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Cycloamylose (cyclodextrin) glucanotransferase degrades intact granules of potato raw starch.

Cycloamylose (cyclodextrin) glucanotransferase (EC 2.4.1.19, CGTase) originated from Bacillus macerans degraded intact granules of potato raw starch and converted them into cyclodextrins (CDs). The degradation required sufficient stirring of starch-CGTase suspension. The morphology of the degraded starch granules was unique; that is, the inner part of the granules was observed by scanning electron microscope to be more susceptible to CGTase than the outer part. Effects of pH, temperature, starch concentration, and enzyme amount on CD production were studied.

Chromatography, High Pressure Liquid↗

Interactions between drug substances and excipients. 1. Fluorescence and HPLC studies of triazolophthalazine derivatives from hydralazine hydrochloride and starch.

The strength of hydralazine hydrochloride (I) 10 mg tablets, containing starch as an excipient, decreases significantly with time. An investigation to determine the basis for the drop in strength showed that starch exposed to the drug exhibited fluorescence at 414 nm. As model compounds IIIa and V, which contain a triazolophthalazinyl moiety, also fluoresce at about 414 nm, it is proposed that the emission is due to a triazolophthalazine derivative (IIIc) resulting from hydralazine hydrochloride and starch. Degradation of IIIc generates s-triazolo[3,4-a]phthalazine (IIIb), and a small amount of IIIb is detected in aged tablets. IIIc in aged tablets can be converted to IIIb by acid-catalyzed hydrolysis. The quantity of IIIb determined by HPLC amounts to most of the "missing" hydralazine hydrochloride. The reaction between hydralazine hydrochloride and starch is believed to cause the unexpected drop in the strength of hydralazine hydrochloride tablets.

Chromatography, High Pressure Liquid↗

Starch nanocrystals with large chain surface modifications.

Nanoscale monocrystalline starch particles were successfully modified using stearic acid chloride and poly(ethylene glycol) methyl ether. Surface modification was confirmed using FTIR, XPS spectroscopy, and contact angle measurements. X-ray diffraction and DSC analysis confirmed that there was no alteration of the starch crystalline structure due to the surface modification. The grafts at the starch surface were also found to crystallize on the surface. TEM showed the individualization of nanoparticles as a result of the reduction of polar and hydrogen bonding forces. These results show our ability to modify the starch nanocrystal surface with plasticizing chains. Modified nanoparticles can find applications as compatibilized polymer additives, surface-active particles, and co-continuous nanocomposite precursors.

Calorimetry, Differential Scanning↗

Structural characteristics of corn starches extruded with soy protein isolate or wheat gluten.

Commercially available corn starches containing 0, 25, 50 and 70% amylose were extruded with 10, 20 and 30% soy protein isolate (SPI) or wheat gluten (WG) at 22% moisture content (dry basis) in a C.W. Brabender single screw laboratory extruder using a 140 degrees C barrel temperature and a 140 rpm screw speed. True, solid and bulk densities; percent total, closed and open pores; and shear strengths of the extrudates were determined. The microstructures of the extrudates were studied by scanning electron microscopy (SEM). The total pores of the extrudates were affected significantly (p > F = 0.0001) by type of protein (SPI or WG) and starch amylose. The open or closed pores, were affected by protein type only. The interaction between amylose and protein contents was highly significant (p > F = 0.0001). In general, the total pores and bulk densities were higher for WG-starch extrudates compared to SPI-starch extrudates. These values decreased as amylose content increased from 0 to 25% and then increased thereafter. The open pores, on the other hand, increased with increasing protein content from 10 to 20% and then decreased. Extrudates containing WG had higher shear strengths than those containing SPI.

Amylose↗

Effect of resistant starch on potential biomarkers for colonic cancer risk in patients with colonic adenomas: a controlled trial.

