Journal articles: 'Amylose'

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Kamasaka, Hiroshi, Kazuhisa Sugimoto, Hiroki Takata, Takahisa Nishimura, and Takashi Kuriki. "Bacillus stearothermophilus Neopullulanase Selective Hydrolysis of Amylose to Maltose in the Presence of Amylopectin." Applied and Environmental Microbiology 68, no. 4 (April 2002): 1658–64. http://dx.doi.org/10.1128/aem.68.4.1658-1664.2002.

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ABSTRACT The specificity of Bacillus stearothermophilus TRS40 neopullulanase toward amylose and amylopectin was analyzed. Although this neopullulanase completely hydrolyzed amylose to produce maltose as the main product, it scarcely hydrolyzed amylopectin. The molecular mass of amylopectin was decreased by only one order of magnitude, from approximately 108 to 107 Da. Furthermore, this neopullulanase selectively hydrolyzed amylose when starch was used as a substrate. This phenomenon, efficient hydrolysis of amylose but not amylopectin, was also observed with cyclomaltodextrinase from alkaliphilic Bacillus sp. strain A2-5a and maltogenic amylase from Bacillus licheniformis ATCC 27811. These three enzymes hydrolyzed cyclomaltodextrins and amylose much faster than pullulan. Other amylolytic enzymes, such as bacterial saccharifying α-amylase, bacterial liquefying α-amylase, β-amylase, and neopullulanase from Bacillus megaterium, did not exhibit this distinct substrate specificity at all, i.e., the preference of amylose to amylopectin.

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Yanase, Michiyo, Hiroki Takata, Takeshi Takaha, Takashi Kuriki, Steven M. Smith, and Shigetaka Okada. "Cyclization Reaction Catalyzed by Glycogen Debranching Enzyme (EC 2.4.1.25/EC 3.2.1.33) and Its Potential for Cycloamylose Production." Applied and Environmental Microbiology 68, no. 9 (September 2002): 4233–39. http://dx.doi.org/10.1128/aem.68.9.4233-4239.2002.

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ABSTRACT Glycogen debranching enzyme (GDE) has 4-α-glucanotransferase and amylo-1,6-glucosidase activities in the single polypeptide chain. We analyzed the detailed action profile of GDE from Saccharomyces cerevisiae on amylose and tested whether GDE catalyzes cyclization of amylose. GDE treatment resulted in a rapid reduction of absorbance of iodine-amylose complex and the accumulation of a product that was resistant to an exo-amylase (glucoamylase [GA]) but was degraded by an endo-type α-amylase to glucose and maltose. These results indicated that GDE catalyzed cyclization of amylose to produce cyclic α-1,4 glucan (cycloamylose). The formation of cycloamylose was confirmed by high-performance anion-exchange chromatography, and the size was shown to range from a degree of polymerization of 11 to a degree of polymerization around 50. The minimum size and the size distribution of cycloamylose were different from those of cycloamylose produced by other 4-α-glucanotransferases. GDE also efficiently produced cycloamylose even from the branched glucan substrate, starch, demonstrating its potential for industrial production of cycloamylose.

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Rendleman, Jr., Jacob A. "Hydrolytic action of α‐amylase on high‐amylose starch of low molecular mass." Biotechnology and Applied Biochemistry 31, no. 3 (June 2000): 171–78. http://dx.doi.org/10.1111/j.1470-8744.2000.tb00570.x.

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High‐amylose starches of low average degree of polymerization (đp 61–71), formed as fine granules by interaction of Bacillus macerans cyclodextrin glucanotransferase with α‐cyclodextrin (CD) at 2–70 °C, are highly insoluble in water and not gelatinizable under normal cooking conditions (100 °C). Samples of CD‐derived starches, both cooked and uncooked, were subjected to hydrolysis in vitro by human salivary α‐amylase at 37 °C under conditions chosen to resemble those in the human intestinal lumen. Released low‐molecular‐mass saccharides were determined quantitatively by HPLC and the results compared with those from similar studies with natural starches. Among uncooked starches, CD‐derived starch showed very low reactivity towards α‐amylase, along with potato starch and a high‐amylose hybrid corn starch (64% amylose). Cooking greatly enhanced reactivity of natural starches, but only moderately increased reactivity of CD‐derived starches. Susceptibility to hydrolysis of cooked starches increased in the following general order: CD‐derived starch (≈100% amylose)<100% corn amylose (isolated by the butan‐1‐ol method)<hybrid high‐amylose corn starch (64–66% amylose)<waxy maize starch (99–100% amylopectin)∼ordinary corn starch (≈25% amylose)<potato starch (≈25% amylose).

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4

Xiang, Yu, and Wanda W. Collins. "Clone and Growth Season Effects on Seven Carbohydrate-related Components and Their Correlation in Sweetpotato." HortScience 33, no. 3 (June 1998): 456a—456. http://dx.doi.org/10.21273/hortsci.33.3.456a.

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Approximately 50% of the world's total sweetpotato output is used for producing starch or starch-derived products and for animal feeding. Knowledge of cultivar and environmental effects on carbohydrate-related components and the correlation among these components is essential for improving the raw products utilization and providing an expanded market for sweetpotato. The objective of this study was to investigate the variation of amylose content and β-amylase activity as well as their correlation with other starch-related components. Dry matter, starch, total sugar, amylose and phosphate content, β-amylase activity, and raw starch digestibility were evaluated for 20 advanced selections in 2 years. Significant clone variation was detected for all seven components. Significant growth season effects were found for amylose and sugar content, β-amylase activity, and starch digestibility. β-amylase activity has a negative correlation with starch (r = –0.57, P ≤ 0.001) and dry matter (r = –0.39, P ≤ 0.05). Starch digestibility has a negative correlation with amylose (r = –0.37, P ≤ 0.05) and phosphate content (r = –0.35, P ≤ 0.05).

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5

Dipnaik, Kavita, and Praneeta Kokare. "Ratio of Amylose and Amylopectin as indicators of glycaemic index and in vitro enzymatic hydrolysis of starches of long, medium and short grain rice." International Journal of Research in Medical Sciences 5, no. 10 (September 28, 2017): 4502. http://dx.doi.org/10.18203/2320-6012.ijrms20174585.

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Background: Rice (Oryzasativa L.) is the staple food of over half the world’s population. The major carbohydrate of rice is starch, which is about 72 to 75%. Rice can be classified into three different types: long-grain, medium-grain and short-grain rice based upon their length as compared to their width. Aim of the study was to predict the glycemic index of long, medium and short grain rice based on amylose, amylopectin ratio and to study in vitro hydrolysis of starch of long, medium and short grain rice by salivary and pancreatic amylases and formulate the right type of rice to be consumed by diabetics. Methods: Starches were isolated from long, medium and short grain rice. Amylose and amylopectin from the isolated starches were estimated. Starches isolated were subjected to enzymatic hydrolysis by salivary amylase and pancreatic amylase under optimum in vitro conditions and reducing sugars released after hydrolysis and incubation period of 0, 5, 10, 15, 20 and 30 minutes were estimated by Folin-Wu method. Results were analysed using unpaired t-test and statistical significance was established.Results: Long grain rice was found to have high amylose and low amylopectin content as compared to medium and short grain rice. Long grain rice showed slow release of reducing sugars as compared to medium and short grain rice.Conclusions: Long grain rice because of its high amylose content is a low glycemic food and can be consumed by diabetics. Sustained slow release of reducing sugars given by long grain rice is desirable in diabetics.

