Standard Casein Research Articles

Protective effect of soy proteins under excessive amount of fats in the diet of rats

Excessive fat intake causes the development of metabolic syndrome (MS). Our studies have shown that soy proteins in the diet improve vascular reactivity in rats with a high-salt dietary load and renal dysfunction. We hypothesized that the introduction of soy proteins into a high-fat diet (HFD) can prevent or reduce vascular dysfunction. The aim of the study was to test the hypothesis about the possible protective effect of soy protein isolate on endothelium-dependent dilation of the mesenteric arteries of male Wistar rats receiving an excess amount of fat in the diet. Material and methods. The study used 3 groups of 20 rats, weighing 220-240 g. The HFD group received a diet containing 50% fat (by calorie value) and 20% casein, HFD + Soy group received a diet containing 50% fat and 20% soy isolate SUPRO-760, the control group - a standard casein diet. After 8 weeks, the responses of mesenteric arteries precontracted with phenylephrine to acetylcholine (ACh) were studied in the absence and with the use of NO synthase (L-NAME), cyclooxygenase (indomethacin), BKCa and Kv channel (tetraethylammonium) blockers, using microphoto- and video recording of the vessel diameter in vivo. Results. Compared with the standard diet, visceral fat mass increased by 54.6% in rats fed HFD and by 25.9% in rats fed HFD + Soy (p<0.01). In the HFD + Soy group, the increase in blood pressure was less than in the HFD group (p<0.01). Consumption of HFD + Soy prevented disorders typical of HFD, reducing glycemia and insulin resistance, normalizing lipid metabolism (p<0.05). Evaluation of the functional state of the mesenteric arteries (in vivo) showed that in the HFD + Soy group the amplitude of dilation on ACh remained close to the control group, whereas in the HFD group the suppression of ACh-induced relaxation was observed (by 19.8% (p<0.01). After blockade of NO synthase by incubation with L-NAME the magnitude of vasodilation on ACh decreased (p<0.001) in the HFD group by 47.0±7.4%, in the HFD + Soy group - by 68.2±6.6% and in the control group - by 68.9±5.6%. After incubation with L-NAME, indomethacin and tetraethylammonium, the amplitude of dilation on ACh in rats of the HFD and HFD + Soy groups was 1.5 fold greater (p<0.05) than in the control. The relaxation amplitude to sodium nitroprusside did not differ between the groups. Conclusion. The introduction of soy proteins into a HFD prevents the development of impairs characteristic of MS: it reduces visceral obesity, improves the state of carbohydrate and lipid metabolism, and has a hypotensive effect. The protective effect of soy proteins on vascular reactivity in rats with excessive fat consumption was confirmed: the introduction of soy protein isolate into the diet leads to the prevention of endothelial dysfunction characteristic of HFD, preventing the disruption of NO-dependent vasodilation mechanisms. It is assumed that the positive effect of soy on vascular reactivity is mediated by maintaining NO synthesis by the endothelium, and may be associated with the anti-inflammatory and antioxidant properties of both proteins and isoflavonoids contained in soy.

Cooking Methods Revealed Differences in Quality Content of Prepared Soyabean Extended Chicken Nuggets

Soyabean extended chicken nuggets (SECN) were prepared, separately fried, grilled and roasted. The cooked nuggets were formulated as diets and fed to weaning rats (n=50) using standard casein and nitrogen free diets as controls. Quality attributes were assessed based on physico-chemical, sensory properties, proximate compositions, amino acids, total cholesterol and shelf stability in terms of lipid oxidation and microbial load as well as the effect of the feed on growth performance of weaned albino rats. Apart from slight variation (P&lt;0.05), fried SECN, followed by grilled SECN improved yield, flavour, overall acceptability, crude protein and amino acid content in comparison to roasted SECN. The reduced lipid oxidation, total cholesterol and microbial load further enhanced the quality of fried SECN. Similarly, fried SECN was considered as the best based on daily feed intake, weight gained, feed conversion ratio, protein efficiency ratio and biological value. Thus, among the different cooking methods, deep-frying enhanced the quality of SECN better than other cooking methods as reflected in growth performance of weaned albino rats. Therefore, to harness acceptability of chicken nuggets, soyabean protein extender which is known for its ability to improve product firmness, chewiness and emulsion stability could be used alongside appropriate cooking methods to prepare chicken nuggets with excellent structural and nutritional qualities readily acceptable by consumers.

