• 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.

• Korean journal of food and cookery science
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• v.20 no.6 s.84
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• pp.658-666
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• 2004

In order to develop and commercialize high quality frozen soy yogurt, the effects of industrial proteases and commercial mixed cultures were examined on the functional properties and the sensory attributes of frozen soy yogurt. For quality improvement, soy protein isolates were primarily hydrolyzed by either Flavourzyme or Neurtrase, industrial Proteases, to reduce the beany flavor and increase the functional properties of the protein. The viable cell count of lactic acid bacteria was higher in the soy protein hydrolysates than whenuntreated. ABT-5 (L. acidophilus, Bifidobacterium lactis, and S. thermophilus) resulted in higher acid tolerance, bile acid tolerance and melt-down percent values than those with YC-X11 (Lactobacillus bulgaricus and Streptococci thermophilus). The overrun of frozen soy yogurt was improved by both Flavourzyme $(193.3\%)$ and Neurtrase $(156.7\%)$ treatments. With regard to thesensory characteristics, Flavourzyme improved the beany flavor, astringency taste, mouth feel and overall quality of frozen soy yogurts fermented with ABT-5. Further studies onproduct formulation will be needed to commercialize the frozen soy yogurt for the market.

• The Korean Journal of Community Living Science
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• v.15 no.3
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• pp.113-120
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• 2004

This study is to investigate the effect of dietary L-carnitine supplementation on lipid metabolism in rats fed with isolated soy protein and casein for their source of protein. Four experimental groups were organized and each group had eight Sprague-Dawley male rats with the initial weight of around 180g. The four groups were CO (casein only supplemented group); CC (casein and 3% L-carnitine supplemented group); ISO (isolated soy protein only supplemented group); ISC (isolated soy protein and 3% L-carnitine supplemented group). All groups were supplemented with the experimental diet for four weeks and carnitine comprised 3% of. their diet. The results were as follows; 1. There was no significant difference in food intake among the groups. 2. Final weight gain was significantly lower in the groups supplemented with isolated soy protein than in the groups supplemented with casein (P<0.05). The groups with supplemented casein and carnitine showed the effect of weight reduction (p<0.05). 3. Food efficiency ratio was lower in the groups supplemented with isolated soy protein than in the groups supplemented with casein (p<0.01). The groups supplemented with casein and carnitine showed low food efficiency ratio. 4. The serum total lipid was higher in the groups supplemented with casein than in the groups supplemented with isolated soy protein (p<0.05). 5. Serum total cholesterol was higher in the groups supplemented with casein than in the groups supplemented with isolated soy protein. 6. There was no significant difference in triglyceride, HDL-cholesterol, and LDL-cholesterol in serum among the groups. 7. Out of the groups supplemented with isolated soy protein the total cholesterol level in liver was low in the groups to which carnitine was supplemented (p< 0.05). However, there was no significant difference of liver total lipid and triglyceride among the groups. 8. There was no difference in TBARS levels and GSH-Px activities in liver among the groups.

• Journal of Nutrition and Health
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• v.38 no.4
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• pp.267-278
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• 2005

Postmenopausal women or ovariectomized rats are associated with increased cholesterol levels, which are risk factors of metabolic syndrome and cardiovascular diseases. Increased prevalence of metabolic syndrome after menopause might be associated with estradiol deficiency. Harmful effect of estradiol hampers the casual usage of hormone to prevent the metabolic syndrome. Soy protein has been reported to show several beneficial effects on health, however it is unclear which components of soy protein is responsible for anti-obesity and hypocholesterolemic effects. Soy isoflavones, gem-stein and daizein, are suggested to have anti-obesity and hypocholesterolemic effects but with inconsistency. The present study investigated the effect of supplementation of genistein (experiment I) and soy protein containing isoflavones (experiment II) to high fat diet on body weight gain, food intake, liver and fat tissue weight and the lipid levels in ovariectomized rats. Plasma and hepatic lipid contents and the mRNA levels of genes encoding lipid metabolism related proteins, such as CPT1 and HMGR were measured. Ovariectomy increased body weight, fat tissue weight and plasma and hepatic lipid levels which increase the risk of metabolic syndrome. Soy protein could improve plasma and hepatic lipids levels. Soy protein also increased hepatic CPT1 and HMGR mRNA levels. Plasma and hepatic lipids levels could not be decreased by dietary genistein alone. In contrast, lipids levels could be decreased by isoflavone-fortified soy protein, suggesting that the ingestion of soy protein enriched with isoflavone gives more benefit for protecting postmenopausal women from metabolic syndrome.

• Food Science and Biotechnology
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• v.14 no.1
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• pp.11-15
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• 2005

Dynamic shear moduli of isolated soy protein solutions upon heating were measured to monitor gelation. Onsets of gelation coincide with onset temperatures of denaturation in glycinin and ${\beta}$-conglycinin solutions, whereas in isolated soy proteins, onset of gelation was above denaturation temperature of ${\beta}$-conglycinin with storage modulus increasing in two steps. The first increase in storage modulus of isolated soy proteins occurred at about $78.5^{\circ}C$, while the second increase started at about $93^{\circ}C$. Gel properties of soy protein gels having different proportions of glycinin and ${\beta}$-conglycinin were measured by compression-decompression test. ${\beta}$-conglycinin was responsible for gel elasticity. Glycinin significantly increased hardness, toughness, and fracturability of gels at high heating temperature near $100^{\circ}C$. Results reveal texture of soy protein gels can be controlled by regulating ratio of glycinin to ${\beta}$-conglycinin and heating temperature.

