scholarly journals Use of pullulanase as a biocatalyst for starch hydrolysis: Part 1. Study of the effect of pullulanase on maize amylopectin starch

Food systems ◽  
2022 ◽  
Vol 4 (4) ◽  
pp. 269-277
Author(s):  
A. A. Papakhin ◽  
Z. M. Borodina
Keyword(s):  
Mass Fraction ◽  
High Performance ◽  
Control Experiment ◽  
Binding Capacity ◽  
Starch Hydrolysis ◽  
Rotational Viscometer ◽  
New Methods ◽  
Debranching Enzymes ◽  
Gelatinized Starch ◽  
Reducing Substances

The use of debranching enzymes in starch hydrolysis is a topical direction for obtaining new types of starch products with controlled properties and a potential for the further use. The aim of the work was to study an effect of pullulanase (EC3.2.1.41) on maize amylopectin starch in the native and gelatinized state. The objects of the research were maize amylopectin starch and enzyme preparation Promozyme D6 (Novozymes, Denmark). High-performance liquid chromatography (HPLC) was used to determine the carbohydrate composition of hydrolysates. The mass fraction of reducing substances (RS) was determined by the Lane and Eynon method. A rotational viscometer was used to measure dynamic viscosity of the starch hydrolysis products. It was found that analyzed starch in the native state showed low enzymatic sensitivity to the action of pullulanase with insignificant changes in viscosity, solubility and iodine binding capacity of the samples. Pullulanase showed the highest effect on gelatinized starch during the first eight hours of incubation. After eight hours, the maximum degree of starch hydrolysis by pullulanase at a dose of 10 units/g dry matter (DM) was 4.7% on DM basis, iodine binding capacity of the hydrolysate was D600 = 0.343 (in the control experiment D600 = 0.154), and the viscosity of the hydrolysate decreased from 7887 mPa · s to 4.3 mPa · s. Hydrolysates cooled to 8 °C and held for 20 hours along with hydrolysates that were not cooled showed high susceptibility to attack by glucoamilase (97–98%) at 60 °C and 24 hours of saccharification, which suggested the absence of their resistance to the action of glucoamilase in the conditions of the experiment. The use of pullulanase in dextrinization of the analyzed starch, which was gelatinized and partly hydrolyzed by α-amylase (RS6.1%), enabled obtaining hydrolysates with the mass fraction of reducing substances in a range of 10–24% on DM basis with the process duration of 2 to 24 hours and the enzyme dose of 2–10 units, which contained mainly maltotriose, maltohexose and maltoheptose with their total amount of 45–60% on DM basis. The results indicate a need for further research of the biocatalytic action of pullulanase to develop new methods for enzymatic modification of starch.

scholarly journals Development and certification of a reference material for zearalenone in maize germ oil

2021 ◽  
Author(s):  
Juliane Riedel ◽  
Sebastian Recknagel ◽  
Diana Sassenroth ◽  
Tatjana Mauch ◽  
Sabine Buttler ◽  
...  
Keyword(s):  
Reference Material ◽  
Reference Materials ◽  
Mass Fraction ◽  
High Performance ◽  
Certified Reference Materials ◽  
Maximum Level ◽  
Whole Process ◽  
Commission Regulation ◽  
Maize Oil ◽  
Maize Germ

AbstractZearalenone (ZEN), an estrogenic mycotoxin produced by several species of Fusarium fungi, is a common contaminant of cereal-based food worldwide. Due to frequent occurrences associated with high levels of ZEN, maize oil is a particular source of exposure. Although a European maximum level for ZEN in maize oil exists according to Commission Regulation (EC) No. 1126/2007 along with a newly developed international standard method for analysis, certified reference materials (CRM) are still not available. To overcome this lack, the first CRM for the determination of ZEN in contaminated maize germ oil (ERM®-BC715) was developed in the frame of a European Reference Materials (ERM®) project according to the requirements of ISO Guide 35. The whole process of CRM development including preparation, homogeneity and stability studies, and value assignment is presented. The assignment of the certified mass fraction was based upon an in-house study using high-performance liquid chromatography isotope dilution tandem mass spectrometry. Simultaneously, to support the in-house certification study, an interlaboratory comparison study was conducted with 13 expert laboratories using different analytical methods. The certified mass fraction and expanded uncertainty (k = 2) of ERM®-BC715 (362 ± 22) μg kg−1 ZEN are traceable to the SI. This reference material is intended for analytical quality control and contributes to the improvement of consumer protection and food safety. Graphical abstract

scholarly journals Improving the marmalade technology by adding a multicomponent fruit-and-berry paste

