Physicochemical Changes Research Articles

Storage quality assessment of a sheet snack produced from liang leaves (Gnetum gnemon var. tenerum)

This study investigates a novel leaf sheet snack from liang, an indigenous vegetable in Southern Thailand. The prepared snack has high protein, fiber, calcium, and vitamins A and B2. Storage conditions and packaging impact its shelf life. Based on the calculation, laminated aluminum foil extended shelf life to 1 year at 30°C and relative humidity (RH) of 60%. Moisture absorption during storage led to physicochemical changes, including reduced vitamin content, while total polyphenols, flavonoids, and antioxidant activity remained stable. Microbiological quality was acceptable over a period of 12 weeks but high RH during storage deteriorated sensory attributes. Liang leaves showed promise of being a functional food ingredient.

Diversity, Length-weight structure and Condition Factor of fish species and physicochemical changes in four reservoirs in Volta basin, Burkina Faso

Diversity, Length-weight structure and Condition Factor of fish species and physicochemical changes in four reservoirs in Volta basin, Burkina Faso

Monitoring the Ripening Process of Rainbow Trout Marinade Prepared in Different Acid and Salt Concentrations by Following the Changes in Physicochemical and Sensory Parameters

ABSTRACT Physicochemical and sensory changes of fish were investigated during marination of rainbow trout. Equilibration in the acidity of A (2% acid, 8% salt), B (4%, 8%), C (2%, 12%), and D (4%, 12%) groups took place at the 24, 24, 30, and 30th hours, respectively; in salt, it occurred at 36, 42, 42, and 36th hours, respectively. With ripening, a* value decreased, and b* value and hardness increased. Salt concentration affected acid taste; acid affected salt taste. This study revealed the effects of the ratio of acid and salt used in rainbow trout marinade on ripening and the resulting changes in sensory properties.

Microbial and physicochemical changes in green bell peppers treated with ultrasonic-assisted washing in combination with Thymus vulgaris essential oil nanocapsules

In this study, the effect of Thymus vulgaris essential oil (TVO) nanoemulsion (NE, 500 mg/L) in combination with ultrasound (ultrasound-NE) on the microbial and physiological quality of green bell pepper was investigated. The TVO-NE droplet size and zeta potential were 84.26 nm and − 0.77 mV, respectively. The minimum inhibitory concentrations of the TVO and TVO-NE against E. coli and S. aureus were about 0.07 and 7 g/L, respectively. The NE-ultrasound treatment exhibited the lowest peroxidase activity and respiration rate with no detrimental effect on texture, total phenolic content, antioxidant activity, pH, and TSS. Although the NE-ultrasound treatment showed the highest weight loss and electrolytic leakage, it exhibited the best visual color and appearance. The NE-ultrasound treatment descended the total viable/mold and yeast counts significantly compared to control. Results showed that treating the bell peppers with NE-ultrasound can result in bell peppers with good postharvest quality and extended shelf life.

The CHIMERE chemistry-transport model v2023r1

Abstract. A new version of the CHIMERE model is presented. This version contains both computational and physico-chemical changes. The computational changes make it easy to choose the variables to be extracted as a result, including values of maximum sub-hourly concentrations. Performance tests show that the model is 1.5 to 2 times faster than the previous version for the same setup. Processes such as turbulence, transport schemes and dry deposition have been modified and updated. Optimization was also performed for the management of emissions such as anthropogenic and mineral dust. The impact of fires on wind speed, soil properties and leaf area index (LAI) was added. Pollen emissions, transport and deposition were added for birch, ragweed, olive and grass. The model is validated with a simulation covering Europe with a 60 km × 60 km resolution and the entire year of 2019. Results are compared to various measurements, and statistical scores show that the model provides better results than the previous versions.