Dietary Soy Prevents Alcohol-Mediated Neurocognitive Dysfunction and Associated Impairments in Brain Insulin Pathway Signaling in an Adolescent Rat Model.

Background: Alcohol-related brain degeneration is linked to cognitive-motor deficits and impaired signaling through insulin/insulin-like growth factor type 1 (IGF-1)-Akt pathways that regulate cell survival, plasticity, metabolism, and homeostasis. In addition, ethanol inhibits Aspartyl-asparaginyl-β-hydroxylase (ASPH), a downstream target of insulin/IGF-1-Akt signaling and an activator of Notch networks. Previous studies have suggested that early treatment with insulin sensitizers or dietary soy could reduce or prevent the long-term adverse effects of chronic ethanol feeding. Objective: The goal of this study was to assess the effects of substituting soy isolate for casein to prevent or reduce ethanol’s adverse effects on brain structure and function. Methods: Young adolescent male and female Long Evans were used in a 4-way model as follows: Control + Casein; Ethanol + Casein; Control + Soy; Ethanol + Soy; Control = 0% ethanol; Ethanol = 26% ethanol (caloric). Rats were fed isocaloric diets from 4 to 11 weeks of age. During the final experimental week, the Morris Water maze test was used to assess spatial learning (4 consecutive days), after which the brains were harvested to measure the temporal lobe expression of the total phospho-Akt pathway and downstream target proteins using multiplex bead-based enzyme-linked immunosorbent assays (ELISAs) and duplex ELISAs. Results: Ethanol inhibited spatial learning and reduced brain weight, insulin signaling through Akt, and the expression of ASPH when standard casein was provided as the protein source. The substitution of soy isolate for casein largely abrogated the adverse effects of chronic ethanol feeding. In contrast, Notch signaling protein expression was minimally altered by ethanol or soy isolate. Conclusions: These novel findings suggest that the insulin sensitizer properties of soy isolate may prevent some of the adverse effects that chronic ethanol exposure has on neurobehavioral function and insulin-regulated metabolic pathways in adolescent brains.

Durability and Strength Characteristics of Casein-Cemented Sand with Slag.

Casein is often used as an eco-friendly wood adhesive. In this study, we used casein for soil cementation by mixing it with Jumunjin sand, sodium hydroxide (SH), and calcium hydroxide (CH) as a standard casein formula. The modified casein binder with different proportions of SH and CH was applied to improve water resistance. Furthermore, a blast furnace slag (BFS) was additionally mixed and reacted with alkalinity of modified casein binder. Thus, three types (standard, modified, and modified + BFS, referred to as STD, MOD, and MBS, hereafter) of casein binders were tested for durability and strength of casein-cemented sand. A piezoelectric sensor was installed within each sample to determine the curing time of the casein-cemented samples. The samples were air-cured at room temperature for seven days and some were repeatedly immersed in water thrice. Unconfined compression and jar slake tests were carried out to evaluate the strength and durability of the casein-cemented sand. Also, the microstructure was analyzed using a scanning electron microscope (SEM). We observed variations of peak conductance and corresponding frequency converged as the curing time increased. It was most significant for the MBS samples, which developed strength early. The unconfined compressive strength (UCS) of the air-cured samples was higher than those repeatedly immersed in water due to wash-off of the casein binder. The UCS of the dry MBS sample was 9900 kPa while that of the immersed sample was 430 kPa, which gradually decreased to 60 kPa upon repeated immersion. The samples with STD and MOD had no resistance to durability and showed cracks on the surface, while the MBS sample exhibited significantly improved durability and no cracks. We found that the MBS binder had a positively significant effect on the durability and strength of casein-cemented sand.

