Search Results (83)

C₆F₁₂O has been recognized as an environmentally friendly substitute applied in the fire protection, insulation equipment, and refrigeration industry. The stability and catalytic decomposition characteristics of C₆F₁₂O in the presence of metals are crucial for evaluating the applicability of such alternatives across different scenarios and recycling treatment. In this study, the adsorption and decomposition mechanisms of C₆F₁₂O on Cu (1 0 0), Cu (1 1 0), and Cu (1 1 1) surfaces have been investigated based on the density functional theory (DFT). The adsorption structures and energies of C₆F₁₂O and its key dissociation products are investigated to obtain the most stable adsorption configurations. Additionally, the projected density of states (PDOS) and electron density difference calculations are performed to explore the electronic properties of the adsorption systems. Four major dissociation reactions involving the C-C bond breakage of C₆F₁₂O that occurred on Cu surfaces are examined individually, with comparisons made to the corresponding homolytic reactions of free C₆F₁₂O. The results indicate that Cu surfaces exhibit a promising catalytic effect for C₆F₁₂O decomposition, which depends on both the kind of surfaces and the reaction pathway. Furthermore, most decomposition pathways of C₆F₁₂O on Cu surfaces are exothermic and C₆F₁₂O tends to decompose into C₅F₉O and CF₃ under the Cu catalytic effect. Full article

Developing the nutritional profile of food through the fermentation produced by lactic acid bacteria is part of sustainable development, but it also helps to improve public health. Thus, the objective of the study was to obtain synbiotic juices of fruit origin, which can successfully substitute well-known probiotic dairy products and also be introduced into the diet of vegetarians or people with certain intolerances to animal products. In this regard, two fermented blueberry juices were obtained: NC, using kefir cultures, and NP with Lactobacillus plantarum inoculation. Two more simple blueberry juices were used as controls: NCM, thermostatted at 24 °C and NPM, at 37 °C. The four types of juices were subjected to physicochemical and microbiological analyses. The results show that NP juice is the best substitute from a physicochemical point of view, presenting the highest polyphenol content and the highest DPPH radical scavenging activity even after refrigeration for 5 days. Additionally, the microbiological results of the analyzed juices can recommend these products for industrial production. Full article

This study investigated the potential of rapeseed protein isolate (RPI) as a sustainable alternative to soy protein isolate (SPI) in chicken pâtés, considering the combined effects of protein (SPI or RPI) and oil (sunflower or rapeseed) sources. The proximate composition, pH, water activity (a_w), and colour of the RPI-based formulations were largely comparable to their SPI counterparts and remained stable over 60 days of refrigerated storage. However, at day 0, the RPI-based samples exhibited lower pH values (approx. 6.09 vs. 6.41), slightly lower lightness (L* approx. 68.9 vs. 72.5), higher redness (a* approx. 4.72 vs. 3.58), and higher yellowness (b* approx. 23.3 vs. 9.38), indicating some initial formulation-dependent differences. Furthermore, RPI-based formulations exhibited enhanced textural properties and improved oxidative stability, likely due to synergistic effects between rapeseed protein and oil. The substitution of sunflower oil with rapeseed oil significantly improved the fatty acid profile (p < 0.05), notably increasing α-linolenic acid (C18:3n-3) and achieving a favourable n-6/n-3 ratio (approx. 2.8). Sensory evaluation revealed that the formulation combining both rapeseed ingredients provided a stable and highly acceptable profile. These results collectively demonstrate that RPI is a viable and functional replacer for SPI, enabling the production of nutritious, high-quality, and sustainable chicken pâtés. Full article

This study explored the utilization of date powder produced from non-marketable Sukkari and surplus dates as a natural sugar substitute in milk chocolate, with the dual objectives of improving product quality and reducing Saudi Arabia’s reliance on imported sugar. Molding chocolates were formulated with 10%, 20%, and 30% sugar substitution, while coating chocolates contained 20%, 40%, and 60%. Physical, chemical, and sensory properties were assessed immediately after production and following six months of refrigerated storage. Increasing substitution levels led to higher viscosity, with peak values observed at 30% in molding chocolate and 60% in coating chocolate. Ash and moisture contents also rose with substitution, whereas fat, protein, and carbohydrate levels remained largely unaffected. Energy content declined as substitution increased, and no significant differences were detected in peroxide or acid values between control and treated samples throughout storage. Sensory evaluations confirmed that molding chocolate with up to 20% substitution and coating chocolate with up to 40% substitution maintained comparable acceptability to control samples both initially and after storage. Overall, the findings recommend sugar replacement with date powder at 20% in molding chocolate and 40% in coating chocolate to achieve high-quality, nutritionally enhanced products with stable sensory and storage characteristics. Full article

