Refrigeration Temperature Research Articles

Selection of refrigerant based on multi-objective decision analysis for different waste heat recovery schemes

Waste heat generation, upgrading, and refrigeration are the fundamental ways to recover and utilize waste heat. The rationalizing the use of refrigerants also contribute in creating energy savings and minimizing carbon emissions. This study evaluated the thermodynamics, economics, and environmental of different types of refrigerants in three kinds of waste heat recovery schemes: generate electricity, heat pump, and refrigeration. Based on this, the entropy weight and Technique for Order Preference by Similarity to an Ideal Solution (TOPSIS) were combined to assess the overall performance of the refrigerants. A thorough analysis revealed that R1234ze(E) can replace R245fa and R123 in the organic rankine cycle (ORC). The best refrigerant for vapor compression refrigeration (VCR) and high temperature heat pump (HTHP) systems is R1243zf. In addition, the multi-objective decision analysis shows that the performance difference among the nine selected refrigerants is the total cost, followed by the environmental impact. The approach is successful in recognizing the variations between different refrigerants in the same waste heat recovery scheme and gives a thorough evaluation. It sets instructions for the future use of eco-friendly refrigerants and their application waste heat recovery schemes.

Carboxymethyl cellulose – Polyvinyl alcohol bioactive films loaded with green extracted date seed polyphenols for active packaging of Shiitake mushrooms

This study investigated the use of a natural deep eutectic solvent-based polyphenolic extract (DSE) from date fruit seed as a bioactive and functional component for the development of carboxyl methylcellulose-poly(vinyl)alcohol (CMCPVA) packaging films. The impacts on the physicochemical, structural, water barrier and bioactive properties of the CMCPVA films were studied. Different concentrations of DSE (1.5%, 2%, 2.5%, and 3%) incorporated into CMCPVA film increased the total phenolic content (0.08–0.17 mg GAE/mL), DPPH scavenging activity (4.08–5.11 mmol GAE/mL), and ferric ion-reducing antioxidant power (0.82–1.46 μmol TE/mL) of the films. The antibacterial activities against S. aureus, L. monocytogenes, S. typhimurium, and E. coli were also improved. In particular, a 4–5 log reduction was recorded for CMCPVA film incorporated with 3% DSE. Also, the presence of DSE enhanced elongation at break (25.53%–93.23%) and film thickness (0.10–0.19 mm), whereas tensile strength (6.39–1.40 MPa) and Young's modulus (25.89–2.85 MPa) decreased. Furthermore, UV-shielding performance improved, opacity decreased from 2.93 to 0.86, while the water vapor permeability was not significantly affected which ranged from 3.01 to 5.83 (X 10−10 g/m.s.Pa). The application of CMCPVA film incorporated with 3% DSE (CMCPVA_3) as a bioactive film for preserving sliced and whole shiitake mushrooms at refrigeration temperature for 8–12 days was studied. The CMCPVA_3 film preserved the mushrooms' color, browning degree, and texture compared to the cling film-covered samples. There is a potential for the successful application of NADES-based polyphenolic extract in biopolymer films for food preservation.

Thermally driven MnCl2[sbnd]NH4Cl resorption cycle for seasonal thermal management of urban buildings

The frequency of extreme weather conditions caused by global greenhouse gas emissions has led to a significant increase in energy consumption for refrigeration and heating supply in urban buildings. However, conventional sensible and latent heat storage technologies hold low thermal energy storage density and short-term energy storage capabilities. Additionally, electrically driven compression refrigeration with non-negligible global warming potential (GWP) is unsuited to high ambient temperatures in summer. We propose an advanced strategy, adopting the MnCl2NH4Cl resorption cycle to achieve efficient desorption refrigeration of NH4Cl and resorption heating supply of MnCl2 under seasonal conditions. Experimental results have demonstrated that our proof-of-concept system can output 70 °C heat with a thermal energy storage density of 166.2 kJ·kg−1, providing continuous heating for 30.5 min under the winter ambient temperature of 10 °C. Moreover, COPref remained at 0.589 for continuous indoor refrigeration lasting 58.5 min under summer ambient and refrigeration temperatures of around 30 °C and 2 °C, respectively. This exceptional adaptability to ambient temperatures enables efficient adjustment of urban building comfort. Our work presents a promising zero-carbon pathway for replacing conventional fossil fuels employed in the thermal management of urban buildings with solar energy.