Hippuric acid and 3-(3-hydroxyphenyl) propionic acid inhibit murine osteoclastogenesis through RANKL-RANK independent pathway.

Nutritional factors influence bone development. Previous studies demonstrated that bone mass significantly increased with suppressed bone resorption in early life of rats fed with AIN‐93G semi‐purified diets supplemented with 10% whole blueberry (BB) powder for 2 weeks. However, the effects of increased phenolic acids in animal serum due to this diet on bone and bone resorption were unclear. This in vitro and in ex vivo study examined the effects of phenolic hippuric acid (HA) and 3‐(3‐hydroxyphenyl) propionic acid (3‐3‐PPA) on osteoclastic cell differentiation and bone resorption. We cultured murine osteoclast (macrophage) cell line, RAW 264.7 cells, and hematopoietic osteoclast progenitor cells (isolated from 4‐week‐old C57BL6/J mice) with 50 ng/ml of receptor activator of nuclear factor κ‐Β ligand (RANKL). Morphologic studies showed decreased osteoclast number with treatment of 2.5% mouse serum from BB diet–fed animals compared with those treated with serum from standard casein diet–fed mice in both RAW 264.7 cell and primary cell cultures. HA and 3‐3‐PPA, but not 3–4‐PPA, had dose‐dependent suppressive effects on osteoclastogenesis and osteoclast resorptive activity in Corning osteo‐assay plates. Signaling pathway analysis showed that after pretreatment with HA or 3‐3‐PPA, RANKL‐stimulated increase of osteoclastogenic markers, such as nuclear factor of activated T‐cells, cytoplasmic 1 and matrix metallopeptidase 9 gene/protein expression were blunted. Inhibitory effects of HA and 3‐3‐PPA on osteoclastogenesis utilized RANKL/RANK independent mediators. The study revealed that HA and 3‐3‐PPA significantly inhibited osteoclastogenesis and bone osteoclastic resorptive activity.

Dietary whey proteins shield murine cecal microbiota from extensive disarray caused by a high-fat diet

High-fat diets are used to induce adverse alterations in the intestinal microbiota, or dysbiosis, generalized inflammation and metabolic stress, which ultimately may lead to obesity. The influence of dietary whey proteins, whether intact or hydrolyzed, has been reported to improve glucose homeostasis and reduce stress. Therefore, the purpose of this work was to test if dietary milk-whey proteins, both in the intact form and hydrolyzed, could have an effect on the compositional changes of the cecal microbiota that can be induced in mice when receiving a high-fat diet in combination with the standard casein. Male C57BL/6 mice were fed a control casein diet (AIN 93-G); high-fat-casein (HFCAS); high-fat-whey protein concentrate (HFWPC) and high-fat whey-protein hydrolysate (HFWPH) for 9weeks. The intestinal microbiota composition was analyzed by 16S-rRNA of the invariant (V1–V3) gene, potentially endotoxemic lipopolysaccharide (LPS) release was determined colorimetrically, and liver fat infiltration assessed by light microscopy. The high-fat diet proved to induce dysbiosis in the animals by inverting the dominance of the phylum Firmicutes over Bacteroidetes, promoted the increase of LPS and resulted in liver fat infiltration. The whey proteins, whether intact or hydrolyzed, resisted the installation of dysbiosis, prevented the surge of circulating LPS and prevented fat infiltration in the liver. It is concluded that dietary whey proteins exert metabolic actions that tend to preserve the normal microbiota profile, while mitigating liver fat deposition in mice consuming a high-fat diet for nine weeks. Such beneficial effects were not seen when casein was the dietary protein. The hydrolyzed whey protein still differed from the normal whey protein by selectively protecting the Bacteroidetes phylum.