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Hirota, Sachiko, and Umeo Takahama. "Suppression of Pancreatin-Induced Digestion of Starch in Starch Granules by Starch/Fatty Acid and Starch/Flavonoid Complexes in Retrograding Rice Flour." Foods 7, no. 8 (August 10, 2018): 128. http://dx.doi.org/10.3390/foods7080128.

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Adzuki beans are used to prepare foods with glutinous and non-glutinous rice in Japan, and adzuki bean pigments are able to color rice starch a purplish red. This study deals with the adzuki bean extract-dependent suppression of starch digestion of non-glutinous rice flour (joshinko in Japanese), which was gelatinized in boiling water and then cooled to 37 °C. Accompanying the treatment of joshinko with pancreatin, amylose and amylopectin were released from the joshinko particles, and the released amylose and amylopectin were further digested. The adzuki extract suppressed the release and digestion by binding to amylose and amylopectin, which were present in the particles and at the surfaces of the particles. Fatty acids and flavonoids in the adzuki extract contributed to the suppression. In addition, the starch digestion in the joshinko particles appeared to be suppressed if the amylose/fatty acid complexes and amylose/flavonoid and amylopectin/flavonoid complexes, which are poor substrates of α-amylase, surrounded the particles. It is discussed that the suppression was due to the prevention of α-amylase access to the particles.

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Totani, Masayasu, Aina Nakamichi, and Jun-ichi Kadokawa. "Enzymatic Assembly of Chitosan-Based Network Polysaccharides and Their Encapsulation and Release of Fluorescent Dye." Molecules 29, no. 8 (April 16, 2024): 1804. http://dx.doi.org/10.3390/molecules29081804.

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We prepared network polysaccharide nanoscopic hydrogels by crosslinking water-soluble chitosan (WSCS) with a carboxylate-terminated maltooligosaccharide crosslinker via condensation. In this study, the enzymatic elongation of amylose chains on chitosan-based network polysaccharides by glucan phosphorylase (GP) catalysis was performed to obtain assembly materials. Maltoheptaose (Glc7) primers for GP-catalyzed enzymatic polymerization were first introduced into WSCS by reductive amination. Crosslinking of the product with the above-mentioned crosslinker by condensation was then performed to produce Glc7-modified network polysaccharides. The GP-catalyzed enzymatic polymerization of the α-d-glucose 1-phosphate monomer from the Glc7 primers on the network polysaccharides was conducted, where the elongated amylose chains formed double helices. Enzymatic disintegration of the resulting network polysaccharide assembly successfully occurred by α-amylase-catalyzed hydrolysis of the double helical amyloses. The encapsulation and release of a fluorescent dye, Rhodamine B, using the CS-based network polysaccharides were also achieved by means of the above two enzymatic approaches.

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8

Winger, Moritz, Markus Christen, and Wilfred F. van Gunsteren. "On the Conformational Properties of Amylose and Cellulose Oligomers in Solution." International Journal of Carbohydrate Chemistry 2009 (June 14, 2009): 1–8. http://dx.doi.org/10.1155/2009/307695.

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Molecular dynamics (MD) simulations were used to monitor the stability and conformation of double-stranded and single-stranded amyloses and single-stranded cellulose oligomers containing 9 sugar moieties in solution as a function of solvent composition, ionic strength, temperature, and methylation state. This study along with other previous studies suggests that hydrogen bonds are crucial for guaranteeing the stability of the amylose double helix. Single-stranded amylose forms a helical structure as well, and cellulose stays highly elongated throughout the simulation time, a behavior that was also observed experimentally. In terms of coordination of solute hydroxyl groups with ions, amylose shows entropy-driven coordination of calcium and sulfate ions, whereas cellulose-ion coordination seems to be enthalpy-dominated. This indicates that entropy considerations cannot be neglected when explaining the structural differences between amyloses and celluloses.

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9

Hofman, M., and M. Shaffar. "Fluorescence depolarization assay for quantifying alpha-amylase in serum and urine." Clinical Chemistry 31, no. 9 (September 1, 1985): 1478–80. http://dx.doi.org/10.1093/clinchem/31.9.1478.

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Abstract We have developed a new method for quantifying alpha-amylase (EC 3.2.1.1) in serum and urine by fluorescence depolarization. Amylase in the sample catalyzes the hydrolysis of the substrate, a fluorescein-labeled amylose. This results in decreased fluorescence polarization, owing to the increased rate of rotation of the amylose fragment relative to the intact substrate. The TDx amylase assay is calibrated with six human-serum-based pancreatic amylase calibrators. Amylase activities are determined by interpolation from the calibration curve, which is stored in the TDx analyzer's memory. Results correlate well with those by the Du Pont aca assay and the Beckman "DRI-STAT" assay. Endogenous glucose does not interfere. CVs are less than 6%, and the reagents are stable in liquid form.

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10

Srividya, N., and Poorna B. Sri Devi. "Bio-Diversity in Neem (Azadirachta ndica A. Juss) with special Emphasis on Seed Yield Parameters." Mapana - Journal of Sciences 2, no. 2 (May 13, 2004): 35–45. http://dx.doi.org/10.12723/mjs.4.5.

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The raw a-amylase Produced by Bacillus c«eus 306 'o by and chrornohgrgphy. The Molecular weight of a-amylose wos estimated 58KDo. enzyme displayedmaximum activity 85 Unifs/rn' pH of 5.0-9.0. Ach.•åy was inhibited in the pæsence Of Hg'v, Cua•. no inhibition u•os Observed in the presence Of Zn?•. Medium containirv CaCJ2.2HaO enhanced amylase production over 'hat on Ca2*deiicient medium. The deiergen' Tween-80 ond Iraon increased Biomass but Significantly Suppressed amylose production. The enzynE released large of glucose and maltose on Fo•drdysis of starch

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11

Lin, Ruo Hui, Ke Gang Wu, Xiang Hua Chai, and Shao Shu Zhong. "The Study of the Preparation of Linolenic Acid-Amylose Complexes and their Oxidation Stability." Advanced Materials Research 317-319 (August 2011): 194–200. http://dx.doi.org/10.4028/www.scientific.net/amr.317-319.194.

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Experimental study had been done to investigate the fatty acid (FA) content of the linolenic acid-amylose complexes which were prepared at different crystallization temperatures, holding time and amylase-linolenic acid ratio. The results showed the optimum conditions to make linolenic acid-amylose complexes were as followed: 80°C of crystallization temperature and 1.5h of the holding time，amylase-linolenic acid ratio of 9:1. Fatty acid composition of the complexes and physical mixtures before and after the heating destruction was detected by Gas chromatography-mass spectrometry (GC-MS). The results showed the complexes maintained higher oxidation stability than the physical mixtures.

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12

Adedayo, Bukola C., Ganiyu Oboh, Sunday I. Oyeleye, and Tosin A. Olasehinde. "Antioxidant and Antihyperglycemic Properties of Three Banana Cultivars (Musaspp.)." Scientifica 2016 (2016): 1–7. http://dx.doi.org/10.1155/2016/8391398.

