The Soy Protein Research Committee(Japan)
MEASUREMENT OF FLOW PROPERTIES OF SOYBEAN PROTEIN-LIPID-WATER SUSPENSION SYSTEMS WITH A COMPUTER-ONLINE VISCOMETER
Fumio YAMAUCHI and Makoto MIURA
Faculty of Agriculture, Tohoku University
Nutr. Sci. Soy Protein, Jpn. 4, 5-8, 1983.
The flow properties of soybean protein-lipid-water suspension systems and coagulated gels were related to a protein-lipid interaction. For powdered soybean lecithin-added soybean protein suspension systems and their heat-induced gels, the yield stress (ɬy) and the consistency index (K) increased with increasing amounts of added lipid, but the flow behavior index (n) and the thixotropy index (TI) decreased. On the other hand, there were only small changes in the magnitudes of the thixotropic parameters and the viscometric parameters (ɬy, K and n) after adding soybean oil at various concentrations to soybean protein dispersions. These facts suggested that the formation of a protein-phospholipid complex increased the effective particle size, and that the intermolecular entanglements and linkages among the protein molecules or among the protein-phospholipid complexes were weakened by the addition of polar lipids. The thixotropy index defined in this study is available for characterizing the stress decay, that occurs within soybean protein dispersions and heat-induced gels as they are sheared.
INTERACTIONS OF SOYBEAN PROTEINS WITH CALCIUM ION AND É»-CASEIN
Masao KANAMORI and Hiroshi DOI
Department of Agricultural Chemistry, Kyoto Prefectural University
Nutr. Sci. Soy Protein, Jpn. 4, 9-14, 1983.
Proteins were extracted with 35 mM potassium phosphate buffer, pH 7.6, containing 0.4 M NaCl (Buffer C) from defatted soybean flour. Extracted proteins were fractionated on a Sephacryl S-200 column with Buffer C to RSP-I, II, III, IV, V and VI. The result of sedimentation experiment suggested that RSP-I, II and IV corresponded to 11S, 7S and 2S proteins, respectively. In fact, RSP-IV had a trypsin inhibitory activity. Precipitation of each fraction by heat treatment and/or calcium ion in the absence and presence of É»-casein was examined. RSP-I, IV, V and VI were heat stable fractions. Sixty-five% of RSP-II were precipitated by heating at 100 Åé for 20 min, while the presence of É»-casein suppressed the precipitation of RSP-II by heating and only 25.3% of RSP-II were precipitated. In any case, calcium ion precipitated about 50% of each fraction. Heat treatment of protein fractions in prior to the addition of calcium ion made more precipitates. When É»-casein was present in soybean protein solutions, the formation of precipitates by the addition of calcium ion decreased. Precipitation of soybean proteins by the addition of calcium ion after heat treatment in the presence of É» -casein was lower than that in the absence of É»-casein. RSP-I, II and IV formed complexes with É»-casein by heat treatment. Those protein fractions contained two types of subunits. One formed the complex with É»-casein without heat treatment and the other did complex by heating.
EXTRACTION OF BEANY FLAVOR COMPOUNDS FROM PROTEIN SOLUTION OF VARIED IONIC STRENGTH WITH MIXED SOLVENTS
Seiichi HOMMA, Ko AIDA and Masao FUJIMAKI
Department of Nutrition and Food Science, Ochanomizu University
Nutr. Sci. Soy Protein, Jpn. 4, 15-17, 1983.
Soybean protein isolates freshly prepared from defatted soybean meal and Fujipro-R were dissolved in the pH 7.6 solution of varied ionic strength (0.001, 0.01 and 0.1). These protein solutions were extracted with mixed solvents of ether-ethanol or ether-methanol. The ether layer was analyzed for GLC for the determination of beany flavor compounds of n-hexanal and n-hexanol. The protein in the aqueous layer was determined by the Biuret method. The low ionic strength (É : 0.001, 0.01) of the protein solution was found to be effective to extract beany flavor compounds with less coagulation of protein.
EFFECT OF CARRAGEENAN ON THE STABILITY OF SOY PROTEIN AND MILK CASEIN SOLUTIONS
Osamu IGARASHI, Chieko DOHMOTO and Junko HIROMOTO
Institute of Environmental Science for Human Life, Ochanomizu University
Nutr. Sci. Soy Protein, Jpn. 4, 18-21, 1983.
