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Biomedical subjects

B Poullain

Publications and source records attributed to B Poullain.

12 recordsLinked to original sources
PubMed1979

The effect of dietary sulfur-containing amino acids on the activity of drug-metabolizing enzymes in rat-liver microsomes.

Male Wistar rats were fed either a balanced diet whose protein source was a mixture of amino acids (diet 1), or a similar diet which differed only in having 48% less the quantity of the sulfur-containing amino acids methionine and cystine (diet 2). The diets were given either continuously for 1 month or for 15 days after a protein-free diet. Both diets 1 and 2 permitted good growth of rats and relatively stable microsomal protein content. Protein depletion decreased the total proteins, total phospholipids, and cytochrome P-450 content, and it strongly increased UDP-glucuronosyltransferase activity in rat-liver microsomes. Repletion with diet 1 restored those values, to the level found in control rats. However, diet 2, given continuously induced an increase in UDP-glucuronosyltransferase activity and in the cytochrome P-450 concentration. Since high UDP-glucuronosyltransferase activity was related to lessened amounts of sulfur-containing amino acids in the diet, we discuss the possible effect of methionine and cystine on the regulation of glucuronoconjugation in relation to sulfoconjugation.

Amino Acids↗
PubMed1978

[Evaluation of soy bean proteins obtained by pressure].

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.

Kinetics↗
PubMed1978

[Nutritional study of spun soy proteins].

Most of metabolic studies in man concerning the ability of soya proteins to obtain an equilibrated nitrogen balance have been made with extruded products. Because of the extending development of spun proteins, it seems necessary to study the protein quality of this type of product. A preliminary study in rat (C.E.P. method) was conducted to improve the nutritional value by complementation of the fibers by the way of binder. The metabolic utilization of this protein was evaluated in human subjects during two periods of 10 days. Soya protein cover respectively 78 and 48% of the total protein intake. Under these experimental conditions in which soya proteins constitute an important percentage of the total protein intake, the mean nitrogen balance is near to be equilibrated and the nitrogen utilization does not present any significative difference between the periods. Parallely to the suppression of animal proteins, the introduction of insatured lipids in the diet, has allowed, moreover, to decrease the concentration of the lipidic parameters of the subjects. This study demonstrated the dietetic interest and the ability of the studied product to provide the supplying of the nitrogen balance.

Animals↗
PubMed1978

[Effect of the extrusion process on the availability of proteins].

The extrusion process has grown rapidly as in the preparation of meat-extenders from vegetal proteins as in the fabrication of cocktail-snacks and food for breakfast. The nutritional modifications induced by the thermic shock during the extrusion affect: -the diminution of the content of nutrient: loss in vitamins, destruction and unavailability of amino-acids; -the structural modification of a few compounds: starch gelatinization; -destruction of antinutritional factors: essentially antitrypsic factor. We studied the effect of extrusion with a model-mixture on the availability of amino-acids and particularly lysin. We effected the systematic study of different factors which can interfer in the intensity of the Maillard reaction in relation to the composition of the mixture (presence and nature of sugar, etc.) and to the technological parameters (screw-section, moisture of the mixture, etc.) The model mixture composed of cereal flours shows a global loss of 32 p. 100 in lysin (destruction 18 p. 100, biological unavailability 16 p. 100) after extrusion. When this mixture is added up with 7,2 p. 100 of saccharose the total loss in lysin reaches 40 p. 100. If saccharose is substituted by a more reducing sugar (fructose) the lysin loss approaches 80 p. 100. The addition of 4 p. 100 water at the mixture containing saccharose (total moisture 14 p. 100) limits the lysin loss to 10 p. 100. The modification of other technological parameters does not improve significatively the level of available lysin. The moisture of the mixture before extrusion appears to be a preponderatting factor in the intensity of the Maillard reaction during extrusion.

Amino Acids↗
PubMed1978

[Relase of organochloride pesticides during acute weight losses (author's transl)].

The increase of blood organochloride pesticide levels and the urinary excretion have been determined in 4 human subjects undergoing a caloric restriction sequence (500 total K. calories per day) followed by a total starvation period of 36 hours. The severe lipolysis due to the caloric restriction causes an important liberation of fat-soluble pesticides especially DDT and DDE (30 ppb of total DDT equivalents) and an increase of urinary excretion (15 ppb of total DDT equivalents).

