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M Champ

Publications and source records attributed to M Champ.

34 records · Page 2Linked to original sources
PubMed1994

Comparative study of the acute effects of resistant starch and dietary fibers on metabolic indexes in men.

The effect of ingestion of the same amount (30 g) of a resistant starch (lintner) and cellulose on energy expenditure (EE), colonic fermentation (breath-hydrogen test), and blood glucose, insulin, and free fatty acid (FFA) concentrations were compared in seven healthy volunteers in a first experiment. In a second experiment the same indexes were measured in six healthy volunteers after the ingestion of diets composed of 50 g glucose alone or mixed with 30 g lintner, or cellulose, or pectin. In the first experiment no differences between lintner and cellulose were observed on the measured indexes. The notable difference was the increased apparent colonic fermentation with lintner after 6 h. In experiment 2, although insulin response was significantly lower in the pectin-added diet, the results obtained with the four different diets were not significantly different. The metabolic characteristics of lintner were closer to cellulose than to pectin. In conclusion, the acute effect of the ingestion of a resistant starch (lintner) on the measured metabolic indexes is similar to that of a known insoluble fiber--cellulose.

Adult↗
PubMed1994

Role of viscous guar gums in lowering the glycemic response after a solid meal.

The aim of the present study was to investigate how guar gum viscosity acts on starch digestion and glucose absorption in humans. Six healthy subjects received a mixed diet composed of 60.4% carbohydrate in the form of maize glucose or pregelatinized starch, to which was added 5.6% low- or high-viscosity guar gums. Meals were ingested or instilled in the duodenum and postprandial insulin and glucose responses were monitored for 3 h. Infusion of meals containing glucose showed that the delay in the diffusion rate to the duodenal mucosa due to bolus viscosity was not significant. Infusion of meals containing starch showed that a decrease in the digestion rate of starch in the upper small intestine accounted for part of the effect of viscosity on glycemic response, whereas the main effect of guar gum was apparently to slow gastric emptying.

Adult↗
PubMed1993

Effects of colonic fermentation on respiratory gas exchanges following a glucose load in man.

Colonic fermentation produces short-chain fatty acids (SCFA). In humans, the amount of energy produced from the oxidation of these compounds is unknown and could modify the metabolic utilization of energetic fuels (eg, carbohydrates and lipids). If it were so, the equations used to evaluate the oxidation of nutrients from indirect calorimetry data should include the contribution of SCFA, which is not usually the case. Indeed, this fermentation process is usually considered as a minor and neglected energetic pathway. In this study, we have addressed the reliability of this assumption. Six normal subjects received orally either 50 g glucose or 50 g glucose plus 20 g lactulose. Their respiratory gas exchanges, breath hydrogen, methane, and 13CO2 concentrations, and plasma glucose, insulin, and free fatty acid (FFA) concentrations were monitored for 8 hours. CO2 production and breath hydrogen concentration were significantly greater with lactulose. No differences in oxygen consumption, breath 13CO2 production, or plasma concentrations of blood glucose, FFA, and insulin could be found between the two experiments. This suggests that the fermentation process induced by lactulose generates extra fuels going through an oxidation pathway. Therefore, the classic equations used to calculate carbohydrate and lipid oxidation and energy expenditure (EE) from indirect calorimetry data are probably not valid when fermentation is taking place. Indeed, in this experiment we could have overestimated glucose oxidation (12.5%) if the fermentation process were not considered. In conclusion, colonic fermentation in humans of nondigestible carbohydrates produces energetic substrates that could be used and oxidized as energetic fuels.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1993

Influence of particle size and sources of non-starch polysaccharides on postprandial glycaemia, insulinaemia and triacylglycerolaemia in pigs and starch digestion in vitro.

Physico-chemical properties of dietary fibres might be involved in metabolic control, particularly of the postprandial blood glucose response. The aim of the present study was to look at the effects of the content of soluble fibres and of the particle size of solid fibres on in vitro and in vivo starch hydrolysis and on the subsequent glucose absorption as well as the triacylglycerolaemia. Two sources of dietary fibres, one, with soluble fibres (beet pulp), the other with mostly insoluble fibres (wheat bran), were added at the rate of 60 g/kg to a meal simulating human food. The fibre sources were ground in order to obtain two different particle sizes (250 and 500 microns). Beet pulp decreased significantly (P < 0.05) initial in vitro hydrolysis whereas wheat bran increased starch hydrolysis in the first 10 min. Wheat bran and beet pulp, whatever its particle size, lowered the post-prandial triacylglycerol response. No significant effect was found with dietary fibre-supplemented diets on postprandial glycaemic and insulinaemic values. High correlation was found between initial in vitro starch hydrolysis and mean areas under the insulinaemic curves. This in vitro model can be used to predict initial in vivo digestion of carbohydrates from complex foods.

Animals↗
PubMed1993

Structural features of resistant starch at the end of the human small intestine.

