Heat-sensitive Substances Research Articles

Desolvation Inability of Solid Hydrates, an Alternative Expression for the Gibbs Free Energy of Solvation, and the Myth of Freeze-Drying.

The term "desolvation inability" is proposed in order to describe the alteration of the original chemical structure of a solute ("decomposition") prior to the solvent's full removal upon the heating of the solvate. This behavior has been sporadically reported; however, it is much more frequent, and it is the basis of various, seemingly unrelated, effects/processes, e.g., the vinegar syndrome of cellulose acetate cinematographic films, in thermal energy storage. An explanation and a criterion/index for the prediction of this behavior are provided based on the comparison of the Gibbs free energies of decomposition and desolvation. A new approach for the expression of the Gibbs free energy of desolvation is proposed by reversing the roles of the solute and solvent and by regarding water as the solute rather than as the solvent, while the solute is treated as a solid solvent. This approach results in lower solvation/desolvation Gibbs free energy values. Based on the above, the experimentally observed thermal behavior of three inorganic hydrates is predicted and explained. Theoretically and experimentally, it is supported that decomposition is possible at sub-zero (°C) temperatures and the regarded simultaneous drying and protection of heat-sensitive substances by freeze-drying, at least in some cases, e.g., for the case of gallic acid, is an unverified myth.

Preparation of β-carotene nanoparticles using supercritical CO2 anti-solvent precipitation by injection of liquefied gas feed solution

This study proposes to further exploit the potential of the carbon dioxide supercritical anti-solvent precipitation (SAS) process by using liquefied gas as a feed solvent in the SAS process. In this study, liquefied dimethyl ether (DME) is compared to conventional ethyl acetate as the feed solvent for β-carotene. DME is a gas in its standard state, and when it is made into a subcritical liquefied gas, it has a larger self-diffusion coefficient and saturated vapor pressure, and smaller viscosity and surface tension than liquid solvents. Because of these characteristics of liquefied DME, liquefied DME prevents primary particle agglomeration and DME residue. When ethyl acetate was used as the feed solvent, the conditions giving the smallest particles were 60 °C and 12 MPa, and 31 ± 5 nm primary particles of β-carotene were obtained. However, most of these were aggregated into secondary particles of several hundred nanometers. In the case of liquefied DME, the condition giving the smallest particles was 40 °C and 12 MPa, and primary particles of 58 ± 8 nm β-carotene were dispersed without aggregation. Furthermore, FT-IR analysis detected residual ethyl acetate in the aggregated β-carotene particles, whereas DME was not detected in the dispersed particles. Liquefied DME is likely to be a suitable solvent for the micronization of heat-sensitive substances using the SAS method without agglomeration. Combining various liquefied gases, not just DME, with the SAS process may create possibilities for applying the SAS process to target materials that are insoluble in conventional liquid solvents and for synthesizing even finer nanoparticles.

A Staphylococcus epidermidis strain inhibits the uptake of Staphylococcus aureus derived from atopic dermatitis skin into the keratinocytes

BackgroundVarious bacterial species form a microbiome in the skin. In the past, dead Staphylococcus aureus derived from atopic dermatitis (AD) are taken up by keratinocytes; however, whether live S. aureus can be taken up by keratinocytes is unknown. ObjectiveThis study aimed to examine whether live AD strains of S. aureus internalize into the keratinocytes and how the internalization changes under conditions in which other bacterial species including S. epidermidis are present. MethodsHaCaT cells were cultured with live S. aureus and S. epidermidis (live or heat-treated) or their culture supernatants. After coculture, the change in the amount of S. aureus in the cytoplasm of HaCaT cells was analyzed using, a high-throughput imaging system, Opera Phenix™. ResultsLive S. aureus were taken up in the cytoplasm of HaCaT cells. Coculturing live S. aureus with live S. epidermidis or the culture supernatants decreased the abundance of S. aureus in the cytoplasm. The heat-treated culture supernatants of live S. epidermidis or culture supernatants of other S. strains did not decrease the abundance of S. aureus in the cytoplasm. ConclusionLive S. aureus was internalized into the cytoplasm of HaCaT cells as does heat-treated S. aureus. In addition, the heat-sensitive substances secreted by coculture with S. epidermidis and keratinocytes inhibited the uptake of S. aureus by keratinocytes.

