Growth, respiration and physicochemical changes during the maturation of cacao fruits

2021 ◽  
Author(s):  
Martha del Pilar López‐Hernández ◽  
Jenifer Criollo‐Núñez ◽  
Camilo Ignacio Jaramillo‐Barrios ◽  
María Denis Lozano‐Tovar
Keyword(s):  
Physicochemical Changes ◽  
Growth Respiration

Wrinkling Poly(trimethylene 2,5-Furanoate) Free-standing Films: Nanostructure Formation and Physical Properties

2020 ◽  
Author(s):  
Michelina Soccio ◽  
Nadia Lotti ◽  
Andrea Munari ◽  
Esther Rebollar ◽  
Daniel E Martínez-Tong
Keyword(s):  
Irradiation Time ◽  
Polymer Surface ◽  
Laser Source ◽  
Free Standing ◽  
Force Microscopy ◽  
Nanostructure Formation ◽  
Physicochemical Changes ◽  
Angle Measurements ◽  
Atomic Force ◽  
Contact Angle Measurements

<p>Nanostructured wrinkles were developed on fully bio-based poly(trimethylene furanoate) (PTF) films by using the technique of Laser Induced Periodic Surface Structures (LIPSS). We investigated the effect of irradiation time on wrinkle formation using an UV pulsed laser source, at a fluence of 8 mJ/cm2. It was found that the pulse range between 600 and 4800 pulses allowed formation of periodic nanometric ripples. The nanostructured surface was studied using a combined macro- and nanoscale approach. We evaluated possible physicochemical changes taking place on the polymer surface after irradiation by infrared spectroscopy, contact angle measurements and atomic force microscopy. The macroscopic physicochemical properties of PTF showed almost no changes after nanostructure formation, differently from the results previously found for the terephthalic counterparts, as poly(ethyleneterephthalate), PET, and poly(trimethyleneterephthalate), PTT. The surface mechanical properties of the nanostructured PTF were found to be improved, as evidenced by nanomechanical force spectroscopy measurements. In particular, an increased Young’s modulus and higher stiffness for the nanostructured sample were measured. <br></p>

Nanostructures for pH-sensitive Drug Delivery and Magnetic Resonance Contrast Enhancement Systems

2018 ◽  
Vol 25 (25) ◽  
pp. 3036-3057 ◽  
Author(s):  
Xiao Sun ◽  
Guilong Zhang ◽  
Zhengyan Wu
Keyword(s):  
Drug Delivery ◽  
Magnetic Resonance ◽  
Drug Release ◽  
Contrast Enhancement ◽  
General Strategy ◽  
Ph Responsive ◽  
Physicochemical Changes ◽  
Magnetic Resonance Contrast ◽  
Resonance Contrast ◽  
Magnetic Resonance Contrast Enhancement

According to the differences of microenvironments between tumors and healthy tissues, if the anticancer drugs or magnetic resonance contrast agents (MRCAs) can be controlled to precisely match physiological needs at targeted tumor sites, it is expected to acquire better therapeutic efficacy and more accurate diagnosis. Over the decade, stimuli-responsive nanomaterials have been a research hotspot for cancer treatment and diagnosis because they show many excellent functions, such as in vivo imaging, combined targeting drug delivery and systemic controlled release, extended circulation time, etc. Among the various stimuli nanosystems, pH-stimuli mode is regarded as the most general strategy because of solid tumors acidosis. When exposed to weakly acidic tumor microenvironment, pH-responsive nanoplatforms can generate physicochemical changes for their structure and surface characteristics, causing drug release or contrast enhancement. In this review, we focused on the designs of various pH-responsive nanoplatforms and discussed the mechanisms of controlled drug release or switch on-off in MRCAs. This review also discussed the efficacy of cellular internalization for these nanoplatforms via endocytosis of acidic tumor cell. Meanwhile, nanoplatforms response to acidic intracellular pH (such as endosome, lysosome) are discussed, along with approaches for improving drug release performance and magnetic resonance contrast enhancement. A greater understanding of these pH-responsive nanoplatforms will help design more efficient nanomedicine to address the challenges encountered in conventional diagnosis and chemotherapy.

scholarly journals Unconventional effects of long-term storage of microwave-modified chicken egg white lysozyme preparations

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Grzegorz Leśnierowski ◽  
Tianyu Yang ◽  
Renata Cegielska-Radziejewska
Keyword(s):  
Microwave Radiation ◽  
Egg White ◽  
Process Time ◽  
High Quality ◽  
Chicken Egg ◽  
Egg White Lysozyme ◽  
Physicochemical Changes ◽  
Long Term Storage ◽  
Term Storage