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Background. This study sought to investigate the antioxidant and antihyperglycemic properties ofMusa sapientum(Latundan banana) (MSL),Musa acuminata(Cavendish banana) (MAC), andMusa acuminate(Red Dacca) (MAR).Materials and Methods.The sugar, starch, amylose, and amylopectin contents and glycemic index (GI) of the three banana cultivars were determined. Furthermore, total phenol and vitamin C contents andα-amylase andα-glucosidase inhibitory effects of banana samples were also determined.Results. MAC and MAR had the highest starch, amylose, and amylopectin contents and estimated glycemic index (eGI) with no significant different while MSL had the lowest. Furthermore, MAR (1.07 mg GAE/g) had a higher total phenol content than MAC (0.94 mg GAE/g) and MSL (0.96 mg GAE/g), while there was no significant difference in the vitamin C content. Furthermore, MAR had the highestα-amylase (IC50= 3.95 mg/mL) inhibitory activity while MAC had the least (IC50= 4.27 mg/mL). Moreover, MAC and MAR inhibited glucosidase activity better than MSL (IC503.47 mg/mL).Conclusion. The low sugar, GI, amylose, and amylopectin contents of the three banana cultivars as well as theirα-amylase andα-glucosidase inhibitory activities could be possible mechanisms and justification for their recommendation in the management of type-2 diabetes.

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13

Yu, S., J. Xu, Y. Zhang, and N. K. Kopparapu. "Relationship between intrinsic viscosity, thermal and retrogradation properties of amylose and amylopectin." Czech Journal of Food Sciences 32, No. 5 (October 1, 2014): 514–20. http://dx.doi.org/10.17221/394/2013-cjfs.

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The relationships between intrinsic viscosity and some properties of amylose and amylopectin were investigated. The intrinsic viscosities determined by Ubbelohde viscometer for rice, maize, wrinkled pea and potato amyloses were 46.28 ± 0.30, 123.94 ± 0.62, 136.82 ± 0.70, and 167.00 ± 1.10 ml/g, respectively; and the intrinsic viscosities of rice, maize, wrinkled pea and potato amylopectins were 77.28 ± 0.90, 154.50 ± 1.10, 162.56 ± 1.20 and 178.00 ± 1.00 ml/g, respectively. The thermal and retrogradation properties of amylose and amylopectin were investigated by differential scanning calorimeter (DSC). Results showed that the thermal enthalpy (ΔH<sub>g</sub>) was positively correlated with intrinsic viscosity, however, the onset and peak temperatures were not related to the intrinsic viscosity. The amylose and amylopectin retrogradation enthalpy values were negatively related to intrinsic viscosity, while the onset and peak temperature values of retrograded amylose and amylopectin were not related to the intrinsic viscosity during storage (except one-day storage). Furthermore, the onset and peak temperatures and retrogradation enthalpy of amylose and amylopectin changed slowly during storage at 4°C.    

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Kadokawa, Jun-ichi. "Chemoenzymatic synthesis of functional amylosic materials." Pure and Applied Chemistry 86, no. 5 (May 19, 2014): 701–9. http://dx.doi.org/10.1515/pac-2013-1116.

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AbstractIn this article, a review of the chemoenzymatic synthesis of functional amylosic materials by means of a-glucan phosphorylase-catalyzed enzymatic polymerization is presented. The first topic of this review deals with the synthesis of amylose-grafted heteropolysaccharides composed of abundant polysaccharide main chains, such as chitin/chitosan, cellulose, alginate, xanthan gum, and carboxymethyl cellulose. The synthesis was achieved by combining the a-glucan phosphorylase-catalyzed enzymatic polymerization forming amylose with the appropriate chemical reaction (chemoenzymatic method). The second topic is the construction of amylosic supramolecular materials such as hydrogels and films by means of the vine-twining polymerization approach, which is a method for the formation of amylose-polymer inclusion complexes in the a-glucan phosphorylase-catalyzed polymerization field. In these studies, the designed graft copolymeric guest compounds were first synthesized. Then, the a-glucan phosphorylase-catalyzed enzymatic polymerization was carried out in the presence of the graft copolymers to produce the amylosic supramolecular materials through the formation of inclusion complexes.

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15

Artignan, B., B. Martignac, C. Robin, C. Marty-Enguehard, L. du Couedic, A. Trehony, C. L’Heveder, E. Lestang, E. Maugin, and P. Guerzider. "Pleurésie amyloïde révélatrice d’une amylose généralisée." Revue des Maladies Respiratoires 36, no. 5 (May 2019): 643. http://dx.doi.org/10.1016/j.rmr.2019.05.026.

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Roesser, David S., Richard A. Gross, and Stephen P. Mccarthy. "Modified amylose biodegradability by α-amylases." Macromolecular Symposia 118, no. 1 (June 1997): 747–52. http://dx.doi.org/10.1002/masy.19971180196.

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17

Sghaier, F., W. Baya, J. Anoun, I. Ben Hassine, N. Adayli, M. Karmani, A. Mzabi, and F. Ben Fredj. "Goitre amyloïde révélant une amylose systémique." La Revue de Médecine Interne 44 (December 2023): A433—A434. http://dx.doi.org/10.1016/j.revmed.2023.10.184.

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18

Shen, G. J., B. C. Saha, Y. E. Lee, L. Bhatnagar, and J. G. Zeikus. "Purification and characterization of a novel thermostable β-amylase from Clostridium thermosulphurogenes." Biochemical Journal 254, no. 3 (September 15, 1988): 835–40. http://dx.doi.org/10.1042/bj2540835.

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An extracellular beta-amylase from Clostridium thermosulphurogenes was purified 811-fold to homogeneity, and its general molecular, physico-chemical and catalytic properties were determined. The native enzyme was a tetramer of 210 kDa composed of a single type subunit; its 20 amino acid N-terminus displayed 45% homology with Bacillus polymyxa beta-amylase. The beta-amylase was enriched in both acidic and hydrophobic amino acids. The pure enzyme displayed an isoelectric point of 5.1 and a pH activity optimum of 5.5. The optimum temperature for beta-amylase activity was 75 degrees C, and enzyme thermostability at 80 degrees C was enhanced by substrate and Ca2+ addition. The beta-amylase hydrolysed amylose to maltose and amylopectin and glycogen to maltose and limit dextrins, and it was inhibited by alpha- and beta-cyclodextrins. The enzyme displayed kcat. and Km values for boiled soluble starch of 400,000 min-1 per mol and 1.68 mg/ml, respectively. The enzyme was antigenically distinct from plant beta-amylases.

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ALTUNER, Ergin Murat. "IN SILICO PROOFS FOR PHLORIDZIN, NARINGENIN, AND CINNAMIC ACID AS ALPHA-AMYLASE ACTIVATORS, WHICH IS IMPORTANT IN INDUSTRIAL MICROBIOLOGY OR BIOCHEMICAL ENGINEERING." Communications Faculty of Science University of Ankara Series C Biology Geological Engineering and Geophysical Engineering 30, no. 2 (December 31, 2021): 134–47. http://dx.doi.org/10.53447/communc.934706.

