The cholesterol-lowering property of soybeans fed to rats is related to the fasting duration.

Numerous factors affect plasma cholesterol and, therefore, represent potential interferences with the specific effects of diet on lipid metabolism. After casein intake, serum cholesterol levels depend on many experimental conditions in rats, such as the type of casein, the presence or absence of cholesterol in the diet, the age and strain of rat, the diet composition, the nutritional status. The effect of fasting duration on selected parameters was studied in adult male Wistar rats fed a 20% casein and 1% cholesterol-based diet. No changes were observed in total serum, lipoproteins-B and HDL cholesterol and in triglyceride values after an 8 h-fast compared to non-fasted animals. A significant decrease was induced in total and lipoproteins-B cholesterol with a 12 h-fast. A prolonged fast resulted in a significant decrease in these parameters and in triglycerides and in HDL-cholesterol levels. Fasted animals fed heated soybean meal instead of casein did not display a marked decrease in serum lipids. It appeared that the fasting effect was more marked in animals fed casein than in animals fed soybeans. These results showed the importance of experimental conditions such as nutritional status of animals when blood samples are taken in studies of the hypocholesterolemic effect of soy protein compared to casein.

Effects of soybean (Glycine max) germination on biologically active components, nutritional values of seeds, and biological characteristics in rats.

We briefly reviewed the effects of soybean germination on biologically active components, nutritive value of seed and biological characteristics in rats. The purpose of this review is to evaluate the effects of soybean germination on nutritional values of seeds and the potential importance for the use of germinated soybeans, from a contemporary conception, in food preparation as well as on soybean possible influence in optimal health. Germination induced a substantial increase in the content of saponin, oestrogenic compounds and almost all phytosterols, particularly beta-sitosterol of seeds. Lecithin content increased slightly and gradually during germination process. Lipase and alpha-galactosidase activities increased whereas lipoxygenase activities reduced after a short period of germination (< or = 72 h). Therefore, the substantial odour and flavour scores of germinated soybean flour were improved. Germinated seeds were also beneficial to heat penetration, their thermolabile antinutritional factors were easier to inhibit than those of dry beans, also the seeds did not require a long cooking time to be palatable. Duration of the germination process greatly influenced the nutritional value and palatability of seeds and biological characteristics in rats. In rat bioassay, one-day germination of soybeans induced a significant increase of daily body weight gain, daily protein intake in rats and protein efficiency ratio (PER) of seed meal. Palatability of seeds was also improved whereas a 5-day germination resulted in a decrease of PER of seed meal (less than the value of unheated seeds) and induced thyroid enlargement in rats. A vapour thermal treatment (100 degrees C, 20 min) eliminated thyroid-active agents and improved PER of seed meal, food intake and final weight of rats. Well prepared germinated soybeans can be used as a good alternate to animal proteins for more balanced nutritional diet. Development of food products from germinated soybean may be another way to further increase the versatility and utility of soybeans for both developing and industrialized countries, as germination induced the modification of certain specific biologically active components, palatability and nutritive value of seeds.

[Effects of treatments (heat and fermentation by Rhizopus oligosporus sp-T3) of sweet white lupin seeds on certain factors of its nutritional use]. / Effets des traitements (chauffage et fermentation par Rhizopus oligosporus sp-T3) de la graine de lupin blanc doux sur certains facteurs de son utilisation nutritionnelle.

For improving the nutritional value and functional properties of sweet white lupin (SWL), a solid fermentation process using Rhizopus oligosporus was developed for the preparation of lupin products. A comparison of the effects of soaking + thermal treatment and fermentation was made from 3 lupin products: non-treated lupin seeds (SWLnt), heated lupin seeds (steamed at 100 degrees C for 30 min) (SWLh), and fermented lupin products (SWLf) from SWLh on chemical characteristics and protein efficiency ratio (PER) in rats. The major effect of soaking and thermal treatment is a loss of protein solubility and available lysine (from 3.02 +/- 0.18 g/16 g N to 2.3 +/- 0.25). Fermentation leads to a modification, of amino acid composition and to an increase in available lysine compared to heating (2.90 +/- 0.12 g/16 g N). The nutritional quality of SWLnt is low (PER = 0.83 +/- 0.09), thermal treatment decreases it (0.58 +/- 0.18) and fermentation compensates heating effect (0.74 +/- 0.25). It is suggested that the modifications of nutritional quality depends on the availability of lysine rather than on the variations of the levels of other amino acids.