Lacticaseibacillus plantarum postbiotics prepared by the combined technique of pasteurization and ultrasound: effective measures to alleviate obesity based on the SCFAs-GPR41/GPR43 signaling pathway.

Postbiotics have recently garnered substantial research attention, especially in obesity research. In this study, upon comparing the proliferative effects of three food-derived media-skim milk, soy milk, and almond milk-on Lactiplantibacillus plantarum J26 (L. plantarum J26), skim milk was found to be the most effective. The metabolomic analysis further unveiled that the metabolites produced by the strain cultured in skim milk influenced the greatest number of lipid metabolism-associated pathways. Additionally, to better preserve heat-sensitive substances, ultrasound and pasteurization were combined and used here for inactivation. L. plantarum J26 postbiotics, prepared through pasteurization combined with 400 W ultrasound treatment for 30 min, exhibited the most effectiveness at inhibiting cellular triglyceride accumulation, reducing its level to 0.99 mg per 104 CFU. The prepared postbiotics significantly reduced the increase in multiple indicators, including body weight, blood lipids, and adipokines in obese mice (p < 0.05). Following treatment, liver tissue damage as well as white and brown adipose tissue damage were also markedly improved in obese mice. According to gut microbiota sequencing, the postbiotic intervention increased Lactobacillus and Bifidobacterium abundances but reduced the abundances of obesity-associated Faecalibacterium and Erysipelotrichaceae. Additionally, the postbiotics elevated the acetate, propionate, and butyrate levels by 14.95%, 23.89%, and 8.31%, respectively. High postbiotic doses significantly upregulated the expression of GPR41/GPR43, short-chain fatty acid (SCFA) receptor genes, in the liver and adipose tissues (p < 0.05), thus correcting the obesity-induced anomalies in the SCFAs-GPR41/GPR43 signaling pathway. This research offers compelling evidence supporting the use of edible postbiotics in targeted obesity regulation.

Improving the stability and bioactivity of curcumin using chitosan-coated liposomes through a combination mode of high-pressure processing

This study used chitosan-coated liposomes of curcumin (cur-chitosomes) coupled with a combination mode of high-pressure processing (HPP) and ethanol injection to improve the bioactivity, preservation, and thermal stability of curcumin. The results revealed cur-chitosomes presented the best thermal stability and encapsulation efficiency. With 0.1% chitosan addition, the encapsulation efficiency increased from 73.8 to 84.0%, accompanying with less increases on particle size and polydispersity index. Storage stability for 28 days incubation demonstrated the particle size of cur-chitosomes remained at a constant value, which presented the long thermal stability due to the static electrostatic repulsive force. The stability of cur-chitosomes presented high value of 85.3% at degradation conditions of 25 °C and 480 min. With thermal kinetic calculation, the half-life of curcumin-loaded liposomes and cur-chitosomes were 625 and 1250 min at 25 °C, so liposome formation and chitosan addition in curcumin could increase the storage time. Over 104 CFU/g Escherichia coli, Staphylococcus aureus, and Staphylococcus aureus could be completely sterilized in the preparation of cur-chitosomes at 400 MPa HPP. Consequently, chitosomes by HPP not only prevented the thermal degradation of heat-sensitive substances but also enhanced the storage stability and the sterilization effect in a non-thermal process.

Extraction of Camphor Tree Essential Oil by Steam Distillation and Supercritical CO2 Extraction.

The essential oil extracted from Cinnamomum camphora leaves is a mixture of volatile compounds, mainly terpenes, and is widely used in medicine, perfume and chemical industries. In this study, the extraction processes of essential oil from Cinnamomum camphora leaves by steam distillation and supercritical CO2 extraction were summarized and compared, and the camphor tree essential oil was detected by GC/MS. The extraction rate of essential oil extracted by steam distillation is less than 0.5%, while that of supercritical CO2 extraction is 4.63% at 25 MPa, 45 °C and 2.5 h. GC/MS identified 21 and 42 compounds, respectively. The content of alcohols in the essential oil is more than 35%, and that of terpenoids is more than 80%. The steam extraction method can extract volatile substances with a low boiling point and more esters and epoxides; The supercritical method is suitable for extracting weak polar substances with a high alcohol content. Supercritical CO2 extraction can selectively extract essential oil components and effectively prevent oxidation and the escape of heat sensitive substances.