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Enzymes are commonly defined as biological catalysts, regulating particular biochemical reactions. α-Amylase (EC 3.2.1.1) is one of the industrially important enzymes, which are extensively used in starch hydrolyzing processes, such as brewing, fermentation, detergent production, food processing, etc. This enzyme breaks down α-1,4 glycosidic bonds in amylose or amylopectin. The end products from amylose are maltotriose and maltose. Maltose, glucose, and limit dextrin are formed from amylopectin. There are many studies in the literature regarding the α-amylase inhibitors, which have the potentials of being used in diabetes and obesity. However, there is a very limited number of studies in the literature about the activation of this enzyme, which could be harmful to such diseases. This study aims to support the activation activity of phloridzin, naringenin, and cinnamic acid for α-amylase, which was previously proved experimentally, with some in silico tests.

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20

Kadokawa, Jun-ichi. "Fabrication of Nanostructured Supramolecules through Helical Inclusion of Amylose toward Hydrophobic Polyester Guests, Biomimetically through Vine-Twining Polymerization Process." Biomimetics 8, no. 7 (November 1, 2023): 516. http://dx.doi.org/10.3390/biomimetics8070516.

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This review article presents the biomimetic helical inclusion of amylose toward hydrophobic polyesters as guests through a vine-twining polymerization process, which has been performed in the glucan phosphorylase (GP)-catalyzed enzymatic polymerization field to fabricate supramolecules and other nanostructured materials. Amylose, which is a representative abundant glucose polymer (polysaccharide) with left-handed helical conformation, is well known to include a number of hydrophobic guest molecules with suitable geometry and size in its cavity to construct helical inclusion complexes. Pure amylose is prepared through enzymatic polymerization of α-d-glucose 1-phosphate as a monomer using a maltooligosaccharide as a primer, catalyzed by GP. It is reported that the elongated amylosic chain at the nonreducing end in enzymatic polymerization twines around guest polymers with suitable structures and moderate hydrophobicity, which is dispersed in aqueous polymerization media, to form amylosic nanostructured inclusion complexes. As the image of this system is similar to how vines of a plant grow around a support rod, this polymerization has been named ‘vine-twining polymerization’. In particular, the helical inclusion behavior of the enzymatically produced amylose toward hydrophobic polyesters depending on their structures, e.g., chain lengths and substituents, has been systematically investigated in the vine-twining polymerization field. Furthermore, amylosic supramolecular network materials, such as hydrogels, are fabricated through vine-twining polymerization by using copolymers, where hydrophobic polyester guests or maltooligosaccharide primers are covalently modified on hydrophilic main-chain polymers. The vine-twining polymerization using such copolymers in the appropriate systems induces the formation of amylosic nanostructured inclusion complexes among them, which act as cross-linking points, giving rise to supramolecular networks at the nanoscale. The resulting materials form supramolecular hydrogels, films, and microparticles.

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Kwaśniewska-Karolak, I., E. Nebesny, and J. Rosicka-Kaczmarek. "Characterization of Amylose-lipid Complexes Derived from Different Wheat Varieties and their Susceptibility to Enzymatic Hydrolysis." Food Science and Technology International 14, no. 1 (February 2008): 29–37. http://dx.doi.org/10.1177/1082013208089986.

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Starches from eight wheat varieties were analyzed for contents of dry matter, protein, pentosans, apparent and total amylose, total lipids, starch lipids, phosphorus, lysophospholipids and amylose-lipid complex (AML). Processes of starch gelatinization, reversible dissociation of AMLs and its susceptibility to degradation by α-amylase were monitored by differential scanning calorimetry (DSC). Degree of crystallinity of starches were evaluated based on X-ray diffraction pattern. Starches from different wheat varieties show some slight differences in terms of chemical composition, thermal properties and susceptibility to enzymatic hydrolysis. Endotherms and exotherms of most starch samples obtained by DSC contained single peaks, which indicated that AML complexes existed in one polymorphic form. Only AMLs formed by amylose from Symfonia cultivar was reflected by the double-peak exotherm on cooling of starch gel. Our studies showed that there was no correlation between AML content and enthalpy of its degradation in native starch. During enzymatic hydrolysis of starch AML complex in all examined starches underwent considerable degradation. Enthalpies of dissociation of AMLs, which remained after amylolysis were significantly lowered (80—90%) as compared to that of undigested starch. The susceptibility of AMLs to degradation by α-amylase did not depend on its amount (based on calculation from LPLs), but probably on its structure.

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Kadokawa, Jun-ichi. "Synthesis of Amylosic Supramolecular Materials by Glucan Phosphorylase-Catalyzed Enzymatic Polymerization According to the Vine-Twining Approach." Synlett 31, no. 07 (January 30, 2020): 648–56. http://dx.doi.org/10.1055/s-0039-1690804.

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This article overviews the synthesis of amylosic supramolecular materials through inclusion complexation in glucan phosphorylase (GP)-catalyzed enzymatic polymerization. Amylose is a polysaccharide that is known to form inclusion complexes with a number of hydrophobic small guest molecules. A pure amylose can be synthesized by the enzymatic polymerization of α-d-glucose 1-phosphate monomer with a maltooligosaccharide primer catalyzed by GP. The author has reported that the propagating amylosic chain in the enzymatic polymerization twines around hydrophobic polymers present in aqueous reaction media to form supramolecular inclusion complexes. As it is similar to the way that vines of a plant grow around a rod, this polymerization is termed ‘vine-twining polymerization’. Amylosic supramolecular network materials have been obtained through the vine-twining polymerization by using copolymers, where hydrophobic guest polymers are covalently grafted on hydrophilic main-chain polymers. The enzymatically produced amylosic chains form complexes with the guest polymers among graft copolymers, which act as cross-linking points to form supramolecular networks, resulting in the formation of soft materials, such as gels and films. Vine-twining polymerization using appropriately designed guest polymers has also been performed, which leads to supramolecular products that exhibit new functionality.1 Introduction2 Vine-Twining Polymerization to Form Supramolecular Inclusion Complexes3 Selective Complexation of Amylose toward Guest Polymers in Vine-Twining Polymerization4 Hierarchical Architecture of Amylosic Supramolecular Network Materials by Vine-Twining Polymerization Approach5 Hierarchical Fabrication of Amylosic Supramolecular Materials by Vine-Twining Polymerization Using Designed Guest Polymers6 Conclusions

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Alqah, Hesham, M. S. Alamri, A. A. Mohamed, S. Hussain, A. A. Qasem, M. A. Ibraheem, and I. A. Ababtain. "The Effect of Germinated Sorghum Extract on the Pasting Properties and Swelling Power of Different Annealed Starches." Polymers 12, no. 7 (July 18, 2020): 1602. http://dx.doi.org/10.3390/polym12071602.

