Search Results (8)

Astringency in persimmon fruit is often eliminated by treatment with gaseous carbon dioxide, dry ice, or alcohol. However, these methods are time-consuming and labor-intensive, and astringency may recur after heat treatment. In this study, a method for easily reducing astringency was investigated by taking advantage of the benefits of combining proteins and polysaccharides. In the first experiment, the protein materials with strong astringency-reducing effects were screened from among 15 protein-rich foods using astringent persimmon juice (APJ), and collagen peptides were found to be highly effective. However, syneresis was observed when 1% collagen peptide powder was added to the astringent persimmon paste (AP). Therefore, in the second experiment, 0.5% collagen peptides (protein) were applied to reduce heating-induced astringency and reversion and 0.5% polysaccharides (guar, and xanthan gums) to maintain color and suppress syneresis. The results demonstrate that the combination of collagen peptide and polysaccharides is optimal for removing astringency in persimmon, inhibiting its recurrence by heating, and maintaining product quality. The results of this study may reduce the labor required for the astringency removal process, broaden the uses of AP, and facilitate the effective utilization of discarded astringent persimmons that do not meet the standards. Full article

The developments in manufacturing technologies are expected to reduce energy input without compromising product quality. Regarding the material densification process, numerical simulation methods are applied to achieve this goal. In this case, relevant material models are built using functions that describe the variation in mechanical parameters of the material in question due to its deformation. The literature review conducted for this research has revealed a shortage of experimental research methods allowing a determination of the coefficient of friction at low temperatures, approximately 200 K. This article proposes a method for determining the friction coefficient of dry ice sliding against steel. The experimental results were analysed to obtain several functions describing the variation in the coefficient of friction. These functions were then compared using goodness-of-fit indexes. Finally, two functions with similar goodness-of-fit values were chosen. The findings of this research project will complement the already available information and may be used in various research and implementation projects related to the development or improvement of currently used crystallised carbon dioxide conversion processes. Full article

This paper presents the experimental findings on fire containment and suppression by dropping CO₂ hydrate granules and tablets on burning solid materials. We used the combustible materials typical of compartment fires—wood, linoleum, and cardboard—to determine the volume and mass of gas hydrate powder necessary for the effective fire suppression. Gaseous emissions were recorded from the combustion with and without fire suppression using hydrates. Conditions were specified in which a fire can be extinguished with minimum air pollution. We also identified the conditions for effective fire containment and suppression using hydrates as compared to water spray, snow, and ice. The necessary volume of hydrate was determined for effective fire suppression in a compartment filled with various materials. Experimental data show that the impact of temperature on the CO₂ hydrate decomposition is highly nonlinear. The carbon dioxide hydrate exhibited a much better fire suppression performance than water spray in the course of total flooding of solid combustible materials. It was established that fine water spray failed to reach the lower levels of multi-tier crib fires. Finally, key patterns of total flooding with CO₂ hydrate powder were identified when applied to fires. Full article

This paper presents experimental findings on heat and mass transfer, phase transitions, and chemical reactions during the interaction of CO₂ hydrate in powder granules and tablets with burning liquid fuels and oil. The experiments involved CO₂ hydrate tablets and spheres made of pressed granules. The fire containment and suppression times were established experimentally. Using the gas analysis data, we studied the effects of the mitigation of anthropogenic emissions from the combustion of liquids and their suppression by gas hydrates. We also compared the performance of water aerosol, foaming agent emulsion, snow, ice, and CO₂ hydrate samples as laboratory-scale fire suppressants. The paper further describes the numerical modeling of the CO₂ hydrate dissociation during liquid fuel combustion. The rapid carbon dioxide release is shown to prevent the oxidizer from the combustion zone. The suppression of a flame using powder with a granule size of 3 mm requires 20-times less carbon dioxide hydrate than in the case of pressed tablets. Effective conditions are identified for using CO₂ hydrates to extinguish fires involving flammable liquids and most common fuels. Full article

Traps for capturing mosquitoes and other blood-feeding arthropods are often baited with carbon dioxide (CO₂) as an attractant. Dry ice is popularly used as a CO₂ source due to its high efficiency and ease of use. However, dry ice can be difficult to obtain in many rural and remote areas. The objective of this study was to develop a simple and inexpensive method that could continuously generate CO₂ overnight (about 10 h) while being used with CDC light traps for sampling adult mosquitoes. In principle, CO₂ was produced from the reaction between hydrochloric acid (HCl) (12% w/w) and limestone powder (mainly composed of calcium carbonate, CaCO₃). In laboratory experiments, an average of 256 mL of CO₂ was produced from 1 g of limestone. For continuous production of CO₂, an intravenous drip infusion set, as commonly used in hospitals, was modified for dripping the acid solution (1 L in a normal saline bag) onto limestone powder (800 g in a 1.5 L bottle) at a flow rate of 30 drops/min (about 1.6 mL/min). With this procedure, an average of 55 mL of CO₂ per min was obtained (approximately equivalent to the CO₂ exhaled by two chickens). The performance of this CO₂ generating system incorporated with CDC light traps for sampling mosquitoes was evaluated in three rural villages of Sanpatong District, Chiang Mai Province, Thailand. Three trap sets were used, i.e., Set I, light trap alone; Set II, light trap with dry ice (1 kg); and Set III, light trap with limestone and acid. In each village, mosquitoes were collected at three fixed sites, each with one of the three trap sets. They were rotated daily for three rounds (9 nights per village and 27 nights in total). A total of 1620 mosquitoes (97.7% being females) consisting of Aedes, Anopheles, Armigeres, Coquilletidia, Culex and Mansonia were captured across three different sampling sets from all villages. The predominant species collected were Culex vishnui (n = 760, 46.91%), Cx. bitaeniorhynchus (n = 504, 31.11%) and Cx. tritaeniorhynchus (n = 157, 9.69%). Light traps alone (Set I) collected very low numbers of mosquitoes (n = 12) and species (6 spp.), whereas light traps with dry ice (Set II) collected the highest numbers of mosquitoes (n = 1341) and species (14 spp.). Although the light trap with limestone and acid (Set III) collected fewer mosquitoes (n = 267) and species (9 spp.) than the trap set with dry ice (Set II), it collected all common vector species in the study areas as collected by Set II. The presence of an acid solution had no bias in the collection of mosquitoes with different physiological ages as determined by the parous rate. The present study demonstrated that this CO₂ generating system is reliable, simple and inexpensive, and could be an alternative to dry ice. The system can be modified to increase the amount of CO₂ generated for higher efficacy of mosquito collection. This CO₂ production method can be applied to collect other blood-sucking arthropods as well. Full article