Soybean and milk proteins have a sensitivity for Ca2+ to coagulate. On the other hand, carrageenans from red seaweed are used to stabilize some dairy products to prevent coagulation of milk protein during heating process. We examined the stabilizing effect of carrageenan upon the soybean acid precipitated protein, 7S and 11S globulin and SPI and upon milk acid casein and ÉøS1-casein under the presence of Ca2+. É»-and É…-Carrageenans from Eucheuma serra were prepared in our laboratory and used as the tested ones. Results obtained are as follows: 1) For the soybean acid precipitated protein, 7S and 11S globulin, É…-carrageenan was effective to form stable suspension than É»-type. This suspension of Ca2+ -protein-carrageenan was stable under the centrifugation at 3,000 g, but by the centrifugation at 50,000 g it formed the precipitate. 2) For the milk ÉøS1-casein É»-carrageenan showed more stronger effect to make stable solution than É…-type. Also, both carrageenans had different stabilizing effect to ÉøS1-casein, because their stabilizing curves were quite different each other. 3) By the heating the soybean protein solution the stabilizing effect of É»-carrageenan was promoted. The same tendency was observed in milk ÉøS1-casein solution. 4) It was confirmed that the stabilizing effect of carrageenan for soybean and milk proteins was due to the formation of stable colloidal solution.
NUTRITIONAL PROPERTIES OF AN OLIGOPEPTIDE MIXTURE PREPARED FROM SOY PROTEIN ISOLATE BY ENZYMATIC MODIFICATION
Soichi ARAI
Faculty of Agriculture, The University of Tokyo
Nutr. Sci. Soy Protein, Jpn. 4, 22-25, 1983.
Soy protein isolate (SPI) was treated with papain and subsequently with trypsin to produce an oligopeptide mixture (OPM) having an average molecular weight of ca. 900 daltons; the amino acid composition of OPM approximated that of SPI. The nutritional properties of OPM were evaluated by feeding tests with rats, where SPI and an amino acid mixture (AA) simulating OPM were used as controls. SPI-, OPM-, and AA-diets, each having a methionine level of 0.1%, were prepared and fed to normal and protein-malnourished rats for three weeks. The results are summarized as follows: (1) for normal rats no significant differences were found among the three diets in terms of protein efficiency ratio (PER), blood hemoglobin content, and the activities of the two enzymes, GOT and GPT; and (2) when malnourished rats were fed, the use of OPM diet led to significantly faster recovery of their body weight than the use of any of the others. Effects of different levels of methionine in the three diets on PER values for normal and malnourished rats are discussed by using the data presented in the preceding paper.
COMPARATIVE STUDIES ON THE GOITROGENIC ACTIVITIES OF DEFATTED SOYBEAN AND SOYBEAN PROTEIN ISOLATE
Shuichi KIMURA and Mieko KAWAMURA
Faculty of Agriculture, Tohoku University
Nutr. Sci. Soy Protein, Jpn. 4, 26-30, 1983.
In a previous study, we demonstrated that soybean contained goitrogenic substances which affect the thyroid function and that some of these substances were sapogenols and isoflavonoids. In addition, our results showed that (1) much less enlargement of thyroid was observed in rats fed soy protein isolate (SPI) as compared with that of defatted soybean, (2) a diet containing SPI produced lower plasma cholesterol than that of defatted soybean, and (3) iodine deficiency gave a higher plasma cholesterol, mainly on the LDL-cholesterol. On the other hand, Beck suggested that the fiber of soybean stimulated the loss of thyroxine into feces. From these observations, it is expected that the goitrogenic substances might be removed by process of the preparation of SPI. The present study was undertaken to examine the goitrogenic activity of these substances, soybean crude saponin fraction (SAP) and soybean crude fiber fraction (SCF). Furthermore, this study was undertaken to determine the mechanism of plasma cholesterol-lowering effect via thyroid function. In the iodine deficient SPI-diet, supplement of SAP exerted clearly an enlargement effect on the thyroid accompanied with high concentration of plasma cholesterol, free-cholesterol and LDL-cholesterol. On the other hand, supplement of SCF had no effect on the thyroid, but enhanced the concentration of plasma cholesterol, free-cholesterol, LDL-cholesterol and HDL-cholesterol. In the iodine deficient gluten-diet, supplement of SAP had no effect on the thyroid and plasma cholesterol. On the contrary, supplement of SCF exerted clearly an enlargement effect on the thyroid, however, significant changes were not observed on the plasma cholesterol.