Resistant starch decreases the concentration of secondary bile acids in the feces and the proliferation rate of colonic mucosal cells in healthy volunteers. This may reduce the risk of colon cancer. We investigated 23 patients with recently removed colonic adenoma(s) in a controlled parallel trial. They consumed 45 g of maltodextrin per day as placebo for four weeks and were randomly assigned to either 45 g of native amylomaize starch, containing 28 g of resistant starch type II or 45 g of maltodextrin for another four weeks. No effect on colorectal cell proliferation, fecal wet and dry weights, pH, and short-chain fatty acid excretion was seen. The bile acid concentration in fecal water decreased by 15% (P = 0.048) and the percentage secondary bile acids decreased by 14% (P = 0.002) on resistant starch relative to placebo. Whether this has a substantial role in colon cancer prevention in these patients remains to be established.

Adenoma↗

Oscillation of mRNA level and activity of granule-bound starch synthase I in Arabidopsis leaves during the day/night cycle.

Granule-bound starch synthase (GBSSI) is one of the most extensively studied enzymes of the starch synthesis pathway and its role in the synthesis of amylose has been well established. However, few studies have been carried out to characterize the regulation of GBSSI gene. Regulation of starch synthesis genes is especially interesting in photosynthetic tissues, where starch is subjected to a periodical alternation of synthesis and degradation during the day/night cycle. In this report we show a circadian oscillation of GBSSI mRNA levels in leaves of Arabidopsis during the day/night cycle, and provide evidence that GBSSI expression is controlled by the transcription factors CCA1 and LHY. Over-expression of both CCA1 and LHY genes causes the elimination of GBSSI mRNA oscillation. Binding shift assays indicate that this control may be exerted through a direct interaction of those regulatory proteins with the GBSSI promoter. Oscillation is not observed on the GBSSI protein levels, which remains constant along the cycle. However, GBSSI activity shows a clear oscillation with a period of 24 h that is altered in transgenic plants over-expressing CCA1. Possible mechanisms controlling GBSSI activity during the day/night cycle are discussed.

Arabidopsis↗

L-Lactic acid production from raw cassava starch in a circulating loop bioreactor with cells immobilized in loofa (Luffa cylindrica).

L-Lactic acid was produced from raw cassava starch, by simultaneous enzyme production, starch saccharification and fermentation in a circulating loop bioreactor with Aspergillus awamori and Lactococcus lactis spp. lactis immobilized in loofa sponge. A. awamori was immobilized directly in cylindrical loofa sponge while the L. lactis was immobilized in a loofa sponge alginate gel cube. In the loofa sponge alginate gel cube, the sponge serves as skeletal support for the gel with the cells. The alginate gel formed a hard outer layer covering the soft porous gel inside. By controlling the rate and frequency of broth circulation between the riser and downcomer columns, the riser could be maintained under aerobic condition while the downcomer was under anaerobic condition. Repeated fed-batch L-lactic acid production was performed for more than 400 h and the average lactic acid yield and productivity from raw cassava starch were 0.76 g lactic acid g(-1) starch and 1.6 g lactic acid l(-1) h(-1), respectively.

Aspergillus↗

Role of dietary starches in induction of immune cells apoptosis in Wistar rats.

We compared the effects of maize and potato starch on Wistar rats. The level of oligonucleosomal DNA fragmentation increased in thymic and splenic cells of animals receiving potato starch. The expression of Fas/CD95/Apo-1 apoptosis receptor in lymphocytes and their response to exogenous ceramide was also higher in rats receiving potato starch compared to the reference group. This led to intensification of spontaneous and induced apoptosis and decreased cell content in immune organs. The authors conclude that higher resistance of potato starch to digestive enzymes leads to modification of cell metabolism and induction of ceramide-dependent apoptosis in immune cells.

Animals↗

Retrograde migration of starch in the genital tract of rabbits.

This study in a rabbit model simulates contamination with glove powder in association with a routine gynaecological examination. Large individual variations of powder contamination were found and there were no overall statistically significant differences between the control and experimental animals. The findings are supported by the observation that some but not all women develop adhesions after gynaecological surgery. Analyzes of variances indicate differences in the migration of starch particles in the genital tract with the highest amount of particles found three days after starch contamination of the vagina. Since no adhesions were observed, there would probably need to be an ongoing post surgical or post infectious inflammation in the tissue, when the starch particles are added. Starch powder from latex gloves can cause adhesions and increase the risk of latex allergy in healthcare workers. Retrograde migration in the genital tract cannot be excluded, powdered examination products should be eliminated from the gynecologicla examination room.