AbstractThermal modification is an effective method that induces significant expansion of the antimicrobial properties and other valuable properties of chicken egg white lysozyme. In our latest research, a new innovative method of enzyme modification was developed, in which microwave radiation was used as an energy source to process liquid lysozyme concentrate (LLC). After modification, high-quality preparations were obtained. However, long-term storage in a concentrated form initiated various processes that caused darkening over time and could also lead to other significant changes to their structure and, consequently, to their functional properties. This necessitated multidirectional research to explain this phenomenon. This paper presents the results of research aimed at assessing the physicochemical changes in the properties of microwave-modified lysozyme in the form of a liquid concentrate after long-term storage under refrigeration conditions. The assessment also considered the conditions under the acidity of the modifying medium and the duration of the microwave modification. The analysis showed that the values of the basic parameters determining the quality and usefulness of the modified enzyme significantly improved during long-term storage of the preparations. The greatest changes were observed in the preparations modified for the longest time and in the most acidic environment (process time 260 s, pH 2.0), the number of oligomers under these conditions increased by 18% after 12 months of holding, and the surface hydrophobicity increased by as much as 31%. In addition, microbiological tests showed that the preparations of microwave-modified lysozyme had an effect on gram-positive bacteria as well as on gram-negative, and this effect was significantly enhanced after 12 months. The results confirm that LLC modification with microwave radiation is a highly efficient method to prepare high-quality and high utility potential lysozyme. Notably, an interesting and important phenomenon was the observation of the unconventional behaviour of the preparations during their long-term storage, which increased their utility potential significantly.

scholarly journals The in vitro assessment of the toxicity of volatile, oxidisable, redox-cycling compounds: phenols as an example

2021 ◽  
Author(s):  
Laia Tolosa ◽  
Teresa Martínez-Sena ◽  
Johannes P. Schimming ◽  
Erika Moro ◽  
Sylvia E. Escher ◽  
...  
Keyword(s):  
Cultured Cells ◽  
Degradation Products ◽  
Degradation Kinetics ◽  
Redox Cycling ◽  
In Vitro Toxicity ◽  
Cross Contamination ◽  
Physicochemical Changes ◽  
In Vitro Assessment ◽  
Biological Performance

AbstractPhenols are regarded as highly toxic chemicals. Their effects are difficult to study in in vitro systems because of their ambiguous fate (degradation, auto-oxidation and volatility). In the course of in vitro studies of a series of redox-cycling phenols, we found evidences of cross-contamination in several in vitro high-throughput test systems, in particular by trimethylbenzene-1, 4-diol/trimethylhydroquinone (TMHQ) and 2,6-di-tertbutyl-4-ethylphenol (DTBEP), and investigated in detail the physicochemical basis for such phenomenon and how to prevent it. TMHQ has fast degradation kinetics followed by significant diffusion rates of the resulting quinone to adjacent wells, other degradation products being able to air-diffuse as well. DTBEP showed lower degradation kinetics, but a higher diffusion rate. In both cases the in vitro toxicity was underestimated because of a decrease in concentration, in addition to cross-contamination to neighbouring wells. We identified four degradation products for TMHQ and five for DTBEP indicating that the current effects measured on cells are not only attributable to the parent phenolic compound. To overcome these drawbacks, we investigated in detail the physicochemical changes occurring in the course of the incubation and made use of gas-permeable and non-permeable plastic seals to prevent it. Diffusion was greatly prevented by the use of both plastic seals, as revealed by GC–MS analysis. Gas non-permeable plastic seals, reduced to a minimum compounds diffusion as well oxidation and did not affect the biological performance of cultured cells. Hence, no toxicological cross-contamination was observed in neighbouring wells, thus allowing a more reliable in vitro assessment of phenol-induced toxicity.

scholarly journals Investigation on the Molecular and Physicochemical Changes of Protein and Starch of Wheat Flour during Heating

Foods ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1419
Author(s):  
Tao Yang ◽  
Pei Wang ◽  
Qin Zhou ◽  
Xiao Wang ◽  
Jian Cai ◽  
...  
Keyword(s):  
Wheat Flour ◽  
Heating Temperature ◽  
Major Change ◽  
Covalent Bonds ◽  
Ordered Structures ◽  
Textural Characteristic ◽  
Physicochemical Changes ◽  
Heating Treatment ◽  
Weight Protein ◽  
Β Sheet

The behaviors of starch and protein in wheat flour during heating were investigated, and the molecular changes of starch and protein and their effects on the textural characteristics were assessed. The results showed that with the increased temperature, soluble protein aggregated to insoluble high-molecular-weight protein polymers when the heating temperature exceeded 70 °C, and the aggregation of protein was mainly caused by covalent bonds of disulfide (SS) bonds. Hydrophobic interaction was the main noncovalent bond that participated in the formation of protein aggregates. The major change in the secondary structure during heating was a pronounced transition towards β-sheet-like structures. Considerable disruption of ordered structures of starch occurred at 70 °C, and starch was fully gelatinized at 80 °C. Typical starch pasting profiles of cooked flour were observed when the temperature was below 70 °C, and heat treatment decreased the pasting viscosity of the cooked flour from control to 80 °C, whereas the viscosity of the wheat flour increased in heating treatment at 90, 95 and 100 °C. The intense protein-starch interaction during heating affected the textural characteristic of flour gelation, which showed higher strength at 90, 95 and 100 °C. This study may provide a basis for improving wheat flour processing conditions and could lead to the production of new wheat products.

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