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Results for “soy protein isolate”

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At least 19 recordsLinked to original sources
PubMed1977

Acute erythroid hypoplasia in malnourished infant squirrel monkeys fed isolated soy protein.

Infant squirrel monkeys fed low protein diets using an isolated soy protein develop an acute anemia. To investigate this syndrome, four groups of animals fed diets containing adequate or restricted amounts of casein or soy protein were studied from 1 through 16 weeks of age. The low protein groups, in which growth was prevented by adjustment of the protein content between 2 through 8 weeks, showed no difference in caloric intake or plasma albumin concentrations. However, the low soy group developed a severe anemia (hemoglobin 4 to 7 g/dl) after 4 to 6 weeks of dietary treatment. The anemia was characterized as normocytic, normochromic, and was associated with reduced reticulocyte concentrations. Bone marrow specimens showed an increased myeloid/erythroid ratio due primarily to an absolute erythroid hypoplasia. Juvenile animals fed similar low soy diets did not become anemic. The selective effect of this isolated soy protein, demonstrable only during the transitional period of early infancy, was attributed to the interaction of the malnourished animal with a component of the isolated soy protein per se. The potential role of soy glycoproteins is discussed.

Aging↗
PubMed2026

Screening of Fermentative Strains for Reducing the Allergenicity of a Whey Protein-Soy Protein System and Genomic Characterization of the Selected Strain.

Dual-protein systems combining whey protein isolate (WPI) and soy protein isolate (SPI) offer complementary nutritional benefits but are limited by the presence of major allergens. Lactic acid bacteria (LAB) fermentation provides a promising strategy to mitigate this limitation. In this study, Lacticaseibacillus paracasei JM053, selected from 13 LAB strains based on phenotypic screening, significantly reduced the in vitro allergenicity of the dual-protein system, increasing the IgE-binding inhibition rate to 48.75%. Whole-genome sequencing and characterization of JM053 revealed a comprehensive proteolytic system, including the proline-specific peptidase genes pepX and pepQ, which may contribute to the degradation of allergenic peptide sequences. Combined with in silico bioinformatic analysis, potential cleavage sites within the linear epitopes of the dual-protein system were predicted based on the substrate specificity of the identified proteases, offering a testable hypothesis for the strain's mechanism of action. In addition, in vitro safety assessment and genomic analysis supported the safety potential, stress tolerance, and probiotic characteristics of JM053. Collectively, this study provides a valuable candidate strain for the development of hypoallergenic dual-protein products and offers preliminary genomic insights into LAB-mediated allergenicity reduction.

Lacticaseibacillus paracasei↗
PubMed1977

[Nitrogen balance in adults and experimental study in rats fed with rice, beans and manioc flour supplemented with proteins].

Rice, beans and manioc flour are foods eaten daily in Northeast Brazil. Manioc flour is a source of energy, having a low protein content. There has been a great interest to supplement manioc flour with proteins. The present study was planned to show the nutritive value of a basic diet including rice, beans, manioc flour and other local foods, supplemented with different sources of proteins. The experiment was carried out in humans and rats. The supplements used were casein (Ca), isolated soy protein (PS) and a dry residue of a soymilk preparation (RSLS). Through nitrogen balance studies in adults it was shown that the diets with casein or isolated soy protein had a good absorption and retention of nitrogen. The addition of the soymilk residue resulted in a poor acceptance of the experimental diet; negative nitrogen retention was observed in the three persons who accepted the food and completed the balances studies. The same diets offered to humans, with the same protein supplements, were fed to rats. The nutritive value measured in the animals were similar, in all diets with all supplements, including the one with the dry residue of soymilk. The present results call the attention to the problems of transfering animal results to humans. It was also discussed the possibility of adding casein or isolated soy protein as an eventual protein supplement to manioc flour for human feeding.

Adolescent↗
PubMed1977

Soy protein intolerance: four patients with concomitant cow's milk intolerance.