COMPARISON OF THE DIGESTIVE PROCESS OF SPI WITH OTHER DIETARY PROTEINS
Hiroshi NAITO and Tadashi NOGUCHI
Faculty of Agriculture, The University of Tokyo
Nutr. Sci. Soy Protein, Jpn. 4, 31-34, 1983.
Digestive process of 4 kinds of dietary proteins was followed in meal-fed rats. Rats fed casein or SPI contained smaller amounts of trichloroacetic acid soluble-amino acids in the small intestine than those fed gelatin or rice protein, 1.5 hr after the withdrawal of the diets. Rats fed a diet containing 20% rice protein contained relatively large amount of lysine in the small intestine. Furthermore, they excreted the largest amount of lysine into urine among the 6 groups of rats, suggesting the availability of lysine in rice is not so high as that in the other dietary proteins. The amino acid composition of trichloroacetic acid-soluble fraction of small intestinal contents well correlated with that of sulfosalicylic acid-soluble fraction of urine. These results show that dietary proteins are digested in various manners according to their physical and chemical properties and the characteristics of the digestive process reflects on the urinary amino acids.
NUTRITIONAL EFFICIENCY AND CHEMICAL FORM OF SELENIUM, AN ESSENTIAL TRACE ELEMENT, CONTAINED IN SOYBEAN PROTEIN
Kyoden YASUMOTO 1, Kimikazu IWAMI 2 and Munehiro YOSHIDA 3
1 Research Institute for Food Science, Kyoto University
2 Faculty of Agriculture, Kyoto University
3 Kansai Medical College
Nutr. Sci. Soy Protein, Jpn. 4, 35-40, 1983.
Selenium content of milk casein, soybean meal, soybean protein concentrate, and soybean protein isolate (Fujipro-R) was determined by a fluorometric method, and its nutritional efficiency was assayed by feeding weanling rats the diet containing either one of these materials at 15% protein level. The selenium content on dry weight basis ranged between 0.3 and 0.6É g per g protein. Nutritional availability of selenium, as assessed by measuring the dietary intake and fecal output and by correcting for the metabolic obligatory fecal loss, ranged between 75 and 88%. The hepatic selenium level and glutathione peroxidase activity were found closely associated with the amount of nutritionally available selenium in the diet. Pepsin and pancreatin digestion of milk casein and soybean protein isolate was accompanied by a concomitant liberation of dialyzable selenium. Pronase digestion of pepsin-and pancreatin digests of these two proteins gave rise to selenium-containing substances which located on paper partition chromatography at the same positions where selenocystine (or selenotrisulfide) and selenomethionine located, respectively. These results indicate that selenium of soybean proteins occurs largely in the form of selenomethionine bound to proteins and its nutritional efficiency is slightly lower than that of milk casein.
EFFECTS OF DIETARY PROTEIN SOURCES AND PHOSPHORUS LEVEL ON LIVING BODY IN RATS
Kazuharu SUZUKI and Shiro GOTO
Faculty of Agriculture, Tokyo University of Agriculture
Nutr. Sci. Soy Protein, Jpn. 4, 41-45, 1983.
Currently, phosphates are added to a wide variety of processed foods including meats, cheeses, dressing, carbonated beverages and refrigerator bakery products etc. Depending on individual food choice, it appears that such additives may increase the intake of phosphorus. This experiment was conducted to assess the physiological effects of high dietary phosphorus on balance of other nutritional elements with balance method and renal analysis using initial body weight 70 grams male rats of Wistar strain with two sources of protein (casein, SPI) and with three levels of dietary phosphorus concentration. Results: The 1.5% phosphorus diet showed the lowest weight gain compared with other groups and raised the constant stream of mortality. Increasing dietary phosphorus level was accompanied with higher renal concentration of calcium and phosphorus. The retention of nitrogen, calcium, phosphorus and magnesium was enhanced by SPI diet compared with casein diet, especially in 1.5% phosphorus level ration.
CALCIUM UTILIZATION IN PREGNANT RATS FED SOY PROTEIN ISOLATE
Yoshiaki NIIYAMA and Sadaichi SAKAMOTO
School of Medicine, The University of Tokushima
Nutr. Sci. Soy Protein, Jpn. 4, 46-51, 1983.