Animals↗

Immunologic significance of respirable atmospheric starch granules containing major birch allergen Bet v 1.

BACKGROUND: Birch-pollen allergens are an important cause of early spring hay fever and allergic asthma. Recently, we reported a mechanism for the release of respirable allergenic particles from birch pollen containing the major allergen Bet v 1. In this study, we aimed to assess the immunologic significance of the released Bet v 1-containing starch granules in the environment. METHODS: A two-site monoclonal antibody-based assay (ELISA) was employed to quantitate Bet v 1 in high-volume air sampler filter extracts, and immunogold-labelling was used on sections of these extracts to localize Bet v 1. Immunoblot analyses were performed with pooled sera from patients sensitive to birch pollen. RESULTS: Atmospheric starch granules contained Bet v 1, and the concentration increased upon light rainfall. Sera from patients allergic to birch allergens recognized extracts from isolated starch granules. CONCLUSIONS: The clinical implications of these findings are that starch granules released from birch pollen are potentially able to trigger allergic asthmatic reactions to Bet v 1, since the allergen occurs in respirable particles. Thus, clinicians can advise asthma patients to remain indoors on days of light rainfall during the birch-pollen season to avoid high levels of allergen exposure.

Air Pollution↗

Retrograded high-amylose corn starch reduces cholic acid excretion from the small bowel in ileostomy subjects.

OBJECTIVE: To study the short-term effect of resistant starch (RS) from retrograded high-amylose corn starch (HACS) on the excretion of bile acids and nutrients from the small bowel in humans. DESIGN: Seven healthy ileostomists were given a controlled, constant diet during three days. On days 2 and 3, 100 g/d of one of two test-products--drum-dried ordinary corn starch and autoclaved retrograded HACS, providing 5 and 39 g RS/d, respectively--was given, in random order. Ileostomy effluents were collected for 24 h per day and analysed for wet weight, dry weight, energy, bile acids and nutrients. SETTINGS: In-patient study at the metabolic ward, Department of Clinical Nutrition, Sahlgrenska University Hospital, Göteborg. RESULTS: Consumption of retrograded HACS caused (1) a 42% lower mean excretion of cholic acid (P = 0.024); (2) a 42% lower mean wet weight concentration of bile acids (P < 0.001); (3) a 70% increased excretion of dry weight (P = 0.001); and (4) a 41% increased excretion of energy (P= 0.036) compared with consumption of drum-dried ordinary corn starch. CONCLUSION: The reduced ileal excretion and concentration of cholic acid would be protective regarding colon cancer risk in addition to the increased fermentation substrate provided by RS and other energy-yielding components.

Adult↗

Replacement of dietary fat by sucrose or starch: effects on 14 d ad libitum energy intake, energy expenditure and body weight in formerly obese and never-obese subjects.

OBJECTIVE: To investigate the impact of a high-sucrose diet vs a high-starch and a high-fat diet on 14 d ad libitum energy intake, body weight, energy expenditure and sympathoadrenal activity. MEASUREMENTS: Food intake; body weight and composition (bioelectrical impedance); 24 h energy expenditure, substrate oxidation rates, spontaneous physical activity, heart rate and appetite sensations in a respiration chamber (VAS scores); plasma catecholamine concentration and blood pressure. SUBJECTS: Twenty normal-weight, healthy women, 9 post-obese (body mass index (BMI): 22.9 +/- 0.7 kg/m2) and 11 closely matched controls (BMI: 22.6 +/- 0.4 kg/m2). RESULTS: Average 14 d ad libitum energy intake was 13% and 12% lower on the starch diet compared with the sucrose and fat diets, respectively (P < 0.05). In both post-obese and normal-weight subjects, body weight and fat mass decreased significantly on the starch diet (by 0.7 +/- 0.2 kg and 0.4 +/- 0.1 kg, respectively, P < 0.05). No changes were observed on the fat or sucrose diets. After 14 d on the sucrose diet, 24 h energy expenditure as well as postprandial plasma adrenaline and noradrenaline concentrations, were significantly increased compared with the other two diets. Overall satisfy and palatability ratings were also highest on the sucrose diet. CONCLUSION: Intake of a 14-d ad libitum high-starch diet decreased energy intake and body weight compared with a high-fat or high-sucrose diet. The increased energy expenditure observed on the sucrose-rich diet can probably be explained both by the increased intake of energy and fructose (mainly from sucrose) on this diet.