The effect of high humidity hot air impingement blanching on the changes in cell wall polysaccharides and phytochemicals of okra pods.

Okra pods contain heat-sensitive substances, such as phenolic compounds and other phytochemicals that can be degraded when okra pods are subjected to heat treatment. The understanding of the impact of high humidity hot air impingement blanching (HHAIB) on the changes in physicochemical properties of polysaccharides and phytochemicals of okra pods is of great importance because over-blanching may result in cell membrane disruption and changes in biologically active compounds under prolonged exposure to the thermal treatment. Therefore, the present study aimed to investigate the effect of HHAIB on the changes in physicochemical properties of pectins and phytochemicals extracted from okra pods. Both the HHAIB time and method of extraction influenced their physicochemical characteristics and biological activity. Pectin fractions subjected to HHAIB were composed of polygalacturonic acid, rhamnogalacturonan, glucomannan, galactan, mannose, arabinose, rhamnose, calcium pectate and arabinogalactan. The contents of total phenolics, total flavonoids and antioxidant activity of extracts mostly increased during HHAIB (i.e. up to 19.0%, 13.2% and 35.3%, respectively). However, HHAIB reduced the chlorophyll-a (up to 55.7%) and lycopene (up to 52.6%) contents of okra pods. The acquired knowledge may be useful for better understanding and optimization of technologies based on HHAIB treatment. The HHAIB treated okra can be a promising natural alternative in different applications, including its use as a replacement of some ingredients in food or non-food systems as a result of richness in polysaccharides and polyphenols, as well as high antioxidant properties. © 2022 Society of Chemical Industry.

A novel method for the microencapsulation of curcumin by high-pressure processing for enhancing the stability and preservation

Curcumin is used for the development of new pharmaceutical and food products, but its application is generally hindered by the poor solubility of curcumin and thermal instability during storage and processing. In this study, the liposomes of curcumin (cur-liposomes) were prepared by a novel combination of ethanol injection and high-pressure processing (HPP) to enhance the stability and preservation of curcumin. The pasteurization, mean particle size, size distribution, and encapsulation efficiency of cur-liposomes and the kinetics of their thermal degradation were also investigated in this research. From the results, the kinetic rate constants of curcumin in samples of free curcumin and cur-liposome at 25 °C were found to be 1.6 × 10−3 and 0.8 × 10−3 min−1, respectively. The phospholipid bilayer structure could protect curcumin. The results propose that the HPP method for liposome preparation is superior to the probe-sonication method in terms of stability, encapsulation efficiency, and homogeneity. Furthermore, the preparation of cur-liposomes by HPP with a hydrostatic pressure of 200 MPa could maintain the optimal particle size (206.4 nm) and polydispersity index (0.19). Conclusively, the combination of ethanol injection and HPP can not only successfully inactivate the microorganisms during liposome preparation for microencapsulation of bioactive compounds but also effectively preventthe thermal degradation of heat-sensitive substances in non-thermal processing for practical applications.

Effects of layer arrangement on heating uniformity and product quality after hot air assisted radio frequency drying of carrot

The conventional drying technology prolongs the shelf life of carrots but may cause the serious loss of nutrients. The aim of this study was to investigate the effects of intermittently rearranging layers on the heating uniformity, drying characteristics and quality of carrot slices under the hot air assisted radio frequency (RF) heating. The carrot slices were dried for 270 min using hot air (60 °C) assisted RF heating at the electrode gap of 100 mm firstly, and then followed hot air drying to achieve the final moisture level (0.11 kg/kg (d.b.)). The results showed that the selected hot air assisted RF drying protocol for the carrot slices reduced 30% of the duration compared to the single hot air drying. The carrot slices dried by the combined drying method had the highest total carotenoid value (P ≤ 0.05) except for possessing accepted color and rehydration. Therefore, the combined drying method could improve the drying rate and maintain heat sensitive substances in carrot slices.

