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PubMed2006

The stability of insulin in solid formulations containing melezitose and starch. Effects of processing and excipients.

Solid insulin formulations obtained by different methods of preparation were compared with respect to chemical stability and morphology. Spray- and freeze-drying, solution enhanced dispersion by supercritical fluids (SEDS) and precipitation into starch microspheres were the methods used for preparation of solid powders. The excipients applied were melezitose, starch, and sodium taurocholate. The stability of the samples was evaluated after storage in open containers at 25 degrees C and 30% RH for 6 months. All samples were amorphous after processing and storage as detected by XRD, except for the starch microspheres which were semi-crystalline. The spray- and freeze-dried samples containing melezitose and sodium taurocholate experienced a significant water uptake during storage, resulting in changes in morphology and disappearance of Tg. However, the chemical stability of these samples did not seem to be affected by the water uptake. Changes in morphology were not observed for the SEDS powders and the starch microspheres. The chemical stability of the samples was assessed by HPLC. In general, conventional spray- and freeze drying resulted in samples with higher chemical stability compared to SEDS powders and starch microspheres. Nevertheless, the excipients applied were observed to be of major importance, and further optimization of the formulation as well as processing conditions may lead to slightly different conclusions.

Calorimetry, Differential Scanning↗
PubMed2001

Corn starches as film formers in aqueous-based film coating.

The purpose of this study was to evaluate the film formation ability and mechanical stress-strain properties of aqueous native corn starches, using free films and film coatings applied to tablets. Free films were prepared from high-amylose corn (Hylon VII), corn and waxy corn starches, using sorbitol and glycerol as plasticizers. The tablets and pellets were film-coated using an air-suspension coater, and characterized with respect to the film coating surface topography, cross-sectional structure and thickness (SEM), and dissolution in vitro. The amylose content of the starch film formers affected both the tensile strength and the elongation. The elongations were under 5% for even the plasticized starches, and in most cases, no plasticization effect was seen by either of the plasticizers. Dissolution of native corn starch film-coated tablets (weight gain 1%) did not differ from uncoated ones. A notable delay in dissolution of the drug was found by increasing Hylon VII film coating thickness, suggesting controlled-release characteristics.

Amylose↗
PubMed2002

Multiple sources of sodium starch glycolate, NF: evaluation of functional equivalence and development of standard performance tests.

Sodium starch glycolate is a commonly used super-disintegrant employed to promote rapid disintegration and dissolution of IR solid dosage forms. It is manufactured by chemical modification of starch, i.e., carboxymethylation to enhance hydrophilicity and cross-linking to reduce solubility. It has been reported in the literature that the source of starch, particle size, amount of sodium chloride (reaction by-product), viscosity, degree of substitution and cross-linking affect the functionality of sodium starch glycolate. Compendial assays provide an accurate representation of the chemical quality of an excipient, but they are not useful in describing the physical properties associated with the excipients. Physical characterization of sodium starch glycolate, NF revealed differences in particle size, surface area, porosity, surface morphology, and viscosity between two of the three sources examined. An automated liquid uptake test (in neutral and acidic medium) demonstrated similar initial rates of uptake, however, the extent of liquid uptake differed for the disintegrant powders examined. Settling volume was also observed to be different for the disintegrant from two sources. Lowering the pH of the medium reduced the rate and extent of liquid uptake and the settling volume in all instances. The extent of liquid uptake and settling volume was observed to be higher for the smaller sieve fractions in either medium, Although differences were also observed in the axial and radial disintegration force measurements of the pure disintegrant compacts, disintegration and dissolution of a model drug (hydrochlorothiazide) from either the soluble or insoluble core did not reveal any significant differences between the multiple sources.

Absorption↗
PubMed1966

Geotropic response of wheat coleoptiles in absence of amyloplast starch.