Calcium balance was determined in order to investigate the effect of protein sources on calcium metabolism during pregnancy. Pregnant rats of the Sprague-Dawley strain, weighing about 190 g, were fed either 20% SPI or 20% casein diet containing 0.6% calcium (most of it as CaCO3), for 21 days. Non-pregnant rats were used as the control. As a result, no difference was observed in fetal growth and fetal calcium content between the diets. In pregnant rats, calcium absorption decreased with progress of pregnancy. The amount of calcium retained also decreased and was inconsistent with the period in which the fetal need for calcium is the greatest. Pregnant rats fed SPI diet accumulated 200 mg less calcium compared to those fed casein diet. When compared to non-pregnant animals, pregnant rats of both diets exhibited greater calcium accumulation as much as the amount needed for the fetuses, but no difference was observed in the calcium content of the femur in the dams.
VITAMIN A CONSUMPTION IN TISSUES OF RATS FED ON A VITAMIN A FREE DIET CONTAINING SOY PROTEIN ISOLATE
Shoichi MASUSHIGE, Masahiro WADA and Tadahiro TADOKORO
Faculty of Agriculture, Tokyo University of Agriculture
Nutr. Sci. Soy Protein, Jpn. 4, 52-57, 1983.
The effect of quality of dietary protein on the development of symptoms due to vitamin A deficiency was demonstrated in rats by the use of casein, soy protein isolate and wheat gluten as the sole protein source respectively. During feeding, vitamin A contents in various tissues and urea concentration in blood were determined, and activities of ornithine carbamoyltransferase and arginase were also assayed at the several stages of vitamin A deficiency. The decrease of vitamin A in the livers with the vitamin deficiency was rapid in the order of casein, SPI and gluten diet groups. Similar changes in vitamin A content were observed in plasma, lung and kidney. Urea content in blood of rats in the vitamin A deficient group increased compared with that of the pair-fed control group. The activities of both enzymes of livers in the deficient group increased compared with those of the control group.
A COMPARISON OF DIGESTION, ABSORPTION AND UTILIZATION BETWEEN SOYBEAN PROTEIN ISOLATE AND ITS CORRESPONDING AMINO ACID MIXTURE IN ADULT RATS
Shigeru YAMAMOTO, Kyoichi KISHI, Akemi ABE, Takashi YAMAMOTO and Goro INOUE
School of Medicine, The University of Tokushima
Nutr. Sci. Soy Protein, Jpn. 4, 58-64, 1983.
Digestion, absorption and utilization of soybean protein isolate and its corresponding amino acid mixture were compared in adult rats. Animals were fed either 20% soybean protein diet or 20% amino acid mixture diet for 3 days or 14 days. After fasting for 24 hours, rats were allowed to take each diet for 1 hour from 9 a.m.. Zero, 1, 2, 3, 4 and 5 hours after the final diets, rats were killed. Body weight gain, food intake, protein efficiency ratio, gastrointestinal nitrogen, portal and venous blood plasma aminogram, body water and body nitrogen were measured. All the results were similar in the two dietary groups, indicating that the digestion, absorption and utilization of soybean protein isolate and its corresponding amino acid mixture are similar.
LIMITING AMINO ACIDS OF SOY PROTEIN ISOLATE AND THEIR SUPPLEMENTARY EFFECTS (Part 4)
Michio YAMAGUCHI, Masako IWAYA and Motoyoshi MIYAZAKI
National Institute of Nutrition
Nutr. Sci. Soy Protein, Jpn. 4, 65-68, 1983.
Our previous reports demonstrated that supplementation of the limiting amino acids to soy protein isolate raised nutritive value of the protein greatly and at the same time elevated serum HDL cholesterol level suggesting an improvement of cholesterol metabolism. Although hypocholesterolemic effect of vegetable proteins, particularly soy protein, has recently been often discussed, there is no definite reason for this phenomenon. In this study, antihypercholesterolemic effect of soy protein isolate added or not their limiting amino acids and soybean (S) foods, i.e. Kinako (roasted and ground S.), Miso (S. paste), Natto (fermented S.), Tofu (S. curd) and Moyashi (S. sprouts) was examined in SD adult rats (8 to 10 m. old) fed a cholesterol-added diet for 2 wks, using whole egg protein and casein as standard references. The diet contained 10% protein. Results showed that antihypercholesterolemic effect of the soy protein isolate and soybean foods was not so large as has been reported. The supplementation of Met, Thr and Lys was rather effective to raise serum HDL cholesterol. Among the soybean foods, S. curd and S. sprouts indicated a higher proportion of HDL cholesterol to total cholesterol. It was suggested that the amino acid score of protein and lipid components of vegetable protein foods are much more related to improvement of cholesterol metabolism in serum.
