scholarly journals Effect of Spherical Elements of Biosensors and Bioreactors on the Physicochemical Properties of a Peroxidase Protein

Polymers ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1601
Author(s):  
Yuri D. Ivanov ◽  
Vadim Yu. Tatur ◽  
Tatyana O. Pleshakova ◽  
Ivan D. Shumov ◽  
Andrey F. Kozlov ◽  
...  

External electromagnetic fields are known to be able to concentrate inside the construction elements of biosensors and bioreactors owing to reflection from their surface. This can lead to changes in the structure of biopolymers (such as proteins), incubated inside these elements, thus influencing their functional properties. Our present study concerned the revelation of the effect of spherical elements, commonly employed in biosensors and bioreactors, on the physicochemical properties of proteins with the example of the horseradish peroxidase (HRP) enzyme. In our experiments, a solution of HRP was incubated within a 30 cm-diameter titanium half-sphere, which was used as a model construction element. Atomic force microscopy (AFM) was employed for the single-molecule visualization of the HRP macromolecules, adsorbed from the test solution onto mica substrates in order to find out whether the incubation of the test HRP solution within the half-sphere influenced the HRP aggregation state. Attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) was employed in order to reveal whether the incubation of HRP solution within the half-sphere led to any changes in its secondary structure. In parallel, spectrophotometry-based estimation of the HRP enzymatic activity was performed in order to find out if the HRP active site was affected by the electromagnetic field under the conditions of our experiments. We revealed an increased aggregation of HRP after the incubation of its solution within the half-sphere in comparison with the control sample incubated far outside the half-sphere. ATR-FTIR allowed us to reveal alterations in HRP’s secondary structure. Such changes in the protein structure did not affect its active site, as was confirmed by spectrophotometry. The effect of spherical elements on a protein solution should be taken into account in the development of the optimized design of biosensors and bioreactors, intended for performing processes involving proteins in biomedicine and biotechnology, including highly sensitive biosensors intended for the diagnosis of socially significant diseases in humans (including oncology, cardiovascular diseases, etc.) at early stages.

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Umar Shah ◽  
Deepak Dwivedi ◽  
Mark Hackett ◽  
Hani Al-Salami ◽  
Ranjeet P. Utikar ◽  
...  

AbstractKafirin, the hydrophobic prolamin storage protein in sorghum grain is enriched when the grain is used for bioethanol production to give dried distillers grain with solubles (DGGS) as a by-product. There is great interest in DDGS kafirin as a new source for biomaterials. There is however a lack of fundamental understanding of how the physicochemical properties of DDGS kafirin having been exposed to the high temperature conditions during ethanol production, compare to kafirin made directly from the grain. An understanding of these properties is required to catalyse the utilisation of DDGS kafirin for biomaterial applications. The aim of this study was to extract kafirin directly from sorghum grain and from DDGS derived from the same grain and, then perform a comparative investigation of the physicochemical properties of these kafirins in terms of: polypeptide profile by sodium-dodecyl sulphate polyacrylamide gel electrophoresis; secondary structure by Fourier transform infra-red spectroscopy and x-ray diffraction, self-assembly behaviour by small-angle x-ray scattering, surface morphology by scanning electron microscopy and surface chemical properties by energy dispersive x-ray spectroscopy. DDGS kafirin was found to have very similar polypeptide profile as grain kafirin but contained altered secondary structure with increased levels of β-sheets. The structure morphology showed surface fractals and surface elemental composition suggesting enhanced reactivity with possibility to endow interfacial wettability. These properties of DDGS kafirin may provide it with unique functionality and thus open up opportunities for it to be used as a novel food grade biomaterial.