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Starches were extracted from chickpea (C.P.), corn (C.S.), Turkish bean (T.B.), sweet potato (S.P.S.), and wheat starches (W.S.). These starches exhibited different amylose contents. The extracted starches were annealed in excess water and in germinated sorghum extract (GSE) (1.0 g starch/9 mL water). The α-amylase concentration in the GSE was 5.0 mg/10 mL. Annealing was done at 40, 50, and 60 °C for 30 or 60 min. The pasting properties of annealed starches were studied using Rapid Visco-Analyzer (RVA), in addition to the swelling power. These starches exhibited diverse pasting properties as evidenced by increased peak viscosity with annealing, where native starches exhibited peak viscosity as: 2828, 2438, 1943, 2250, and 4601 cP for the C.P., C.S., T.B., W.S., and S.P.S., respectively, which increased to 3580, 2482, 2504, 2514, and 4787 cP, respectively. High amylose content did not play a major role on the pasting properties of the tested starches because sweet potato starch (S.P.S.) (22.4% amylose) exhibited the highest viscosity, whereas wheat starch (W.S.) (25% amylose) had the least. Therefore, the dual effects of granule structure and packing density, especially in the amorphous region, are determinant factors of the enzymatic digestion rate and product. Swelling power was found to be a valuable predictive tool of amylose content and pasting characteristics of the tested starches. The studied starches varied in their digestibility and displayed structural differences in the course of α-amylase digestion. Based on these findings, W.S. was designated the most susceptible among the starches and S.P.S. was the least. The most starch gel setback was observed for the legume starches, chickpeas, and Turkish beans (C.P. 2553 cP and T.B. 1172 cP). These results were discussed with regard to the underlying principles of swelling tests and pasting behavior of the tested starches. Therefore, GSE is an effortless economic technique that can be used for starch digestion (modification) at industrial scale.

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Chebil, A., M. Tibini, M. Ghabi, A. Abbess, O. Kharrat, H. Jaafoura, I. Riahi, R. Lahieni, and M. Ben Salah. "Amylose systémique révélée par un goitre amyloïde." Annales d'Endocrinologie 82, no. 5 (October 2021): 294. http://dx.doi.org/10.1016/j.ando.2021.08.107.

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Chraibi, A., L. Msyah, O. Laaribi, A. Marrakchi, and A. Hafidi. "Goitre amyloïde : première manifestation d’une amylose systémique." Annales d'Endocrinologie 70, no. 1 (March 2009): 80–82. http://dx.doi.org/10.1016/j.ando.2007.10.002.

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Lagha, E. K., I. M'sakni, F. Bougrine, B. Laabidi, D. B. Ghachem, and A. Bouziani. "Goitre amyloïde : première manifestation d’une amylose systémique." Annales françaises d'Oto-rhino-laryngologie et de Pathologie Cervico-faciale 127, no. 3 (June 2010): 134–36. http://dx.doi.org/10.1016/j.aforl.2010.02.013.

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Quek, Wei Ping, Wenwen Yu, Glen P. Fox, and Robert G. Gilbert. "Molecular structure-property relations controlling mashing performance of amylases as a function of barley grain size." Amylase 3, no. 1 (January 1, 2019): 1–18. http://dx.doi.org/10.1515/amylase-2019-0001.

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Abstract In brewing, amylases are key enzymes in hydrolyzing barley starch to sugars, which are utilized in fermentation to produce ethanol. Starch fermentation depends on sugars produced by amylases and starch molecular structure, both of which vary with barley grain size. Grain size is a major industrial specification for selecting barley for brewing. An in-depth study is given of how enzyme activity and starch structure vary with grain size, the impact of these factors on fermentable sugar production, and the underlying mechanisms. Micro-malting and mashing experiments were based on commercial methodologies. Starch molecular structural parameters were obtained using size-exclusion chromatography, and fitted using biosynthesis-based models. Correlation analysis using the resulting parameters showed larger grain sizes contained fewer long amylopectin chains, higher amylase activities and soluble protein level. Medium grain sizes released most sugars during mashing, because of higher starch utilization from the action of amylases, and shorter amylose chains. As starch is the substrate for amylase-driven fermentable sugars production, measuring its structure should be a prime indication for mashing performance, and should be used as an industry specification when selecting barley grains for brewing.

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Umemoto, Takayuki, and Kazuo Terashima. "Research note: Activity of granule-bound starch synthase is an important determinant of amylose content in rice endosperm." Functional Plant Biology 29, no. 9 (2002): 1121. http://dx.doi.org/10.1071/pp01145.

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Effects of temperature on amylose synthesis in rice endosperm were investigated using 13 cultivars known to differ in amylose contents in endosperm. Both amylose content and granule-bound starch synthase (GBSS) activity was increased when endosperms were developed under lower temperature in low- and medium-amylose cultivars, while this was not the case for high-amylose cultivars. Amylose content in high-amylose cultivars was stable under different temperature, with varying GBSS activity. A nearly linear correlation between GBSS activity and amylose content was observed as far as activity levels about 250 nmol min-1 g-1 DW. These results suggest that GBSS activity is an important determinant of amylose content in endosperm of low- and medium-amylose cultivars, while factors other than the enzyme activity limit amylose synthesis in the high-amylose cultivars.

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Bertolotti, A., G. Dupire, E. Amazan, J. Seneschal, O. Cogrel, M. S. Doutre, B. Richert, M. Beylot-Barry, J. André, and A. Taieb. "Amylose unguéale : manifestation révélatrice d’une amylose systémique ?" Annales de Dermatologie et de Vénéréologie 139, no. 12 (December 2012): B202. http://dx.doi.org/10.1016/j.annder.2012.10.340.

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СУЛЕЙМЕНОВА, Ж. Б., Р. К. БЛИЕВА, Г. Б. НАРМУРАТОВА, Г. К. ЖУМАГАЛИЕВА, А. К. КАЛИЕВА, Г. A. AЛЬ-MААЛИ, Г. Б. АДМАНОВА, and Б. БАҚЫТЖАНҚЫЗЫ. "α-AMYLASE AND ITS APPLICATIONS IN INDUSTRY." МИКРОБИОЛОГИЯ ЖӘНЕ ВИРУСОЛОГИЯ, no. 3(42) (September 20, 2023): 52–67. http://dx.doi.org/10.53729/mv-as.2023.03.03.

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Амилазы представляют собой группу ферментов, которые широко распространены в микробном, растительном и животном мире. Они разлагают крахмал и родственные полимеры с образованием олигосахаридов. По субстратной специфичности амилазы классифицируются на α- и β- амилазу, которые катализируют гидролиз гликозидных связей в амилозе и амилопектине. Настоящий обзор посвящен ферменту α-амилаза, который составляет основную долю ферментов на мировом рынке и находит широкое применение в разных отраслях промышленности, таких как пищевая, текстильная, бумажная, крахмалоперерабатывающая, где он полностью заменил химический гидролиз. Amylases are a group of enzymes that are widely distributed in microbial, plant and animal kingdoms. They degrade starch and related polymers to small oligosaccharides. By substrate specificity, amylases are classified to α-, and β- amylases, which catalyze the hydrolysis of glycoside bonds in amylose and amylopectin. This review focuses on the microbial α-amylase, which has potential application in a wide number of industrial processes such as food, textile, paper, starch processing, where enzymes have completely replaced chemical hydrolysis.

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Rani, Anam, and Usman Ali. "Degree-Based Topological Indices of Polysaccharides: Amylose and Blue Starch-Iodine Complex." Journal of Chemistry 2021 (April 1, 2021): 1–10. http://dx.doi.org/10.1155/2021/6652014.