THE CONTROL EFFECT OF SOYBEAN COMPONENTS ON THE LIVER FAT DEPOSITION RESULTED FROM FEED COMBINATION IN RATS
Masaharu HORII, Yuriko MURAMATSU and Seiji YOSHIKAWA
National Food Research Institute
Nutr. Sci. Soy Protein, Jpn. 4, 69-74, 1983.
Unusual fatty liver was observed in rats fed combined diet of rice and egg yolk at low protein level (6-7%) or high protein level (over 14-15%), and content of liver fat was significantly higher than that caused by diet of egg yolk alone. It was, however, observed that the addition of whole soybean powder to the combined diet containing rice and egg yolk seemed to prevent the fatty liver. This experiment was conducted to study the lipotropic effect of soybean components in rats fed the combination diet. Male Wistar-Imamichi rats weighing 120g (5 weeks old) were fed 6% protein diets using rice + egg yolk (RE), RE + soy protein isolate (SPI=Fujipro U) (RUE), RE + defatted soybean (RDE), RE + whole soybean (RSE), RE + miso (RME), RUE + 1% soy oil (RUoE), RDE + 1% soy oil (RDoE) as protein source and supplement for 5 weeks. Protein ratios in diets were R : E = 1:1 and R : E : another protein = 4 : 3 : 3. Liver fat content was significantly higher in RE diet group (55% per dry matter) than in other diet groups (p ÅÉ0.001). Liver fat contents in RDE and RUE diet groups were 44-45%, and in RSE and RME diet groups they were similar each other, being 33-34%. However values between the former and the latter groups were significantly different at the level of 0.5-0.1%. When 1% soybean oil was supplemented, liver fat content in RDoE diet group was significantly lower than in RDE diet group, but fat contents in RUoE and RUE diet groups were almost the same. In the case of the diet composed of rice + egg yolk + soy oil, we have already observed that liver fat content was almost same with that in RDE diet group. It is suggested that there are some components in the part removed from SPI, which produce significant control effect by interaction with soy oil against unusual deposition of liver fat.
EFFECT OF SULFUR AMINO ACID SUPPLEMENT TO THE SOY PROTEIN ISOLATE ON LIPID METABOLISM IN RATS
Akira YOSHIDA and Hidehiko YOKOGOSHI
School of Agriculture, Nagoya University
Nutr. Sci. Soy Protein, Jpn. 4, 75-78, 1983.
Supplementation with sulfur-amino acid to a 8% casein diet produces fatty liver in rats. However, methionine supplement to a 8.8% soy protein diet (containing the same amount of sulfur amino acids with the 8% casein diet)did not produce liver fat accumulation. Dietary level of protein is a delicate factor affecting the liver lipid. The effect of supplemental methionine on liver lipid accumulation was reexamined using female rats of Wistar strain. Test diets contained 8% casein or 8% soy protein isolate (SPI) with or without supplemental methionine. Animals were fed the test diets for 2 weeks and liver lipids were determined. Supplement of methionine to either a casein or a SPI diet, significantly increased the body weight gain accompanying the elevation of liver lipid concentration. Thus in low dietary level, SPI diet also produced fatty liver in rats. In the other experiments, effects of methionine supplement to a 10% SPI diet in the presence of a xenobiotic (PCB) on lipid metabolism were studied. Methionine supplement to the SPI diet in the presence of 300 ppm of PCB, significantly increased the serum cholesterol although the effect was little when the diet was devoided of PCB. The effects of methionine supplement to the SPI on lipid metabolism may be exaggerated in the presence of xenobiotics in diets.
HYPOCHOLESTEROLEMIC EFFECT OF SOY PROTEIN ISOLATE IN RATS
Michihiro SUGANO, Naomu ISHIWAKI and Katsuko NAKASHIMA
Kyushu University School of Agriculture
Nutr. Sci. Soy Protein, Jpn. 4, 79-84, 1983.