2021 ◽  
Vol 6 (11 (114)) ◽  
pp. 6-14
Author(s):  
Olga Samokhvalova ◽  
Kateryna Kasabova ◽  
Nataliа Shmatchenko ◽  
Aleksey Zagorulko ◽  
Andrii Zahorulko
Keyword(s):  
Mass Fraction ◽  
Dry Matter ◽  
Nutritional Value ◽  
Raw Materials ◽  
Partial Replacement ◽  
Black Currant ◽  
Reducing Substances ◽  
Improved Technique ◽  
Improved Technology ◽  
Functional Components

The necessity to optimize the nutritional value of marmalade by using physiologically functional ingredients containing vitamins, dietary fiber, minerals, and other useful substances in its composition has been substantiated. Specifically, using the multicomponent fruit-and-berry paste from apples, quince, black currant has been proposed, which is obtained by an improved technique. The technique is characterized by the rapid dehydration (30...45 s, at 50 °C) of the blended paste in a rotor plant to 28...30 % of dry matter. When studying the dependences of the effective viscosity of paste compositions on the shear rate, it was found that the paste that demonstrated the best indicators contained apple in the amount of 40 %; quince ‒ 50 %; black currant ‒ 10 %. It has been experimentally proven that the rational amount of fruit-and-berry paste is 30 % with a decrease in agar by 30 %. This makes it possible to obtain the jelly-fruit marmalade on agar with a mass fraction of moisture of 18 %, a total acidity of 10 degrees, and a mass fraction of reducing substances not more than 28 %. The products have a sweet-sour taste, with a pleasant aftertaste and the smell of black currant, rich purple color, jelly-like form, and non-tight consistency. The strength of the new samples of marmalade with a decrease in the amount of agar is 18.9 kPa, similar to that of control. The improved technology makes it possible to expand the range of "healthy products", which is achieved by the partial replacement of raw materials with a fruit-and-berry paste, which contains a significant number of physiologically functional components. This allows for an increase in the nutritional value of marmalade, as well as a decrease in the formulation amount of agar, which is expensive, by 30 %. In addition, gentle concentration modes improve the process of paste making

scholarly journals A New Construction of High Performance LDPC Matrices for Mobile Networks

Sensors ◽  
2020 ◽  
Vol 20 (8) ◽  
pp. 2300
Author(s):  
Moein Sarvaghad-Moghaddam ◽  
Waheed Ullah ◽  
Dushantha Nalin K. Jayakody ◽  
Sofiène Affes
Keyword(s):  
Information Flow ◽  
Mobile Networks ◽  
High Performance ◽  
Additive White Gaussian Noise ◽  
Iterative Algorithms ◽  
Research Problem ◽  
Optimal Method ◽  
New Methods ◽  
New Construction ◽  
Geometric Designs

Secure and reliable information flow is one of the main challenges in social IoT and mobile networks. Information flow and data integrity is still an open research problem. In this paper, we develop new methods of constructing systematic and regular Low-Density Parity-Check Matrices (LDPCM), inspired by the structure of the Sarrus method and geometric designs. Furthermore, these codes have cyclic structure and therefore, are less complex in computation and also require less memory in hardware implementation. Besides, an optimal method of post-processing for deleting girths four is presented. Numerical results show that the codes constructed by these methods perform well over the additive white Gaussian noise (AWGN) channel when decoded with the sum-product LDPC iterative algorithms. The proposed methods can be very efficient in terms of reducing memory consumption and improving the convergence speed of the decoder particularly in IoT and mobile networks.

scholarly journals Novel 500-GHz Band Waveguide Stepped Septum-Type Circular Polarizer with a New High-Accuracy and Very Small Waveguide Flange