Adult↗
PubMed1977

[Influence of prolonged protein-free diet on the amino acid content of blood and muscles in rats].

The influence of a protein-free diet in adult male rats has been evaluated for a 6-week period. Nitrogen retention, hepatic protein and free amino acid content in blood and muscle were determined as adaptation criteria. Long-lasting protein depletion did not modify the pattern of response affering in a shorter period: i.e. sparing of nitrogen and use of endogenous amino acids for protein synthesis. Except for lysine, arginine and histidine, the essential amino acids decreased in blood and the non-essential acids increased. The final effect was a decrease of the essential to non-essential amino acid ratio and a decrease in all amino acids in muscle.

Adaptation, Physiological↗
PubMed1976

[Nitrosamines. Review].

Nitrosamines are an extremely carcinogenic class of compounds. The hasard, bound with the occurrence of this compounds in the food and the possibility to be formed in vivo, during the digestion, justifies the current works. The authors quoting numerous works on different laboratory's animals, remind the toxicity. and carcinogenicity of this compounds. The metabolism is also discussed. The N-nitroso, compounds may be formed in food from the presence of the precursors (nitrite or nitrate, amines and amino-acides). The synthesis takes place during the technological processes, the storage and the house cooking. Today, the marginal effect dose is estimated as 10 mug/kg of daily food. The carcinogenicity has not been demonstrated in human, but is strongly suspected. The amount of N-nitroso compounds in human food is generally low. Many factors can influence the reaction; it is inversely related to the basicity of secondary amine and optimum pH is around pH 4. A lot of compounds such as sodium ascorbate inhibit the synthesis in food. A number of recent reports using reliable methodology have identified nitrosamines at the lower part per billion level. Dimethyl-nitrosamines occurs, very sporadically in a number of cooked meat samples. The nitrosopyrrolidine appears frequently in fried but not in uncooked products. The nitrosopiperidine seems to be bind with the presence of pepper in food. Finally the presence of nitrosamides (nitrososarcosine) and nitrosoaminoacides (nitrosoproline, nitrosohydroxy-proline) is being quested. The N-nitroso compounds may be synthetized in vivo during the digestion at the acide medium of the stomach or by bacterial action during the transit in the gut...

Amino Acids↗
PubMed1975

[Nutritional value and acceptibility of soy proteins in human diet].

These studies on textured soya protein (TSP) were directed towards the evaluation of its acceptability and nutritional value in man. ACCEPTABILITY. In the beginning, the reaction of adults to the incorporation of 40 g TSP in their daily diet was studied. After a three-week period, no intolerance or fatigue with the regim was shown. In a following study, observations made on young children's attitudes along with quantitative measurements of their food intake were noted during four one-wekk periods: -- period of "imposed diet", without TSP; -- period of imposed diet", with TSP; -- period of "free diet", without TSP; -- period of "free diet", with STP; During the periods of "imposed diets", children could eat only the proposed quantities of foodstuffs. During periods of "free diets", children were able to choose the quantity and sort of food they preferred from the proposed menu. Total protein ingested (differentiating between that of animal and vegetable origin) was calculated for each child from his daily food record. Results show that only one of the twenty-four children systematically refuse soya-containing preparations. Average consumption of soya protein during "free diet" periods was close to the desired level and not significantly different to levels achieved in the "imposed diet" period. The acceptance of TSP by the children was therefore evident. NUTRITIONAL VALUE. The following studies were designed to determine the effects of the replacement of animal protein by TSP (at the maximal levels of its tolerability) in a normal diet. In the first nitrogen balance study, with 10 convalescent subjects, the following protocol was developed: -- the habitual caloric and protein intakes of the subjects was established; -- following a four-day adaptation period, the subjects entered consecutively: a control period at established levels of calories and protein, and a test period in which 20 g of soya protein replaced an equivalent quantity of animal protein. The average nitrogen balances for control and test periods were + 4.49 g and 3.62 g. The difference not being significant at a probability of 5 p. 100. In a second study with 12 adults in good health (6 males and 6 females) soya protein replaced 34-39 p. 100 of the daily protein intake (according to the menu) and the average nitrogen balances in control and test periods were + 0.16 g and 0.91 g. These studies confirm the TSP replacement of animal protein in the normal diet does not affect nitrogen balance and that TSP can make a contribution to the fulfilment protein requierements in man.

Adult↗