The effects of dietary proteins with different arginine/lysine ratios on serum cholesterol levels and hormonal status were studied in male rats fed cholesterol-free semipurified diets for 4 weeks. The dietary proteins examined were casein, pollack protein, sardine protein, egg yolk protein, soybean protein, rice protein and peanut protein. The antihypercholesterolemic effect of vegetable proteins compared to animal proteins was certified. There was a negative correlation (É¡ = - 0.74) between the serum cholesterol level and the arginine/lysine ratio of dietary protein, indicating a crucial role of this ratio to determine the serum cholesterol level. In general, the fasting level of circulating insulin was lower whereas that of glucagon was higher on feeding vegetable proteins, thus resulting in a reduction of the insulin/glucagon ratio. Changes in the hormonal status may be relevant to the cholesterol-lowering action of the vegetable protein.
MECHANISM FOR PLASMA CHOLESTEROL-LOWERING EFFECT OF SOY PROTEIN ISOLATE
Yoshiko FUJITA, Yasuko MURAKAMI and Shin-ichi HAYASHI
Department of Nutrition, Jikei University School of Medicine
Nutr. Sci. Soy Protein, Jpn. 4, 85-88, 1983.
Plasma cholesterol-lowering effect of soy protein isolate (SPI) was consistently observed in rats older than 17 weeks of age but not in younger rats. Although restricted feeding (80%) caused general suppression of plasma cholesterol levels, some difference in the cholesterol level was still observed between SPI-fed group and casein-fed group. Compared to casein diet, SPI diet caused an increase in fecal excretion of both cholesterol and coprostanol while gluten diet caused a marked increase in that of coprostanol. SPI diet, as well as gluten diet and zein diet supplemented with tryptophan and lysine, caused a significant reduction in the intestinal transit time as measured by an excretion of chromic oxide. A high protein diet containing 50% casein caused some suppression in plasma cholesterol level as well as a significant reduction in intestinal transit time. These results suggested the possibility that plasma cholesterol lowering effect of SPI was due, at least in part, to an increased fecal excretion of sterols, which was somehow related to a reduction of intestinal transit time.
EFFECTS OF DIETARY PROTEINS ON SERUM LEVELS OF CHOLESTEROL AND APOLIPOPROTEINS IN RATS
Yoshikazu SANNO, Tatsuya KIMURA and Takehiko TANAKA
Osaka University Medical School
Nutr. Sci. Soy Protein, Jpn. 4, 89-92, 1983.
(1) The authors established dietary conditions under which hypercholesterolemia was induced constantly within a short period of time in young rats. (2) Components in the diet to cause this hypercholesterolemia were proved to be protein, fat and cholesterol, indicating that this animal model might be a good model of human hypercholesterolemia. Sucrose, however, was found to play no role in producing hypercholesterolemia. (3) The hypercholesterolemia caused by casein diet was associated with higher plasma levels of apoB and it was furthermore suggested that turnover of this apoprotein might be accelerated under this condition.
COMPARISON OF NUTRITIVE VALUES BETWEEN SOY PROTEIN ISOLATE AND TOFU
Tetsuzo TAKAHASHI, Shigeji MURAMATSU and Yuriko MURAMATSU
Institute of Health and Sports Sciences, University of Tsukuba
Nutr. Sci. Soy Protein, Jpn. 4, 93-98, 1983.
Nutritive value of soy protein isolate (Fujipro R) was compared with that of Tofu by the nitrogen balance method using four healthy university students as the subjects. The mean apparent digestibility of soy protein isolate and Tofu was respectively 83.3% and 82.3%, and the mean true digestibility was respectively 95.9% and 95.7% on the assumption that metabolic fecal N loss was 10.2 mg/kg/day. The minimal daily nitrogen requirement to maintain a zero nitrogen balance estimated by the pooled data was 99.4 mg/kg in soy protein isolate and 99.8 mg/kg in Tofu. It was concluded that there was no difference between soy protein isolate and Tofu in both digestibility and nutritive value of protein.
UTILIZATION OF SPI AND RICE MIXED PROTEIN IN WOMEN
Kayoko KANEKO and Goro KOIKE
Kagawa Nutrition College
Nutr. Sci. Soy Protein, Jpn. 4, 99-104, 1983.