2020 ◽  
Author(s):  
Yutaka Hasegawa ◽  
Hiroyuki Maezawa ◽  
Hideo Ogawa
Keyword(s):  
High Performance ◽  
High Accuracy ◽  
Circular Polarizer ◽  
New Methods ◽  
Position Errors ◽  
Surface Flatness ◽  
Atmospheric Observations ◽  
Dimensional Errors ◽  
Determination Mechanism ◽  
Better Than

Abstract A new waveguide stepped septum-type circular polarizer (SST-CP) was developed to operate in the 500-GHz band for radio astronomical and planetary atmospheric observations. In a previous study, we developed a practical SST-CP for the 230-GHz band. However, several issues prevent this device being easily scaled down to the 500-GHz band, such as manufacturing dimensional errors and waveguide flange position errors. In this study, we developed a new waveguide flange with a high-accuracy position determination mechanism and a very small size of 10 × 10 mm. We also developed a new fabrication technique to obtain very good flatness for the device’s blank materials by high-accuracy polishing using a resin fixture. Using these new methods, the manufactured 500-GHz band SST-CP achieved a cross-polarization talk level of better than – 30 dB at 465–505 GHz, a device surface flatness of within 3 μm, and also the horizontal positioning error of ± 3 μm. These results indicate that the developed 500-GHz band SST-CP has high performance in the high-frequency band, and thus the new manufacturing methods are effective in the 500-GHz band.

scholarly journals In vitro binding of mutagenic heterocyclic aromatic amines by Bifidobacterium pseudocatenulatum G4

2010 ◽  
Vol 1 (2) ◽  
pp. 149-154 ◽  
Author(s):  
F. Faridnia ◽  
A. Hussin ◽  
N. Saari ◽  
S. Mustafa ◽  
L. Yee ◽  
...  
Keyword(s):  
High Performance ◽  
Binding Capacity ◽  
Bifidobacterium Longum ◽  
Heterocyclic Amines ◽  
Heterocyclic Aromatic Amines ◽  
Human Origin ◽  
Bacterial Strains ◽  
In Vitro Binding ◽  
Vitro Binding

Consumption of probiotics has been associated with decreased risk of colon cancer and reported to have antimutagenic/ anti-carcinogenic properties. One possible mechanism for this effect involves physical binding of the mutagenic compounds, such as heterocyclic amines (HCAs), to the bacteria. Therefore, the objective of this study was to examine the binding capacity of bifidobacterial strains of human origin on mutagenic heterocyclic amines which are suspected to play a role in human cancers. In vitro binding of the mutagens Trp-p-2, IQ, MeIQx, 7,8DiMeIQx and PhIP by three bacterial strains in two media of different pH was analysed using high performance liquid chromatography. Bifidobacterium pseudocatenulatum G4 showed the highest decrease in the total HCAs content, followed by Bifidobacterium longum, and Escherichia coli. pH affects binding capacity; the highest binding was obtained at pH 6.8. Gram-positive tested strains were found to be consistently more effective than the gram-negative strain. There were significant decreases in the amount of HCAs in the presence of different cell concentrations of B. pseudocatenulatum G4; the highest decrease was detected at the concentration of 1010 cfu/ml. The results showed that HCAs were able to bind with all bacterial strains tested in vitro, thus it may be possible to decrease their absorption by human intestine and increase their elimination via faeces.

Overexpression of metallothionein decreases sensitivity of pulmonary endothelial cells to oxidant injury

1997 ◽  
Vol 273 (4) ◽  
pp. L856-L865 ◽  
Author(s):  
Bruce R. Pitt ◽  
Margaret Schwarz ◽  
Elizabeth S. Woo ◽  
Emily Yee ◽  
Karla Wasserloos ◽  
...  
Keyword(s):  
Lipid Peroxidation ◽  
Endothelial Cells ◽  
Pulmonary Artery ◽  
Metal Binding ◽  
High Performance ◽  
Binding Capacity ◽  
Peroxyl Radicals ◽  
Intact Cells ◽  
Tert Butyl Hydroperoxide ◽  
Liquid Chromatography Separation