Effect of different kinds of dietary casein on blood cholesterol and triglycerides in pair fed rats.

After casein intake, serum cholesterol levels are dependent on many experimental conditions in rats. The effect of the method of casein preparation was assessed in Wistar rats pair-fed for 4 wk with three identical diets differing only by the type of casein used. Compared with dietary casein and Na caseinate, ingestion of lipid- and vitamin-free casein resulted in higher liver weights (4.35 +/- 0.23 vs. 3.89 +/- 0.30 and 3.90 +/- 0.25 g) and fasting serum cholesterol levels (0.55 +/- 0.13 vs. 0.49 +/- 0.09 and 0.44 +/- 0.09 g/L). Compared with the two other casein diets, ingestion of Na caseinate produced the lowest fasting serum triglyceride levels (0.62 +/- 0.13 vs 0.74 +/- 0.12 and 0.73 +/- 0.13 g/L). Peptic digestibility of caseins used might be a regulating factor of serum cholesterol levels in Wistar rats.

Effects of the nature of dietary proteins, lecithin and methionine on rat plasma lipids.

In order to study the complex interrelationships between on the one hand, dietary proteins, lecithin and methionine and, on the other, blood cholesterol and triglyceride levels, groups of .10 rats were fed for six weeks with diets only differing by the nature of proteins which comprised 10% of the diet. These diets were composed of egg white, heated soybean flour, casein, heated soybean flour supplemented with 1% methionine, or with 4% of the lipids replaced by soybean lecithin, heated 5-day germinated soybean supplemented or not with 1% methionine and casein with 4% of the lipids replaced by lecithin. Egg white caused no change in blood cholesterol compared to heated soybean meal (0.955 +/- 0.18 vs 0.83 +/- 0.14), but caused a significant increase in blood cholesterol levels compared to casein (0.955 +/- 0.18 vs 0.81 +/- 0.11 g/l). No effect was found on blood triglycerides levels. Lecithin caused no change when it partially replaced lipids in the soybean or casein diets thought it increased triglycerides with the casein diet (1.16 +/- 0.31 vs 0.84 +/- 0.24 g/l). Supplementation of the heated soybean diet with 1% methionine led to an increase in blood triglycerides (0.85 +/- 0.26 vs 1.18 +/- 0.34 g/l). After germination, this effect disappeared. The effects of the type of protein, partial replacement of dietary lipids by lecithin and supplementation with methionine are discussed.

[Refeeding after ingestion of diets containing 10% soybean protein associated with various concentrations of alginate or sodium carrageenan. Effects on growth and lipid parameters in the rat]. / Renutrition après ingestion de régimes comprenant 10% de protéines de soja associées à diverses concentrations d'alginate ou de carraghénate de sodium. Effets sur la croissance et les paramétres lipidiques chez le rat.

Male 21-d-old Wistar rats were fed over 3 experimental periods. During the first period of 4 wk, diets contained 10% casein or defatted soy flour proteins, with or without 0.5, 1, 2 or 3% sodium alginate or sodium carrageenan, and were heated. During the second period, they were fed a standard diet for 16 wk with 17% proteins, and during the third period, they received the same diet as in the first period, but with 20% proteins. Rat body weights were measured throughout the study period; plasma lipid levels were then determined after fasting. Presence of sodium alginate in the diet had no effect on growth, but rats fed carrageenan presented growth retardation at the end of the experimental period, which was not altered by refeeding the standard diet. Sodium alginate did not modify rat triglyceridemia, except at the 1% level. Carrageenan had a hypotriglyceridemic effect. Alginate and carrageenan had no effect on blood cholesterol. Compared to soybean protein, casein intake did not increase plasma cholesterol levels as generally described. The effect of carrageenans on growth and plasma triglyceride levels could be a result of their physico-chemical properties.

[Effects of alginates and sodium carrageenates mixed with soy proteins on the coefficient of protein efficiency]. / Effets des alginates et des carraghénates de sodium associés aux protéines de soja sur le coefficient d'efficacité protéique (CEP).