Application of high-pressure homogenization-assisted pH-shift to enhance techno-functional and interfacial properties of lentil protein isolate

High-pressure homogenization (HPH) is a promising physical non-thermal approach to improve protein techno-functionality. This study aims to examine the effects of HPH on the lentil proteins through the perspective of the interfacial adsorption mechanism. The impact of HPH treatment on lentil protein isolate (LPI) at varying pressure levels (0–150 MPa) was determined using several analytical techniques, including SDS-PAGE, FTIR, solubility, and techno-functional properties (foaming and emulsifying properties), alongside analyses of interfacial tension and interfacial shear rheology at the o/w and a/w interfaces for two pH values (2.0 and 4.5). Results reveal that HPH treatment up to 100 MPa effectively unfolds lentil proteins by disrupting disulfide-bonded subunits into lower molecular weight fractions and unfolding highly-ordered secondary structures into random coils. LPI's capacity to produce emulsions and foams was found to be enhanced concurrently with these physicochemical changes, particularly at pressures up to 50 MPa. The findings aligned with the interfacial tension and shear rheology analyses, which show that proteins can form interfacial viscoelastic films on both o/w and a/w interfaces. Furthermore, the interfacial behavior of LPI and the effect of HPH on the interfacial behavior were found to be pH-dependent. The lower interfacial tension and the higher interfacial viscoelastic moduli (G′ and G″) were recorded at 50 MPa and 0 MPa at pH 2.0 and 4.5, respectively. These results stated that the effects of the HPH on the technofunctionality of LPI can be further enlightened by investigating the interfacial adsorption kinetics.

Macadamia (Macadamia integrifolia) Nut-Based Beverage: Physicochemical Stability and Nutritional and Antioxidant Properties

The present work presents an investigation of the effects of xanthan gum (XG) and soy lecithin (SL) on the physicochemical stability, fatty acid profile (FAP), and antioxidant capacity (AC) of macadamia nut-based beverages with thermal treatment (TT), as well as physicochemical changes during storage and sensorial acceptability. An extreme vertices mixture design was used, varying the macadamia nut, SL, and XG. The results show that adding XG and SL decreased the Sauter (D[3,2]) and Brouckere (D[4,3]) diameters of particles in macadamia beverages and increased the zeta potential (ZP), which represents greater stability. After applying TT in beverages, D[3,2], D[4,3], and ZP increased. After processing and TT, the FAP and fat nutritional indices changed due to reducing SFA and PUFA and increasing MUFA relative to macadamia nut. No significant difference (p ≥ 0.05) was observed in the FAP of beverages with and without TT. The AC determined by DPPH and ABTS decreased in most beverages upon TT application. During storage for two months, the beverage particle size increased, there was a decrease in brightness, and no significant difference (p ≥ 0.05) was observed in ZP. Sensory analysis showed that the most stable beverage was not the most acceptable due to its viscosity.

Efikasi Bakterostatik Kulit Bawang Merah Pada Ikan Bandeng (Chanos chanos) Selama Penyimpanan Suhu Ruang

Biochemical and physicochemical changes result in a decrease in fish freshness. The decline in quality of fresh fish can be influenced by several things, one of which is storage temperature, where the higher the storage temperature, the faster the fish rots. Red onion skin contains flavonoid compounds which function as bacteriostatics, namely quercetin. The aim of this research is to provide scientific information about the bacteriostatic efficacy of shallot skin on histamine inhibition in milkfish during room temperature storage. The research design used was a Randomized Block Design (RAK) with three treatment factors with two replications. Based on the research results, it was found that it showed the best concentration and had a significant effect on the quality (pH, histamine and TPC) of crushed milkfish during 48 hours of storage at room temperature with the addition of 3% shallot skin. The results of the organoleptic test showed that the red onion skin of crushed milkfish experienced a decrease in organoleptic values for each parameter (Appearance, Smell, Texture) for 48 hours so it was necessary to increase the concentration of red onion skin.