Metallothionein (MT) is a low-molecular-weight cysteine-rich protein with extensive metal binding capacity and potential nonenzymatic antioxidant activity. Despite the sensitivity of vascular endothelium to either heavy metal toxicity or oxidative stress, little is known regarding the role of MT in endothelial cells. Accordingly, we determined the sensitivity of cultured sheep pulmonary artery endothelial cells (SPAEC) that overexpressed MT to tert-butyl hydroperoxide ( t-BOOH), hyperoxia, or 2,2′-azobis(2,4-dimethylvaleronitrile) (AMVN; peroxyl radical generator). Nontoxic doses of 10 μM Cd increased MT levels from 0.21 ± 0.03 to 2.07 ± 0.24 μg/mg and resulted in resistance to t-BOOH and hyperoxia as determined by reduction of Alamar blue or [3H]serotonin transport, respectively. SPAEC stably transfected with plasmids containing either mouse or human cDNA for MT were resistant to both t-BOOH and hyperoxia. In addition, we examined transition metal-independent, noncytotoxic AMVN-induced lipid peroxidation after metabolic incorporation of the oxidant-sensitive fluorescent fatty acid cis-parinaric acid into phospholipids and high-performance liquid chromatography separation. SPAEC that overexpressed MT after gene transfer completely inhibited peroxyl oxidation of phosphatidylserine, phosphatidylcholine, and sphingomyelin (but not phosphatidylethanolamine) noted in wild-type SPAEC. These data show for the first time that MT can 1) protect pulmonary artery endothelium against a diverse array of prooxidant stimuli and 2) directly intercept peroxyl radicals in a metal-independent fashion, thereby preventing lipid peroxidation in intact cells.

A Series of Imidazolyl-Containing Bisphosphonates with Abundant Hydrogen-Bonding Interactions: Syntheses, Structures, and Bone-Binding Affinity

2014 ◽  
Vol 67 (2) ◽  
pp. 192 ◽  
Author(s):  
Ling Qiu ◽  
Jianguo Lin ◽  
Liqing Wang ◽  
Wen Cheng ◽  
Yang Cao ◽  
...  
Keyword(s):  
High Performance ◽  
Binding Capacity ◽  
Imidazole Ring ◽  
Binding Affinities ◽  
Robust Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Hydrogen Bonding Interactions ◽  
Alkyl Groups ◽  
Hydroxy Groups

A series of novel bisphosphonates (BPs) were designed and synthesised as longer-chain analogues of the clinically widely used BP–zoledronate (ZL). They were characterised by mass spectrometry, infrared spectroscopy, NMR spectroscopy, and single-crystal X-ray diffraction. All the crystals are zwitterions with one of the phosphonate oxygen atoms deprotonated and the hydrogen atom transferred to the nitrogen of the imidazole ring. A lot of strong hydrogen bonds are observed among the phosphonate oxygens, hydroxy groups, and protonated nitrogen atoms. An accurate, precise, and robust method was developed to determine the bone binding affinities of BPs based on high performance liquid chromatography. The results show that these five BPs have a strong affinity for hydroxyapatite and the binding capacity decreases when the substituted alkyl groups increase in size.

scholarly journals Characterization and Uncertainty Assessment of a Certified Reference Material of Chloramphenicol in Methanol (GBW(E)082557)

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Mengrui Yang ◽  
Min Wang ◽  
Jian Zhou ◽  
Yinqing Song ◽  
Tongtong Wang
Keyword(s):  
Nuclear Magnetic Resonance ◽  
High Performance Liquid Chromatography ◽  
Mass Fraction ◽  
High Performance ◽  
Uncertainty Assessment ◽  
Stability Study ◽  
Property Value ◽  
Routine Measurement ◽  
Quantitative Nuclear Magnetic Resonance ◽  
Comparability Of Results

Prior to preparation of CRM candidate of chloramphenicol in methanol with a concentration of 100 mg/L, two independent methods including mass balance (MB) and quantitative nuclear magnetic resonance (qNMR) were employed to precisely measure the mass fraction of pure chloramphenicol materials. The mass fraction was assigned to be 99.8% with uncertainty of 0.3%. Homogeneity testing and stability study of chloramphenicol in methanol were examined by using high performance liquid chromatography. Additionally, the uncertainties originating from the process of CRM development were comprehensively evaluated. The experimental results indicate that the property value of this CRM is homogeneous and stable at 4°C for at least six months. The new CRM (GBW(E)082557) can be applicable to calibration of instrument and assurance of accuracy and comparability of results in routine measurement.

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