scholarly journals Electrochemical Study of Enzymatic Glucose Sensors Biocatalyst: Thermal Degradation after Long-Term Storage

Chemosensors ◽  
2018 ◽  
Vol 6 (4) ◽  
pp. 53 ◽  
Author(s):  
Marcelinus Christwardana ◽  
Domenico Frattini
Keyword(s):  
Thermal Degradation ◽  
Storage Temperature ◽  
Protein Denaturation ◽  
Transfer Constant ◽  
Glucose Response ◽  
C Storage ◽  
Long Term Storage ◽  
Glucose Oxidation Reaction ◽  
Term Storage

The thermal degradation related to stability in long-term storage of a carbon nanotube-based biosensor has been investigated. The effect of storage temperature on detachment and denaturation of glucose oxidase (GOx) biocatalyst has been proved. The carbon nanotubes (CNTs) coated with polyethyleneimine (PEI) as entrapping polymer to attract more GOx to form a durable and layered CNT/PEI/GOx structure is used for long-term storage to minimize GOx detachment from the structure and minimize the possibility of enzyme and protein denaturation. After 120 days, the glucose response of the CNT/PEI/GOx biosensor stored under 4°C is preserved up to 66.7% of its initial value, while under a 25 °C storage the response is maintained up to 41.7%. The enzyme coverage activity of CNT/PEI/GOx stored at 4 °C and 25 °C has decreased by 31.1% and 51.4%, respectively. Denaturation and detachment of GOx are the common causes of thermal degradation in biosensors under improper storage temperatures, but the presence of PEI in the structure can slow-down these phenomena. Moreover, the electrons transfer constant of CNT/PEI/GOx biocatalyst stored at 4 °C and 25 °C were 7.5 ± 0.5 s−1 and 6.6 ± 0.3 s−1, respectively, indicating that also electrons mobility is damaged by detachment and denaturation of enzyme protein and the detection of glucose from the glucose oxidation reaction (GOR) is compromised.

Combined effects of storage temperature variation and dynamic controlled atmosphere after long-term storage of ‘Maxi Gala’ apples

2022 ◽  
Vol 31 ◽  
pp. 100770
Author(s):  
Lucas Mallmann Wendt ◽  
Vagner Ludwig ◽  
Fabiane Portella Rossato ◽  
Magno Roberto Pasquetti Berghetti ◽  
Erani Eliseu Schultz ◽  
...  
Keyword(s):  
Temperature Variation ◽  
Storage Temperature ◽  
Combined Effects ◽  
Controlled Atmosphere ◽  
Long Term Storage ◽  
Term Storage

scholarly journals Long-Term Storage of Vegetable Juices Treated by High Hydrostatic Pressure: Assurance of the Microbial Safety

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Justyna Nasiłowska ◽  
Barbara Sokołowska ◽  
Monika Fonberg-Broczek
Keyword(s):  
Hydrostatic Pressure ◽  
High Hydrostatic Pressure ◽  
Storage Temperature ◽  
Plate Count ◽  
Bacterial Cells ◽  
Carrot Juice ◽  
Beetroot Juice ◽  
C Storage ◽  
Long Term Storage

Food business operators search for new, mild technologies, which extend the shelf life of product without changing the sensory and nutritional properties. High hydrostatic pressure (HHP) meets these requirements; however it also triggers sublethal injury of bacterial cells. Sublethal injuries could spoil the product during storage and potentially pose major public health concerns. This study aims to examine the changes of sublethally injured pathogens cells in two vegetable juices: carrot juice (pH 6.0-6.7) and beetroot juice (pH 4.0-4.2) that are induced by HHP (300-500 MPa). The possibilities of recovery of bacterial cells during 28 days of juices storage at two different temperatures (5°C and 25°C) were determined using plate count methods. During the entire period of storage of carrot juice at refrigerated temperature, the propagation and regeneration ofL. innocuastrains were observed. Storage at 25°C showed that the number of these bacteria drastically decreased between 14 and 21 days. The above phenomenon was not detected inE. colicase. There was no cells recovery during long-term refrigerated storage for all strains in beetroot juice. However, in some cases spoiling of this product intermittently occurred at 25°C storage temperature. This work demonstrates that carrot juice supports growth and regeneration of HHP-sublethally injuredL. innocua, while beetroot juice can be classified as a safe product.

scholarly journals Storage Temperature, Controlled Atmosphere, and 1-Methylcyclopropene Effects on α-Farnesene, Conjugated Trienols, and Peroxidation in Relation with Superficial Scald, Pithy Brown Core, and Fruit Quality of ‘d’Anjou’ Pears during Long-term Storage

