1,244 research outputs found

    Increased demand for rapid access to UK magnetic observatory data : implications for quality control procedures

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    During the last decade the demand for magnetic observatory data has steadily increased both from the scientific community and in particular from commercial organisations. Not only are the quantity of data products greater now but the speed at which they are delivered is faster and the quality of the data provided better. The modern user requirements for timely data have prompted the need for improved automatic procedures utilising the new technologies available. This has to be balanced against the user requirements for accuracy, which necessitate rigorous quality control procedures. While some of these have been automated, as is shown in the flow diagram, there remains a requirement for human interpretation and action if and when the data contain errors. Software development to reduce this human intervention is on-going

    Linalyl acetate and other compounds with related structures as antioxidants in heated soybean oil

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    Linalyl acetate and undecylenic acid were studied to determine their abilities to reduce oxidative changes in soybean oil held at frying temperature. All compounds to be tested were added to soybean oil and heated to 180 C for 56-70 h. Fatty acid changes and conjugated diene formation were monitored. Acetylation of linalool to linalyl acetate (LA) caused the formation of many byproducts, which were separated by thin-layer chromatography into three bands. The materials isolated from the bands were tested and found to be equally effective antioxidants. Purchased LA had an antioxidant effect similar to that of the bands. The LA materials from the bands were further purified and identified by GC-MS. All the effective compounds were similar in structure to LA. Undecylenic acid provided some protective effect but less than that of LA, which had less antioxidant effect than i17-avenasterol and poly- (dimethylsiloxane)

    Interactional Effects of β-Glucan, Starch, and Protein in Heated Oat Slurries on Viscosity and In Vitro Bile Acid Binding

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    Three major oat components, β-glucan, starch, and protein, and their interactions were evaluated for the impact on viscosity of heated oat slurries and in vitro bile acid binding. Oat flour from the experimental oat line “N979” (7.45% β-glucan) was mixed with water and heated to make oat slurry. Heated oat slurries were treated with α-amylase, lichenase, and/or proteinase to remove starch, β-glucan, and/or protein. Oat slurries treated with lichenase or lichenase combined with α-amylase and/or proteinase reduced the molecular weight of β-glucan. Heat and enzymatic treatment of oat slurries reduced the peak and final viscosities compared with the control. The control bound the least amount of bile acids (p \u3c 0.05); heating of oat flour improved the binding. Heated oat slurries treated with lichenase or lichenase combined with α-amylase and/or proteinase bound the least amount of bile acid, indicating the contribution of β-glucan to binding. Oat slurries treated with proteinase or proteinase and α-amylase together improved the bile acid binding, indicating the possible contribution of protein to binding. These results illustrate that β-glucan was the major contributor to viscosity and in vitro bile acid binding in heated oat slurries; however, interactions with other components, such as protein and starch, indicate the importance of evaluating oat components as whole system

    In Vitro Fermentation of Oat Flours from Typical and High β-Glucan Oat Lines

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    Two publicly available oat (Avena sativa) lines, “Jim” and “Paul” (5.17 and 5.31% β-glucan, respectively), and one experimental oat line “N979” (7.70% β-glucan), were used to study the effect of β-glucan levels in oat flours during simulated in vitro digestion and fermentation with human fecal flora obtained from different individuals. The oat flours were digested by using human digestion enzymes and fermented by batch fermentation under anaerobic conditions for 24 h. The fermentation progress was monitored by measuring pH, total gas, and short-chain fatty acid (SCFA) production. Significant effects of β-glucan on the formation of gas and total SCFA were observed compared to the blank without substrate (P \u3c 0.05); however, there were no differences in pH changes, total gas, and total SCFA production among oat lines (P \u3e 0.05). Acetate, propionate, and butyrate were the main SCFA produced from digested oat flours during fermentation. More propionate and less acetate were produced from digested oat flours compared to lactulose. Different human fecal floras obtained from three healthy individuals had similar patterns in the change of pH and the production of gas during fermentation. Total SCFA after 24 h of fermentation were not different, but the formation rates of total SCFA differed between individuals. In vitro fermentation of digested oat flours with β-glucan could provide favorable environmental conditions for the colon and these findings, thus, will help in developing oat-based food products with desirable health benefits

    In Vitro Digestion Rate and Estimated Glycemic Index of Oat Flours from Typical and High β-Glucan Oat Lines