Impacts of Age, Snack Food, and Whole and Refined Wheat on the Rat Fecal Microbiome

Early exposures that promote gut microbiome dysbiosis are associated with childhood and adult disease. The ability of whole (vs refined) grains to enhance gut microbiome composition and function and host immunometabolic health remains controversial. We assessed the impact of whole vs refined wheat on gut microbiome maturation in Sprague Dawley rats fed a snack food‐based diet.Individually‐housed male Sprague Dawley rats were weaned at 4 weeks onto either: 1) AIN‐93G (control), a standard casein‐, cornstarch‐ and soy oil‐based diet; 2, 3) AIN‐93G containing 18% (wt) refined wheat (RW) rusk or whole wheat (WW) rusk; 4,5) A 65% snack (S) mixture of chips, crackers, candy, etc. supplemented with either 18% refined wheat (SRW) or whole wheat (SWW) rusk. Diets were balanced to match protein and micronutrient content. Oral glucose tolerance tests were performed at 20 weeks. Fecal samples were collected at weaning and after 24 weeks and frozen. DNA extraction, V4 region amplification of 16S rRNA, 250 bp paired‐ end sequencing and downstream processing were performed as described (PLoS One. 2015 Aug 18;10(8):e0135758.) Closed reference OTUs (99% threshold), OTU tables, heat‐maps, diversity measures and phylogenetic distances were obtained (QIIMEv1.8 and R). PCoA and jackknifed UPGMA clustering were performed. Defining OTUs were identified with LDA (Linear Discriminant Analysis) Effect Size (Lefse) and OTU relationship to glucose (in)tolerance were assessed by Multivariate Association with Linear Models (MaAsLin).210 samples generated 12.2 million quality reads and 738 OTU designations. Alpha diversity (Shannon) was greater at 24 weeks (p = 0.04), coincident with decreased Bacteroidetes and increased Firmicutes across all diets. 4 and 24 week samples were separable by PCoA and UPGMA (p &lt; 1010). Distinguishing OTUs at 4 weeks included B. fragilis, A. muciniphila, P. gordoni and C. perfringens; mature microbiomes were distinguished by Coprococcus, Allobaculum and the Bacteroidales lineage S24‐7. Alpha diversity was comparable among the 5 diets and C, WW and RW diets were taxonomically indistinguishable. SWW or SRW microbiomes were distinct from C, WW and RW microbiomes (UPGMA, p&lt; 107), coincident with impaired glucose tolerance in snack‐based vs wheat‐supplemented groups (p&lt;0.05). Defining OTUs of snack‐based diets were S24‐7, C. areofaciens, and Oscillospora, Lachnospira, Clostridium and Holdemania; non‐snack diets were distinguished by A. muciniphila, C. eutactus, L. salivarius and Adlercreutzia. Microbiomes of SWW and SRW diets were indistinguishable.Maturation per se most significantly impacted the adult fecal microbiome in this study. A diet high in sucrose and fat and lower in fiber (S) was associated with dysbiosis and impaired glucose tolerance. Supplementation of this diet with whole (WW) or refined (RW) wheat protected glucose tolerance but did not detectably alter fecal microbial community structure.Support or Funding InformationSupported by Mondelez International, Inc and USDA ARS Cooperative Agreement no. 58‐1950‐7‐707.

Whey Proteins Are More Efficient than Casein in the Recovery of Muscle Functional Properties following a Casting Induced Muscle Atrophy