Structural features of in vivo resistant starch were assessed using the ileal contents of four humans. Two of the latter were collected by ileostomy after ingestion of bean flakes or potato flakes and the other two were collected by an intubation technique after ingestion of retrograded high-amylose maize starch or complexed high-amylose maize starch. The degree of polymerizations (DP), solubility and crystallinity were assessed. For all samples, starch fractions which escaped digestion in the small intestine were composed of three populations of alpha-glucans with proportions differing according to the substrate. Small quantities of oligosaccharides made up the first population, illustrating a limitation of absorption in the small intestine. The second population, the main resistant fraction, was comprised of retrograded amylose of mean DPn of about 35 glucose units with a melting temperature at 150 degrees C and exhibiting a B-type pattern. Finally high molecular weight semi-crystalline alpha-glucans were attributed to fragments of starch. This study showed that some potentially digestible starch could reach the colon and crystalline fractions constituted only part of the starch that escaped digestion in the human small intestine.

Crystallization↗
PubMed1992

Determination of resistant starch in foods and food products: interlaboratory study.

A collaborative study was conducted to compare methods of determining resistant starch (RS) in various foods and food products. Principally, two methods derived from Berry (1986, Journal of Cereal Science, 4, 301-314) (method A) and Björck et al. (1986, Journal of Cereal Science, 4, 1-11) (method B) were used to analyse four samples containing various forms of RS. Several methods were also used to determine total starch. The RS yield by method A compared to method B was higher in all samples except unmilled bean flakes. When the starch was a raw B-type (potato starch), method B failed to detect any RS because of its initial heating step, whereas method A yielded 48% RS on an 'as is' basis.

Dietary Fiber↗
PubMed1991

Comparative continuous-indirect-calorimetry study of two carbohydrates with different glycemic indices.

Six healthy young men were studied by indirect calorimetry for 6 h after eating a meal composed of glucose or manioc starch (equivalent to 50 g dextrose). Blood was drawn every 30 min for 6 h to measure plasma glucose, free fatty acid (FFA), and insulin concentrations. The glycemic index of the starch was 57%. Plasma insulin and glucose concentrations were significantly higher from 150 to 210 min and FFA concentrations remained significantly lower from 210 to 360 min after starch than after glucose. Carbohydrate oxidation rose from a similar initial concentration for glucose and starch, to a constant concentration until 200 min before becoming significantly higher for the starch load until the end of the test. Total glucose oxidation was significantly higher with starch. Total fat oxidation did not differ after the two loads. A negative correlation was found between glucose oxidation and plasma FFA concentrations. Use of low-glycemic-index carbohydrates increases carbohydrate oxidation because of lower plasma FFA concentrations and fat oxidation.

Absorption↗
PubMed1990

Action of guar gums on the viscosity of digestive contents and on the gastrointestinal motor function in pigs.

The apparent viscosity of three test meals containing 6% of different guar gums was measured in the gastric, duodenal and jejunal contents and related with the gastrointestinal myoelectric activity and transit time in pigs. The motility index (mV/min) and the spike burst frequency (number of spike bursts/min) were closely related to the digesta viscosity: they were significantly increased by most viscous contents in stomach and small intestine. This effect was associated with an increase in the orocecal transit time of liquids and solids.

Animals↗
PubMed1987

Effect of pelleting and associations with maize or wheat on the nutritive value of smooth pea (Pisum sativum) seeds in adult cockerels.

Four types of diet were tested: 960 g maize/kg (M), 960 g wheat/kg (W), 463 g maize added to 497 g of smooth peas/kg (PM) and 463 g wheat added to 497 g smooth peas/kg (PW). Three treatments were applied to each of these 4 diets: grinding (OP), one steam pelleting (1 P) and two successive steam pelleting (2 P). The pelleted diets were ground before feeding. Adult cockerels received all the diets whereas rats received only W and PW diets. Apparent metabolisable energy values corrected for N-equilibrium (AMEn), protein and starch digestibilities were measured in adult cockerels. Digestible energy (DE) values were measured in rats. The AMEn values of cereals remained practically unchanged by pelleting, whereas that of smooth peas was increased by between 1.8-4.6% after pelleting. Pelleting also induced 3.5 and 5.4% increases respectively in the digestibilities of pea protein and starch. Pelleting did not change the DE values measured in rats. The AMEn values of smooth peas mixed with maize were 4.6% higher than those of smooth peas mixed with wheat. The true digestibility of pea protein was 8.4% higher in the former mixture, whereas the pea starch digestibility remained unchanged. Calculation showed that most of the pea AMEn variations could be explained in terms of variations in protein and starch digestibilities.

Animal Feed↗
PubMed1985

[Carbohydrate digestion in monogastric animals].

The main dietary carbohydrates are starch, cell wall polysaccharides (cellulose, hemicelluloses and pectins), some monosaccharides (glucose, fructose, galactose, etc.) and oligosaccharides (sucrose, lactose, alpha-galactosides, etc.). Recent analytical methods applied to these substances are described and criticized. A-type starches (cereals), cooked starches and some oligosaccharides are mainly digested in the small intestine of monogastric animals by enzymes of the salivary glands, pancreas and intestinal brush border. The total digestibility of these carbohydrates is almost 100%, whereas it is less than 70% for B-type starches (ex. potato). Cellulose, hemicelluloses, pectins and some oligosaccharides are partly digested by the microflora of the large intestine. Fiber total digestibility varies considerably and depends on the nature of the fiber and the animal species. It is less than 10% in chickens, whereas pigs seem to digest fibers as well as sheep. Hydrothermic treatments usually have no effect on starch digestibility but can be used for B-type starches. Some chemical treatments may improve fiber digestibility in monogastric animals.