Adult↗

Two starch-branching-enzyme isoforms occur in different fractions of developing seeds of kidney bean.

The nature and enzymic properties of starch-branching enzyme (SBE) are two of the dominant factors influencing the fine structure of starch. To understand the role of this enzyme's activity in the formation of starch in kidney bean (Phaseolus vulgaris L.), a study was undertaken to identify the major SBE sequences expressed during seed development and to characterize the enzymic properties of the coded recombinant enzymes. Two SBE cDNA species (designated pvsbe2 and pvsbe1) that displayed significant similarity (more than 70%) to other family A and B SBEs respectively were isolated. Northern blot analysis revealed that pvsbe1 and pvsbe2 were differentially expressed during seed development. pvsbe2 showed maximum steady-state transcript levels at the mid-stage of seed maturation, whereas pvsbe1 reached peak levels at a later stage. Western blot analysis with antisera raised against both recombinant proteins (rPvSBE1 and rPvSBE2) showed that these two SBEs were located in different amyloplast fractions of developing seeds of kidney bean. PvSBE2 was present in the soluble fraction, whereas PvSBE1 was associated with the starch granule fraction. The differences in location suggest that these two SBE isoenzymes have different roles in amylopectin synthesis in kidney bean seeds. rPvSBE1 and rPvSBE2 were purified from Escherichia coli and their kinetic properties were determined. The affinity of rPvSBE2 for amylose (K(m) 1.27 mg/ml) was lower than that of rPvSBE1 (0.46 mg/ml). The activity of rPvSBE2 was stimulated more than 3-fold in the presence of 0.3 M citrate, whereas rPvSBE1 activity was not affected. The implications of the enzymic properties and the distribution of SBEs and amylopectin structure are discussed.

1,4-alpha-Glucan Branching Enzyme↗

Effect of cyclodextrins and undigested starch on the loss of chenodeoxycholate in the faeces.

Starch that escapes digestion in the small intestine increases the elimination of chenodeoxycholate and its metabolites in the faeces of both mice and hamsters. In contrast, the elimination of cholate and its metabolites is not increased. In vitro, the affinity of starch for chenodeoxycholate is about 90-fold greater than for cholate. beta-Cyclodextrin, which approximates to one turn of the helical structures formed by the 1,4-linked glucose units of starch, shares these properties. It is proposed that these helical structures in starch act as binding sites for bile salts.

Animals↗

Long-term fructose versus corn starch feeding in the spontaneously hypertensive rat.

1. Fructose feeding, as opposed to vegetable starch feeding, has been shown to elevate blood pressure and to decrease insulin sensitivity in normotensive rats. The long-term relevance of this is unclear, and data in hypertensive strains are scarce. 2. We studied the effects of 27 weeks of a fructose-versus a corn-starch-enriched (69.5% w/w) diet in the spontaneously hypertensive rat. 3. In both dietary groups, blood pressure increased with ageing, with no apparent difference between the diets. The fructose-fed rats gained less weight. However, even selecting fructose-fed rats that matched the weight gain in the corn starch group, did not reveal a significant elevation of systolic blood pressure over time. 4. Extracellular fluid volume was comparable in fructose-fed and corn-starch-fed rats. No effects on creatinine clearance, proteinuria or renal histology were found. Fasting values of plasma triacylgycerols and cholesterol were increased mildly after 2 weeks on the fructose diet. However, fasting glucose and insulin measured after 2 weeks, and the response to an intraperitoneal glucose load, were no different. After 23 weeks of the diets, fasting values of plasma glucose, insulin, triacylglycerols and cholesterol did not differ. There were small differences in the response of plasma glucose levels to the intraperitoneal glucose load, but the area under the curve was not different. The baseline insulin resistance present in spontaneously hypertensive rats possibly blunts the metabolic response to dietary fructose. 5. After 27 weeks, the diets were switched in cross-over design, and measurements were continued until 39 weeks. The fructose diet did not elevate systolic blood pressure in this follow-up experiment.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

Effects of hydroxyethyl starch on blood coagulation profile.