The purpose of this study was to investigate the effect of whey supplementation, as compared to the standard casein diet, on the recovery of muscle functional properties after a casting-induced immobilization period. After an initial (I0) evaluation of the contractile properties of the plantarflexors (isometric torque-frequency relationship, concentric power-velocity relationship and a fatigability test), the ankle of 20 male adult rats was immobilized by casting for 8 days. During this period, rats were fed a standard diet with 13% of casein (CAS). After cast removal, rats received either the same diet or a diet with 13% of whey proteins (WHEY). A control group (n = 10), non-immobilized but pair-fed to the two other experimental groups, was also studied and fed with the CAS diet. During the recovery period, contractile properties were evaluated 7 (R7), 21 (R21) and 42 days (R42) after cast removal. The immobilization procedure induced a homogeneous depression of average isometric force at R7 (CAS: − 19.0±8.2%; WHEY: − 21.7±8.4%; P<0.001) and concentric power (CAS: − 26.8±16.4%, P<0.001; WHEY: − 13.5±21.8%, P<0.05) as compared to I0. Conversely, no significant alteration of fatigability was observed. At R21, isometric force had fully recovered in WHEY, especially for frequencies above 50 Hz, whereas it was still significantly depressed in CAS, where complete recovery occurred only at R42. Similarly, recovery of concentric power was faster at R21 in the 500−700°/s range in the WHEY group. These results suggest that recovery kinetics varied between diets, the diet with the whey proteins promoting a faster recovery of isometric force and concentric power output as compared to the casein diet. These effects were more specifically observed at force level and movement velocities that are relevant for functional abilities, and thus natural locomotion.

Assessment of Microbial Changes and Nutritional Qualities of Extruded White Yam (&amp;lt;i&amp;gt;Dioscorea rotundata&amp;lt;/i&amp;gt;) and Bambara Groundnut (&amp;lt;i&amp;gt;Vigna subterranean&amp;lt;/i&amp;gt;) Blends

Two flavoured extruded products were developed by co-extruding yam grits (750 μm) obtained from white yam (Dioscorea rotundata) and bambara groundnut flour (250 μm) in 160:40 respectively obtained from white bambara groundnut with added flavouring agents of salt (1% - 3%) and sugar (4% - 6%) in the feed blends at screw speed of 70 rpm, 17.5%, feed moisture and at the barrel temperature of 145℃. The extruded products were packaged in low density polyethylene bag (0.02 μm gauge size) and stored at room temperature (28℃ ± 2℃) and at refrigeration temperature (9℃ ± 2℃) for a period of twenty weeks. The microbiological changes in the extruded products as determined by the total plate under both storage conditions showed that maximum total plate counts were 0.5 × 104 and 5.4 × 104 cfu/g at 9℃ ± 2℃ and 28℃ ± 2℃ respectively. Nutritional evaluation studies of extrudates were comparable (p ≥ 0.05) with standard casein diet with minimum crude protein content of 13.51% providing 1707.2 KJ energy per 100gof diet and supported weight gain and growth of laboratory animals.

The effect of dietary sericin on rats

Dietary proteins have been reported to be beneficial for lipid metabolism, tissue growth, development, and repair, as well as immune response. The interactions of dietary proteins and their digested products may regulate the physiology and metabolism of the gastrointestinal tract. However, proteins are largely digested before reaching the large intestine. The present study investigated the use of the non-dietary protein, silk sericin, in rats. Rats were fed either with casein or sericin proteins. Their body weight, food consumption, and complete blood count were measured. The results showed that during the experimental periods, rats fed with casein and sericin diets had no significant changes on body weight, food consumption, or complete blood count. Sericin-fed rats had a significantly decreased CD8a and CD80 positive cells when compared with standard casein protein. In conclusion, dietary proteins may have a differential impact on the leukocyte profile. The mechanisms underlying these changes are not clear but they might be due to the different amino acid compositions of the proteins studied.

Amaranth Grain Brings Health Benefits to Young Normolipidemic Rats

This paper reports the impact of an extruded amaranth (Amaranthus spp) supplement on intestinal bile and fatty acids of normolipidemic rats. Forty-eight rats were fed either a control diet AIN 93-G (12 or 18% protein), or one of two levels of supplemental extruded amaranth flour for 48 days. Plasma glucose, insulin, total cholesterol, their fractions, and triacylglycerols, liver weight and lipid content, cecum short-chain fatty acids and fecal excretion of bile acids were determined. While no significant differences in the levels of plasma triacylglycerols, glucose or insulin, and liver parameters due to the diet were detected. Although amaranth promotes reduction of both total and LDL serum cholesterol, increased production of butyric acid in cecum and fecal excretion of deoxycholic acid in the feces. These results suggest that amaranth used routinely as a supplement to the standard casein diet could have a health-promoting value in the normal rat.