An infrequently encountered and poorly understood infantile disorder is gastrointestinal soy protein intolerance. Four patients who had intractable diarrhea of infancy and who failed to thrive were tested by oral challenge with soy protein isolate and were found to have soy protein intolerance. All four exhibited concomitant sensitivity to cow's milk protein. The response to challenge with soy protein included diarrhea, vomiting, hypotension, lethargy, and fever. These symptoms were immediate, of short duration, and occurred with each subsequent challenge dose. No patient exhibited cutaneous, pulmonary, or hematologic evidence of allergy although it was prominent in their families. A diet devoid of intact soy and cow's milk protein allowed symptomatic recovery and rapid weight gain. Oral disodium cromoglycate therapy was ineffective in one trial. Soy protein intolerance should be suspected in infants with diarrhea resistant to therapy with soy based formulas.

Body Weight↗
PubMed1979

Plasma lipoprotein changes in suckling and weanling rabbits fed semipurified diets.

The distribution and composition of the plasma lipoproteins were studied in suckling rabbits and in rabbits either weaned to or fed as young adults cholesterol-free, semipurified diets containing protein of animal (casein) or plant (soy protein isolate) origin. The raised cholesterol levels of the suckling period resulted in an increase of very low density and intermediate density lipoproteins in a making similar to that seen in adult rabbits fed a high fat diet supplemented with cholesterol. Young rabbits fed the cholesterol-free, semipurified, diet containing casein also became hypercholesterolemic but, in this case, the increased cholesterol was found primarily in lipoproteins of intermediate density. Cholesterol levels remained low in those rabbits fed the soy protein isolate diet, and the lipoprotein distribution was somewhat similar to that of chow-fed animals. It appears that the raised cholesterol levels during the suckling period result in different lipoprotein patterns to those produced in young adult animals by a cholesterol-free, semipurified diet.

Aging↗
PubMed1979

Assessment of the efficiency of protein utilization in young squirrel and macaque monkeys.

The efficiency of protein utilization was assessed in three groups of infant squirrel monkeys fed diets containing restricted amounts of lactalbumin, casein, and soy protein isolate as the sole nitrogen source for 3-week periods. Lactalbumin was fed in similar conditions to a group of macaques for comparison. The regression of weight gain on protein intake was calculated for each dietary protein yielding an estimate of protein needs for weight maintenance and an estimate of the efficiency of utilization of protein for growth (slope X percentage protein in tissue). Mean requirements for weight maintenance of infant squirrel monkeys for lactalbumin, casein and soy protein isolate were 3.43, 3.63, and 7.96 g/kg per day and growth was accomplished with an efficiency of 27.8, 32.1, and 22.2%, respectively. In contrast, the macaques utilized lactalbumin with an efficiency of 65%, similar to that of the infant cebus monkey and adult man. The low efficiency found in young squirrel monkeys was altered neither when the habitual feeding schedule was prolonged from 16 to 24 hr per day in a group of casein-fed animals nor when sulfur amino acids were added to casein.

Animals↗
PubMed1979

Methionine fortification of a soy protein formula fed to infants.

Data from study of nine normal full-term infants fed a soy isolate-based formula unsupplemented with methionine were compared with similar data from study of 10 similar infants fed the same formula supplemented with L-methionine and with data from previous studies of larger groups of infants receiving various other feedings. Food intake, growth, and serum chemical values were studied from 8 through 111 days of age. In addition, nitrogen balance studies were carried out. Statistically significant differences were as follows: lesser weight gain per 100 kcal by infants fed the unsupplemented soy isolate-based formula than by infants fed milk-based or other soy isolate-based formulas; lesser serum concentrations of albumin at age 28 days by infants fed the unsupplemented soy isolate-based formula than by breast-fed infants; greater serum concentrations of urea nitrogen by infants receiving the unsupplemented soy isolate-based formula than by those receiving the same formula supplemented with L-methionine. A number of other differences was noted but were not statistically significant. The results suggest that normal infants fed a formula providing 2.25 /100 kcal of a soy protein isolate not fortified with methionine performed less well during the first 6 weeks of life than did breast-fed infants and infants fed milk-based formulas or other soy isolate-based formulas fortified with methionine. The limiting nutrient appears to have been methionine.

Aging↗
PubMed1978

The role of dietary protein in hypercholesterolemia and atherosclerosis.