2016 ◽  
Vol 141 (2) ◽  
pp. 177-185 ◽  
Author(s):  
Yan Wang
Keyword(s):  
Storage Temperature ◽  
Storage Conditions ◽  
Controlled Atmosphere ◽  
Metabolic Balance ◽  
Superficial Scald ◽  
Long Term Storage ◽  
Temperature Controlled ◽  
Term Storage

Alternatives to ethoxyquin (Etq) are needed for controlling superficial scald of ‘Anjou’ european pears (Pyrus communis) during long-term storage. The current commercial standard storage conditions [Etq + −1 °C + controlled atmosphere (CA) with 1.5 kPa O2] reduced scald occurrence compared with control fruit (−1 °C + CA) during 6–8 months storage. At 1 °C in air, 1-methylcyclopropene (1-MCP) fumigation at 0.15 µL·L−1 at harvest was more efficient on reducing scald than Etq but did not prevent scald during 6–8 months storage. The 1-MCP-treated fruit at 1 °C in air developed their ripening capacity at 20 °C following 6–8 months storage but had deceased shipping ability (softening and yellowing of fruit). Although Etq inhibition of scald was associated with the inhibition of α-farnesene oxidation to conjugated trienols (CTols); 1-MCP reduced α-farnesene synthesis and thereby the availability of substrate to oxidize to CTols. CA storage at 1.5 kPa O2 totally prevented scald and retarded the loss of shipping ability without affecting the ripening capacity of 1-MCP-treated fruit at 1 °C through further decreases in the syntheses of ethylene, α-farnesene and CTols during 6–8 months storage. In addition, 1-MCP prevented a CA-induced disorder, pithy brown core (PBC), in ‘Anjou’ pears possibly through enhancing an oxidative/reductive metabolic balance during extended storage. In conclusion, the combinations of 1 °C + 1-MCP + CA is a potential commercial alternative to Etq for scald control while allowing the 1-MCP-treated ‘Anjou’ pears to recover ripening capacity during the shelf life period after 6–8 months storage.

scholarly journals Chemical and Biological Stability of Indole-3-Butyric Acid (IBA) After Long-term Storage at Selected Temperatures and Light Regimes

1988 ◽  
Vol 6 (2) ◽  
pp. 39-41 ◽  
Author(s):  
James A. Robbins ◽  
Mark J. Campidonica ◽  
David W. Burger
Keyword(s):  
Butyric Acid ◽  
Storage Temperature ◽  
Naphthaleneacetic Acid ◽  
Light Regimes ◽  
Long Term Storage ◽  
Color Development ◽  
Clear Glass ◽  
Indole 3 Acetic Acid ◽  
Term Storage

Concentrated [4.9 mM (1,000 ppm) and 24.6 mM (5,000 ppm)] IBA solutions in 50% isopropyl alcohol were stored in amber and clear glass bottles at 3 temperatures [22–25°, 6°, O°C (72–77°, 43°, 32°F)]. No significant change in biological activity of the solutions or breakdown of IBA was observed for solutions stored for 4 and 6 months. Solution color changed during storage. Color development was dependant on storage temperature, but not on exposure to light. Chemical names used: IAA = indole-3-acetic acid; IBA = indole-3-butyric acid; NAA = 1-naphthaleneacetic acid

scholarly journals Storage and Viability Testing of Protea Pollen

1996 ◽  
Vol 121 (5) ◽  
pp. 804-809 ◽  
Author(s):  
I. David van der Walt ◽  
Gail M. Littlejohn
Keyword(s):  
Storage Temperature ◽  
Pollen Viability ◽  
Germination Percentage ◽  
Long Term Storage ◽  
Fresh Pollen ◽  
The Relationship ◽  
Term Storage ◽  
Storage Temperatures

The influence of storage temperature and humidity on pollen viability was studied in four Protea species. Pollen was stored at a range of temperatures and relative humidities for up to 1 year and tested for ability to germinate in vitro. Pollen of P. repens (L.) L. `Sneyd', P. eximia (Salisb. ex Knight) Fourcade `Fiery Duchess' and P. magnifica Link. clone T 84 07 05 stored at -196 °C and -14 to -18 °C retained a germination percentage as high as that of fresh pollen regardless of humidity. Humidity control became increasingly important at storage temperatures above 0 °C. The study showed that long-term storage of Protea pollen is not feasible at temperatures above 0 °C. The relationship between germinability and fluorochromasia (FCR) was studied during storage of `Sneyd' pollen. The correlations between FCR and germinability were found to be low and nonsignificant. Fifteen-month-old cryopreserved `Sneyd' pollen functioned in fertilization and seed set as effectively as fresh pollen.