Leucine: a nutrient 'trigger' for muscle anabolism, but what more?

Leucine: a nutrient 'trigger' for muscle anabolism, but what more?

Assaying pharmacodynamic endpoints with targeted therapy: Flavopiridol and 17AAG induced dephosphorylation of histone H1.5 in acute myeloid leukemia

Histone H1 is commonly used to assay kinase activity in vitro. As many promising targeted therapies affect kinase activity of specific enzymes involved in cancer transformation, H1 phosphorylation can serve as potential pharmacodynamic marker for drug activity within the cell. In this study we utilized a phosphoproteomic workflow to characterize histone H1 phosphorylation changes associated with two targeted therapies in the Kasumi-1 acute myeloid leukemia cell line. The phosphoproteomic workflow was first validated with standard casein phosphoproteins and then applied to the direct analysis of histone H1 from Kasumi-1 nuclear lysates. Ten H1 phosphorylation sites were identified on the H1 variants, H1.2, H1.3, H1.4, H1.5 and H1.x. LC MS profiling of intact H1s demonstrated global dephosphorylation of H1.5 associated with therapy by the cyclin-dependent kinase inhibitor, flavopiridol and the Heat Shock Protein 90 inhibitor, 17-(Allylamino)-17-demethoxygeldanamycin. In contrast, independent treatments with a nucleotide analog, proteosome inhibitor and histone deacetylase inhibitor did not exhibit decreased H1.5 phosphorylation. The data presented herein demonstrate that potential of histones to assess the cellular response of reagents that have direct and indirect effects on kinase activity that alters histone phosphorylation. As such, this approach may be a highly informative marker for response to targeted therapies influencing histone phosphorylation.

Weight analyses and nitrogen balance assay in rats fed extruded African breadfruit (Treculia africana Decne) based diets

Weight analyses and nitrogen balance assay in adult rats in raw and extruded African breadfruit (Treculia africana) based diets were carried out using response surface methodology in a central composite design. Process variables were feed composition (40 - 100 % Africanbreadfruit, 0 - 5 % corn and 0 - 55 % soybean, respectively), feed moisture (15 – 27 %) and screw speed (100 – 180 rpm). One hundred and two adult rats weighing 71 – 86 g were housed in stainless steel metabolism cages, and fed different diets comprising 5 (raw), 25 (extruded), standard casein and N-free diets in groups of 6 rats percage on the basis of body weight. Data generated were used in calculating nitrogen intakes and balances, biological values, net protein utilization and protein efficiency ratio during the 7-day feeding period. Rats fed the standard raw diet made from casein had the highestfood intake (47.20 g) while those fed diets made from 100 % African breadfruit had the least food intake (29.40 g). Food intake was generally higher in the extruded diets ranging from 35 g in diet containing 70 % African breadfruit, 5 % corn and 25 % soybean to 48.90 g for dietsmade from 40 % African breadfruit, 5 % corn and 55 % soybean. Maximum body weight gain, carcass, organ and liver weights were 6.20, 53.80, 13.30 and 3.10 g for rats fed raw diets and 11.60, 93.40, 23.40 and 6.40 g respectively, for those fed extruded diets. Biologicalvalues (0.77 - 0.94), net protein utilization (0.72 - 0.91) and protein efficiency ratio (1.04 - 2.22) for extruded diets were reported. Diet intake was quadratically affected by feed moisture and screw speed.