This study analyzes the effects on global greenhouse gas (GHG) emissions of various combinations of lifecycle refrigerant management (LRM) practices and refrigerant substitutions in residential air conditioners (ACs) until the year 2070. Six scenarios involving three refrigerant types with different levels of global warming potential (GWP)—high, medium, and ultralow—and three levels of LRM involving leakage reduction during operation and end-of-life refrigerant recovery are examined. The findings reveal that combining medium GWP refrigerants (e.g., R32) with the highest level of LRM could achieve as much as a 95% reduction in emissions (933 MtCO₂eq) by 2050 and a 97% reduction (1660 MtCO₂eq) by 2070, when compared to using high GWP refrigerants (e.g., R410A). The substitution of ultralow GWP refrigerants (e.g., R290) is projected to achieve up to a 97% emissions reduction (954 MtCO₂eq) by 2050 and a 100% (1709 MtCO₂eq) reduction by 2070. Global mean temperature decreases in 2070 are nearly identical under scenarios in which either medium GWP refrigerants or ultralow GWP refrigerants are combined with the highest level of LRM (0.067 °C versus 0.069 °C). The implication is that combining medium GWP refrigerants, already underway in some regions, with the highest level of LRM offering an effective and pragmatic strategy for mitigating the climate impacts of refrigerant emission from residential ACs. Full article

It is of particular interest to use eco-friendly working fluids in ocean thermal energy conversion (OTEC) systems. In response, this study develops a thermo-economic model to evaluate the feasibility of fourth-generation refrigerants, including R1234yf, R1234ze(Z), and R1336mzz(Z), as potential alternatives to ammonia. The analysis examines the effects of system scale and cold seawater pumping depth on capital investment distribution and key economic indicators, such as the levelized cost of energy (LCOE) and net present value (NPV). The findings highlight the viability of R1234ze(Z) as a substitute for ammonia, demonstrating a slightly lower LCOE and requiring 8.6% less installed capacity to achieve financial breakeven. Additionally, the economic impact of pumping depth varies with system scale: in small-scale OTEC systems, LCOE initially decreases with depth before rising beyond an optimal point, while in large-scale systems, it continuously declines and eventually stabilizes. Moreover, capital investment allocation shifts with system size, making pipeline optimization crucial for small-scale systems, whereas minimizing heat exchanger costs is key to enhancing the economic feasibility of large-scale OTEC plants. The results offer guidance for cost-effective OTEC deployment and refrigerant selection, supporting a sustainable energy supply for tropical islands. Full article

This study examines the effects of an emulsion gel (EG) and a fat bulking agent (BA), both formulated with pork lard (PL) and an alginate-based gelling system, as animal fat replacers in the reformulation of reduced-fat fresh pork sausages. Both fat analogs were characterized in terms of texture, color, and in vitro gastrointestinal digestion (GID) before being used in the reformulation of four fresh pork sausages, without and with added silicon (Si) from diatomaceous earth powder: S/EG, S/EG-Si, S/BA, and S/BA-Si. Reduced-fat sausages elaborated exclusively with pork backfat (PB), without and with Si, were used as controls (S/C and S/C-Si). Both EG and BA showed adequate physicochemical characteristics and slowed in vitro GID compared to PL and PB. Replacing 75% PB with EG or BA did not negatively impact the technological, nutritional, or sensory properties of the reformulated pork sausages, which were kept for 14 days under refrigeration. Additionally, sausages containing EG or BA as fat substitutes presented lower lipid digestibility after in vitro digestion compared to the control samples. The addition of Si further limited fat digestion, as reflected by the lower release of free fatty acids after in vitro GID compared to products without added Si. This effect was more pronounced in EG-based formulations. Therefore, the use of EG as a PB replacer, together with the addition of Si, could become a promising strategy for developing healthier meat products. This finding may have important implications for the development of functional meat products aimed at reducing fat content and lipid absorption, thereby laying the foundation for precision nutrition strategies focused on improving individual health outcomes. Full article

