, as a result of 66% removal from defatted rapeseed flour and the protein: phytate ratio was 58:1. Solubility of rapeseed protein isolate at pH 2.0 and pH 11.5 was much higher than near the isoelectric point, pH 5.0. It's solubility was lowered by adding an increased amount of phytate especially at pH 2.0. The inhibitory effect of phytate toward pepsin digestibility of rapeseed protein isolate decreased by the increasing amount of phytate added. It is suggested that the production of low-phytate rapeseed protein isolate is necessary to improve the functionality and nutritional value in order to utilize it as food material.

• Korean Journal of Plant Resources
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• v.11 no.3
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• pp.272-278
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• 1998

This study was carried out to investigate the functional properties such as nitrogen solubility, emulsifying property , foaming capapcity , water and oil absorption of Camellia (Camellia japonica .) seed protein isolate in condition of distilled water and 0.5M NaCl solution at pH 2.0∼10.0. Nitrogen solubility of Camellia protein isolate in distilled water showed the minimum value at pH 4.0 and increased at pH lower or higher than the isoelectric point(pH 4.0). It was 90.0 %at pH 10.0 Nitrogen solubility of 0.5M NaCl solution showed a similar pattern with that of distrille dwater but was higher than that of distilled water except pH 2.0 and pH 10.0. Emulsifying activity of Camellia seed protein islate showed the minimum value at pH 4.0, but was higher at ether value of pH. Emulsifying stability of protein isolate was stable by heat treatment for 30min, at 80℃ and increased in 0.5M NaCl solution more than that of distille dwater. Foaming capacity of Camellia seed protein isolate in distill3ed water showed the minimum value near the isoelectric point, While it changed little at other values of pH. Foaming stability slowly decreased as, but didn't make a significant difference as time was delayed . Oil absorption was 1.4ml per a sample of 1g and water absorption was 0.9ml per a sample of 1g. The former was higher than the latter . The content of total amino acid of Camellia protein isolate was 43.67% and the major total amino acid of Camellia protein isolate was 43.67% and the major total amino acid was in the order of glutamic acid , arginine, aspartic acid, and leucine.

• Korean Journal of Food Science and Technology
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• v.25 no.4
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• pp.360-365
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• 1993

This study was carried out to examine the effects of phytate addition on the solubility and digestibility of the low-phytate soy protein isolate (LSPI) and high-phytate soy protein isolate (HSPI). In SDS-polyacrylamide gel electrophoresis of soy protein isolate, different patterns of proteins were observed in both HSPI and LSPI at various phytate and pH levels, suggesting that phytate may bind specifically to certain protein fractions at a particular pH. For example, proteins of M.W $1.8{\sim}3.5\;kDa$ resisted phytate binding at acidic pH. LSPI was fractionated into albumin, globulin, gliadin and glutelin, and phytate was shown to bind with difficultly to all three gliadin bands. Effects of phytate on the pepsin digestibility of soy proteins were apparent, especially in the short term digestion.

• Korean journal of food and cookery science
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• v.5 no.2
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• pp.9-17
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• 1989

This study was carried out in order to study the emulsifying properties of kidney bean protein isolate. Kidney bean protein isolate was tested for the purpose of finding out the effect of pH, addition of NaCl, and heat treatment on the solbulity and emulsion capacity, emulsion stability, surface hydropobicity and emulsion viscosity. The results were summarized as follows. 1 The solubility of kidney bean protein isolate was affected by pH and showed the lowest value at pll 4.5 which is isoelectric point of kidney bean isolate. When the kidney bean protein isolate was heated, the highest value observed at pH 2 and pH 7 was 96.11%, 97.41% respectively. 2. The emulsion capacity of kidney bean protein isolate was not significantly different with each pH. With addition of NaCl, emulsion capacity decreased steadily. When heated thr highest value observed at pH 2 and pH 7 was 82.91 ml oil/100 mg protein ($60^{\circ}C$), 82.08 m1 oil/100 mg protein ($80^{\circ}C$) respectively. 3. The emulsion stability was significantly higher at pH 4.5 than that of pH 2 and pH 7 (p 0.05) When NaCl was added, emulsion stability was generally increased after 2hrs. When heated, the highest value observed at pH 2 and pH 7 was 21.25% ($80^{\circ}C$),23.7%($100^{\circ}C$) respectively after 2hrs. 4. Surface hydrophobicity increased sharply as 0.2 M NaCl was added to pH 4.5. When heated, the surface hydrophobicity increased as the temperature increased. 5. The highest value of emulsion viscosity was observed at pH 4.5 and pH 7 when 0.2 M NaCl was added. Under heat treatment, the highest value was 48,000 cps at pH 4.5 ($40^{\circ}C$). In the case of pH 7, the highest value was 105,000 cpa at $100^{\circ}C$.