Evaluation of different drying models for jabuticaba peel, dried in spouted bed dryer through performance indicators and the impact on anthocyanins

Jabuticaba fruit stands out for its energetic and nutritional value being widely consumed in the fresh form and used for the production of jellies, vinegar, wines, and liquor. The jabuticaba peel has a high content of natural antioxidants, such as carotenoids, anthocyanins, tocopherols, and phenolic compounds, these compounds give protection to the fruit. In order to promote preservation of the jabuticaba peel for an extended period of time, the drying process is applied to remove water from the product and, consequently, reduce the risks of microbial growth and enzymatic reactions. The objectives of this study were to evaluate four drying models for spouted bed drying of jabuticaba peel using the following performance indicators: accuracy factor (Af), bias factor (Bf) and mean square error (RMSE), and analyze the impact of drying temperatures on the content of monomeric anthocyanins. The drying process was done in a pilot spouted bed dryer unit at temperatures: 50, 60 and 70°C for 2.5 h. The total monomeric anthocyanin content was determined using the pH differential method. It was observed that for the temperatures of 60°C and 70°C, the Two-term, and Page models, respectively, are appropriated to describe the drying kinetic of the jabuticaba peel in a spouted bed drying under the studied conditions. Moreover, for anthocyanins content, it was noted that there was a greater degradation at the highest temperature studied (70°C) as expected since anthocyanins are heat-sensitive substances.

Analytical assessment of Akika Pishti based on Ancient and Modern Parameter

Pishti Kalpana is one of the Kharaliya Kalpanas of Rasashastra which brings the heat sensitive substances to micro particle level without applying the heat for better therapeutic efficacy and is considered as Sukshma as Bhasma. In Rasa texts it is said that Marana of Ratna and Uparatna are not worthwhile hence, Pishti Kalpana is advocated. There is no direct reference for the Siddhilakshana of Pishti, but our Acharyas has mentioned that Pishti is a Anagnisidhdha Bhasma i.e. Pishti should be Bhasmavat, so the parameters mentioned for quality control of Bhasma in ancient text are applicable for assessing the Siddhi Lakshanas of Pishti. So an attempt has been made to study analytically Sidddhilaxana of Pishti by both ancient and modern parameters with special reference to Akika Pishti. Akika is one of the semiprecious gems grouped under the Paradadi Varga, Uparatna Varga and Spatika Varga Ratna. In present study Pishti was prepared as per pharmacopeal standards and subjected to both ancient and modern tests to analyze them viz. Pishtivarna, Mrudutva and Slakshanatva, Rekhapurnata, Varitara, Nirdhooma, Unama and Nischandratva tests according to classics and according to modern parameters, organoleptic tests, physio chemical like LOD, pH, ash values, instrumental analysis like XRD , SEM-EDAX and particle size.

The Effect of Holder Pasteurization on Nutrients and Biologically-Active Components in Donor Human Milk: A Review.

When a mother’s milk is unavailable, the best alternative is donor milk (DM). Milk delivered to Human Milk Banks should be pasteurized in order to inactivate the microbial agents that may be present. Currently, pasteurization, performed at 62.5 °C for 30 min (Holder Pasteurization, HoP), is recommended for this purpose in international guidelines. Several studies have been performed to investigate the effects of HoP on the properties of DM. The present paper has the aim of reviewing the published papers on this topic, and to provide a comparison of the reported variations of biologically-active DM components before and after HoP. This review was performed by searching the MEDLINE, EMBASE, CINHAL and Cochrane Library databases. Studies that clearly identified the HoP parameters and compared the same DM samples, before and after pasteurization, were focused on. A total of 44 articles satisfied the above criteria, and were therefore selected. The findings from the literature report variable results. A possible explanation for this may be the heterogeneity of the test protocols that were applied. Moreover, the present review spans more than five decades, and modern pasteurizers may be able to modify the degradation kinetics for heat-sensitive substances, compared to older ones. Overall, the data indicate that HoP affects several milk components, although it is difficult to quantify the degradation degree. However, clinical practices demonstrate that many beneficial properties of DM still persist after HoP.