A high intake of saturated fats and cholesterol from processed meats is associated with increased cardiovascular disease risk. This study aimed to develop a nutritionally enhanced Bologna-type sausage by partially replacing the beef content with a structured emulsion gel (EG) formulated from pine nut oil, inulin, carrageenan, and whey protein concentrate. The objective was to improve its lipid quality and functional performance while maintaining product integrity and consumer acceptability. Three sausage formulations were prepared: a control and two variants with 7% and 10% EG, which substituted for the beef content. The emulsion gel was characterized regarding its physical and thermal stability. Sausages were evaluated for their proximate composition, fatty acid profile, cholesterol content, pH, cooking yield, water-holding capacity, emulsion stability, instrumental texture, microstructure (via SEM), oxidative stability (TBARSs), and sensory attributes. Data were analyzed using a one-way and two-way ANOVA with Duncan’s test (p < 0.05). The EG’s inclusion significantly reduced the total and saturated fat and cholesterol, while increasing protein and unsaturated fatty acids. The 10% EG sample achieved a PUFA/SFA ratio of 1.00 and an over 80% reduction in atherogenic and thrombogenic indices. Functional improvements were observed in emulsion stability, cooking yield, and water retention. Textural and visual characteristics remained within acceptable sensory thresholds. SEM images showed more homogenous matrix structures in the EG samples. TBARS values increased slightly over 18 days of refrigeration but remained below rancidity thresholds. This period was considered a pilot-scale evaluation of oxidative trends. Sensory testing confirmed that product acceptability was not negatively affected. The partial substitution of beef content with pine nut oil-based emulsion gel offers a clean-label strategy to enhance the nutritional quality of Bologna-type sausages while preserving functional and sensory performance. This approach may support the development of health-conscious processed meat products aligned with consumer and regulatory demands. Full article

This theoretical research study proposes a novel hybrid algorithm that integrates an improved quasi-dynamical oppositional learning mutation scheme into the Mountain Gazelle Optimization method, augmented with chaotic sequences, for the thermal and economical design of a shell-and-tube heat exchanger operating with nanofluids. The Mountain Gazelle Optimizer is a recently developed metaheuristic algorithm that simulates the foraging behaviors of Mountain Gazelles. However, it suffers from premature convergence due to an imbalance between its exploration and exploitation mechanisms. A two-step improvement procedure is implemented to enhance the overall search efficiency of the original algorithm. The first step concerns substituting uniformly random numbers with chaotic numbers to refine the solution quality to better standards. The second step is to develop a novel manipulation equation that integrates different variants of quasi-dynamic oppositional learning search schemes, guided by a novel intelligently devised adaptive switch mechanism. The efficiency of the proposed algorithm is evaluated using the challenging benchmark functions from various CEC competitions. Finally, the thermo-economic design of a shell-and-tube heat exchanger operated with different nanoparticles is solved by the proposed improved metaheuristic algorithm to obtain the optimal design configuration. The predictive results indicate that using water + SiO₂ instead of ordinary water as the refrigerant on the tube side of the heat exchanger reduces the total cost by 16.3%, offering the most cost-effective design among the configurations compared. These findings align with the demonstration of how biologically inspired metaheuristic algorithms can be successfully applied to engineering design. Full article