• Nutritional Sciences
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• v.9 no.4
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• pp.240-247
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• 2006

In this study we investigated the neuroprotective, antioxidative, and hypocholestrolemic effects of dietary soy protein and soy isoflavone in a rat focal brain ischemia model. Weaning Sprague-Dawley rats were fed a 20% casein-based diet (CA), 20% soy protein-based diet (SP), or 0.2% soy isoflavones-supplemented diet (ISO) for 6 weeks. The cortical infarction volume of the ISO group was significantly lower than that of the SP group. The thiobarbituric acid reactive substances (TBARS) were considerably lower in the ISO group than the CA group. Glutatbione peroxidase activities of the SP group were notably higher than those of the CA group. Acetylcholinesterase (AchE) activities of the SP group were significantly decreased compared to the CA group. LDL cholesterol levels and LDL/HDL ratios of the ISO group were lower than those of the CA and SP groups. Our results collectively suggest that soy isoflavones may contribute to neuroprotection by reducing the TBARS and serum LDL/HDL ratio, whereas soy protein may be associated with the regulation of cognitive functions by modulating AchE activity.

• Proceedings of the KSCN Conference
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• 2004.05a
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• pp.437.2-438
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• 2004

The purpose of this study was to investigate the effects of garlic, soy protein and taurine on blood lipid profiles in postmenopausal hyperlipidemic model rats. Seventy-two female Sprague-Dawley rats weighing 200g were fed a commercial diet for one week. All rats were ovariectomized and then were randomly assigned to eight groups (high fat diet group; HFD group, 2% garlic powder group; GP group, taurine group; TR group, soy protein group; SP group, 2% garlic powder ＋ taurine group; GP＋TR group, 2% garlic powder+ soy protein group; GP＋SP group, taurine＋soy protein group; TR＋SP group, 2% garlic powder＋taurine＋soy protein group; GP＋TR＋SP group).(omitted)

• Journal of Nutrition and Health
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• v.27 no.1
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• pp.3-11
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• 1994

This study was carried out to examine how dietary protein and calcium levels in rats fed fat-enriched diet affect the total lipid and cholesterol contents of blood and tissues. Male Sprauge-Dawley rats weighing approximately 200g were fed six purified diets which contained 18%(w/w) beef tallow, 1% (w/w) cholesterol, two source of protein, casein or isolated soy protein (ISP) and three levels of dietary calcium, 0.1%, 0.4% and 1.0%, first, for four weeks, and second, for eight weeks. The contents of the total lipid, cholesterol and triglyceride in blood, liver, heart and feces were determined. After four weeks feeding serum lipid and cholesterol concentrations significantly decreased in rats fed 1.0% (w/w) level calcium, regardless of dietrary protein sources. After eight weeks, these concentrations were significantly lower in the rats fed soy protein than in casein-fed rats. As dietary calcium level increased serum and tissue lipid and cholesterol contents were decreased and fecal lipid excretion increased. It is concluded that hypolipidemic and/or hypocholesterolemic effects of soy protein and calcium were partly due to decrease in lipid absorption.

• Current Research on Agriculture and Life Sciences
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• v.32 no.1
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• pp.34-42
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• 2014

Soy and fermented soy are popular and recognized as a health food among Koreans. Since soy proteins are known to be protease resistant, even to pepsin and pancreatin, it is hypothesized that soy proteins may interact with the intestinal tract and trigger certain physiological reactions. To test this hypothesis, mice were fed diets supplemented with soy, Chunkukjang, or casein. The differentially expressed proteins were analyzed using 2-D gels and identified by peptide mass fingerprinting using mass spectrometry. The majority of the differentially expressed proteins could be functionally grouped into metabolic enzymes and calcium-binding proteins. The differential protein expression by the soy-fed groups was also verified based on a representative protein, tropomyosin, using a Western blotting analysis. In addition, the soy-fed groups exhibited a taller villi structure. Therefore, this study suggests that soy proteins can be an effective nutrient and physiological stimulant for the intestines.

• Journal of the Korean Society of Food Science and Nutrition
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• v.26 no.5
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• pp.784-787
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• 1997

Enzymatically hydrolyzed soy sauce(eHSS) was prepared by the treatment of defatted soy flake using two types of proteases, followed by maillard reaction and formulation with some ingredients. The eHSS was mixed with fermented soy sauce(FSS) to make enzymatically hydrolyzed mixed soy sauce(eHMSS). The properties and sensory characteristics were evaluated and compared with commercially available soy sauces. The control of salt and total nitrogen contents in eHSS and eHMSS was easy, and the production of soy sauce of low salt and high protein was possible. However, the free amino acid content of eHSS was lower than FSS. due to lower degree of hydrolysis. In sensory evaluation, the eHSS have no loss taste and overall acceptance than FSS. Consequently, the eHSS and eHMSS have the potential for use with FSS to produce high quality soy sauce of low salt and high protein contents.