Different Amounts Of Starch Research Articles

Effect of sample transparency in powder diffractometry with Bragg–Brentano geometry as a convolution

The effect of transparency and finite thickness of the sample on the peak profile in powder diffractometry with Bragg–Brentano geometry is treated as a convolution with an asymmetric aberration function. The formula of the aberration function and a practical method for numerical calculation of the convolution are proposed. The model function for the total profile is given by triple convolution of the pseudo-Voigt function with asymmetric functions based on vertical (axial) divergence, horizontal (equatorial) divergence and sample transparency. The validity of the model profile function is examined by fitting the CuKα X-ray diffraction profile of diluted lanthanum hexaboride (LaB6) standard samples (SRM660) of 0.5 mm thickness, the transparency of which is varied by mixing with different amounts of starch; all the parameters that may affect the shape of the profile function are treated as fixed parameters. Even in the case of heavily distorted profiles of highly transparent samples with the inverse linear absorption coefficients μ−1= 0.34 and 1.19 mm, experimental profiles are fairly well reproduced by the model function, typically within several % inRfactor. It is also demonstrated that the lattice constants of the transparent samples are precisely evaluated by applying this model function.

Effects of ruminal administration of supplemental degradable intake protein and starch on utilization of low-quality warm-season grass hay by beef steers.

Hereford x Angus steers were used in a 13-treatment, four-period, incomplete Latin square design to examine the effects of starch and degradable intake protein (DIP) supplements on forage utilization and ruminal function. Steers were given ad libitum access to low-quality hay (4.9% CP) and were not supplemented (NS) or received different amounts of starch (cornstarch grits; 0, .15, and .3% of initial BW) and DIP (Na-caseinate; .03, .06, .09, and .12% of initial BW) administered via ruminal fistulae in a 3 x 4 factorial arrangement of treatments. Supplemented steers consumed more (P < .01) forage OM, total OM, NDF, and digestible OM (DOM) than NS steers. Forage OM, total OM, NDF, and DOM intakes increased linearly (P < .01) as the amount of supplemental DIP increased. The addition of starch to supplements linearly decreased ( P < .01) the intake of forage OM, NDF, and DOM. The digestion of DM, OM, and NDF increased linearly (P < .01) with supplemental DIP and decreased linearly (P < or = .06) with supplemental starch. Particulate and liquid passages generally increased with DIP; however, starch level influenced the nature of the response (P = .03 and .06, respectively). Similarly, ruminal acid detergent-insoluble ash content generally decreased as starch increased, but the effect was dependent on DIP level (P < .01). Supplementation increased (P < .01) ruminal NH3 and total VFA and decreased (P < .01) ruminal pH relative to NS. All treatments supported average pH values in a range (6.3 to 6.7) unlikely to inhibit fibrolytic bacteria. Ruminal NH3 concentration increased quadratically (P = .03) with DIP and decreased linearly (P = .02) with starch. As DIP increased, total VFA concentration increased linearly (P = .02). Providing supplemental DIP to steers fed low-quality forage increased OM intake and digestion, whereas addition of starch to supplements decreased forage intake and digestion.

Starch biosynthesis and modification of starch structure in transgenic plants

AbstractStarch is synthesised through the ADP‐glucose pathway, involving the three enzymes ADP‐glucose pyrophosphorylase, starch synthase and starch branching enzyme. ADP‐glucose pyrophosphorylase is the key enzyme of the pathway, determining the flux of carbon into starch. It generates ADP‐glucose, which is the substrate for the starch synthases, from glucose‐1‐phosphate and ATP releasing pyrophosphate. The enzyme is stimulated by 3‐phosphoglycerate and inhibited through inorganic phosphate. The starch synthases, which catalyse the transfer of glucose from ADP‐glucose to the nonreducing end of a growing α‐1,4‐glucan, are divided into two classes, the granule‐bound starch synthases (GBSS) and the soluble starch synthases (SS). In both classes several isoforms have been described from many different plant species. The branching enzyme, which introduces branchpoints into the amylopectin, can also occur in different isoforms. Other enzymes present in plants, which also act on α‐1,4‐glucans, such as the starch phosphorylases, disproportionating enzyme and different starch hydrolases, might also be important for dertermining the starch structure and, therefore, its processibility. Many aspects of starch synthesis are not fully understood to date. Starch metabolism can be manipulated through genetic engineering, either by the ectopic expression of different heterologous genes, or through the repression of the expression of endogenous genes using antisense RNA technology. This not only allows the functional analysis of starch biosynthetic proteins, but also the manipulation of starch structure in order to widen its industrial applications.In this way many different potato lines have been generated, containing either different amounts of starch, or which synthesize a structurally modified starch. These structural changes relate to the amylose content, the phosphate content, or the gelatinisation and gelation characteristics of the starch.