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Starch is a polymer of glucose where alpha-linkages are associated with glucopyranose units. It comprises a mixture of amylose and amylopectin. Furthermore, amylose is a linear chain of hundreds of glucose molecules. Starches are not allowed to be dissolved in water. They can be digested by breaking down alpha bonds (glycosidic bonds). Its cyclic degradation products, called cyclodextrins, are the best role models for amylose. They can be considered simple turns of the amylose propeller that has imploded into a circular path. Both humans and animals have amylases, which allow them to digest starches. The important sources of starch include potatoes, rice, wheat, and maize for human consumption. The production of starches is how plants store glucose. The blue colour of starch produced by an iodine solution or iodine reaction is used for its identification. Polysaccharides with a reduced degree of polymerization, known as dextrins, are produced in the starch’s partial acid hydrolysis. Complete hydrolysis leads to glucose. In this article, we compute the topological properties: Zagreb index M 1 Γ and M 2 Γ , Randić index R α Γ for α = − 1 / 2 , − 1 , 1 / 2 , 1 , atom-bond connectivity index ABC Γ , geometric-arithmetic index GA Γ , fourth atom-bond connectivity index ABC 4 Γ , fifth geometric-arithmetic index GA 5 Γ , and degree-based topological indices of a graph Γ representing polysaccharides, namely, amylose and blue starch-iodine complex. In the end, we compare these indices and depict their graphic behavior.

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Wang, Chaofan, Na Ji, Lei Dai, Yang Qin, Rui Shi, Liu Xiong, and Qingjie Sun. "The Mechanism Underlying the Amylose-Zein Complexation Process and the Stability of the Molecular Conformation of Amylose-Zein Complexes in Water Based on Molecular Dynamics Simulation." Foods 12, no. 7 (March 27, 2023): 1418. http://dx.doi.org/10.3390/foods12071418.

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The aim of this study was to employ molecular dynamics simulations to elucidate the mechanism involved in amylose–zein complexation and the stability of the molecular conformation of amylose–zein complexes in water at the atomic and molecular levels. The average root mean square deviation and radius of gyration were lower for amylose–zein complexes (1.11 nm and 1 nm, respectively) than for amylose (2.13 nm and 1.2 nm, respectively), suggesting a significantly higher conformational stability for amylose–zein complexes than for amylose in water. The results of radial distribution function, solvent-accessible surface area, and intramolecular and intermolecular hydrogen bonds revealed that the amylose–zein interaction inhibited water permeation into the amylose cavity, leading to enhanced conformational stabilities of the V-type helical structure of amylose and the amylose–zein complexes. Furthermore, the amylose in amylose–zein complexes displayed the thermodynamically stable 4C1 conformation. These findings can provide theoretical guidance in terms of the application of protein on starch processing aiming to improve the physicochemical and functional properties of starch (such as swelling capacity, pasting properties, and digestibility) for developing novel low-digestibility starch–protein products.

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Wang, Yamei, Yixiong Tian, Xiaofeng Ban, Caiming Li, Yan Hong, Li Cheng, Zhengbiao Gu, and Zhaofeng Li. "Substrate Selectivity of a Novel Amylo-α-1,6-glucosidase from Thermococcus gammatolerans STB12." Foods 11, no. 10 (May 16, 2022): 1442. http://dx.doi.org/10.3390/foods11101442.

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Amylo-α-1,6-glucosidase (EC 3.2.1.33, AMY) exhibits hydrolytic activity towards α-1,6-glycosidic bonds of branched substrates. The debranching products of maltodextrin, waxy corn starch and cassava starch treated with AMY, pullulanase (EC 3.2.1.41, PUL) and isoamylase (EC 3.2.1.68, ISO), were investigated and their differences in substrate selectivity and debranching efficiency were compared. AMY had a preference for the branched structure with medium-length chains, and the optimal debranching length was DP 13–24. Its optimum debranching length was shorter than ISO (DP 25–36). In addition, the debranching rate of maltodextrin treated by AMY for 6 h was 80%, which was 20% higher than that of ISO. AMY could decompose most of the polymerized amylopectin in maltodextrin into short amylose and oligosaccharides, while it could only decompose the polymerized amylopectin in starch into branched glucan chains and long amylose. Furthermore, the successive use of AMY and β-amylase increased the hydrolysis rate of maltodextrin from 68% to 86%. Therefore, AMY with high substrate selectivity and a high catalytic capacity could be used synergistically with other enzyme preparations to improve substrate utilization and reduce reaction time. Importantly, the development of a novel AMY provides an effective choice to meet different production requirements.

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34

Vitol, I. S., E. P. Meleshkina, and G. N. Pankratov. "Bran from composite grain mixture as an object of deep processing. Part 2. Carbohydrate-amylase and lipid complexes." Food systems 6, no. 1 (April 7, 2023): 22–28. http://dx.doi.org/10.21323/2618-9771-2023-6-1-22-28.

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Polycomponent bran obtained by joint grinding of a grain mixture from cereals (wheat), legumes (lentils) and oilseeds (flax) should be considered as a valuable secondary raw material, the use of which for deep processing will make it possible to obtain various food and feed ingredients. An assessment of the carbohydrate-amylase and lipid complexes of the three variants of multicomponent bran showed that the ratio of amylose and amylopectin in the starch of three-component bran is almost the same, however, in lentil-flax bran, the proportion of amylose is 1.6 times higher than in the first two variants. The specific activity of amylases in three-component bran is about 2 times higher than in lentil-flax bran. In addition, the latter are characterized by a higher content of reducing sugars and fiber. The molecular weight of amylases isolated from three-component bran, according to gel chromatography, was: α-amylase — 40,000 Da; β-amylase — 60,000 Da. It has been established that the addition of flax seeds to the grinding mixture significantly increases the fat content in bran 6.4; 6.0 and 12.9%. The fatty acid composition of the studied bristles is characterized by the predominance of unsaturated fatty acids. At the same time, the ratio of essential acids — linoleic acid (ɷ‑6) to α-linolenic acid (ɷ‑3) in favor of the most deficient α-linolenic acid — was typical for lentil-flax bran and amounted to 1:4.2. The activity of alkaline lipases, which exhibit their effect at pH 8.0 (mainly cereal lipases), and acid lipases (mainly oilseed lipases) with an optimum of action at pH 4.7 in three-component bran samples are approximately the same, and lentil-flax bran is characterized by a high specific acid lipase activity, which is approximately 4.2 times higher than the activity of acid lipases of three-component bran. The data obtained, along with data on the characteristics of the protein-proteinase complex of the studied types of bran, will be used in the development of methods for enzymatic modification (deep processing) and in the preparation of components for the creation of new food products with increased nutritional and biological value.

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35

Grateau, G. "Amylose AA." EMC - Néphrologie 1, no. 1 (January 2006): 1–6. http://dx.doi.org/10.1016/s1762-0945(06)75731-x.

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Ferré, Romuald, Marie-Christine Mathieu, and Corinne Balleyguier. "Amylose mammaire." Imagerie de la Femme 18, no. 1 (March 2008): 58–61. http://dx.doi.org/10.1016/s1776-9817(08)71703-6.

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Stojanovic, Katia Stankovic, Sophie Georgin-Lavialle, and Gilles Grateau. "Amylose AA." Néphrologie & Thérapeutique 13, no. 4 (June 2017): 258–64. http://dx.doi.org/10.1016/j.nephro.2017.03.001.

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38

Stankovic, Katia, and Gilles Grateau. "Amylose AA." Néphrologie & Thérapeutique 4, no. 4 (July 2008): 281–87. http://dx.doi.org/10.1016/j.nephro.2008.02.002.