2014 ◽  
Vol 28 (3) ◽  
pp. 311-317 ◽  
Author(s):  
Agnieszka Nawrocka

Abstract Silver nanoparticles have antimicrobial properties since they can be regarded as an efficient protector against pathogenic microorganisms. Fourier transform infrared spectroscopy was used to examine conformational changes in the secondary structure of wheat gluten washed out from grain treated with an aqueous solution of silver nanoparticles stabilized by tri-sodium citrate. Silver nanoparticles were used as a protective layer on the grain surface against bacterial and fungal infections (antimicrobial agent). Analysis of the amide I band revealed significant changes in the secondary structure after using silver nanoparticles. An increase in the β-sheet content (from 36.2 to 39.2%) was observed at the expense of the α-helix and β-turn content. To find factors causing these changes, the wheat grains were treated by an aqueous solution of trisodium citrate and water. The results obtained indicate that the changes in the gluten structure were connected mainly with the trisodium citrate action due to presence of a small number of free molecules of the stabilizer in the solution of silver nanoparticles. Additionally, the conformational changes in gluten pointed out that gluten flexibility increased (decrease in the αH/βS ratio from 1.40 for the control sample to 1.26 for the silver nanoparticle-treated samples) as well as the solubility of gluten decreased (decrease in the β-turn content from 13.1 to 11.4%).


Food systems ◽  
2021 ◽  
Vol 4 (1) ◽  
pp. 12-18
Author(s):  
A. I. Chirsanova ◽  
A. V. Boistean ◽  
N. Chiseliță ◽  
R. Siminiuc

The objective of the study was to investigate the potential application of beta-glucans obtained from yeast sediment resulting from the manufacture of local Viorica wine (2018 harvest). To determine the amount of beta-glucans in the yeast sediment, two were used: the calculation method and the laboratory method, obtaining similar quantities, 29.92 ± 0.47 and 28.17 ± 0.32 respectively. The beta -glucans obtained were incorporated in various concentrations (0.1%; 0.2%; 0.3%; 0.4% and 0.5%) in the yogurt obtained from skimmed milk. The effect of beta-glucan addition on the physicochemical properties of freshly prepared yogurts was investigated. The addition of beta-glucans positively influenced the formation of the gel relay resulting in a decrease in the fermentation time of yogurt. The final pH point of 4.5 was reached one hour earlier (in 4 hours) compared to the control sample (in 5 hours). The results showed that there are no significant changes in physicochemical properties (titratable acidity, pH, viscosity and syneresis). The results obtained report that beta-glucans can be used as a thickening agent for low-fat yogurts by shortening the fermentation period and not essentially changing the sensory characteristics. Experimental results showed that the glycemic index of yogurt samples with the addition of beta-glucans have similar values in the range of 28-30. Respectively, the yogurts under study are attributed to food category with low glycemic index.


2019 ◽  
Vol 121 (12) ◽  
pp. 3208-3232 ◽  
Author(s):  
Hamed Hosseini ◽  
Shadi Bolourian ◽  
Fakhri Shahidi

Purpose Jujube fruit (JF) (Ziziphus jujuba Mill.) is used as pharmaceuticals food, flavors and food additives. The purpose of this paper is to study the suitability of JF incorporation into a commercial sponge cake formulation, and to produce a nutritious bakery product with appropriate organoleptic and technological characteristics. Design/methodology/approach The optimal level of JF was incorporated into sponge cake using a custom mixture design with three independent variables, namely, refined wheat flour (RWF, 15–28 percent), sugar (7–22 percent) and JF (0–28 percent), as well as several responses, including physical properties, texture profile analysis (TPA), sensorial evaluation and color features. Moreover, physicochemical properties (TPA and oxidative indices) of optimal cake (two of the best JF levels) were compared with control sample (without JF) during 51 days storage period, while two baking temperatures (180°C and 170°C) were used. Findings The optimal amounts of RWF (21.19 percent), sugar (21.20 percent) and JF (7.61 percent) required for making the sample with maximum springiness, cohesiveness, specific volume, sensorial scores and yellowness, as well as the lowest firmness, baking loss and browning were determined. Desirable effects of JF on the cake quality well maintained throughout the storage period, as TPA attributes, peroxide value, ultraviolet absorbance and acid value showed less changes in JF-incorporated cake than the control sample. Originality/value Incorporating JF (~7 percent) into the batter was successful to improve the physicochemical properties in both fresh and stored cake with chocolate-like color.


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