Soy Concentrate Research Articles

Potential of genistein-induced autophagy in the treatment of neurodegenerative diseases

Development of therapies for neurodegenerative diseases, disorders characterized by progressing loss of neurons, is a great challenge for current medicine. Searching for drugs for these diseases is being proceeded in many laboratories in the world. To date, several therapeutical strategies have been proposed which, however, are either of insufficient efficacy or at the early preclinical stages. One of the newest concepts is elevated efficiency of degradation of protein aggregates which are causes of 70% of these diseases. Autophagy, i.e. lysosomal degradation of macromolecules, is a process which could be employed in such a strategy Searching for a compound which would not only stimulate autophagy but also reveal safety in a long-term usage and be able to cross the blood-brain-barrier led to studies on one of flavonoids, genistein which occurs at high concentrations in soy. Experiments with this compound indicated its enormous efficiency in removing protein aggregated formed by beta-amyloid, hyperphosphorylated tau protein, and mutant huntingtin. Moreover, using animal models of these diseases, correction of cognitive and motoric symptoms was demonstrated. Considering safety of genistein as well as its ability to crossing the blood-brain-barrier, one may assume that this molecule is a candidate for an effective drug in therapies of not only Alzheimer disease and Huntington disease, but also other disorders caused be protein aggregates. In this article, recent results of studies on the use of genistein in different models of neurodegenerative diseases are summarized, with special emphasis on its autophagy-dependent action.

Comment on the published data concerning the identification of biochanin A and prunetin by LC/ESI-MS

Biochanin A is one of the most common phytoestrogens, occurring in high concentrations in soy and red clover, for instance, which shows a wide spectrum of biological activity. Prunetin is an isomer of biochanin A, and even though it is not very common, its structural relationship to the latter makes it interesting, regarding its biological activity. Nowadays, LC/ESI-MS methods are widely used for identification of natural compounds, including biochanin A and prunetin. However, we found that the published data concerning the identification of biochanin A and prunetin are sometimes disputable. Namely, the identification is based on the product ions which cannot be regarded as characteristic of biochanin A or prunetin. The reported retention times sometimes may be also disputable.

Technical objects' ecological efficiency indicators control

Traditional automatic control systems do not solve the task of limiting the harmful effects of technical objects on the environment. The problem is to increase the effectiveness of means of its protection against the harmful effects of industry. Relevant is the use of indicators of environmental performance of technical objects as controlled parameters. A new approach to the control of technical objects is proposed. As the main control parameter it proposed to adopt the level of their ecological efficiency. Complicating circumstances of solving the problem is the insufficient knowledge of the factors of harmful effects on objects of living nature, their intensity, interrelation, mechanism, strength, and dynamics of exposure. Improving the economic efficiency of technical objects leads to an increase in their ecological efficiency. The solution to the problem is facilitated by the fact that traditional ACS should be left in action, adding to them an ecological efficiency control component. Heat-powerengineering has a large impact on the environment through emissions and discharges of harmful substances and heat. To give to ASC the functions of controlling the ecological efficiency of the boiler (for SOy emission), it is necessary to apply an additional, new control loop - regulator of SOy concentration in furnace gases. An urgent task in the use of direct control of the ecological efficiency of boiler-furnace systems is the development and production of physical quantity sensors, reflecting the level of aggressiveness of the source of hazard, working in real time. Direct control of indicators of ecological efficiency is much easier in other branches of industry, in particular, in its food branch, where objects do not have a large-scale complex negative impact on the environment.

Effects of partial dietary supplementation of fish meal with soymeal on the stress and apoptosis response in the digestive system of common dentex (Dentex dentex)