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    The in vitro starch digestion rate and estimated glycemic index (GI) of oat flours and oat starches from typical and high β-glucan oat lines were evaluated along with the impact of heating on starch digestion. Flour from oat lines (\u27Jim\u27, \u27Paul\u27, IA95, and N979 containing 4.0, 5.3, 7.4, and 7.7% β-glucan, respectively) was digested by pepsin and porcine pancreatin. To determine the impact of heating on starch digestion, oat slurries were prepared by mixing oat flour and water (1:8 ratio) and heating for 10 min prior to digestion. Viscosity, as measured on a Rapid Visco Analyzer, increased with increases in concentration and molecular weight of β-glucan. The in vitro starch digestion of oat flours and a control, white bread made from wheat flour, increased as the digestion time increased. Starch digestion of oat flour was slower than that of the control (p \u3c 0.05). Heat treatment of oat-flour slurries increased the starch digestion from a range of 31–39% to a range of 52–64% measured after 180 min of in vitro digestion. There were no differences in starch digestibility among oat starches extracted from the different oat lines. The GI, estimated by starch hydrolysis of oat flours, ranged from 61 to 67, which increased to a range of 77–86 after heating. Oat-flour slurries prepared from IA95 and N979 lines with high β-glucan concentrations had lower GI values than did slurries made from Jim and Paul lines. Starch digestion was negatively correlated with β-glucan concentrations in heated oat-flour slurries (R2 = 0.92). These results illustrate that the oat soluble fiber, β-glucan, slowed the rate of starch digestion. This finding will help to develop new food products with low GI by using oat β-glucan

    In Vitro Bile-Acid Binding and Fermentation of High, Medium, and Low Molecular Weight β-Glucan

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    The impact of β-glucan molecular weight (MW) on in vitro bile-acid binding and in vitrofermentation with human fecal flora was evaluated. β-Glucan extracted from oat line ‘N979-5-4’ was treated with lichenase (1,3−1,4-β-d-glucanase) to yield high (6.87 × 105 g/mol), medium (3.71 × 105 g/mol), and low (1.56 × 105 g/mol) MW fractions. The low MW β-glucan bound more bile acid than did the high MW β-glucan (p \u3c 0.05). If the positive control, cholestyramine, was considered to bind bile acid at 100%, the relative bile-acid binding of the original oat flour and the extracted β-glucan with high, medium, and low MW was 15, 27, 24, and 21%, respectively. Significant effects of high, medium, and low MW β-glucans on total SCFA were observed compared to the blank without substrate (p \u3c 0.05). There were no differences in pH changes and total gas production among high, medium, and low MW β-glucans, and lactulose. The low MW β-glucan produced greater amounts of SCFA than the high MW after 24 h of fermentation. Among the major SCFA, more propionate was produced from all MW fractions of extracted β-glucans than from lactulose. In vitro fermentation of extracted β-glucan fractions with different MW lowered pH and produced SCFA, providing potential biological function

    Dosage Effect at the Sugary-2 Locus on Maize Starch Structure and Function.

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    Structural characteristics and functional properties of starches isolated from kernels of a sugary-2 (su2) dosage series were examined to determine whether the normal allele (Su2) was completely dominant to the recessive allele (su2). Differential scanning calorimetry revealed intermediate values for gelatinization onset, gelatinization peak, range, total enthalpy, and retrogradation among genotypes possessing one and two mutant su2 alleles. No effect of gene dosage on amylose content was observed, but X-ray diffraction patterns revealed an intermediate degree of crystallinity relative to normal and mutant genotypes upon addition of two su2 alleles. Development of a peak at 19 degrees 2(theta) became more evident upon increasing doses of the su2 allele. Viscosity of the starch paste and gel strength resulting from the genotype possessing two doses of the su2 allele exceeded that of both mutant and normal genotypes. An intermediate retrogradation as detected by differential scanning calorimetry and from gel strengths of starches after storage for seven days suggested an increased stability of the Su2su2su2 starch relative to that of normal starch

    Improving the fatty acid composition of corn oil by using germplasm introgression