Cooked Rice and Oat Meal Similarly Reduce Hypercholesterolemia in Rats

Five groups of rats were given five different diets for 4 weeks after one week adaptation with standard casein. These diets include: casein diet as a control group (C), cooked rice ( R), cooked rice with 1% exogenous cholesterol (RC), oat meal (O), and oat meal with 1% exogenous cholesterol (OC) (Different analysis was determined on animals of these groups at the end of the experiment). The rats weights at the end of experiment showed that weight gain of control group rats was significantly higher (p.0.01) than other groups but there were no differences among other groups. The concentration of serum total cholesterol for (O) group (64.6 mg/100 ml) and that of (R) group (67.7 mg/100 ml) were significantly lower (p.0.01) than those of other groups and the control group was the highest one in all groups (112.42 mg/100 ml). The results also showed significant differences among mean relative weights of Liver, spleen and heart of different groups. The highest and lowest values of mean relative weight of rat's liver, spleen and heart in experimental groups were : (O) group (3.87) and R group (3.29) for liver, (R) group (0.48) and (O) group (0.38) for spleen, both RC and R groups (0.37) and (O) group (0.33) for heart respectively. The (R) and (O) diets significantly lowered the total fat content (24.0, 26.16 mg/kg respectively) while (O) diet lowered the cholesterol content (1.36 mg/kg) of the liver compared to the control diet (51.9 and 2.47 mg/kg for total fat and cholesterol respectively). For bile acid content in the feces, there were significant differences (p.0.01) among the different groups; (OC) group showed the highest (10.4 mg/gm of feces) and the control group showed the lowest

Mood and cortisol responses following tryptophan-rich hydrolyzed protein and acute stress in healthy subjects with high and low cognitive reactivity to depression

It is suggested that stress particularly in subjects with high cognitive reactivity (CR), a psychological vulnerability marker of depression, may increase or even induce serotonergic vulnerability, which in turn may lead to reduced serotonin (5-HT) function, decreased stress coping and an increased risk to develop depressive symptoms. The aim of the present study was to investigate the beneficial effects of 5-HT augmentation through a tryptophan-rich hydrolyzed protein (HP) on mood and stress coping in subjects with high and low CR. We hypothesized that subjects with high CR are more responsive to the beneficial effects of HP than subjects with low CR particularly after acute stress exposure. In a double-blind, crossover study, participants' mood and cortisol was assessed before and after acute stress exposure either following intake of HP or a standard casein protein (CP) as control condition. HP significantly increased positive mood in all subjects and dampened the cortisol response to acute stress. No differences were found between high and low CR subjects. To conclude, because dietary treatment with HP has beneficial effects on mood and physiological stress coping in both high and low CR subjects, HP may be a good dietary method for augmenting brain TRP and 5-HT and thus 5-HT linked stress resilience.

EFFECT EXTRACTION METHODS OF RICE BRAN PROTEIN ON THEIR FUNCTIONAL PROPERTIES

This investigation was carried out to study the functional properties and amino acids compositions of rice bran protein isolate (RBPI) and rice bran protein concentrate (RBPC). The results indicate that (RBPI) had better water binding capacity, protein content and yield as compared to (RBPC), while oil binding capacity lower in (RBPI) than (RBPC). Nitrogen solubilities of (RBPI) were 52.3, 8.4, 63.5, 79.1, 83.7 and 81.5% at pH 2, 4, 6, 8, 10 and 12, respectively. RBPI had better foaming and emulsifying properties than (RBPC). While, RBPI had similar foaming properties in comparison to egg white, but emulsifying properties of RBPI were lower than those of bovine serum albumin. The results of amino acid analysis showed that the relative content of cystine and methionine in RBPC were lower than that of RBPI and RBP, while leucine and phenylalanine were higher in RBPC .The computed protein efficiency ratio(C-PER) and biological value (B V) of RPBI were higher than those of RBPC and value of all samples were lower than that of standard casein protein. Obtained results indicate that the RBPC and RBPI have high qualities of both nutritional and functional properties and could be competitive proteins ingredients in food products.