BackgroundSoybean is a common alternative protein source of plant origin in aquafeeds as it has a reasonably balanced amino acid profile and is widely available. This study aimed to investigate the influence of partial substitution of fish meal with soy meal on cytoprotective pathways and apoptosis in the digestive system of common dentex (Dentex dentex), using the activation of Hsp70, p38 MAPK, Bcl-2 and caspase-3. The experimental approach involved feeding of common dentex with three isoprotein and isoenergetic diets that contained fish meal as a protein source (FM), partial replacement of fish meal by soy meal 25% (SM25) and 40% (SM40) for 3 months.ResultsThe SM40 diet induced Hsp70 activation only in the middle part of intestine. On the other hand, both SM25 and SM40 diets diminished the phosphorylation of p38 MAPK in the anterior and the middle part of intestine, whereas only SM25 induced p38 MAPK phosphorylation in the stomach. Moreover, a decrease in the levels of caspase-3 activity was observed in the middle and posterior intestine, as well as in the stomach after feeding with SM25 diets. Furthermore, Bcl-2 levels were increased by SM40 in the anterior and by SM25 in the middle part of intestine.ConclusionsSM25 and SM40 diets elicited a tissue and soy concentration specific cellular and cell protective response in the different parts of the digestive tract in common dentex.

Genistein administered as a once-daily oral supplement had no beneficial effect on the tibia in rat models for postmenopausal bone loss

Estrogen deficiency after menopause results in rapid bone loss, predisposing women to osteoporotic fractures. Genistein, a phytoestrogen present in high concentrations in soy, is an ingredient in dietary supplements aggressively marketed for bone health. However, in a recent long-duration clinical trial in postmenopausal women, the efficacy of soy extracts in reducing bone loss was disappointing. To better understand the failure of soy extracts to consistently induce a robust skeletal response in women, we investigated the long-term (5 mo) efficacy of genistein, administered as a daily oral supplement, (1) in preventing cancellous bone loss in skeletally mature virgin Long-Evans rats ovariectomized at 7 months of age and (2) in improving cancellous bone mass and architecture in aged retired-breeder rats ovariectomized at 16 or 22 months of age. Rats within each age group were randomly assigned into one of three treatment groups (n = 7-12 rats/group): (1) vehicle control, (2) genistein 485 μg/day, or (3) genistein 970 μg/day, resulting in mean (SE) serum genistein levels of 0.18 (0.10), 0.76 (0.15), and 1.48 (0.31) μM, respectively. Total tibia bone mass and density were evaluated using dual-energy x-ray absorptiometry, whereas cancellous bone mass and architecture in the tibial metaphysis, as well as cortical bone mass and architecture in the tibial diaphysis, were evaluated by micro-CT. Oral genistein administered as a dietary supplement did not influence the cumulative effects of ovariectomy, aging, and/or reproductive history on cancellous and cortical bone mass and architecture. Serum levels of genistein similar to those in women consuming a high-soy diet are ineffective in preventing or treating bone loss in rat models for postmenopausal osteoporosis.

Effects of Gum Arabic Concentration and Soy Proteins on the Flow and Viscoelasticity of their Dispersion

The present study analyzed the flow and viscoelasticity behavior of dispersions of 15 to 45% (w/v) gum arabic, 1 to 8% (w/v) soy proteins, and of gum arabic/soy proteins mixtures. Flow of gum arabic dispersions showed Newtonian behavior, while soy protein dispersions and gum arabic/soy proteins mixtures presented non-Newtonian behavior (n < 1) of shear thinning type. Viscosity increased by 239% in the gum arabic/soy protein mixture (45/8%) compared with gum arabic/soy proteins dispersions (45/0%). The consistency coefficient (K) increased with rising gum arabic or soy proteins concentration in the dispersions. The viscoelastic behavior of mixtures with low gum arabic concentrations showed G′ > G″ values (1712% in gum arabic/soy protein [15/1%] dispersions), behaving as predominantly elastic systems (viscoelastic solids). However, at higher gum arabic concentrations (35 and 45%), the gum arabic/soy protein mixtures presented G′ < G″ values (389% for [45/8%] gum arabic/soy protein), behaving as viscose dispersions (viscoelastic liquids); this shows an antagonistic effect as gum arabic and soy protein concentrations increase, which is more evident in the rheological behavior of the studied mixtures. The interaction between polysaccharides and proteins leads to a better understanding of the rheological behavior of complex mixtures, at high concentrations, allowing these model systems to be useful in the future applications in the food industry.