Fifteen female students aged 18 to 22 were fed a protein-free diet for one day and in the following ten days the diets containing SPI and polished rice, 0.3g protein/kg, 0.45 g/kg and 0.6 g/kg for each five subjects. Ratio of SPI and rice protein in the test diets was 6 : 4, and the amino acid score of the mixed protein was calculated as 91 by using the reference amino acid pattern proposed by FAO/WHO (1973). Mean energy intake was 36.0Å}3.3 kcal/kg/day which corresponds to about 1.7 times as their basal metabolism and was considered as the maintenance level. Twenty-four hour urine was collected completely during the experimental period and urinary creatinine and nitrogen contents were measured. Subjects were given three grams of carbon powder as a fecal marker before and after the experimental period. Feces from marker to marker were collected, dried and their nitrogen content was determined. Nitrogen balance was calculated from the intake N, fecal N excretion and the mean urinary N excretion of the last four experimental days when urinary N excretion reached a constant level. Linear regression equation between N balance (Y) and N intake (X) was calculated as Y = 0.401X -33.3 (n=15, r=0.738), and mean maintenance requirement of SPI and rice mixed protein was 83 mg/kg/day. Digestibility and net protein utilization (NPU) of SPI and rice mixed protein were calculated from these N balance data with the figures of 32.3 mg/kg and 10.1 mg/kg for obligatory urinary and fecal N losses respectively, which were previously determined in seven subjects. Digestibility was 93.1Å}6.1% (n=15) and NPUs were 67Å}13 at protein intake of 0.3 g/kg (n=5), 51Å}7 at 0.45 g/kg (n=5) and 54Å}12 at 0.6 g/kg (n=5). The results were compared with the data of SPI or egg protein obtained from other Japanese subjects.
THE NUTRITIONAL EVALUATION OF SOY PROTEIN ISOLATE IN ADULT MALES
Hideo KOISHI 1, Toyoko OKUDA 1 and Naemi KAJIWARA 2
1 Faculty of the Science of Living, Osaka City University
2 Department of Home Economics, Kobe WomenÅfs College
Nutr. Sci. Soy Protein, Jpn. 4, 105-110, 1983.
Present studies were carried out to compare the nutritional value of soy protein isolate (SPI) with that of protein of rice or skim milk in 8 healthy male students. Energy intake was about 45 kcal/kg/day which maintained the body weight of the subjects. The experimental diets contained 0.8 g/kg/day of protein and one third of protein in all experimental diets was composed of dry egg yolk protein. In diet A, the remaining protein was composed of rice protein, in diet B a half of rice protein was substituted for skim milk and for SPI in diet C. The three fourth of rice protein was substituted for SPI in diet D. In exp 1, four men were fed diets A, B, C and D for 6 days respectively. In exp. 2, four men were fed diet A for 1 week and fed diet C for 3 weeks. No difference was found in absorption and availability of energy for the last three experimental days between SPI and rice or skim milk. Nitrogen balance and nitrogen absorption of SPI were superior than rice but the same with skim milk. There were no differences between experimental diets in hematocrit value, the concentration of hemoglobin and total protein and albumin in plasma. In this experiment, SPI showed no hypocholesterolemic effect, although the intake of cholesterol was about 640 mg/day which was mainly derived from egg yolk. However, we found that the assortment of SPI with rice and egg yolk was evaluated equal the nutritional value of protein to skim milk in this condition.
EFFECTS OF NEW PROPLUS SA ON SERUM LIPIDSÅF CLINICAL EXPERIMENTS
Haruo NAKAMURA , Toshitsugu ISHIKAWA , Norio TADA , Naoki SUZUKI ,
Kazuo KONDO, Emiko MIYAZIMA and Sizue TAKEYAMA
Jikei University School of Medicine
Nutr. Sci. Soy Protein, Jpn. 4, 111-114, 1983
To assess the clinical effects of dietary fibers derived from soybeans, 3 grams of New Proplus SA were administered to 5 normal subjects for two weeks. Total cholesterol decreased significantly from 212 mg/100 ml to 176 mg/100 ml. LDL-cholesterol tended to decrease and HDL2-cholesterol increased without statistical significance. VLDL and HDL3-cholesterol were not altered. Apo C subgroups in VLDL also remained unchanged, reflecting the fact that triglyceride and VLDL-cholesterol were not altered.
The soy protein protein reserch(Japan)