Development of three-layered rumen escapable capsules for cattle

A new rumen escapable tool is presented for cattle in prospect of developing medical treatment or supplementing trace elements for disease prevention. This tool consists of a three-layered capsule that dissolves in the lower digestive tract, but not in the rumen. The capsule was manufactured by capsule-forming techniques through the use of liquid surface tension. This method does not involve high-temperature treatment, so the capsule can contain not only lipophilic substances but also hydrophilic or heat-sensitive substances. Furthermore, the capsule has a specific gravity of 1.3 and diameter of 6.0 mm, which were previously shown to be appropriate to avoid rumination. The objective of this study was to confirm the effectiveness of the capsule pertinent to rumen escaping. In order to validate rumen escape, capsules containing 30 g of water-soluble vitamin (thiamine hydrochloride) per head were administered to four lactating cows assigned in a crossover trial. In the group administered encapsulated thiamine hydrochloride, blood thiamine levels increased from 12.4 ± 1.03 ng/ml before administration to 54.8 ± 2.21 ng/ml at 6 hr following administration, whereas the level remained at 13.3 ± 2.05 ng/ml in the control group administered via aqueous solution. This indicates that the three-layered capsules passed through the rumen and dissolved in the lower digestive tract, thus functioning as a rumen escapable tool.

Application of integrated membrane technology in purification of chlorogenic acid

Integrated membrane technology is a membrane separation system, which can overcome the disadvantage of single membrane, save the cost, and improve the product quality. Chlorogenic acid, which is an effective component of Chinese medicine and a heat-sensitive substance, is not stable at high operation temperature. Chlorogenic acid with molecular weight of 354 Da and good solubility in water can be treated by nanofiltration (NF) membrane. In this work, polyetherimide (PEI) ultrafiltration (UF) membrane with good chemical and thermal stability is used in the purification of chlorogenic acid solution. Positively charged HACC/PEI NF membrane with good antibacterial performance and hydrophilicity is used to concentrate chlorogenic acid solution. It is found that, the PEI UF membrane can separate chlorogenic acid with other components and improve the purity of chlorogenic acid. At the same time, the rejection to chlorogenic acid of the positively charged NF membrane is about 92% which is suitable for the concentration of chlorogenic acid solution. The integrated membrane technology is very useful in the production of chlorogenic acid.

Wafer-level capping and sealing of heat sensitive substances and liquids with gold gaskets

This paper reports on a novel wafer-level packaging method employing gold gaskets and an epoxy underfill. The packaging is done at room-temperature and atmospheric pressure. The mild packaging conditions allow the encapsulation of sensitive devices. The method is demonstrated for two applications; the wafer-level encapsulation of a liquid and the wafer-level packaging of a photonic gas sensor containing heat sensitive dye-films.

Effects of Asian sand dust particles on the respiratory and immune system

Epidemiologic studies have reported that Asian sand dust (ASD) particles can affect respiratory health; however, the mechanisms remain unclear. We investigated the effects of ASD on airway epithelial cells and immune cells, and their contributing factors to the effects. Human airway epithelial cells were exposed to ASD collected on 1-3 May (ASD1) and on 12-14 May (ASD2) 2011 in Japan and heat-treated ASD1 for excluding heat-sensitive substances (H-ASD) at a concentration of 0, 3, 30 or 90 µg ml(-1) for 4 or 24 h. Furthermore, bone marrow-derived dendritic cells (BMDC) from atopic prone mice were differentiated by culture with granulocyte-macrophage colony-stimulating factor (GM-CSF) then these BMDC were exposed to the ASD for 24 h. Also splenocytes as mixture of immune cells were exposed to the ASD for 72 h. All ASD dose dependently reduced viability of airway epithelial cells. Non-heated ASD showed a dose-dependent increase in the protein release of interleukin (IL)-6 and IL-8. The raises induced by ASD1 were higher than those by ASD2. ASD1 and ASD2 also elevated ICAM-1 at the levels of mRNA, cell surface protein and soluble protein in culture medium. In contrast, H-ASD did not change most of these biomarkers. Non-heated ASD showed enhancement in the protein expression of DEC205 on BMDC and in the proliferation of splenocytes, whereas H-ASD did not. These results suggest that ASD affect airway epithelial cells and immune cells such as BMDC and splenocytes. Moreover, the difference in ASD events and components adhered to ASD can contribute to the health effects.