Structural and Thermal Investigations of Biomimetically Grown Casein–Soy Hybrid Protein Fibers

A hybrid protein fiber from different protein sources such as casein and soybean using wet-spinning technique was prepared. The casein/soybean hybrid fibers were synthesized at different weight ratios such as 100/0 (casein), 75/25, 50/50, 25/75, and 0/100 (soy) and characterized. Electron microscopic analysis confirmed the growth of pure and hybrid fibers and shows an increased surface roughness as the soy concentration increases in the hybrid fibers. Infrared spectra did not exhibit any significant changes in the functional groups between pure and hybrid fibers. X-ray diffraction pattern indicates slight increase in the diffraction peak values of hybrid fibers compared with the neat fibers. Thermal analyses show a moderate increase in the thermal stability of hybrid fibers when compared with the pure fibers. These results implicitly indicate that the casein and soy proteins are homogeneous in the hybrid fiber form. It has been demonstrated that the hybrid fiber with ≥50 wt.% casein content exhibits better morphology and increased thermal stability, which has scope for application in technical and medical industries.

Effect of a Soy Protein-Based Diet on Ribonucleic Acid Metabolism in the Small Intestinal Mucosa of Goat Kids

This study was designed to investigate the effect of soy protein inclusion in milk replacer diets for goat kids on protein, RNA, and DNA contents in small intestinal mucosa, on the importance of RNA biosynthesis from dietary RNA precursors for mucosal RNA synthesis, and on the activities of enzymes involved in nucleotide degradation in small intestinal mucosa. Diets were based on cow's milk. In the control group, 35% of the milk protein was replaced by casein (CN) protein, and in the soy group (SPAA), the same amount of milk protein was replaced by soy protein supplemented with essential AA known to be at lower concentrations in soy than in CN (Thr, Val, Ile, Leu, His, Lys, Met). Diets were isonitrogenous and isoenergetic. At 47 d of age, goats were harvested and samples of proximal, middle, and distal jejunal mucosa were collected 5h after feeding 15N-labeled RNA from yeast (13 mg/kg of body weight). Growth and feed conversion did not differ between the control and SPAA kids. Mucosal protein concentrations were lower in the SPAA than the control kids. Concentrations of RNA and DNA did not differ between feeding groups, but in all kids mucosal RNA concentrations were higher in proximal than in middle and distal jejunum. Protein:RNA ratios were higher in the control than the SPAA kids and were lowest in proximal jejunum. Activities of alkaline phosphatase in enterocytes were higher in proximal than in middle and distal jejunum. Activities of mucosal xanthine oxidase were highest in distal jejunum and were higher in the SPAA than the control kids, especially in the middle and distal sites. The 15N-enrichment of mucosal RNA was higher in the control than the SPAA kids, especially in distal jejunum, and was lowest in distal jejunum. In contrast, 15N-enrichment of urea in plasma tended to be higher and Gly concentration in plasma was lower in the SPAA than the control kids. Data indicate that protein content and the protein:RNA ratio were lower in jejunal mucosa of goat kids fed milk replacer with partial replacement of CN protein by soy protein. These findings were accompanied by a lower level of reutilization of preformed dietary RNA precursors for RNA biosynthesis in jejunal mucosa and a higher activity of xanthine oxidase. Thus, feeding soy protein instead of CN protein reduced the incorporation of preformed dietary RNA precursors for RNA biosynthesis in the mucosa and activated key enzymes involved in nucleic acid breakdown.

Genistein restricts leptin secretion from rat adipocytes

The isoflavones – genistein and daidzein – compounds found in high concentrations in soy play an important role in prevention of many diseases and affect some metabolic pathways. In the performed experiment it was demonstrated that genistein (5 mg/kg b.w.) administered intragastrically for three days to male Wistar rats substantially diminished blood leptin level. Studies with isolated rat adipocytes revealed that this phytoestrogen strongly restricted leptin secretion from these cells. These effects were not accompanied by any changes in leptin gene expression in adipocytes. Daidzein – an analogue of genistein – used at similar concentrations did not affect blood leptin concentration, leptin secretion and expression of its gene. To determine the influence of genistein and daidzein on leptin release, adipocytes isolated from the epididymal fat tissue were incubated for 2 h in Krebs–Ringer buffer. Leptin secretion stimulated by glucose with insulin was significantly diminished by genistein (0.25–1 mM). This effect of genistein may arise from several aspects of its action in adipocytes documented in the literature such as the inhibition of glucose transport and metabolism, the attenuation of insulin signalling, the inhibition of cAMP phosphodiesterase and the stimulation of lipolysis. However, the bypassing of the restrictive action of genistein on glucose transport and glycolysis (by the use of alanine instead of glucose) and on insulin action (by the use of nicotinic acid) was not sufficient to restore leptin secretion from isolated adipocytes. It was also demonstrated that the restriction of the stimulatory influence of genistein on cAMP/protein kinase A (PKA) pathway (by the inhibition of PKA activity) did not improve leptin release. Results obtained in our experiments point at the restriction of glucose metabolism following formation of pyruvate as the pivotal reason of the inhibitory action of genistein on leptin release.