Almond bagasse, a by-product of almond milk production, is rich in fibre, protein, polyunsaturated fatty acids, and bioactive compounds. Its incorporation into food products provides a sustainable approach to reducing food waste while improving nutritional quality. This study explored the impact of enriching rice flour with almond bagasse powders—either hot air-dried (HAD60) or lyophilised (LYO)—at substitution levels of 5%, 10%, 15%, 20%, 25%, and 30% (w/w), to assess effects on gluten-free bread quality. The resulting flour blends were analysed for their physicochemical, techno-functional, rheological, and antioxidant properties. Gluten-free breads were then prepared using these blends and evaluated fresh and after seven days of refrigerated storage. The addition of almond bagasse powders reduced moisture and water absorption capacities, while also darkening the bread colour, particularly in HAD60, due to browning from thermal drying. The LYO powder led to softer bread by disrupting the starch structure more than HAD60. All breads hardened after storage due to starch retrogradation. The incorporation of almond bagasse powder reduced the pasting behaviour—particularly at substitution levels of ≥ 25%—as well as the viscoelastic moduli of the flour blends, due to fibre competing for water and thereby limiting starch gelatinisation. Antioxidant capacity was significantly enhanced in HAD60 breads, particularly in the crust and at higher substitution levels, due to Maillard reactions. Furthermore, antioxidant degradation over time was less pronounced in formulations with higher substitution levels, with HAD60 proving more stable than LYO. Overall, almond bagasse powder improves the antioxidant profile and shelf-life of gluten-free bread, highlighting its value as a functional and sustainable ingredient. Full article

This review paper addresses the design and testing of ultra-low temperature (ULT) freezers, highlighting their critical functions in various industries, particularly foods, medicine, and research. ULT freezers operating at temperatures of −86 °C and lower have come a long way with improvements in freezing technology, for instance, from traditional vapor compression systems to new multi-stage refrigeration technologies. This progress has added operational reliability and energy efficiency, essential for preserving delicate samples and facilitating groundbreaking research. The article deeply explores the contribution of refrigerants to ULT freezer efficiency and sustainability. With the use of chlorofluorocarbons (CFCs), previously reliant on them, being prohibited due to environmental concerns, the sector opted for environmentally friendly substitutes like hydrofluorocarbons (HFCs), natural refrigerants, and hydrofluoroolefins (HFOs). Regulatory compliance is ensured by rigid validation protocols to guarantee ULT freezers are safe and meet quality requirements without compromising the integrity of the stored material. In addition to their wide-ranging advantages, ULT freezers also have disadvantages, such as energy efficiency, incorporating automation, the integration of IoT and AI for proactive maintenance, and the development of environmentally sustainable refrigerants. Adequate management strategies, including regular employee training and advanced monitoring systems, are vital to counteract threats from temperature variations and reduce long-term diminished performance. Finally, subsequent innovations in ULT freezer technology will not only aid in research and medical initiatives but also support sustainable practices, ensuring their core role as beacons of innovation in preserving the quality of precious biological materials and increasing public health gains. Full article

Public concerns about the health risks of synthetic antioxidants have prompted the meat industry to look for natural alternatives rich in phenols with strong antioxidant properties. This study investigates the use of blackcurrant (BCP), lingonberry (LP), and sour cherry (SCP) powders as natural substitutes for synthetic nitrites in reformulating two clean-label salami types, smoked and cooked and smoked and scalded, with a focus on their effects on oxidative stability during processing and refrigerated storage (4 °C). Nitrite-free formulations were prepared with each fruit powder at three inclusion levels to provide total phenolic contents of 90, 200, and 300 mg gallic acid equivalents (GAE)/kg of processed meat. A nitrite-containing control (90 mg/kg) and an additive-free control were included for comparison. The phytochemical profiles of powders were characterized by total phenolic, flavonoid, monomeric anthocyanin contents, and L-ascorbic acid levels. Antioxidant activity was assessed via 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging and ferric reducing antioxidant power (FRAP) assays. Salami samples were analyzed for proximate composition, and lipid oxidation was monitored at 0, 15, and 30 days of storage using peroxide value, inhibition of oxidation, p-anisidine value, TOTOX, and thiobarbituric acid value. Fruit powders demonstrated dose- and type-dependent inhibition of primary and secondary lipid oxidation, enhancing oxidative stability during processing and storage. After 30 days of storage, oxidation markers in fruit-enriched salami remained below recommended thresholds, confirming effective control of lipid oxidation. The inhibitory potential followed the order BCP > LP > SCP, consistent with antioxidant profiles as reflected by DPPH and FRAP values. BCP at 300 mg GAE/kg showed a stronger lipid oxidation inhibition than sodium nitrite. Promising improvements in lipid oxidation resistance were also observed with LP at 300 mg GAE/kg and BCP at 200 mg GAE/kg. These findings highlight the potential of fruit-derived antioxidants to support the development of more sustainable, value-added meat products without compromising quality. Full article