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39

Elyes, Hamayed, Pierre-Yves Brillet, and Jacques Foucher. "Amylose pulmonaire." La Presse Médicale 35, no. 3 (March 2006): 547–48. http://dx.doi.org/10.1016/s0755-4982(06)74632-2.

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40

Jaccard, A., E. Desport, D. Mohty, and F. Bridoux. "Amylose AL." La Revue de Médecine Interne 36, no. 2 (February 2015): 89–97. http://dx.doi.org/10.1016/j.revmed.2014.08.003.

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41

Dao, T., K. Bouhier, R. Gloro, V. Rouleau, and P. Rousselot. "Amylose hépatique." EMC - Hépato-Gastroenterologie 2, no. 4 (October 2005): 330–38. http://dx.doi.org/10.1016/j.emchg.2005.07.004.

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Dao, T., K. Bouhier, R. Gloro, V. Rouleau, and P. Rousselot. "Amylose hépatique." EMC - Hépatologie 1, no. 1 (January 2006): 1–6. http://dx.doi.org/10.1016/s1155-1976(05)40573-2.

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43

Iwamoto, Masa-aki, and Jun-ichi Kadokawa. "Vine-Twining Inclusion Behavior of Amylose towards Hydrophobic Polyester, Poly(β-propiolactone), in Glucan Phosphorylase-Catalyzed Enzymatic Polymerization." Life 13, no. 2 (January 20, 2023): 294. http://dx.doi.org/10.3390/life13020294.

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This study investigates inclusion behavior of amylose towards, poly(β-propiolactone) (PPL), that is a hydrophobic polyester, via the vine-twining process in glucan phosphorylase (GP, isolated from thermophilic bacteria, Aquifex aeolicus VF5)-catalyzed enzymatic polymerization. As a result of poor dispersibility of PPL in sodium acetate buffer, the enzymatically produced amylose by GP catalysis incompletely included PPL in the buffer media under the general vine-twining polymerization conditions. Alternatively, we employed an ethyl acetate–sodium acetate buffer emulsion system with dispersing PPL as the media for vine-twining polymerization. Accordingly, the GP (from thermophilic bacteria)-catalyzed enzymatic polymerization of an α-d-glucose 1-phosphate monomer from a maltoheptaose primer was performed at 50 °C for 48 h in the prepared emulsion to efficiently form the inclusion complex. The powder X-ray diffraction profile of the precipitated product suggested that the amylose-PPL inclusion complex was mostly produced in the above system. The 1H NMR spectrum of the product also supported the inclusion complex structure, where a calculation based on an integrated ratio of signals indicated an almost perfect inclusion of PPL in the amylosic cavity. The prevention of crystallization of PPL in the product was suggested by IR analysis, because it was surrounded by the amylosic chains due to the inclusion complex structure.

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Liu, Haiying, Yongcai Lai, Zhenhua Xu, Zhonliang Yang, Yanmin Yu, and Ping Yan. "Expression Characteristics and Sequence Variation Analysis of Rice Starch Regulator 1 Gene in Japonica Rice With Transgressive Variation." International Journal of Agricultural and Environmental Information Systems 14, no. 1 (February 3, 2023): 1–12. http://dx.doi.org/10.4018/ijaeis.317417.

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The parents and transgressive variation lines of hybrids with significant difference in amylose content were selected to compare and analyze the accumulation characteristics of amylose and the change of OsRSR1 expression in grains in the process of grain filling, and the PCR technology was used to clone the OsRSR1 gene base sequence of four varieties. The results showed that the amylose content in grains increased gradually with grain filling process, the amylose content of offspring and parents with high amylose content were higher than the offspring and parents with low amylose content, hybrids could obtain the transgressive variation lines through the continuous directional selection of amylose content in grain, and the accumulation of amylose content in grain was closely related to genotypes. The expression quantity of OsRSR1 gene in grain was increasing during the grain filling process, the amylose content of grain was closely related to the activity of OsRSR1 gene, and the expression of grain OsRSR1 gene could also produce transgressive variation.

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45

Ang, Kim, Carla Bourgy, Haelee Fenton, Ahmed Regina, Marcus Newberry, Dean Diepeveen, Domenico Lafiandra, Sara Grafenauer, Wendy Hunt, and Vicky Solah. "Noodles Made from High Amylose Wheat Flour Attenuate Postprandial Glycaemia in Healthy Adults." Nutrients 12, no. 8 (July 22, 2020): 2171. http://dx.doi.org/10.3390/nu12082171.

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Previous research has not considered the effect of high amylose wheat noodles on postprandial glycaemia. The aim of the study is to investigate the effect of consumption of high amylose noodles on postprandial glycaemia over 2-h periods by monitoring changes in blood glucose concentration and calculating the total area under the blood glucose concentration curve. Twelve healthy young adults were recruited to a repeated measure randomised, single-blinded crossover trial to compare the effect of consuming noodles (180 g) containing 15%, 20% and 45% amylose on postprandial glycaemia. Fasting blood glucose concentrations were taken via finger-prick blood samples. Postprandial blood glucose concentrations were taken at 15, 30, 45, 60, 90 and 120 min. Subjects consuming high amylose noodles made with flour containing 45% amylose had significantly lower blood glucose concentration at 15, 30 and 45 min (5.5 ± 0.11, 6.1 ± 0.11 and 5.6 ± 0.11 mmol/L; p = 0.01) compared to subjects consuming low amylose noodles with 15% amylose (5.8 ± 0.12, 6.6 ± 0.12 and 5.9 ± 0.12 mmol/L). The total area under the blood glucose concentration curve after consumption of high amylose noodles with 45% amylose was 640.4 ± 9.49 mmol/L/min, 3.4% lower than consumption of low amylose noodles with 15% amylose (662.9 ± 9.49 mmol/L/min), p = 0.021. Noodles made from high amylose wheat flour attenuate postprandial glycaemia in healthy young adults, as characterised by the significantly lower blood glucose concentration and a 3.4% reduction in glycaemic response.

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Li, Changfeng, Yi Ji, Shaobo Zhang, Xiaoyan Yang, Robert Gilbert, Songnan Li, and Enpeng Li. "Amylose Inter-Chain Entanglement and Inter-Chain Overlap Impact Rice Quality." Foods 11, no. 10 (May 23, 2022): 1516. http://dx.doi.org/10.3390/foods11101516.

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Retrogradation of cooked rice happens in two ways: one is by the formation of ordered structures, and the other is through intra- and inter-chain entanglement and inter-chain overlap, which in turn are affected by the amylose chain-length distribution. Both entanglement and overlap could affect rice texture. Here, four amylose samples were isolated from starch by precipitation from a dimethyl sulfoxide solution with butan-1-ol and isoamyl alcohol. Following enzymatic debranching, they were then characterized using size-exclusion chromatography. Amylose solutions (10%, m/v) were made by dissolving amylose in 90% (v/v) DMSO. Amylose gels (10%, w/v) were made by dissolving amylose powders into hot water, followed by cooling. The rigidity of the amylose gels and the structural order were measured using a texture analyzer and X-ray diffractometer, respectively. In the amylose solution, for a given mass of polymer in a fixed amount of solvent, the total occupied volume was reduced when the polymer molecular weight was smaller, resulting in less inter-chain overlap and a lower viscosity of the amylose solution. The overall mobility and diffusion of the molecules were inversely related to the square of the molecular weight until the gelation concentration. Thus, amylose gels in which amylose had a lower molecular weight had a greater chance to permeate into other molecules, which counterintuitively led to more inter-chain entanglement and more rigid amylose gels during retrogradation. This information could help rice breeders improve rice quality by using the molecular structure of starch as a guide.