Rabbits become hypercholesterolemic and develop atherosclerotic lesions when fed a cholesterol-free, semipurified diet. This provides a useful experimental model in which a moderate hypercholesterolemia can be maintained for long periods of time. The elevation of plasma cholesterol and development of atherosclerosis are dependent on the kind of protein in the diet and can be prevented by replacing casein with isolated soy protein. Feeding trials with enzymatic digests or mixtures of amino acids indicate that this difference is at least partly due to the differing amino acid composition of the two proteins. Rabbits on the soy protein diet showed higher rates of oxidation and turnover of cholesterol than those on the casein diet. Dietary protein has generally been considered to be of little significance in the etiology of atherosclerosis in humans, but evidence is accumulating which indicates that it can have a significant influence on human plasma cholesterol levels.

Animals↗
PubMed1979

Effects of soy protein and saponins on serum, tissue and feces steroids in rat.

Four groups of rats were fed, for 45 days, one of the following semipurified diets containing sucrose 55% (w/w) and (a) casein 25%, (b) casein 24%, saponins (from Saponaria officinalis) 1%, (c) isolated soy protein 25%, (d) soy protein 24%, saponins 1%. The soy protein diet, compared to the casein one, produced an increase in the fecal excretion of neutral sterols on the 29th and 42nd days, without any modification in the liver, aorta and serum cholesterol concentrations. The effect of soy protein cannot be attributed to its saponin content but other substances associated to soy protein may interfere. With the casein diet, added saponins increased the fecal excretion of neutral sterols and bile acids and decreased liver and aorta cholesterol levels. Serum cholesterol was found unchanged. The effects of saponins were suppressed or greatly reduced with the soy protein diet. These results could be explained by binding of the sterols in insoluble forms.

Animals↗
PubMed1978

Amino acid supplementation of isolated soybean protein in milk replacers for preruminant lambs.

The growth of preruminant calves and lambs fed on milk replacers containing vegetable proteins is generally inferior to that of preruminants given cows' milk. The inferior performance has variously been attributed to an amino acid imbalance, to heat damage in preparation, and to the presence of growth-retarding substances. Soybean products that have been treated to remove, or destroy, growth-retarding substances are now available commercially. An experimental design is described that has been used to determine the order of limiting amino acids in soy protein isolates, and which may also be used to estimate requirements for individual amino acids. The design allows an economy in time and in experimental animals, and gives results that are not significantly different from those determined in classical balance experiments.

Amino Acids↗
PubMed1979

Carnitine content of liquid formulas and special diets.

Radioisotopic analyses for carnitine content were done on infant formula, formulas for tube feeding, food supplements, and chemically defined diets. The carnitine content of the diets depend on the protein source. Products whose main protein source is soy protein isolate, casein, or egg white solids contain 4 nmole carnitine per milliliter or less, with most of them containing undetectable amounts of carnitine. Products based on milk or beef contain 50 to 656 nmole carnitine per milliliter. The daily requirement of the body for carnitine is unknown. Evidence is discussed that indicates that the possible use of carnitine as a supplement to formula diets intended for long-term care needs to be considered.

Animals↗
PubMed1979

Influence of diet on plasma cholesterol concentrations in suckling and weanling rabbits.

Rabbits were weaned to different semipurified diets to determine which characteristics of the diet were required to maintain the hypercholesterolemia of the suckling period. Gradual weaning to a diet similar in fat, cholesterol, protein and carbohydrate content to rabbit milk maintained and enhanced the hypercholesterolemia. Reduction of the cholesterol content, and to some extent the fat content of this diet, decreased the plasma cholesterol level, but the type of dietary protein did not alter the results. After weaning, however, animals fed milk protein (casein) in the absence of dietary cholesterol became hypercholesterolemic, whereas those fed plant protein (soy protein isolate) remained normocholesterolemic.

Animal Population Groups↗
PubMed1978

Soy protein utilization in food systems.