Animals↗
PubMed1983

Amylase production by three Lactobacillus strains isolated from chicken crop.

Three amylolytic Lactobacillus strains designated LEM 220, LEM 207 and LEM 202 were isolated from the chicken crop. They belonged to the subgenus Thermobacterium. Strain LEM 220 resembled Lact. acidophilus. Amylase production was more abundant in cells grown in media containing amylopectin or starch than in media containing glucose or maltose. Optimum pH and temperature of the amylase were 5.5 and 55 degrees C respectively. Hydrolysis of amylopectin gave maltose, maltotriose and small amounts of glucose. Stain LEM 207 also resembled Lact. acidophilus, but differed from strain 220. It had a lower amylase activity. Optimum pH and temperature of the amylase were 6.4 and 40 degrees C, respectively, and hydrolysis of amylopectin gave maltose, maltotriose and carbohydrates higher than maltopentaose. Strain LEM 202 was similar to Lact. vitelinus. It had the lowest amylase activity which was increased only in presence of maltose. Amylase properties were similar to those of LEM 220.

Amylases↗
PubMed1981

The influence of microflora on the breakdown of maize starch granules in the digestive tract of chicken.

Influence of the microflora on the extent of degradation of starch in the chicken digestive tract has been studied by scanning electron microscopy. Axenic (germfree), holoxenic (conventional), and monoxenic (only one germ) chickens inoculated with two strains of lactobacillus (strains 220 and 207) isolated from the crop of the cock were used in these experiments. In vitro starch granules were less hydrolyzed by strain 207 than by strain 220. A more extensive degradation was observed when starch was included in feed. This breakdown resulted in formation of cavities and pin holes in the starch granules. In vivo starch granules in the crop of holoxenic and monoxenic chickens were scarcely damaged and erosion was always superficial. In monoxenic 207 chicken as in holoxenic ones, bacteria were fixed on the crop wall. In feces, the pattern of the breakdown was dependent on the type of animal. These results demonstrated the role of the total microflora in the breakdown of starch and the specific intervention of the two strains of lactobacilli.

Animals↗
PubMed1980

[Role of five Lactobacillus strains on carbohydrate degradation in monoxenic chickens].

Five strains of Lactobacillus were isolated in holoxenic roosters; two of these which had an alpha-amylase were inoculated separately into 5 groups of axenic chickens fed the same diet. Some differences among these 5 groups were noted. Lactobacillus proliferation varied between ten and a thousand-fold, depending on the strain, and for the same strain depending on whether the crop, caecum or faeces was examined. Amylolytic lactobacilli in vivo played a role in starch degradation in various ways related to the specific properties of their amylase. Lactic acid production in the crop was higher with the three strains producing the two lactic acid isomers than with the two strains producing only one of the isomers. Finally, monoxenic caecal digestion was different from that of both the axenic and the holoxenic.

Animals↗
PubMed1976

[Formation of nitrosamines in the digestive tract].

Nitrosamines are carcinogenic compounds synthetized from amines and nitrites or nitrates, if nitrates in the reaction medium may be reduced to nitrites. Nitrosation is determined in the digestive tract of several species of laboratory animals. Two physiochemical factors appear to determine in vitro nitrosamine formation: the type of amine and the medium pH. The property of secondary amines to nitrosate is inversely related to amine basicity (checked in vivo), and it increases with the medium acidity. In vitro studies show that different types of bacteria can, even at neutral pH, catalyze nitroamine formation from their precursors. However, the role of digestive tract microbial flora in nitrosamine synthesis in the gut cannot be affirmed due to lack of in vivo studies.

Amines↗
PubMedDate not supplied

Digestion of starch and glycaemic response to mixed meals in pigs.

The digestion in the proximal intestine of mixed meals (5,160 kJ) containing either native (NS) or pregelatinized (PS) maize starches (approximately 200 g), and the postprandial glycaemic responses they induced were compared in pigs. For both meals, approximately 25% of the ingested starch was assimilated above the duodenal cannula (positioned 75 cm beyond the pylorus). Larger amounts of starch were collected for NS than for PS during the first 30 min. The glycaemic responses, however, indicated a higher rate of glucose absorption for PS during the first 30 min, which could be explained by the higher susceptibility of PS to hydrolysis, as we observed in vivo. Indeed, malto-oligosaccharides (G1-G3) represented almost 80% of the total alpha-glucans collected at 150 min in the duodenum after the PS meal. At that time, after the NS meal, only 30% of the alpha-glucans were malto-oligosaccharides. Thus, even after a mixed meal, the starch digestion rate can alter the observed postprandial glycaemic response.

Animals↗