Estrogenic agonism and antagonism of the soy isoflavone genistein in uterus, bone and lymphopoiesis in mice

The isoflavone genistein (Gen) is a naturally occurring phytoestrogen found in high concentrations in soy. The biological effects of Gen have been extensively studied. The immunomodulating properties of Gen are, however, less well investigated and the results are contradictory. Our aim was to study possible estrogen agonistic and antagonistic properties of Gen in uterus, bone, lymphopoiesis and B-cell function by comparing effects in castrated and intact female mice, respectively. Oophorectomized (OVX) and sham-operated mice were treated with s.c. doses of 17beta-estradiol (E2) (0.16 mg/kg), Gen (50 mg/kg), or vehicle (olive oil) as control. Effects on bone mineral density (BMD) were studied using peripheral quantitative computerized tomography, uterine and thymus weights were examined, lymphopoiesis in thymus and bone marrow was analyzed using flow cytometry, and the frequency of immunoglobulin-producing B cells in bone marrow and spleen was studied using an ELISPOT assay. Gen was clearly antagonizing endogenous estrogen in sham-operated female mice as shown by inhibiting the uterine weight and by increasing the frequency of B lymphopoietic cells in bone marrow. The only agonistic effect of Gen was shown by increased BMD in OVX mice. Our results are discussed in the context of estrogen receptor biology.

EFFECTS OF SWEETENER, SWEETENER CONCENTRATION, AND FRUIT FLAVOR ON SENSORY PROPERTIES OF SOY FORTIFIED YOGURT

ABSTRACTThe effects of sweetener type, sweetener concentration, and fruit flavor on the sensory attributes of soy fortified yogurt were determined. Soy fortified dairy yogurts were made by the addition of soy protein concentrate (0, 2.5, 5%) to standard yogurt mixes prior to fermentation. Sweetener type (sucrose, fructose, sucrose/fructose) and sweetener concentration (6, 8, 10%) were incorporated into yogurts in a split plot experiment with soy concentration as a subplot factor. Flavor effects (plain, lemon, strawberry) were studied in a 3 × 3 factorial experiment (soy concentration × flavor). A trained descriptive panel (n=13) evaluated yogurts for seven flavor and aroma terms. Sweetener type had no effect on sensory properties with the exception of perceived sweetness. Soy flavors and astringency decreased with increasing sweetener concentration. Fruit flavors decreased soy aromas, soy flavors, and astringency in yogurts containing soy protein. These results indicate that sweetener concentration and fruit flavors play a crucial role in formulating yogurts fortified with soy protein.

Soybean Protein Products as Regulators of Liver Low-Density Lipoprotein Receptors. II. α−α‘ Rich Commercial Soy Concentrate and α‘ Deficient Mutant Differently Affect Low-Density Lipoprotein Receptor Activation

Activation of low-density lipoprotein (LDL) receptors has been decribed in a human hepatoma cell line (Hep G2) exposed to the 7S globulin from soy (Lovati et al. J. Agric. Food Chem. 1998, 46, 2474−2480). This in vitro model supports a direct activity of soy protein component(s) in lowering LDL cholesterolemia. To ascertain whether α or α‘ subunits from 7S globulin, or both, are responsible for the biochemical effect, a mutant soy cultivar, devoid of the α‘ subunit (Keburi), was evaluated in the same model. A commercial isoflavone-poor, heat-hydrolyzed soy preparation found effective in human hypercholesterolemia (Croksoy) was also tested. While Croksoy proved to have a similar activity as the whole 7S globulin, the α‘-free Keburi variant showed no effect on LDL receptor activation. These findings support the reliability of the human liver cell model in predicting a human hypocholesterolemic activity and suggest that specific peptide(s) may be responsible. Furthermore, they indicate that some soy cultivar...