Low temperature, atmospheric pressure, direct current microplasma jet operated in air, nitrogen and oxygen

Micro-plasma jets in atmospheric pressure molecular gases (nitrogen, oxygen, air) were generated by blowing these gases through direct current microhollow cathode discharges (MHCDs). The tapered discharge channel, drilled through two 100 to 200 μm thick molybdenum electrodes separated by a 200 μm thick alumina layer, is 150 to 450 μm in diameter in the cathode and has an opening of 100 to 300 μm in diameter in the anode. Sustaining voltages are 400 to 600 V, the maximum current is 25 mA. The gas temperature of the microplasma inside the microhollow cathode varies between ~2000 K and ~1000 K depending on current, gas, and flow rate. Outside the discharge channel the temperature in the jet can be reduced by manipulating the discharge current and the gas flow to achieve values close to room temperature. This cold microplasma jet can be used for surface treatment of heat sensitive substances, and for sterilization of contaminated areas.

Preparation of Antimicrobial Membranes: Coextrusion of Poly(lactic acid) and Nisaplin in the Presence of Plasticizers

Nisin is a naturally occurring antimicrobial polypeptide and is popularly used in the food and food-packaging industries. Nisin is deactivated at temperatures higher than 120 degrees C and, therefore, cannot be directly incorporated into poly(L-lactic acid) (PLA), a biomass-derived biodegradable polymer, by coextrusion because PLA melts at temperatures around 160 degrees C or above. However, PLA can remain in a melt state at temperatures below the T(m) in the presence of lactic acid or other plasticizers. In the present study, PLA was coextruded with lactic acid, or lactide, or glycerol triacetate at 160 degrees C. After the PLA was melted, the temperature of the barrels was reduced to 120 degrees C, and then Nisaplin, the commercial formulation of nisin, was added and the extrusion was continued. The resultant extrudates possess the capability to suppress the growth of the pathogenic bacterial Listeria monocytogenes , demonstrating a significant antimicrobial activity. The present study provides a simple method to produce PLA-based antimicrobial membranes. The method can also be used for the coextrusion of other heat-sensitive substances and thermoplastics with high melting temperature.

Dehydration of caprolactam–water mixtures through cross-linked PVA composite pervaporation membranes

ɛ-Caprolactam (CPL) is the monomer of nylon-6 used extensively in the manufacture of high quality nylon-6 fibers and resins. Since CPL is a very heat-sensitive substance and water is the most important impurity in the final CPL purification, reduced pressure distillation through triple-effect evaporation sets is widely adopted by chemical industry. But high energy consumption, high wastage and condensate pollution have restricted the wide-scale production of CPL and the commercial profit of the manufactures. To improve or develop a new CPL dehydration process, pervaporation separation of CPL–water mixtures was investigated using composite membranes consisting of a selective poly(vinyl alcohol) (PVA) membrane as top layer and a porous polyacrylonitrile (PAN) substrate. The selective layer was formed by PVA matrix followed by the cross-linking reaction of PVA with glutaraldehyde. The membranes were characterized by SEM, FTIR and TGA. Due to the formation of more compact cross-linked structure, cross-linked PVA composite membranes exhibited enhanced thermal stability. Through evaluating the pervaporation performance, we introduced a pervaporation transport equation to normalized permeation fluxes in terms of water permeance, CPL permeance and selectivity. The evaluated results have revealed that the separation performances of PVA composite membranes are strongly related to its hydrophilic/hydrophobic nature as well as the operating parameters, such as feed concentration and operating temperature. Experimental data showed that the PVA composite membranes had superior pervaporation separation performances for dehydration of caprolactam–water mixtures, which provided a new way for CPL dehydration.

Study of the solubility and the metastable zone of 1,3-dihydroxyacetone for the drowning-out process

The 1,3-dihydroxyacetone (DHA) is an important raw material in the cosmetic industry for its skin pigmentation property. The DHA is highly soluble in water, which leads to a very important viscosity value and a huge metastable zone width. In addition, the DHA is a heat-sensitive substance. The drowning-out process (water-out or salting-out) is then necessary to reduce the solubility and to favor the mobility of the molecular species in solution. In this work, the solubility curves of DHA in different water/ethanol mixtures have been established experimentally. The turbidimetric method is used successfully to study the metastable zone in the water/ethanol mixture. The results show that the metastable zone is large, both the dissolution and the crystallization of DHA are time consuming, which could be due to the low diffusivity in the high-concentration solutions and at low temperatures.