Male 21 d-old Wistar rats, were fed for 4 wk with diets containing casein or soybean proteins (10%) with 0.5, 1, 2 or 3% sodium alginate or sodium carrageenan or without any alginate or carrageenan. Daily protein intake and weight gain of casein-fed rats were not significantly different (P less than 0.05) from those of rats fed soybean meal with alginate, whatever the dose received. Rats fed 3% carrageenan in soybean meal had significantly higher feed intake than that of rats fed casein. At the levels studied, alginate had no effect on the Protein Efficiency Ratio (PER), but carrageenan did. The addition of increased quantities of carrageenan to soybean meal followed by heating the mixture led to a progressive and significant decrease in PER at all levels of carrageenan compared to casein feeding. The addition of 3% carrageenan to heated soybean meal, corresponding to 0.62% of meal diet, led to a significant decrease in PER. These results confirm the precipitating role of carrageenans on proteins.

Effect of germinated and heated soybean meals on plasma cholesterol and triglycerides in rats.

Soybean may be useful in diets for the prevention of cardiovascular disease and the treatment of type II hyperlipoproteinemia as it lowers blood cholesterol levels. However, unpleasant organoleptic qualities and the presence of antinutritional substances hinder its use. Some of these problems may be partially solved by germinating the seeds or heating the meals. The effects of the duration of soybean germination and of heating the meal were studied in Wistar rats. Dietary meal composition, plasma cholesterol and triglyceride levels were evaluated after feeding rats with various soybean meal or casein diets containing 10% protein for 6 weeks. Plasma cholesterol and triglyceride levels were 0.81 +/- 0.11 and 0.82 +/- 0.23 g/l respectively after the casein diet and 0.90 +/- 0.10 and 0.51 +/- 0.17 g/l after the raw soybean diet. Soybean germination had a hypercholesterolemic effect (1.05 +/- 0.11 g/l after 5 d). Heating the raw meal or germinated soybean meal did not affect cholesterol levels, though it suppressed the hypotriglyceridemic effect. The triglyceride-lowering effect of soybean was probably caused by the presence of thermolabile substances or by the quantity of food ingested. The unexpected increase in blood cholesterol levels may have been due to the effect of the low dietary protein levels.

Metabolic effects of acarbose in young healthy men.

To explore the long-term metabolic effects of acarbose in man, 6 healthy men (25 +/- 2 years; BMI: 21.6 +/- 2.7) were fed a controlled diet in a metabolic ward for 7 consecutive weeks. After an initial 3-week period to ensure a metabolic steady-state, they received 300 mg/d of acarbose (100 mg before each meal) for the remaining 4 weeks. Stool and urine collections were made over 7 d on weeks 3 and 7. Faecal excretion of water, nitrogen, carbohydrate, fat, zinc, magnesium, copper, chromium, iron, calcium and phosphorus and urinary excretion of nitrogen, urea and calcium were measured. In addition, fasting and postprandial blood glucose and insulin levels, as well as fasting triglycerides, total cholesterol, apolipoproteins (Apo) A-I, A-II, and B, zinc and copper, vitamins A, B1, B2, B6, C, and E concentrations were measured before and at the end of the acarbose period. Weight, food consumption, and water balance were not modified by acarbose. Faecal nitrogen excretion increased significantly but the nitrogen balance remained positive. Faecal excretion of carbohydrate, fat, iron and chromium were significantly increased by acarbose. Apos A-I and A-II decreased significantly. Plasma levels of vitamin B6 increased and vitamin A concentrations decreased with acarbose. This study provides new insights into the metabolic effects of acarbose with respect to nitrogen, mineral and vitamin metabolism.

Long-term influence of a wheat-bran supplemented diet on secretion of gastrointestinal hormones and on nutrient absorption in healthy man.