Differences in seedling emergence and growth among rice (oryza sativa L.) ecospecies under reduced soil conditions.

To analyze the differences in the rate of seedling emergence and seedling height among rice ecospecles at different soil reduction levels, five blocks were prepared containing soils with different amounts of starch, i.e. 10, 20, 30, 83 and 167g per block, and no starch addition block (control) was also prepared. The mean rate of seedling emergence and seedling height were increased by the addition of a maximum amount of 20g starch per block in the three ecospecies. However, the mean rate of seedling emergence markedly decreased with the increase of the amount of starch added over 20g per block. The mean rate of seedling emergence in the japoeeica cultivar group was higher than that in the iudica cultlvar group at all the redox potential levels, whereas that in the javanica cultivar group was intermediate. However, the rate of increase and/or decrease of the mean seedling height with changes in starch amount added was almost similar in the three ecospecies.

Ruminal and Post-Ruminal Utilization of Starch in the Young Bovine

In the first of two experiments, ten calves, randomized into two groups, were fed a semi-purified diet containing 62% of either corn starch or lactose in the form of dry milk solids as the sole source of carbohydrate. At the end of 12 weeks, ration digestibility and blood glucose responses were determined, and the animals were switched to the opposite rations to test adaptive responses to carbohydrates. Calves in each group were then randomly assigned to five treatments to test digestibility and blood glucose responses. Treatments were 8.8 g/kg body weight of lactose or one of four amounts of starch (2.2, 4.4, 8.8, and 13.2g/kg body weight).Daily gains for the starch and lactose-fed calves averaged .12kg and .78kg for the 12 weeks. Blood sugar was two and one-half times greater during lactose ingestion than for starch. Digestibility of starch averaged 72.8% as compared to 92.5% for lactose. No adaptation to starch was evident. Blood sugar responses to different starch intakes were erratic. Starch digestion coefficients decreased linearly (P<.01) with increasing intake. Actual starch digested increased with starch intake.In the second experiment, 40 calves were randomly assigned to 10 rations containing five increasing per cents of straw (5 to 60%) and decreasing amounts of soluble carbohydrates (1 to 53%). Starch and cerelose were studied at ratios of 1:1 and 3:1. At 20 weeks of age, blood sugar response to test meals of starch and lactose were determined. After a readjustment period, calves were slaughtered and samples from various sites of the alimentary tract were analyzed for total carbohydrate content.Soluble carbohydrates, ratio of carbohydrates, and hour of sampling had no effect (P>.05) on blood sugar response to a ruminal bypass test meal of starch. Total carbohydrate recovery from the abomasum and fecal residue of calves receiving the different amounts of starch and cerelose increased with decreasing starch in the ration. Amylase activity determined on pancreatic tissue homogenate was not affected by dietary starch or cerelose.

All‐Vegetable Protein Mixtures for Human Feeding. VIII. Biological Testing of INCAP Vegetable Mixture Nine in Ratsa,b

SUMMARYThe nutritive value of INCAP Vegetable Mixture 9 in young and protein‐depleted adult rats was studied. This mixture contains 28% lime‐treated corn, 28% sorghum grain, 38% cottonseed flour, 3% kikuyu leaf meal, and 3% torula yeast. When Mixture 9, skim milk, casein, or meat flour was fed combined with different amounts of starch to give a range of dietary protein levels, the nutritive value of the vegetable mixture for rats compared favorably with that of animal proteins at the higher levels of protein intake. Both young growing rats and protein‐depleted rats were used. The growth response was generally less to the vegetable mixture at low protein levels than when animal proteins were fed at the same dietary level, presumably because of a lysine deficiency also observed in previous chick trials.When the corn and sorghum combination was replaced in the mixture by processed corn, sorghum, rice, whole wheat, or oats, no significant changes were noted in the nutritive value. Furthermore, roasting, boiling, and lime‐treating corn and sorghum did not affect the nutritive value of the mixture.

HUMIN FORMATION DURING WHEAT GLUTEN HYDROLYSIS

The effect of different amounts of starch and crude fat on humin formation during the hydrolysis of gluten prepared from a commercial flour depended on the acid/protein ratio, high ratios giving less humin nitrogen and less humin weight. The nitrogen content of humin was almost independent of the acid/protein ratio but increased with decreasing humin formation. Filtration time increased markedly with increasing purity of the samples. The color of the hydrolyzates varied slightly with impurities and acid/protein ratios.