Efficacy of the Antigenicity-Retaining Ability of Fixative Solutions for Liquid-Based Cytology: Immunocytochemistry of Long-Term Storage

2021 ◽  
pp. 1-12
Author(s):  
Hiaki Sato ◽  
Yoshiaki Norimatsu ◽  
Satoshi Irino ◽  
Takeshi Nishikawa
Keyword(s):  
Cell Membrane ◽  
Room Temperature ◽  
Storage Temperature ◽  
Storage Period ◽  
Storage Conditions ◽  
Immunocytochemical Staining ◽  
Long Term Storage ◽  
Liquid Based Cytology ◽  
Term Storage

<b><i>Introduction/Objective:</i></b> Liquid-based cytology (LBC) is advantageous as multiple stained specimens can be prepared and used for additional assays such as immunocytochemical and molecular-pathological investigations. Two types of preservative-fixative solutions (fixatives) are used for nongynecologic specimens used in the BD SurePath-LBC (SP-LBC) method, and their components vary. However, few studies have evaluated the differences in antigen-retaining ability between these fixatives. Therefore, we investigated and compared the antigen-retaining ability of the fixatives in immunocytochemical staining (ICC) under long-term storage conditions. <b><i>Materials and Methods:</i></b> Sediments of cultured RAJI cells (derived from Burkitt’s lymphoma) were added to each fixative (red and blue) and stored at room temperature for a specified period (1 h; 1 week; and 1, 3, and 6 months). The specimens were then prepared using the SP-LBC method and subjected to ICC. Positivity rate was calculated using the specimens fixed at room temperature for 1 h as a control. Antibodies against Ki67 expressed in the nucleus and against CD20 and leukocyte common antigen (LCA) expressed on the cell membrane were used. <b><i>Results:</i></b> For CD20 and LCA, the positivity rate increased with time in the red fixative compared with that in the control. In the blue fixative, the positivity rate was highest at 1 h and was maintained at a high level throughout the storage period. In contrast, the Ki67 positivity rate was highest at 1 h in both red and blue fixatives and markedly decreased with time. Therefore, although refrigerated (8°C) storage was used, no improvement was noted. <b><i>Conclusions:</i></b> Long-term storage is possible for cell membrane antigens at room temperature; however, it is unsuitable for intranuclear antigens. Therefore, we conclude that suitable fixative type and storage temperature differ based on antigen location. Further investigation is warranted.

scholarly journals Kinetic Analysis of Stabilizing C-Phycocyanin in the Spirulina platensis Extracts from Ultrasonic Process Associated with Effects of Light and Temperature

2018 ◽  
Vol 8 (9) ◽  
pp. 1662 ◽  
Author(s):  
Woon Yong Choi ◽  
Hyeon Yong Lee
Keyword(s):  
Storage Temperature ◽  
Extraction Process ◽  
Storage Conditions ◽  
Second Order ◽  
Light Illumination ◽  
First Order ◽  
Long Term Storage ◽  
Ultrasonic Process ◽  
Term Storage

A kinetic model was developed to reflect the stability of C-Phycocyanin (C-PC) from ultrasonic extraction process under different storage conditions. The decrease of C-PC contents was most accelerated at a high temperature of 40 °C along with light illumination, resulting in ca. 60% drop of an initial concentration for two months of storage. However, ca. 93% of the initial contents remained at 4 °C without light, which would be a most favorable condition for long-term storage. It was first shown that the decrease of the residual concentrations followed second-order kinetics under light illumination. However, without light, the decrease of the C-PC contents showed first order reaction kinetics, which implies initial C-PC concentrations are important. On the contrary, initial storage temperature seemed to be more influential under light illumination. It was also first revealed that the rate of degrading the C-PC was faster with light than without light even at the same temperature, having 0.0108 (1/h) and 0.0138 (1/h) of rate constants of first order (no light) and second order kinetics (with light) at 40 °C, respectively. Moreover, the cleavage of C-PC was also found to follow the Arrhenius relationship. Therefore, this work could provide desirable storage conditions of C-PC from non-thermal ultrasonic process for long-term storage.

Sign in / Sign up

Export Citation Format

Share Document