Effects of UV light on physicochemical changes in thermoplastic polyurethanes: Mechanism and disinfection byproduct formation

The presence of microplastics (MPs) products and particles in the environment can significantly impact the human body. Most MPs that enter the environment also enter the water cycle. During sunlight light irradiation (especially ultraviolet (UV) part) or UV disinfection, many of these MPs, particularly those rich in surface functional groups like thermoplastic polyurethanes (TPU), undergo physicochemical changes that can affect the formation of disinfection byproducts (DBPs). This study investigates the physicochemical changes of TPU in water after exposure to UV irradiation and incubation in the dark, as well as the formation of DBPs after chlorination. The results show that TPU undergo chain breakage, oxidation, and cross-linking when exposed to UV irradiation in an aqueous system. This leads to fragmentation into smaller particles, which facilitates the synthesis of DBPs. Subsequent research has demonstrated that the TPU leaching solution produces a significantly higher DBP content than the chlorination of TPU MPs, particularly at high concentrations of CHCl3. Therefore, it is important to give greater consideration to the soluble DBP precursors released by TPU.

Physicochemical change and sensory quality profile of koji fermented-sorghum during the fermentation process using Aspergillus oryzae culture.

Abstract Sorghum although rich in nutrients is known to have a low digestibility rate which hinders their usage. In this research, sorghum was subjected to koji fermentation to increase its digestibility rate. Koji fermentation, which utilizes the Aspergillus oryzae mold, is known for its ability to hydrolyze carbohydrates and protein in food products. Three different boiling times (5 minutes, 10 minutes, and 20 minutes) and three different fermentation times (2 days, 4 days, and 8 days) fermentation were done and the digestibility rate will be expressed as the reduced sugar content, total soluble protein content, and degree of hydrolysis. The result showed that sorghum boiled for 20 minutes and fermented for 8 days, produced the highest reducing sugar content and the highest degree of hydrolysis which were 45.6 mg/g and 77.3%, respectively. While sorghum that had been boiled for 20 minutes and fermented for 2 days showed the highest soluble protein, 21.8 mg/g. Sorghum boiled for 20 minutes was then chosen as the best treatment along with different fermentation times to ferment sorghum before being applied to the sorbet formulation. Throughout the sensory evaluation, the highest acceptance was from koji sorbet made from 4 days of fermentation and 20 minutes of boiling time was the most preferred in sensory with moderate likeness. The sorbet also can be considered as a high protein and light fat food based on its nutritional value with >13% protein content and <5% fat content per serving.

Exploring the diversity of clays: Impacts of temperature on physicochemical changes, mechanical characteristics, and permeability, and their relevance to membrane applications

This study investigates the characterization of two clays obtained from the Safi and Fez regions, focusing on their analysis for filtration membrane applications. Various analytical techniques were employed, including chemical composition analysis, elemental analysis, mineralogical characterization, carbonate content determination, color assessment, plasticity evaluation, thermal treatment analysis (DTA-TG), mineralogical transformation study, fusion tests, membrane tests, and scanning electron microscopy (SEM).The results reveal significant differences between the two clays regarding their chemical composition. The red clay exhibits a mineralogical composition comprising quartz, calcite, dolomite, hematite, illite, and kaolinite, whereas the gray clay contains quartz, calcite, dolomite, illite, talc, and montmorillonite. Furthermore, upon thermal treatment, both clays exhibit changes in their physical properties.Despite the decrease in porosity and water absorption, as well as the increase in compression strength for both clays, the permeability of the grey clay increases, unlike the red clay, which exhibits a constant permeability beyond 1000°C.These findings highlight the diversity and industrial significance of clays from the Safi and Fez regions for filtration membrane applications. The contrasting properties of red and gray clays provide insights into their potential utilization in different industries. Exploring these clays’ behavior can lead to better filtration membranes and new industrial applications.