Soy protein products are utilized in food systems as whole beans, flours and grits, concentrates and isolates, and textured products. Soy proteins play a significant role in food systems as a source of supplementary and complementary protein and contribute functional properties such as solubility, water absorption, viscosity, emulsification, texture, and antioxidation. Whole soybeans are processed into snack foods, beverages, and fermented foods. Soy protein is an ideal supplement for cereal protein because it corrects lysine and other amino acid deficiencies. Blends of soy flour or grits with cereals such as corn, wheat, or sorghum are widely used in world feeding programs. The blends are also valuable in domestic food systems such as breakfast cereals and baked foods. Concentrates and isolates are utilized in processed meats and baby foods. Isolates are utilized in processed meats and baby foods. Isolates are employed as whipping agents and coffee whiteners. Thermoplastic extrusion of defatted flours or protein concentrates produces an expanded type of textured protein. Isolated soy protein is converted to meat analogs by a spun fiber process. Textured soy protein products are used to extend or replace meat products in food systems.

Amino Acids, Essential↗
PubMed1977

Inhibitory effect of mercaptoamino acids on lysino-alanine formation during alkali treatment of proteins.

Alkali treatment of food proteins converts some amino acid residues to the unnatural amino acid lysinoalanine which has been found to cause kidney damage when fed to rats. Formation of lysinoalanine was essentially prevented when isolates of soy protein and casein were exposed to alkali in the presence of thio-alamino acids such as cysteine. The results suggest that added thiols minimize the formation of potentially toxic lysinoalanine.

Alanine↗
PubMed1979

Effects of nutritional factors on metabolism of dietary cadmium at levels similar to those of man.

Several nutrients are known to affect cadmium toxicity, but little is known about the effect of dietary nutrient levels on absorption and tissue retention of cadmium at low dietary levels, similar to those of man. Feeding gradedlevels of zinc in a casein-gelatin diet to young Japanese quail with 109Cd (as the chloride) and 0.062 ppm added cadmium decreased the cadmium concentrations in the proventriculus-ventriculus, duodenum, jejunum-ileum, and the liver, but not in the kidney. Zinc also affected some zinc, iron, manganese, and copper tissue levels. Different tissue concentration patterns of cadmium and essential minerals were obtained with two purified control diets, one based on casein-gelatin and the other on soy isolate as the principal protein sources. The data show that relatively small dietary changes can markedly affect tissue levels of cadmium and that a low intake of zinc may increase the risk to dietary cadmium exposure. The complexity of the nutrient interrelationships and their effects on cadmium require further study to define mechanisms, which may be similar to those produced by low cadmium intakes in man.

Animal Nutritional Physiological Phenomena↗
PubMed1978

Enzymatic hydrolysis of soy protein for nutritional fortification of low pH food.

Enzymatic hydrolysis of proteins is an attractive means of obtaining the changes in the functional properties often necessary for incorporating the protein in low pH food, e.g. soft drinks. The main problem associated with protein hydrolysis is the welldel-known formation of bitter-tasting peptides. The bitterness seems to be related to a too high degree of hydrolysis (DH). DH is defined as the percentage of cleaved peptide bonds and serves as the controlling parameter for the hydrolysis process. The choice of hydrolysis parameters is briefly discussed in relation to studies on the hydrolysis kinetics which in many respects can be described by classical enzyme kinetics. Several pilot plant productions of isoelectric soluble soy protein hydrolyzates have been carried out using soy isolate or soy concentrate as the raw material. The preferred enzyme for this type of hydrolysis is Alcalase 0.6 L, a food-grade liquid preparation of subtilism Carlsberg. The chosen hydrolysis parameters are : Substrate conc. : 8 per cent protein (N x 6.25). Enzyme-substrate ratio : 2 per cent. pH : 8.0. Temperature : 50 degrees C. The optimal DH value with regard to taste seems to be 10 per cent, corresponding to about 2 hours' hydrolysis time. The hydrolysis is terminated by the addition of citric or malic acids until pH reaches a value of 4.2. Separation of the supernatant from the unconverted protein is carried out in a continuous, solids-ejecting centrifuge. Preliminary rat trials show a satisfactory nutritional quality of the hydrolyzates. Possible end-uses for soy protein hydrolyzates are briefly discussed.

Food, Fortified↗