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    The general public has shown increasing interest in consuming oils that are beneficial to health. Thus, oil from corn (Zea mays L.), along with most major edible oils, has been the target of genetic alterations to improve the fatty acid composition. The fatty acid profile goals vary, depending upon the intended use for the oil. We have targeted the development of corn oil with 1) low total saturated fatty acids, 2) high total saturated fatty acids, and 3) mid-oleic acid, in each case via two different sources: exotic germplasm identified through an international program to broaden the corn germplasm base and introgression of a wild, grassy relative of corn, Tripsacum (Tripsacum dactaloides L). We have been successful at identifying corn lines with each of the noted traits

    Individual and Interactional Effects of β-Glucan, Starch, and Protein on Pasting Properties of Oat Flours

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    Seven experimental oat lines with high (6.2−7.2%), medium (5.5−5.9%), and low (4.4−5.3%) β-glucan concentrations were evaluated for contributions of β-glucan, starch, protein, and their interactions, to pasting properties of oat flours by using a Rapid Visco Analyser (RVA, Newport Scientific, Warriewood, NSW, Australia). Significant correlations (P \u3c 0.05) between β-glucan concentration and pasting parameters of oat slurries were obtained under autolysis without 1 h of incubation, inhibition, and amylolysis. The relative decrease of viscosity after enzymatic hydrolysis of β-glucan correlated with β-glucan concentration (P \u3c 0.05). These data demonstrated the important contribution of β-glucan to pasting. The relative decrease of viscosity after either amylolysis or enzymatic removal of protein correlated with β-glucan concentration (P \u3c 0.1), which might be explained by the considerable contribution of the interaction of β-glucan with starch and protein, to pasting. The viscosity decrease by hydrolysis of protein was much greater than the actual viscosity remaining after hydrolysis of both β-glucan and starch, reconfirming the importance of interactions between protein and other oat components to pasting. Optimal multiple linear regression (MLR) models were generated to predict key pasting parameters in both buffer without 1 h of incubation and silver nitrate solution by using a stepwise procedure. The β-glucan concentration alone or together with the concentration of starch, rather than protein, was selected as the predictor under certain conditions. These results illustrated the major unit contribution of β-glucan, secondary unit contribution of starch, and minimal unit contribution of protein to pasting

    Structure and Function of Starch and Resistant Starch from Corn with Different Doses of Mutant Amylose-Extender and Floury-1 Alleles

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    Four corn types with different doses of mutant amylose-extender (ae) and floury-1 (fl1) alleles, in the endosperm, including no. 1, aeaeae; no. 2, fl1fl1fl1; no. 3, aeaefl1; and no. 4,fl1fl1ae, were developed for use in making Hispanic food products with high resistant starch (RS) content. The RS percentages in the native starch (NS) of 1−4 were 55.2, 1.1, 5.7, and 1.1%, respectively. All NS were evaluated for pasting properties with a rapid viscoanalyzer (RVA) and for thermal properties with a differential scanning calorimeter (DSC). NS 1 had a low peak viscosity (PV) caused by incomplete gelatinization, whereas NS 3 had the greatest PV and breakdown of all four starch types. On the DSC, NS 2 had the lowest onset temperature and greatest enthalpy. NS 1 and 3 had similar onset and peak temperatures, both higher than those of NS 2 and 4. The gel strength of NS heated with a RVA was evaluated by using a texture analyzer immediately after RVA heating (fresh, RVA-F) and after the gel had been stored at 4 °C for 10 days (retrograded, RVA-R). NS 1 gel was watery and had the lowest strength (30 g) among starch gel types. NS 3 gel, although exhibiting syneresis, had greater gel strength than NS 2 and 4. The structures of the NS, the RS isolated from the NS (RS-NS), the RS isolated from RVA-F (RS-RVA-F), and the RS isolated from RVA-R (RS-RVA-R) were evaluated by using size exclusion chromatography. NS 1 had a greater percentage of amylose (AM) (58.3%) than the other NS (20.4−26.8%). The RS from all NS types (RS-NS) had a lower percentage of amylopectin (AP) and a greater percentage of low molecular weight (MW) AM than was present in the original NS materials. The RS-RVA-R from all starches had no AP or high MW AM. The percentages of longer chain lengths (DP 35−60) of NS were greater in 1 and 3 than in 2 and 4, and the percentages of smaller chain lengths (DP 10−20) were greater in 2 and 4 than in 1 and 3. In general, NS 3 seemed to have inherited some pasting, thermal, and structural characteristics from both NS 1 and 2, but was distinctly different from 4
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