Young coleoptiles of wheat (Triticum durum var. Henry), depleted of amyloplast starch by incubation at 30 degrees C with gibberellin plus kinetin, retained their geotropic responsiveness. Depleted coleoptiles curved upward more slowly than controls, but this was commensurate with their slower growth. The ratio of curvature to growth was about 50 degrees per mm of elongation in both cases. Newly excised coleoptiles, though containing much more starch than incubated controls, curved only about 25 degrees per mm. The tissue treated in gibberellin plus kinetin appeared to contain no starch when examined (a) freshly squashed, (b) as fixed material sectioned thin and stained by the PAS procedure, and (c) as electron micrographs. Shrunken, starch-free amyloplasts could be identified in certain regions, but these did not show evidence of asymmetric distribution under the influence of gravity. The possibilities that other organelles function as statoliths are considered, and it is concluded not only that georeception is independent of starch grains, but further that it may not be due to statoliths at all in an ordinary sense.

Gibberellins↗
PubMed1981

Factors affecting the rate of hydrolysis of starch in food.

After accurate determination of the content of available carbohydrate in a wide variety of cereals, as in vitro method was used to study factors that influence hydrolysis rates of starch in foods. Fiber, physical form, cooking, and the possible presence of a natural amylase inhibitor were all shown to affect hydrolysis rates of starch. Fiber only exerted an inhibiting effect on the rate of hydrolysis when it formed a physical barrier to limit access of the hydrolytic enzymes to the starch (as in whole brown rice, for example). Particle size played an important role in determining the rate of hydrolysis. Cooking made the starch much more readily available for enzymic hydrolysis presumably by gelatinizing it. Stoneground wholemeal flour was hydrolyzed more slowly than white flour. This is consistent with the presence of a natural amylase inhibitor that has been isolated from wheat germ in the whole grain. Our results suggest that such amylase inhibitor activity is destroyed by passage through the roller mill, since the starch in wheat germ and standard wholemeal flour (i.e., not stoneground but reconstituted after passage through the roller mill) was hydrolyzed at a rate identical to white flour.

Amylases↗
PubMed1994

Effect of resistant starch on breath-hydrogen and methane excretion in healthy volunteers.

Colonic fermentation of dietary carbohydrates and fiber might produce a protective effect against the development of large bowel cancer. Resistant starch, ie, starch that escapes small bowel digestion, is a candidate fermentable substrate that has been hitherto little studied. We supplemented 19 healthy volunteers with 15 g native amylomaize (Hylon-VII) three times a day, containing 28 g type II resistant starch, or with dextrins as a placebo for 7 d in a crossover design. Pre-experimentally, 11 subjects regularly produced breath methane and 8 did not. Resistant starch increased 24-h integrated excretion of breath hydrogen. The mean rise relative to placebo was 35% (P = 0.03) for all subjects and 60% for eight subjects not producing methane (P = 0.02). The 11 methane producers showed a 93% increase in breath-methane excretion on resistant starch (P = 0.03). Continued consumption of 28 g type II resistant starch/d is well tolerated and increases colonic fermentation in healthy volunteers.

Adult↗
PubMed2002

Kinetics of ruminal degradation of wheat and potato starches in total mixed rations.

Wheat and potato are rich in starch but their starches differ in their rate of ruminal degradation. Kinetics of in sacco disappearance and profiles of ruminal fermentation were studied for these two concentrates in total mixed rations based on grass silage or corn silage. Wheat starch was more rapidly (34%/h) degraded by rumen microorganisms than potato starch (5%/h). The differences in starch degradation in sacco were found again in the VFA concentrations, mainly in grass silage-based diets. Overall ruminal pH, total VFA concentration, and proportions of acetate, propionate, and butyrate are more variable for wheat during the kinetic (amplitude and quickness) than for potato in grass silage-based diets. In these diets, risks of acidosis were more elevated with wheat than with potato but the VFA concentrations were also higher. These differences of fermentation profile were so reduced in corn silage-based diets that, in this case, wheat can be substituted by potato without any effect on digestion and no risk of acidosis.