Responses of gastric inhibitory polypeptide (GIP), gastrin and vasoactive intestinal polypeptide (VIP) to a test meal and also nutrient absorption were measured in five healthy men before and after 1, 3 and 7 weeks of daily ingestion of 20 g of wheat bran added to a normal balanced diet. Basal levels of the three hormones were not affected by bran ingestion. Bran ingestion induced a progressive decrease of GIP response to the test meal which became significant after 7 weeks at 30 min (373.9 +/- 71.4 vs 231.1 +/- 47.8 pg/ml, mean +/- s.e.m., P less than 0.05) and at 180 min (389.4 +/- 43.9 vs 262.2 +/- 37.9 pg/ml, P less than 0.01). Gastrin release did not change except for a slight but not significant decrease after 3 weeks. There was no VIP secretion after meal ingestion and addition of bran caused no change. Blood glucose response decreased with time with the greatest effects during the third week with fibre at 30 min (5.00 +/- 0.50 vs 7.38 +/- 0.05 mmol/l before bran), and at 60 min (3.88 +/- 0.34 vs 5.94 +/- 0.27 mmol/l before bran, P less than 0.05). Wet and dry weight of faeces increased by at least 60 per cent from the first week with bran onwards. Faecal nitrogen and fat also increased from 1.77 +/- 0.16 to 2.44 +/- 0.13 g/d for nitrogen (P less than 0.02) and threefold for fat (from 3.78 +/- 0.58 to 10.35 +/- 0.67 per cent dry weight, P less than 0.005) at the third week. Fat and nitrogen contents remained higher until the end of the experiment.(ABSTRACT TRUNCATED AT 250 WORDS)

[Evaluation of soy bean proteins obtained by pressure]. / Etude d'aliments protéiques a base de soja obtenus par compactage.

Besides the processes of extrusion and protein fiber spinning, analogous utilization research with a range of protein sources is continuing at an accelerated pace. However, the pressure forming process, an attractive process for producing protein foods, has not received the attention as it merits. The fabrication techniques contribute the advantages of nutritional value, economic and simplicity in manufacture; it can be extend to utilize in the development of useful textured vegetable protein foods. Here, we present a pressure forming process for producing protein foods with soybean grains. In this paper, we evaluated the composition, and the yield of the products obtained by this process; the trypsin inhibitor and enzymatic proteolyse of the products were also studied. The product obtained contents soluble and insoluble proteins of soybean, 45 p. 100 of protein (N x 6,25), 20-25 p. 100 of carbohydrates of which the fibers are included; moreover it contents 6-7 p. 100 of ash and 20-22 p. 100 of fat. It does not content any starch, the oligosaccharides and antinutritional factors were almost eliminated. This product presents in acceptable textural form resembling traditional animal protein foodstuffs; its fonctional and nutritional properties can meet different utilizations in foodstuffs such as dietetic products and protein complements.

[Denaturation and enzymatic proteolysis in vitro of protein fractions of soya flour]. / Dénaturation et protéolyse enzymatique in vitro de fractions protéiques de la farine de soja

Soya, in spite of its high nutritional value and moderate cost, possesses certain undesirable qualities which limit its use in animal and human nutrition. The amendment of these qualities has resulted in much work. In this study the effects of technological treatments on the properties of certain protein fractions capable of being produced industrially were observed. Three fractions were prepared from defatted soybean flour of the "Harosoy 63" variety: an acid-precipitated fraction, a cold-insoluble fraction at 0-3 degrees C, and a water-soluble fraction. The properties of the fractions were studied both before denaturation and after denaturation by either heat or alcohol. The degree of proteolysis of each fraction by two digestive enzymes, pepsin and trypsin, was measured by the increase of non-protein nitrogen as a function of time. Several methods were used for electrophoretic analysis. The results showed that the thermal treatment at 100 degrees C and the treatment with varying concentrations of ethanol (from 10 to 100 p. 100) modified electrophoretic diagrams and the solubility of the proteins in trichloracetic acid. Moderate, moist heating of the protein fractions (100 degrees C, 20 mn) before proteolysis by pepsin and trypsin, in general, favored proteolysis. The most marked effect observed was in the acid-precipitated fraction (in which Kunitz inhibitor was concentrated treated by trypsin. Heating the fractions beyond thirty minutes had a negative effect on proteolysis: the level of proteolysis was the same, or in some cases, lower than before denaturation, especially on subsequent treatment with pepsin. The effects of the ethanol treatment were different from that of heat: the proteolysis was accelerated only with the acid-precipitated fraction.