To evaluate the vibration effect caused by carbon dioxide phase-transition fracturing, the Hilbert–Huang transform was used to study the change of vibration energy with distance in different frequency bands. The results are drawn as follows: (1) The peak particle velocity (PPV) decreases as a power function with an increase in distance and has fallen below 25 mm/s at 2.8 m. (2) The energy of vibration signals induced by carbon dioxide phase-transition fracturing is mainly distributed at the frequency band of 10–50 Hz. With the increase in distance, the energy distribution of vibration signals falls in four phases: Propagation to high frequency (0–13.9 m); a rapid high-frequency energy decrease (20–30 m); energy fluctuation (30–47.2 m) and a stable energy distribution (larger than 50 m). (3) The proportion of the low-frequency vibration energy (0–10 Hz) increases as a result of the increase in distance (less than 8.7 m), which should be paid more attention. Full article

In this study, high-value, carotenoid-rich oleoresin obtained by supercritical carbon dioxide (SFE-CO₂) extraction was used to develop five variants of microencapsulated delivery system, based on whey proteins isolate (WPI), in combination with inulin (I), pectin (P) or lactose (L). The WPI:I and WPI:L variants were also obtained by conjugation via Maillard reaction. The microencapsulation of the SFE-CO₂ sea buckthorn pomace oleoresin was performed by emulsion, complex coacervation and freeze-drying, which allowed for the obtaining of five powders, with different phytochemicals profile. The WPI:I conjugate showed the highest level of total carotenoids, whereas the counterpart WPI:L showed the highest content in linoleic acid (46 ± 1 mg/g) and palmitoleic acid (20.0 ± 0.5 mg/g). The β-tocopherol and β-sitosterol were identified in all variants, with the highest content in the conjugated WPI:L variant. Both WPI:L and WPI:I conjugate samples presented similar IC50 value for inhibitory activity against pancreatic lipase and α-amylase; the highest activity was observed for the conjugated WPI:I. The WPI:P combination allowed the highest release of carotenoids in the gastro-intestinal environment. All the powders exhibited poor flowing properties, whereas water activity (a_w) ranged from 0.084 ± 0.03 to 0.241 ± 0.003, suggesting that all variants are stable during storage. In case of solubility, significant differences were noticed between non-heated and glycated samples, with the highest value for the WPI:I and the lowest for glycated WPI:I. The structural analysis revealed the presence of finer spherosomes in WPI:I and WPI:L, with a reduced clustering capacity, whereas the particles in the conjugated samples were more uniform and aggregated into a three-dimensional network. Full article

Bcakground: Extracts obtained from natural sources such as plants are of immense importance for humans. Methods: Therefore this study was conducted to obtain essential oil from the seeds of T. ammi by conventional and non-conventional methods. Hydrodistillation (HD), Solvent Extraction (SE), Ultrasonication (US), and Supercritical Carbon-dioxide (SC-CO₂) extraction techniques were used to extract essential oil from the powdered seeds of T. ammi. A quality control method for each extracted oil was developed using HPTLC, FTIR, and GC-MS. The optimization process was carried out using fractional factorial design (FFD) under which three parameters were considered: pressure (150, 175, and 300 bar), temperature (25, 30, and 40 °C), and CO₂ flow rate (5, 10, 15 g/min). Results: The yield of essential oil obtained from the HD, SE, US, and SC-CO₂ methods were 1.20%, 1.82%, 2.30%, and 2.64% v/w, respectively. Antioxidant activity was determined by the DPPH and superoxide scavenging methods and the IC₅₀ (Inhibition Concentration) values of the T. ammi oil sample were found to be 36.41 and 20.55 µg mL⁻¹, respectively. Conclusion: The present paper reported that different extraction methods lead to different yields of essential oils and the choice of a suitable method is extremely important to obtain more preferred compounds. The yield was higher in the SC-CO₂ method and it is a sustainable and green extraction technique. Many important constituents were detected in analytical techniques. Antioxidant activities carried out showed that essential oil extracted from T. ammi seeds possess significant antioxidant activity. Full article