Physicochemical and organoleptic changes in goat’s milk cheddar cheese with the addition of Lactobacillus casei as a starter during ripening

Abstract The fermentation process using lactic acid bacteria (LAB) in cheese manufacturing plays important roles to enhance the nutritional content of cheese. This study aims to observe the effect of the addition of Lactobacillus casei in goat’s milk cheese manufacturing. Changes in physicochemical and organoleptic characteristics were observed during cheese ripening. Cheese was made using 8% of L. casei as starter and its changes were observed for 8 weeks of ripening. The results showed that the acidification process in cheese by L. casei resulted in a yield value of 10.85%. The ripening period affects significant changes in physical and chemical indicators, except for pH. Observations during cheese ripening from the 4th to the 8th week indicate that pH tends to stabilize at pH 5, protein increases by approximately 16%, and the decrease in moisture and fat content was by 18% and 15%, respectively. The best quality of cheese was obtained by 8 weeks of ripening. After 8 weeks of ripening, the cheese was yellow in color, has a hard texture with cheesy aroma, sour taste, and contains approximately 1.8 × 106 CFU/ml of LAB. The study of LAB application in goat’s milk cheddar cheese will provide an innovation in cheese production.

Fluorinated Azobenzenes in UiO‐66: Unveiling Unprecedented Photoswitching Stability and Efficiency in Azobenzene‐Based Switch@MOF Systems

AbstractUnderstanding the interactions between hosts and guests in two‐component systems remains a formidable challenge due to the diverse array of adjusting factors at play. Particularly intriguing within the realm of two‐component systems are those incorporating a photoswitchable molecule within a porous metal‐organic framework (MOF) host. In such configurations, the non‐covalently attached guest molecule undergoes distinct physicochemical changes influenced by factors like guest structure, guest density, and the shape of the MOF pores. In this study, fluorinated azobenzenes (Fx‐AZB) were introduced into the rigid UiO‐66 host, and the resulting optical properties were examined with a focus on the degree of fluorination. The photoisomers of all examined compounds exhibited remarkable stability under repetitive light exposure, showing no signs of fatigue. Moreover, both photoisomers remained stable at room temperature, defying the typical T‐type photochromism associated with azobenzenes. Most notably, all fluorinated azobenzene derivatives displayed nearly complete photoswitching upon exposure to visible light within the UiO‐66 MOF host. This positions these composite materials as leaders in the realm of azobenzene‐based switch@MOF systems.

Distribution and Enrichment Mechanisms of Selenium in Stibnite from the Xujiashan Sb Deposit, Hubei Province, China

The Xujiashan Sb deposit located at the Mufushan fold thrust belt of the Yangtze block is one of the most important Sb deposits in this district. Stibnite in this deposit contains high and various contents of Se, but research on the distribution and enrichment of Se in stibnite remains limited. This paper conducts geochemical composition, C-H-O isotopic composition, and scanning electron microscopy morphology of the Xujiashan deposit to discuss the sources of ore-forming materials and fluid, as well as the distribution and enrichment mechanisms of selenium in stibnite. The results showed that the ores have trace element compositions comparable with the wall rocks, and Sb and Se contents are significantly higher than the average carbonate rocks. The δ13CPDB values of calcite and quartz range from −12.8‰ to 5.5‰, the δ18OSMOW values range from 20.4‰ to 24‰, and the δDV-SMOW values range from −57.8‰ to −86.9‰. Trace element and isotope compositions indicate that the ore-forming materials were mainly derived from the wall rocks (sedimentary–metamorphic rocks) that S, Se, and Sb dissolved during fluid–rock interactions. The ore-forming fluids were metamorphic water produced by metamorphism, which had experienced multistage mixing with meteoric water and organic-rich fluids. Selenium substitutes for sulfur in the stibnite crystal lattice, causing rhythmically distributed Se contents in stibnite, which resulted from multistage physicochemical changes in ore-forming fluids during crystallization. The varied patterns of Se contents are the result of different cross-sections of the stibnite.