A diffusion absorption heat transformer is a completely thermally driven heat upgrading technology with significant application potential in low-grade thermal energy recovery. However, existing diffusion absorption heat transformers have problems such as complex circulation processes, limited solution flow rates, and insufficient stability due to their reliance on bubble pumps. A jet pump was proposed for application in a diffusion absorption heat transformer cycle to replace the bubble pumps in the original diffusion absorption heat transformer cycle. In the novel cycle, without electricity consumption, the diffusant gas was used as the primary flow of the jet pump to transport the solution, and the diffusion generation of the refrigerant was realized in the jet pump for more efficient and stable thermal energy upgrading. The performance of the novel cycle with H₂O/LiBr/C₅H₁₀ or H₂O/HCOOK/C₅H₁₀ as working fluids was analyzed based on a constructed theoretical model validated by numerical simulation. It was found that the performance of the jet pump was sensitive to the generator temperature and the pressure difference of the cycle. Increasing the temperature of the jet pump and reducing the temperature of the absorber were conducive to improving the COP. As a potential absorbent substitute for LiBr, HCOOK also led to slightly better performance in most cases. Full article

To implement the Kigali Amendment to the Montreal Protocol, the global academic community has intensified its research on environmentally friendly refrigerant substitutes. This effort aims to effectively reduce greenhouse gas emissions and facilitate the achievement of carbon neutrality goals. In this study, 14 key influencing factors were identified through the Delphi method, and the Decision-making Trial and Evaluation Laboratory (DEMATEL) approach was innovatively applied to systematically analyze the interrelationships among these factors. The results indicate that technological innovation related to refrigerant substitution ranks first with a centrality score of 5.429, confirming it as the core driving factor for refrigerant substitution. Subsequently, through the integration of Interpretive Structural Modeling (ISM) and Cross-impact Matrix Multiplication Applied to Classification (MICMAC), a hierarchical structure of influencing factors was further developed. This clarified high-driving factors such as government policies and life-cycle costs, as well as highly interrelated factors including climate conditions, greenhouse gas emissions, and performance coefficients. The key contribution of this paper is its success in overcoming the limitations of single-factor analysis by integrating multiple dimensions of influencing factors to construct a hierarchical classification. This innovative and systematic theoretical framework not only offers a scientific basis and decision-making support for refrigerant substitution but also possesses substantial theoretical value and practical guidance. Furthermore, it serves as an essential reference for advancing the development of low-carbon refrigeration technologies. Full article

This study explores the structural, magnetic, and magnetocaloric properties of ${\mathrm{Ce}}_2$(Fe, Co${)}_{17}$ (x = 0, 0.5, 0.6, and 0.7) compounds synthesized via arc melting under high temperatures exceeding 2300 K. The as-cast ingots are subsequently sealed and subjected to a heat treatment at 1323 K to improve homogeneity and crystallinity. Detailed analyses using X-ray diffraction and magnetometry reveal that cobalt substitution significantly impacts the structural and magnetic behavior, enabling precise tuning of the magnetic transition temperature and magnetic order. The substitution induces an anisotropic increase in cell parameters and shifts the magnetocaloric effect (MCE) from low temperatures (200 K for x = 0) to near room temperature (285 K for x = 0.7), enhancing the operating temperature range. The magnetocaloric effect is studied across different magnetic transitions: a metamagnetic and ferro-antiferromagnetic transition followed by a paramagnetic state in one sample, and a direct ferro-paramagnetic transition in another. The compounds exhibit a second-order magnetic phase transition, ensuring a reversible MCE, with a relative cooling power (RCP) that is approximately 85% of that of pure Gd. Moreover, the use of cerium, the most cost-effective rare-earth element (5 $/kg), combined with its low atomic concentration (10%) in these intermetallics, enhances the sustainability and affordability of these materials. These findings underline the potential of iron-rich Ce-based compounds for next-generation refrigeration and energy-harvesting applications. Full article