The effects of hydroxyethyl starch on blood coagulation were investigated in 20 patients undergoing surgery to determine whether its use places recipients at risk of haemorrhage or thrombosis. The partial thromboplastin times are significantly prolonged; factor VIII activities and fibrinogen levels are decreased. After infusion of hydroxyethyl starch, no significant differences were detected in platelet count or prothrombin time. A decreased platelet aggregation was also found after the infusion of hydroxyethyl starch. According to our results, hydroxyethyl starch can cause haemorrhagic problems in patients when administered as a colloidal volume-expanding agent.

Adult↗

Utilization of starch and synthesis of a combined amylase/alpha-glucosidase by the human colonic anaerobe Bacteroides ovatus.

Bacteroides ovatus preferentially utilized starch and pectin when grown on a mixture of polysaccharides in batch culture, indicating that these carbohydrates are important substrates for the bacterium in the human large intestine. Further studies on starch breakdown showed that continuous cultures grew on the polysaccharide when it provided the sole carbohydrate source, to yield a single hydrolytic product at low dilution rates (D = 0.04 h-1), with an estimated molecular mass of 13 kDa. In contrast, two major types of oligomeric products were formed at higher dilution rates (D = 0.44 h-1), with approximate molecular weights of 11 and 140 kDa. Analysis of cell-associated starch-degrading enzymes produced by Bact. ovatus using ion exchange chromatography and HPLC gel-filtration showed that amylase and alpha-glucosidase activities eluted in the same fractions. The single peak containing amylase and alpha-glucosidase activities obtained by HPLC gel-filtration chromatography corresponded to a molecular mass of approximately 140 kDa, and activity staining of gels for alpha-glucosidase activity after polyacrylamide gel electrophoresis, in the presence of sodium dodecyl sulphate, gave an estimated molecular mass of 70 kDa, indicating this enzyme to be a dimer. After renaturation, the 70 kDa band was cut from the gels and solubilized. The extract hydrolysed gelatinized starch and p-nitrophenyl-alpha-D-glucopyranoside.

Amylases↗

Evaluation of microencapsulation of a Bifidobacterium strain with starch as an approach to prolonging viability during storage.

AIMS: To optimize a spray coating process for the production of encapsulated microspheres containing viable Bifidobacterium cells and to determine whether the readily gelatinized modified starch coating used in this study improved bacterial survival in foods or under acid conditions. METHODS AND RESULTS: An air inlet temperature of 100 degrees C was demonstrated to be optimal for the spray drying process, as it afforded good drying, low outlet temperatures (45 degrees C) and resulted in less than 1 log reduction in bifidobacteria numbers during drying. Maximum recovery yields of 30% were obtained after optimizing the air aspiration conditions. The average size of the Bifidobacterium PL1-containing starch microparticles was determined by scanning electron microscopy to be of the order of 5 microm. The starch-coated cells did not display any enhanced viability compared with free PL1 cells when exposed to acid conditions for 6 h or in two dry food preparations over 20 d storage at ambient temperature (19-24 degrees C). Determination of 1491 nucleotides of the 16S rRNA gene from PL1 indicated that it shared 97% homology with a previously sequenced Bifidobacterium ruminantium strain. CONCLUSIONS: Our data demonstrated that, although spray drying is a valuable process for encapsulating bifidobacteria, further work is required to ascertain a more appropriate coating material that will protect this strain against adverse environmental conditions. SIGNIFICANCE AND IMPACT OF THE STUDY: The production of small, uniformly coated microspheres containing viable bifidobacteria using an affordable and industrially convenient process, such as spray drying, has commercial implications for the production of probiotic products. Although popular for use as a coating polymer by the food industry, this study indicated that modified starches might not be suitable for use as an encapsulating material for probiotic strains.

Aerosol Propellants↗