Technological and Nutritional Aspects of Bread Production: An Overview of Current Status and Future Challenges.

Bakery products, especially bread, exist in many homes worldwide. One of the main reasons for its high consumption is that the main raw material is wheat, a cereal that can adapt to a wide variety of soils and climates. However, the nutritional quality of this raw material decreases during its industrial processing, decreasing the value of fibers, proteins, and minerals. Therefore, bread has become a product of high interest to increase its nutritional value. Due to the high consumption of bread, this paper provides a general description of the physicochemical and rheological changes of the dough, as well as the sensory properties of bread by incorporating alternative flours such as beans, lentils, and soy (among others). The reviewed data show that alternative flours can improve fiber, macro, and micronutrient content. The high fiber content reduces the quality of the texture of the products. However, new processing steps or cooking protocols, namely flour proportions, temperature, cooking, and fermentation time, can allow adjusting production variables and optimization to potentially overcome the decrease in sensory quality and preserve consumer acceptance.

Influence of Discharges and UV Irradiation on the Electrical Properties of High Pressure Polyethylene and Compositions on Its Base

ABSTRACT The composition and concentration of a low-molecular organic additive, leading to a significant improvement in the electrical properties of low-density polyethylene of high pressure grade 10,803-020, were experimentally determined. Phthalic anhydride and phthalic acid were used as modifying organic additives. The content of additives in the polyethylene of high pressure composition varied in the range of 0.01–0.1 wt%. It has been shown that the content of 0.05 wt% phthalic anhydride and phthalic acid in the composition polyethylene of high pressure (PEHP + 0.05 wt% PhAn + 0.05 wt% PhAc) is the optimal composition, since the electrical strength of the film has increased significantly. The dependences of the dielectric loss tangent and specific volumetric electrical resistance on temperature, as well as the kinetics of physicochemical changes in them under the influence of electrical discharges in air and UV irradiation, have been studied. It was established that the dielectric characteristics of the polymer composition PEHP + 0.05 wt% PhAn (storage life 40 years) changed slightly.

Carbonate Hydroxyapatite - A Multifunctional Bioceramics with Non-Medical Applications

Carbonate hydroxyapatite is the common derivative of hydroxyapatite found in living systems. It is the building block of most hard tissues, including the teeth and bones. A vast majority of the applications of this versatile material focus on its biomedical applications, which is attributable to its closeness to biological apatites. Hydroxyapatite is a strong precursor to carbonate apatite in nature, and many experiments show that both are similar in a few respects. A significant divergence point is carbonate's obvious impact on its physicochemical properties and concomitant applications. The inclusion of carbonate ions into the lattice of hydroxyapatite results in morphological and physicochemical changes that vary with the method of synthesis and extent of substitution. The unique crystal structure, improved surface area, and porous morphology of carbonate hydroxyapatites also make it useful for catalysis and environmental remediation as adsorbents for heavy metals. This review briefly examines carbonate hydroxyapatite, its synthesis, its modification, and its characterization. It also highlights its biomedical applications while drawing attention to its non-medical potential.

Wildfire Effects on the Soil Respiration and Bacterial Microbiota Composition in Mediterranean-Type Ecosystems

This work provides insights into the effect of fire on soil processes in Mediterranean-type ecosystems in Cyprus. Soil samples from mountainous sites that were subjected to a summer wildfire and adjacent control samples were collected. Incubations were used to estimate basal respiration and isolate soil CO2 release of heterotrophic microorganisms from autotrophic root respiration and heterotrophic respiration from litter decomposition. Physicochemical property changes, bacteria community changes using DNA extraction and 16S rRNA gene analysis, and the effects of ash and fresh litter addition were studied to reveal the microbial composition and the post-fire soil function. Laboratory incubation showed that burned soils constantly showed higher microbial respiration rates compared with control unburned areas, even six months after a fire. Adding ash to unburned samples increased microbial respiration, suggesting that increased nutrient availability positively corelates with the increased release of CO2 from fire-affected soil. Elevated temperatures due to the wildfire exerted significant effects on the composition of soil bacterial microbiota. Nevertheless, the wildfire did not affect the alpha-diversity of soil bacteria. New communities of microorganisms are still able to decompose fresh plant material after a fire, but at a slower rate than natural pre-fire populations.