Acidosis↗
PubMed1995

Starch, gloves and extradural catheters.

We have investigated contamination of extradural catheters during normal handling with starch powdered gloves. In the laboratory, extradural catheters were handled in sterile fields with both powdered and non-powdered gloves, simulating preparation for patient insertion. The catheters together with glove samples were then examined using a Zeiss 940 scanning electron microscope. Microscopy of samples revealed starch contamination of the catheters handled with powdered gloves, especially in the side hole areas. We conclude that extradural catheters may be contaminated easily by starch powder from surgical gloves. This powder may then be deposited into the extradural space. The effect of starch in the extradural space is not known but starch is known to cause inflammatory and granulomatous reactions in other parts of the body as well as being directly allergenic. Powder contamination of catheters may be avoided easily by the use of powder-free gloves and we feel that these should be used whenever possible.

Analgesia, Epidural↗
PubMed2001

Activities of starch hydrolytic enzymes and sucrose-phosphate synthase in the stems of rice subjected to water stress during grain filling.

To understand the effect of water stress on the remobilization of prestored carbon reserves, the changes in the activities of starch hydrolytic enzymes and sucrose-phosphate synthase (SPS) in the stems of rice (Oryza sativa L.) during grain filling were investigated. Two rice cultivars, showing high lodging-resistance and slow remobilization, were grown in the field and subjected to well-watered (WW, psi(soil)=0) and water-stressed (WS, psi(soil)=-0.05 MPa) treatments 9 d after anthesis (DAA) till maturity. Leaf water potentials of both cultivars markedly decreased during the day as a result of WS treatment, but completely recovered by early morning. WS treatment accelerated the reduction of starch in the stems, promoted the reallocation of prefixed (14)C from the stems to grains, shortened the grain filling period, and increased the grain filling rate. More soluble sugars including sucrose were accumulated in the stems under WS than under WW treatments. Both alpha- and beta-amylase activities were enhanced by the WS, with the former enhanced more than the latter, and were significantly correlated with the concentrations of soluble sugars in the stems. The other two possible starch-breaking enzymes, alpha-glucosidase and starch phosphorylase, showed no significant differences in the activities between the WW and WS treatments. Water stress also increased the SPS activity that is responsible for sucrose production. Both V(limit) and V(max), the activities of the enzyme at limiting and saturating substrate concentrations, were enhanced and the activation state (V(limit)/V(max)) was also increased as a result of the more significant enhancement of V(limit). The enhanced SPS activity was closely correlated with an increase of sucrose accumulation in the stems. The results suggest that the fast hydrolysis of starch and increased carbon remobilization were attributed to the enhanced alpha-amylase activity and the high activation state of SPS when the rice was subjected to water stress.

Amylases↗
PubMed1981

Effect of casein and starch infusion in the large intestine on nitrogen metabolism of growing swine.

Eight crossbred female pigs (40 kg) with cannulae placed in the terminal ileum were used to evaluate the effect of infusions of casein starch and casein plus starch on organic matter fermentation and microbial protein synthesis in the large intestine, and their effect on urinary urea and orotic acid excretion, and on nitrogen (N) retention. Infused casein and starch were both totally digested. Nitrogen retention was increased (P greater than 0.05) when casein was infused. Starch infusion resulted in an increase (P greater than 0.05) in fecal N in the form of total protein (amino acids). The high correlation (P greater than 0.01) between fecal total protein and RNA indicates that the increase in fecal N resulted from an increase in microbial protein synthesis. About 5.2 g of bacterial protein was synthesized per 100 g of cornstarch fermented in the large intestine. Casein infusion increase (P greater than 0.05) total urinary N. Differences between treatments for urinary N were entirely because of changes in urinary urea. Urinary ammonia and unaccounted N were not affected by treatments. Urinary orotic acid was a good indicator of the urea cycle activity because of its hig correlation (P greater than 0.0) with urinary urea. Plasma urea N concentration was increased (P greater than 0.05) only when casein plus starch was infused.