Fat, Soy and Carrageenan Effects on Sensory and Physical Characteristics of Ground Beef Patties

ABSTRACTSensory and physical characteristics of beef patties containing 20% fat, 8% fat, or 8% fat plus 20% soy protein isolate (SI), soy flour (SF), soy concentrate (SC), or a mixture (MIX) of carrageenan (0.5%), starch (0.5%), and phosphate (0.2%) were compared after 0, 4, 8, and 12 wks storage at ‐ 18°C. MIX had higher Hunter a* values than other treatments. Cook loss was lowest for MIX and highest for all beef patties. Soy extenders decreased beefy flavor and increased off‐flavor scores. Time in frozen storage increased off‐flavor, rubbery texture, and TBA value, and decreased red color and Hunter b* value of ground beef patties. Quality may be lowered in frozen‐stored high fat, or low‐fat‐soy extended beef patties.

COMPARATIVE STUDY OF SHELF-LIFE OF FRANKFURTERS CONTAINING PLANT PROTEIN ADDITIVES

Soy flour (SF), soy concentrate (SC), soy isolate (SI) and corn germ protein flour (CGPF) were incorporated in frankfurters. The sensory analysis, chemical, and microbiological tests were conducted to investigate the effect of plant proteins on stability during vacuum-packaged storage. No significant difference in meaty aroma was found between all samples after 45 days storage. Atypical flavor and aroma of all samples, including the all-meat control increased (P < 0.05) after 45 days storage. A tendency was found of increase in atypical aroma and flavor with increase in total volatile nitrogen values and total psychrophiles during storage. Salty flavor increased with storage time in experimental samples, but juiciness decreased. Samples containing SF and SC had higher total volatile nitrogen than SI and CGPF containing samples at 2, 30 and 45 days of storage. No significant differences were found in TBA values between tested samples, except higher TBA values for SI containing samples. There was no significant difference among samples in total psychrophilic counts.

COMPARATIVE STUDY OF CORN GERM AND SOY PROTEINS UTILIZATION IN COMMINUTED MEAT PRODUCTS1

AbstractSoy flour (SF), soy concentrate (SC) and corn germ protein flour (CGPF) at 3.5%, or 2% of soy isolate (SI) were incorporated in the formulations of frankfurters. There was no significant differences in proximate composition of frankfurters containing SF, SC. SI, and CGPF. Frankfurters formulated with high plant protein flour had lower cholesterol, and higher protein content than the all‐meat control frankfurters. Control frankfurters had lower water holding capacity and higher cooking losses than those containing plant proteins. No significant differences (P &lt; 0.05) were found in textural and color characteristics. Atypical aroma and flavor profiles increased in frankfurters with SF nd CGPF extension.

Emulsifying Capacity and Emulsion Stability of Soy Proteins Compared with Corn Germ Protein Flour

ABSTRACTBoth emulsifying capacity (EC) and emulsion stability (ES) increased with increasing concentrations from 0.4% to 0.8% of soy flour (SF), soy concentrate (SC), soy isolate (SI) and corn germ protein flour (CGPF) when studied by response surface methodology. EC and ES increased as pH increased from 6 to 8 in all samples. Increasing incubation temperatures of protein solutions from 20–70°C or from 4–20°C did not affect EC or ES, respectively. SF had the highest EC, followd by SI, SC, and CGPF.