• Food Science of Animal Resources
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• v.42 no.5
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• pp.849-860
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• 2022

The myofibril protein (MP) isolate-saccharide graft reactions was prepared using the Maillard reaction with saccharides. The effects of various saccharides on protein functionality and quality of the Maillard reaction were investigated and compared with those of MP. The grafting degree of the MP isolate-saccharide graft reaction was significantly higher in the reducing sugar-treated groups (lactose, glucose, fructose, and palatinose). The browning intensity of the MP isolate-saccharide graft reaction with fructose, sucrose, and erythitol was higher than that observed in the control reaction (p<0.05). MP that reacted with reducing sugars (glucose, fructose, palatinose, and lactose) had fainter bands than MP that reacted with non-reducing sugars (sucrose, erythitol, trehalose, sorbitol, and xylitol). MPs conjugated with glucose exhibited higher protein solubility. The palatinose and lactose treatments were maximum in water binding capacity, though no significant difference in oil binding capacity among the saccharide treatments was observed. The emulsion stability of the MP isolate-saccharide graft reaction with palatinose and erythitol was higher than that of the control reaction. Therefore, reducing sugars have good protein functionality in the MP isolate-saccharides graft reaction.

• Korean Journal of Food Science and Technology
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• v.12 no.4
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• pp.263-271
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• 1980

Detoxified and deallergenized castor bean protein isolate was prepared from defatted castor bean pomace for use in animal feedstuffs and human foods. Succinylation and acetylation of the ${\varepsilon}-amino$ groups of the protein improved markedly the water solubility of the protein at $pH\;7{\sim}8$. The results of the amino acid analysis of the protein isolate revealed that the sulfur-containing amino acids and L-lysine were limiting amino acids and that succinylation and acetylation caused some little loss of the amino acid content. The L-methionine enriched plastein was synthesized from the protein isolate or the acylated protein isolates and DL-methionine ethyl ester by one step process with papain. By this method the extent of incorporation of L-methionine was about 50%. Pepsin hydrolyzed both unmodified and modified protein isolates at the same rate (about 92%). Tryptic hydrolysis, however, was less for the succinylated protein isolates (about 42%) and less for the acetylated protein isolates (about 26%). The protein efficiency ratio of L-methionine enriched protein isolate (about 2.5 weight %) was 90% that of reference casein. The protein efficiency ratio values of succinylated (88%) and acetylated (84%) protein isolate were 55 and 69% of reference casein, respectively.

• Korean Journal of Food Science and Technology
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• v.22 no.5
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• pp.590-595
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• 1990

The destructive effect of peroxidized lipid on the amino acid in protein isolate and the proteolytic activity of protease were studied in the model system of rice bran. The content of amino acids in the protein isolate decreased significantly when they reacted with peroxidized lipid (pov. 1200 meq/kg). Most of amino acids were lost by more than 90% in salt soluble protein isolates when analyzed by the method of enzyme hydrolysis. Formaldehyde reduced the activity most severely among peroxidized products. Formic acid, peroxidized lipid and hydroperoxide were also found to reduce the protease activity. The damaging effect of the secondary products on the protease activity was more serious than that of the primary products of lipid peroxidation. The destruction of amino acids in the total protein and Inhibition of protease activity by the peroxidized lipid were apparent.