Animals↗
PubMed1986

Influence of sucrose and starch on the development of anemia in copper- and iron-deficient rats.

The purpose of this investigation was to compare the effects of sucrose and starch on the development of copper and iron deficiency. Male Sprague-Dawley rats (n = 48) were fed one of eight diets in a 2 X 2 X 2 factorial design for 24 d. Two levels of copper (deficient, 0.7 microgram/g, or adequate, 8.3 micrograms/g) and iron (deficient, 8.3 micrograms/g, or adequate, 50 micrograms/g), and two types of carbohydrate (sucrose or starch, 62% of the diet) were fed. Copper-deficient rats had significantly lower hematocrit, hemoglobin and tibia iron levels and depressed copper and iron absorption when fed sucrose instead of starch. The apparent absorption of copper, but not iron, was significantly lower when rats deficient in both copper and iron were fed sucrose rather than starch. Iron-deficient rats fed sucrose apparently absorbed significantly more iron than those fed starch; however, sucrose did not significantly improve hematocrit and hemoglobin levels. The metabolism of copper and iron by rats fed diets adequate in these nutrients was not affected by the type of dietary carbohydrate. These data indicate that the type of dietary carbohydrate alters both copper and iron metabolism, particularly in copper-deficient rats.

Anemia↗
PubMed1988

Use of immunoresponsiveness to demonstrate that the dietary requirement for copper in young rats is greater with dietary fructose than dietary starch.

Weaned male Lewis rats were pair-fed diets containing 62.7% fructose or starch and either 6-7 mg Cu/kg diet (adequate) or 0.7 mg Cu/kg diet (deficient) for 33 d. Antibody titers after primary immunization with sheep erythrocytes were significantly lower in rats fed copper-deficient diets. Compared to starch, fructose markedly attenuated antibody production in copper-deficient rats. Dietary carbohydrate did not affect the humoral immune response of rats fed diets with adequate copper. Concentrations of copper in thymus, spleen, liver and heart were also significantly lower in rats fed fructose with deficient copper (F-Cu) than in the group fed starch with deficient copper. Thymic hypogenesis was observed only in the F-Cu group. Tissue concentrations of copper were reduced before antibody production was impaired. Repletion of previously copper-deficient rats rapidly restored immunocompetence and stimulated thymic growth. Immunoresponsiveness and tissue concentrations of copper reached control levels in rats fed diets containing starch and fructose at 1.2-1.6 and 2.2-2.9 mg Cu/kg diet, respectively. The results demonstrate that the amount of dietary copper required for optimal function of the humoral immune system, thymic growth and maintenance of normal tissue levels of this essential micronutrient is greater when young rats are fed diets with fructose than with starch.

Animals↗
PubMed1989

The effects of guar gum or wheat bran on the disappearance of 14C-labeled starch from the rat gastrointestinal tract.

An animal model was used to test the hypothesis that guar gum, a source of soluble fiber, will slow the disappearance of starch from the gastrointestinal tract. Male Wistar rats were adapted for 1 wk to a purified diet and then divided into three groups and given 30 min to consume a test meal. The test meal contained 5% fiber derived from guar gum (GG) or wheat bran (WB) or was fiber-free (FF), and each contained 2.5 microCi 14C-labeled starch. At 1, 2.5, or 5 h postprandial, a group from each dietary treatment was killed, and stomach, small and large intestine and cecum were removed to determine the distribution of radioactivity. The isotope emptied from the stomach at a similar rate for all three groups. The percent ingested dose in the small intestine (SI) was highest in the upper half at 1 h and highest in the lower half at 2.5 h for all groups. The percent ingested dose of 14C-starch was significantly higher from upper SI segments in the GG group than from those in the FF group at 2.5 and 5 h, whereas percent ingested dose did not differ in the upper SI segments in the WB group compared to the FF group at 1, 2.5 and 5 h. These data indicate that a viscous polysaccharide (GG) can delay the disappearance of starch from the SI whereas a source of insoluble fiber (WB) did not slow starch disappearance.