Comparative assessment of soy and milk protein quality in infant Cebus monkeys

Protein qualities of lactalbumin (L), casein (C), soy concentrate (SC), soy isolate (SI), and soy isolate plus 15.3 mg methionine/g protein (SIM) were investigated in a slope-ratio assay using 32, 8-wk old cebus monkeys. Growth (28 days) and nitrogen balance (NB) (days 19–28) data were evaluated in a multiple-regression format with nitrogen intake and body weight as the independent variables. Based upon growth, potencies compared to L were: C, 72.1; SC, 52.5; SI, 40.6; and SIM, 72.2. Based upon NB, comparable potencies were: C, 62.2; SC, 69.0; SI, 46.8; and SIM, 90.7. NB data showed that the potency of SC was significantly greater than SI and that methionine supplementation of SI improved it to a potency not distinguishable from the standard. The marked improvement from SI to SIM emphasizes the beneficial effect of sulfur amino acid supplementation of soy protein for an infant primate species.

Relative Bioavailability of Dietary Iron from Three Processed Soy Products

ABSTRACTThe relative bioavailability of iron from soy flour (SF), freeze‐dried soy beverage (SB) and soy concentrate (SC) was determined utilizing a hemoglobin repletion bioassay. Weanling male rats were fed a low iron depletion diet (3.5 ppm Fe) for 4 wk. For the next 2 wk groups of rats were fed repletion diets containing 0, 6, 12, or 18 ppm added iron from ferrous sulfate, SF, SB, or SC. Slope ratio analysis revealed that the relative iron bioavailabilities from SC (92%) and SF (81%) were not different from the reference standard, ferrous sulfate added to a casein‐based diet, whereas that from SB (66%) was significantly less (P&lt;0.01) than the inorganic source of iron. Analysis of results at individual iron levels suggested an iron bioavailability of SC&gt;SF&gt;SB.

Bioavailability of Zinc to Rats from Defatted Soy Flour, Acid-Precipitated Soy Concentrate and Neutralized Soy Concentrate as Determined by Intrinsic and Extrinsic Labeling Techniques

The bioavailability of 65Zn from intrinsically and extrinsically labeled soy flour, acid-precipitated soy concentrate and neutralized soy concentrate was evaluated in rats. Weanling rats were fed marginally zinc-deficient diets, providing 8 ppm zinc from one of these three soy products, for 7 days. The rats then received a radioactively labeled test meal, identical in composition to the previous diet except that the soy product was either intrinsically or extrinsically labeled with 65Zn. After the test meal the rats were again fed diets the same as those consumed prior to the test meal. Whole-body retention of 65Zn at 24 hours and 12 days as well as 65Zn retained in tibias of rats given meals containing neutralized concentrate-based meals was significantly lower than for rats given meals containing the soy flour or acid-precipitated concentrate. In addition, retention of 65Zn from the extrinsically labeled acid-precipitated concentrate-based meal was significantly higher than from the same product intrinsically labeled. These findings confirm the results of previous feeding studies from which it was suggested that neutralization of soy protein concentrates reduces zinc bioavailability to the rat. In addition, the results are taken to suggest that experimental conditions may influence the validity of the extrinsic labeling technique for zinc.

An Evaluation of the Nutritional Value of a Soy Protein Concentrate in Young Adult Men Using the Short-Term N-Balance Method

Eight healthy young men participated in a metabolic balance study designed to assess the protein quality of soy protein concentrate (STAPRO-3200). Subjects received varying intakes of the test protein [0.35, 0.45, 0.55 and 0.65 g protein (N 6.25) per kilogram body weight per day] during 10-day experimental periods. Each was preceded by a 1-day protein-free diet. A final diet period with a 0.65 g milk protein intake was included for comparative purposes. During this period and that with the 0.65 g test intake of soy concentrate the stable isotopes 70Zn and 53Fe were added to the diet for 2 days to obtain initial data on the absorption of zinc and iron when soy concentrate was the sole source of protein intake. Mean ( SEM) intake of soy concentrate determined to be sufficient for N balance (including allowance of 5 mg N/kg per day for integumental and miscellaneous losses) was 95 ( 7) mg N/kg per day. Absorption of the extrinsic doses of labeled iron and zinc did not differ between the soy protein- and milk-based diets. Comparison of these data was made with findings obtained previously with other protein sources evaluated in the same way. The conclusion is that the capacity of the soy concentration to support short-term nitrogen equilibrium in adult protein nutrition is the same as that for good quality animal protein sources. Thus, well-processed soy concentrates can make a nutritionally significant contribution to meeting adult human protein needs.