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Sissons, Mike, Samuela Palombieri, Francesco Sestili, and Domenico Lafiandra. "Impact of Variation in Amylose Content on Durum Wheat cv. Svevo Technological and Starch Properties." Foods 12, no. 22 (November 13, 2023): 4112. http://dx.doi.org/10.3390/foods12224112.

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Reserve starch, the main component of durum wheat semolina, is constituted of two glucan homopolymers (amylose and amylopectin) that differ in their chemical structure. Amylose is mainly a linear structure formed of α-1,4-linked glucose units, with a lower polymerization degree, whereas amylopectin is a highly branched structure of α-1,4-chains linked by α-1,6-bonds. Variation of the amylose/amylopectin ratio has a profound effect on the starch properties which may impact the wheat technological and nutritional characteristics and their possible use in the food and non-food sector. In this work a set of genotypes, with a range of amylose from 14.9 to 57.8%, derived from the durum wheat cv. Svevo was characterised at biochemical and rheological level and used to produce pasta to better understand the role of amylose content in a common genetic background. A negative correlation was observed between amylose content and semolina swelling power, starch peak viscosity, and pasta stickiness. A worsening of the firmness was observed in the low amylose pasta compared to the control (cv. Svevo), whereas no difference was highlighted in the high amylose samples. The resistant starch was higher in the high amylose (HA) pasta compared to the control and low amylose (LA) pasta. Noteworthy, the extent of starch digestion was reduced in the HA pasta while the LA genotypes offered a higher starch digestion, suggesting other possible applications.

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Tan, F. P. Y., L. F. Wang, E. Beltranena, and R. T. Zijlstra. "261 Increasing dietary amylose reduces rate of starch digestion and increases microbial fermentation in weaned pigs." Journal of Animal Science 98, Supplement_3 (November 2, 2020): 86. http://dx.doi.org/10.1093/jas/skaa054.152.

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Abstract Beneficial effects of SCFA in modulating gut health stimulated interest on dietary strategies to increase intestinal microbial activity and digesta SCFA. Amylose has lower apparent ileal digestibility (AID) than amylopectin. In the large intestine, undigested starch is fermented by microbes producing SCFA. The objective was to determine effects of increasing dietary amylose on starch flow and metabolite profile along the intestinal tract in weaned pigs. Weaned pigs (n=32; initial BW, 8.4 kg) were randomly allocated to 4 diets containing 67% starch with 0, 20, 35, or 70% amylose in a randomized complete block design. On day 21, pigs were euthanized to collect digesta and feces for evaluating starch digestion and metabolite profiles. Apparent hindgut fermentation (AHF) was calculated as apparent total tract digestibility minus AID. Feed intake was 12% lower (P < 0.05) and growth rate was 18% lower (P < 0.05) for pigs fed 70% amylose than pigs fed 0, 20, or 35% amylose. Feed efficiency was greatest (P < 0.05) for pigs fed with 35% amylose. The AID of starch was 44% lower (P < 0.05) in pigs fed 70% amylose. Starch was completely digested by the proximal colon in pigs fed 0, 20, or 35% amylose, but AHF of starch was 14% greater (P < 0.05) in pigs fed 70% amylose. Increasing dietary amylose did not alter digesta SCFA in the small intestine, but increased (P < 0.05) digesta SCFA in the cecum, specifically acetate and total SCFA, and increased (P < 0.05) propionate and valerate in all sections of the colon. In conclusion, increasing dietary amylose in weaned pigs stimulated hindgut fermentation of starch with a corresponding increase in digesta total SCFA in the cecum and colon. Optimizing dietary amylose may exert its effect as dietary prebiotic while promoting an optimal growth rate in young pigs.

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Lim, Si J., Siti Nur Hazwani-Oslan, and Siti N. Oslan. "Purification and characterisation of thermostable α-amylases from microbial sources." BioResources 15, no. 1 (November 26, 2019): 2005–29. http://dx.doi.org/10.15376/biores.15.1.2005-2029.

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α-Amylases (E.C 3.2.1.1) hydrolyse starch into smaller moieties such as maltose and glucose by breaking α-1,4-glycosidic linkages. The application of α-amylases in various industries has made the large-scale productions of these enzymes crucial. Thermostable α-amylase that catalyses starch degradation at the temperatures higher than 50 °C is favourable in harsh industrial applications. Due to ease in genetic manipulation and bulk production, this enzyme is most preferably produced by microorganisms. Bacillus sp. and Escherichia coli are commonly used microbial expression hosts for α-amylases (30 to 205 kDa in molecular weight). These amylases can be purified using ultrafiltration, salt precipitation, dialysis, and column chromatography. Recently, affinity column chromatography has shown the most promising result where the recovery rate was 38 to 60% and purification up to 13.2-fold. Microbial thermostable α-amylases have the optimum temperature and pH ranging from 50 °C to 100 °C and 5.0 to 10.5, respectively. These enzymes have high specificity towards potato starch, wheat starch, amylose, and amylopectin. EDTA (1 mM) gave the highest inhibitory effect (79%), but Ca2+ (5 mM) was the most effective co-factor with 155%. This review provides insight regarding thermostable α-amylases obtained from microbial sources for industrial applications.

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Lim, Si J., Siti Nur Hazwani-Oslan, and Siti N. Oslan. "Purification and characterisation of thermostable α-amylases from microbial sources." BioResources 15, no. 1 (November 16, 2019): 2005–29. http://dx.doi.org/10.15376/biores.15.1.lim.

Full text

Abstract:

α-Amylases (E.C 3.2.1.1) hydrolyse starch into smaller moieties such as maltose and glucose by breaking α-1,4-glycosidic linkages. The application of α-amylases in various industries has made the large-scale productions of these enzymes crucial. Thermostable α-amylase that catalyses starch degradation at the temperatures higher than 50 °C is favourable in harsh industrial applications. Due to ease in genetic manipulation and bulk production, this enzyme is most preferably produced by microorganisms. Bacillus sp. and Escherichia coli are commonly used microbial expression hosts for α-amylases (30 to 205 kDa in molecular weight). These amylases can be purified using ultrafiltration, salt precipitation, dialysis, and column chromatography. Recently, affinity column chromatography has shown the most promising result where the recovery rate was 38 to 60% and purification up to 13.2-fold. Microbial thermostable α-amylases have the optimum temperature and pH ranging from 50 °C to 100 °C and 5.0 to 10.5, respectively. These enzymes have high specificity towards potato starch, wheat starch, amylose, and amylopectin. EDTA (1 mM) gave the highest inhibitory effect (79%), but Ca2+ (5 mM) was the most effective co-factor with 155%. This review provides insight regarding thermostable α-amylases obtained from microbial sources for industrial applications.

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Journal articles on the topic 'Amylose'

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