Animals↗
PubMed1993

Rats fed high starch diets have lower colonic proliferation and fecal bile acids than high sucrose-fed controls.

We studied the effects of sucrose or starch in the diet (460 g/kg diet) on fecal bile acid concentrations in Sprague Dawley rats after 4 wk of feeding. Total bile acid concentration in the feces was significantly lower in the rats fed the starch diet than in those fed the sucrose diet (4.56 +/- 0.47 mg/g dry weight and 8.03 +/- 0.94, respectively, SEM), due to a reduction of deoxycholic, alpha-muricholic and beta-muricholic acids. Fecal and cecal pH values were significantly lower in the rats fed the starch diet compared to those fed the sucrose diet (6.79 +/- 0.08 and 7.15 +/- 0.09 for fecal pH and 7.02 +/- 0.05 and 7.2 +/- 0.04 for cecal pH in the two diet groups, respectively). Colon proliferation was also significantly lower in the starch-fed rats compared to those fed sucrose (labeling index 3.51 +/- 0.6 and 5.69 +/- 0.74, respectively), and the reduction was apparent in the middle and upper compartments of the colon crypts. The mucosal proliferation, expressed as percentage of labeled cells in the upper compartment of the colon crypts, was positively correlated with the concentration of deoxycholic, lithocholic, alpha-muricholic, beta-muricholic, cholic and total bile acids in the feces (per gram wet weight). The results indicate a protective effect of starch versus sucrose diets on colon mucosa.

Administration, Oral↗
PubMed1995

Sourdough fermentation or addition of organic acids or corresponding salts to bread improves nutritional properties of starch in healthy humans.

Postprandial blood glucose and insulin responses to barley bread containing organic acids or corresponding salts were evaluated in healthy human subjects. The satiety score and the rate and extent of in vitro starch digestion were also studied. Lactic acid was generated by use of a homofermentative starter culture or added to the dough. In addition, products were baked with Ca-lactate, or with Na-propionate at two different concentrations. Consumption of the product baked with a high concentration of Na-propionate significantly lowered the postprandial blood glucose and insulin responses, and significantly prolonged the duration of satiety compared with all other breads. When subjects consumed the breads baked with sourdough, lactic acid and Na-propionate, their glucose and insulin responses were reduced compared with the wholemeal bread alone. The rate of in vitro amylolysis was reduced only by ingestion of the breads containing lactic acid, suggesting that the beneficial impact of Na-propionate on metabolic responses and satiety was related to effects other than a reduced rate of starch hydrolysis. All bread products had a similar concentration of in vitro resistant starch of 1.3-2.1 g/100 g (starch basis). It is concluded that sourdough baking and other fermentation processes may improve the nutritional features of starch. The results also demonstrate that certain salts of organic acids may have metabolic effects.

Adult↗
PubMed1996

Dietary starch composition and level of energy intake alter nutrient oxidation in "carbohydrate-sensitive" men.