Assessment of lyophilized microencapsulated multi strain probiotic for improved shelf life and stability

A Multi species Probiotics (MSP) of calf gut origin was encapsulated either with chitosan (ECMSP) or without chitosan (EMSP). Further, the probiotic was encapsulated and lyophilized (ELMSP) using three types of cryoprotectant solutions sucrose (ELMSP(S)), skim milk (ELMSP(SM)) and sucrose + skim milk combination (ELMSP (SSM)). The encapsulation yield was good and ranged from 75 % to 80 % for MSP products. These MSP products were stored at refrigeration temperature (4 °C), deep freeze and room temperature for 12 weeks. The shelf life (mean CFU) of encapsulated microcapsules was significantly better (P < 0.001) at the refrigeration temperature (9.44 Log10 CFU/g) than deep freeze (7.42 Log10 CFU/g) and room temperature (6.67 Log10 CFU/g). At the end of the 12 weeks storage period, EMSP maintained 25.1 %, 49.6 % and 32.6 % viable counts at room temperature, refrigeration and deep freeze condition respectively. For the lyophilized-encapsulated MSP, the mean probiotic counts of ELMSP(S) and ELMSP (SSM) were significantly (P < 0.001) higher (9.62 Log10 CFU/g) than those of ELMSP(SM) ((9.36 Log10 CFU/g) at room temperature. At refrigeration temperature, the mean probiotic counts for ELMSP (SSM. (10.1 Log10 CFU/g)) were significantly higher (P < 0.001) than ELMSP(S, (9.97 Log10 CFU/g) and ELMSP(SM, (9.86 Log10 CFU/g). Further, a 12 weeks storage study for ELMSP (SSM) showed that the microcapsules stored at refrigeration temperature (4°C) showed only 6.4 % drop in viability which was significantly lower (P < 0.001) than that of room temperature showing 15.3 % drop and deep freeze storage with 17.1 % drop in viability. It was appreciable that even at room temperature; there was only one log drop in the viability of MSP showing that it can be comfortably stored at room temperature for longer periods at field level.

Exploring the genetic variability, virulence factors, and antibiotic resistance of Listeria monocytogenes from fresh produce, ready-to-eat hummus, and food-processing environments.

Listeria monocytogenes is ubiquitous in nature and persistent in food-processing facilities, farms, retail stores, and home and restaurant kitchens. Current research suggests ready-to-eat (RTE) products (including RTE hummus and fresh produce) to be of increasing interest and concern. These foods are typically stored at refrigeration temperatures suited to the survival of L. monocytogenes and are consumed without further processing. Since L. monocytogenes is ubiquitous in agricultural environments, the cultivation of fresh produce predisposes it to contamination. The contamination of RTE foods originates either from raw ingredients or, more commonly, from cross-contamination within food-processing facilities. Research on the food-processing environment has been recommended to reduce the incidence of L. monocytogenes in foods. The consumption of contaminated foods by immunocompromised individuals causes invasive listeriosis, with a 20% to 30% fatality rate despite treatment. The emergence of antibiotic-resistant strains has reduced the effectiveness of modern medicine and may increase morbidity and mortality. Without epidemiological surveillance and identifying trends in disease determinants, no action can be taken to improve food safety and mitigate the risk of such outbreaks.

Cells Total Antioxidant Capacity (TAC) and External Expression of Enzymatic Browning for the Commercially Important Penaeids Prawns Parapenaeus longirostris and Penaeus kerathurus

The enzymatic browning process, known also as melanosis, is a significant indicator of oxidative damage in commercially important shrimps and prawns. Total Antioxidant Capacity (TAC) serves as a vital measure of molecular defense against melanosis, a crucial mechanism for organisms to combat detrimental factors such as free radicals. This contribution delves into the assessment of this process for the penaeid species, Parapenaeus longirostris and Penaeus kerathurus. Samples were stored at refrigerator temperature (4 °C) for 0, 1, 2, 4, and 8 days for P. longirostris, and for 0, 2, 4, 8, and 16 days for P. kerathurus. Each day’s samples consisted of groups of ten individuals (5 males, and 5 females). TAC was determined using the CrO5 method. Results revealed an initial TAC increase followed by a gradual decrease over time. Additionally, exterior changes in both species were visually documented daily to capture the macroscopic manifestation of enzymatic browning, aligning with the molecular profile of the samples. Furthermore, Quality Index Method was conducted, where five evaluators graded the organoleptic qualities (texture, odor, color) of the prawn individuals, daily. This assessment aimed to scrutinize the external alterations of the shrimps under refrigeration conditions, revealing changes via sensory evaluation and the Quality Index Method.