Choline Deprivation Induces Hyperhomocysteinemia in Rats Fed Low Methionine Diets

To clarify the relationship between dietary choline level and plasma homocysteine concentration, the effects of choline deprivation on plasma homocysteine concentration and related variables were investigated in rats fed a standard (25%) casein (25C) diet or standard soybean protein (25S) diet. Using the 25S diet, the time-dependent effect of choline deprivation and the comparative effects of three kinds of lipotropes were also investigated. Feeding rats with the choline-deprived 25S diet for 10 d significantly increased plasma total homocysteine concentration to a level 2.68-times higher than that of the control group, whereas choline deprivation had no effect in rats fed the 25C diet. Increases in hepatic S-adenosylhomocysteine and homocysteine concentrations, decreases in hepatic betaine concentration and the activity of cystathionine beta-synthase, but not betaine-homocysteine S-methyltransferase, and fatty liver also occurred in rats fed the choline-deprived 25S diet. Plasma homocysteine concentration increased when rats were fed the choline-deprived 25S diet for only 3 d, and the increase persisted up to 20 d. The hyperhomocysteinemia induced by choline deprivation was effectively suppressed by betaine or methionine supplementation. Choline deprivation caused hyperhomocysteinemia also in rats fed a choline-deprived low (10%) casein diet. The results indicate that choline deprivation can easily induce prominent hyperhomocysteinemia when rats are fed relatively low methionine diets such as a standard soybean protein diet and low casein diet, possibly through the suppression of homocysteine removal by both remethylation and cystathionine formation. This hyperhomocysteinemia might be a useful model for investigating the role of betaine in the regulation of plasma homocysteine concentration.

Effects of dietary fats and proteins on rat testicular steroidogenic enzymes and serum testosterone levels

It is known that certain dietary fats can modulate rat testosterone metabolism. In the current study we have investigated testicular steroidogenic enzyme activities and serum testosterone levels in rats fed diets containing either different protein sources (casein, fishmeal, whey) or different lipid sources (soybean oil, docosahexaenoic acid (DHA), seal oil, fish oil, lard). The diets examined reflect different marine oils and proteins which are significant components of Northern Canadian diets. Male rats (42–45 days old, 6 per group), were assigned to specific diets for 42 days. On the 43rd day of the study, rats were sacrificed and blood plasma and testes frozen (−80 °C) until analysis. Microsomal steroidogenic enzyme activities (3β-HSD, 17-OHase, C-17,20-lyase, 17β-HSD) were measured radiometrically. There were no differences in enzyme activities between the three dietary protein sources. In contrast, compared with the standard casein diet, all lipid sources caused reductions in C-17,20-lyase activity (>50%); seal oil and fish oil reduced 17-OHase activity (approximately 30%) and soybean oil, DHA fish oil and lard reduced 17β-HSD activity (approximately 30%). No effect on 3β-HSD activity was evident. Serum testosterone levels were determined using ELISA kits and were not affected by any diet with the exception of the soybean oil diet which was significantly elevated compared with the casein protein diet. Body and testis weights were not affected by diet. In conclusion, these data demonstrate that some dietary lipid sources caused reductions in testicular 17-OHase and C-17,20-lyase activities but not to the extent that serum T levels were affected, while soybean oil caused elevated serum testosterone in the absence of elevated steroidogenic enzyme activities.

Nutritional studies with Lentinus squarrosulus (Mont.) Singer and Psathyrella atroumbonata Pegler: I. animal assay

Lentinus squarrosulus and Psathyrella atroumbonata , two edible indigenous mushroom species, were dried, ground and used in nutritional studies. According to the results L. squarrosulus and P. atroumbonata had significantly lower protein efficiency ratio (PER) values than the standard casein diet but gave rise to net protein retention (NPR) values which were at par, but slightly higher than that of the standard casein diet. In addition, the mean albumin and bilirubin levels were significant at p<0.01 while the total serum protein level was significant at p<0.05. The animals fed the protein free and P. atroumbonata diets produced comparable total serum protein levels that were significantly higher than the comparable total serum protein levels produced by the animals fed L. squarrosulus and the standard casein diet. The albumin levels produced by mice fed the protein free diet were at par with those of the P. atroumbonata diet, but significantly higher than the albumin levels of animals fed L. squarrosulus and the standard casein diets, which were similar. Keywords: Lentinus squarrosulus , P. atroumbonata protein efficiency ratio, net protein retention ratio, total serum protein, albumin, bilirubin