The effect of dietary starch type on components of 24-h energy expenditure (total, sleep, exercise) were examined in 13 hyperinsulinemic and nine control men, aged 28-58 y. Subjects consumed products containing 70% amylopectin or 70% amylose cornstarch for two 14-wk periods in a crossover design. A 10-wk period of starch replacement in the subjects' self-selected diets was followed by a 4-wk controlled feeding period at 100% maintenance energy intake; diets during the last 4 d of the controlled feeding period provided excess energy, i.e., 125% of maintenance energy. Data for insulin, glucose, 24-h energy expenditure and its components, respiratory quotient and nutrient oxidation were analyzed by ANOVA for mixed models. Although insulin and glucose responses to a starch tolerance test remained greater for hyperinsulinemic than for control subjects, both were reduced with high amylose consumption (P < 0.04). No component of energy expenditure was significantly affected by dietary starch or subject type. However, excess energy intake did increase metabolic energy expenditure (P < 0.0001). Protein oxidation increased with excess energy intake when subjects consumed the high amylopectin starch but did not increase in response to excess energy consumption when the high amylose diet was consumed, suggesting increased protein retention. The magnitude of the response in carbohydrate and fat oxidation was blunted in hyperinsulinemic subjects consuming excess levels of the amylose diet. This may be due to an improvement in overall insulin response or to a change in available substrates for oxidation resulting from microbial fermentation.

Adult↗
PubMed1997

Consumption of retrograded (RS3) but not uncooked (RS2) resistant starch shifts nitrogen excretion from urine to feces in cannulated piglets.

To study the effect of resistant starch (RS) on the route of nitrogen excretion, we fed three groups of six cannulated piglets each a diet containing either uncooked resistant starch (RS2 ), retrograded resistant starch (RS3 ) or glucose. The use of piglets with a cannula at the end of the ileum allowed measurement of the amount of nitrogen that entered the colon. Ileal digesta, urine and feces were collected quantitatively and weighed, and dry matter, starch and nitrogen content were determined. We hypothesized that RS2 would lower colonic absorption of nitrogen when compared with RS3 , because RS2 may be more fermentable than RS3 , thus trapping more nitrogen in bacteria. The piglets fed RS3 had a significantly higher production of ileal digesta and feces than the piglets fed glucose or RS2 . In the piglets fed RS2 , 44% of the amount of RS fed was recovered in the ileal digesta; in the piglets fed RS3 , 71% was recovered. Thus, more fermentable material entered the colon in the RS3 -fed piglets than in the RS2 -fed piglets. Virtually no starch was recovered in the feces of any dietary group. Replacement of glucose by either RS2 or RS3 did not affect nitrogen retention but increased fecal nitrogen excretion. Compared with glucose, RS3 but not RS2 reduced urinary nitrogen excretion, mainly in the form of urea, and reduced the amount of nitrogen absorbed by the colon when expressed as a percentage of the amount of nitrogen entering the colon. This study provides evidence that RS3 , but not RS2 , shifts nitrogen excretion from urine to feces in cannulated piglets.

Animals↗
PubMed2000

Coarse brown rice increases fecal and large bowel short-chain fatty acids and starch but lowers calcium in the large bowel of pigs.

Young male pigs were fed a diet formulated from human foods including either boiled white rice plus rice bran or heat-stabilized brown rice at equivalent levels of fiber for 3 wk. Stool and starch excretion were low in pigs fed white rice during the first 2 wk of the experiment. In pigs fed brown rice, their excretion was high during wk 1 but declined in wk 2 while short-chain fatty acid (SCFA) excretion was higher at both times. Large bowel digesta mass, measured during wk 3, was higher in pigs fed brown rice but only in the proximal colon. Large bowel and fecal starch concentrations were higher in pigs fed brown rice but the difference was insufficient to explain the increase in large bowel digesta mass. In pigs with a cecal cannula, digesta starch concentrations were equally higher when white or brown rice was fed compared with the corresponding rice which had been finely milled, indicating that particle size was a determinant of ileal digestibility. Concentrations and pools of total and individual SCFA were higher in all regions of the colon but not the cecum of pigs fed brown rice. Large bowel Ca(2+) concentrations were lower in pigs fed brown rice, suggesting greater absorption. The data confirm earlier findings that brown rice raises large bowel digesta mass and SCFA through greater fermentation of starch but show that starch itself makes a relatively small contribution to digesta and stool mass. Apparently, the rate of passage of digesta is a determinant of the concentrations and pools of SCFA in the distal colon and in feces.

Animals↗