In situ and Operando Characterisation in the Preferential Oxidation of Carbon Monoxide over Base Metal Oxide Catalysts: A Review

AbstractPolymer electrolyte membrane fuel cells (PEMFCs) are the core technology of the steadily growing hydrogen (H2) economy as they can convert chemical energy, in the form of H2, to electrical energy. If the H2 is derived from (green) hydrocarbons, via steam reforming and the water‐gas‐shift reaction, then it would contain small amounts of carbon monoxide (CO, 0.5–2 %), among other gases. CO poisons the platinum‐based anode catalyst in the PEMFC, and the current recommendation is to decrease its concentration to below 0.01 % (or 100 ppm) in the H2‐rich PEMFC feed. The preferential oxidation of CO (CO‐PrOx) is a promising strategy for decreasing the CO concentration, and base metal oxide catalysts have shown great potential in this regard. However, such catalysts tend to undergo physicochemical changes that cause undesirable catalytic activity and selectivity changes. This review discusses the different base metal oxide catalysts that have been evaluated in CO‐PrOx, while paying special attention to the various in situ and operando techniques that have been used to monitor the physicochemical changes of base metal oxides during operation. We conclude the review by highlighting the recent and possible future attempts of circumventing the undesired physicochemical changes of base metal oxides during CO‐PrOx.

In situ sulfide saturation induced by geometric changes of magma conduit in the world-class Jinchuan magmatic Ni-Cu sulfide deposit, China

When and how sulfide saturation occurred in the Jinchuan magmatic Ni-Cu sulfide deposit are poorly constrained. To address this issue, we investigated compositional variations and crystallization temperatures of olivine in various ores and rocks in orebody 1 of the Jinchuan deposit. The forsterite (Fo) values and Mn contents in olivine vary respectively from 79.6 to 85.2 and 1270 to 2463 ppm in net-textured ores, 76.7 to 84.2 and 1425 to 2865 ppm in patchy net textured ores, 78.7 to 84.1 and 1440 to 2649 ppm in disseminated ores, and 69.7 to 81.8 and 1495 to 3191 ppm in sulfide-barren lherzolites. The estimated crystallization temperatures of olivine in these ores/rocks range from 803 to 1163 ℃, 871 to 1314 ℃, 821 to 1507 ℃, and 929 to 1652 ℃, respectively. These data revealed two distinct groupings in both olivine Fo-Mn correlations and crystallization temperatures cluster splitting at a Fo of 79.5 and a temperature of 1100 ℃. The wider range of Mn content with a given Fo value higher than 79.5 compared to those with Fo values lower than 79.5 indicates the onset of in situ sulfide saturation at a Fo of 79.5. The termination of sulfide saturation is epitomized by olivine in disseminated ores with a peak Fo content of 84. The abrupt temperature drops from ca. 1400–1500 °C to ca. 800–1100 °C in the parental magma likely occurred when the magma flowed through the westernmost portion of this segment, which resembles a de Laval nozzle. This geometry could have induced rapid cooling and decompression of the magma, consequently promoting degassing through decompression. These reductions in temperature and H2O content of the magma would collectively result in a decrease in the sulfur concentration at sulfide saturation (SCSS), which would exceed any SCSS increase due to decompression. Our findings emphasize the critical role of magma conduit geometry in physicochemical changes of the parental magma for sulfide saturation and subsequent mineralization in the Jinchuan deposit, which may also be applicable to other magmatic deposit worldwide.