Variation of vitamin C content and antioxidant capacities during the post-harvest storage of fresh fruits under different temperatures

During post-harvest storage, vitamins and health promoting compounds of fresh fruits are prone to change. Variation in ascorbic acid (ASC), total vitamin C (VitC), total phenolic (TPC) and total flavonoid (TFC) and antioxidant capacities (ACs) were studied during storage of fresh fruits (31 species) for 14 days at three different temperatures. During storage, ASC (1.6–90.0%) and VitC (0.1–71.6%) contents decreased significantly in most of the fruits, irrespective to the storage temperature. Interestingly accumulation of ASC (1.0–245.0%) and VitC (0.5–102.8%) was also observed in some fruit species; Musa paradisiaca, Aegal marmelos, Citrus aurantifolia and Passiflora edulis. All the fruits with the highest rate of accumulation of ASC and VitC are climacteric fruits; Musa paradisiaca, Persea americana etc. In Psidium guajava, almost all the measured health promoting compounds were significantly lost during storage. In most of the under-utilized fruits, significant loss in TPC (Artocarpus heterophyllus (‘Wela’) at room temperature: 87.4%), TFC (Averrhoa carambola: 100.0%) and ACs could be observed. The highest percentage of losses (100.0%) in DPPH radical scavenging assay and Ferric reducing antioxidant potential were observed in Citrullus lantanus. According to the results of multivariate analysis of variance (MANOVA), there is a statistically significant effect (p < 0.0005) of fruit species, storage temperature and an interaction effect of those on changing rates of measured antioxidants. The reduction rates of measured antioxidants are significantly highest at room temperature, while which are significantly highest under freezing conditions compared to refrigeration. Refrigeration temperature is recommended for optimization of preservation of vitamin C and antioxidants during storage of fresh fruits.

Temperature Excursions in Cold Chain Management-Assessing the Accuracy of Refrigerator Temperature Probes.

Background: Medications requiring refrigeration for stability are commonly used across hospitals. Temperature-sensitive medications may not have their temperature requirements maintained due to breaches in the cold chain, especially refrigerator failure. This is usually caused by malfunction of the refrigerator unit or by power outage. After multiple power outages at our institution involving refrigerators with temperature probes located in different areas of the refrigerator, we hypothesised that the fixed temperature probe may not accurately reflect the temperature of the medications themselves. Methods: We conducted simulations of power outages in a commonly used medication refrigerator, using additional temperature data loggers, placed on the refrigerator shelf and inside a cardboard box to replicate the temperature inside medication containers to determine if there was a difference in the time to breach cold chain conditions (>8°C) and to return to appropriate refrigerated temperatures (<8°C) when power was restored. Results: All data loggers took a longer time to breach cold chain conditions than the refrigerator probe (12.5 minutes vs 23-26 minutes) but took longer to return to acceptable temperature after power was restored (17.5 minutes vs 70.5-89 minutes). Conclusion: This exploratory research suggests that temperatures vary within a refrigerator depending on the type and location of probe and that medications within may take longer to breach cold chain conditions but also take longer to return to cold chain conditions compared with fixed refrigerator temperature probes. Further research is required to determine whether these variations occur across different sizes/brands of refrigerators and the effect on stability on refrigerated medications.

Crystal growth and magnetocaloric effect of Li9Fe3(P2O7)3(PO4)2 with Kagome lattice

With the growing demand for low-temperature technologies, magnetic refrigeration, which is based on magnetocaloric effect (MCE) of magnetic materials, has attracted increasing attention. In this work, Li9Fe3(P2O7)3(PO4)2 (LFPP) crystals have been grown by the high-temperature flux method. The crystal structural characterization is analyzed, and its magnetocaloric effect (MCE) is in detail investigated for the first time. The maximum magnetic entropy changes (−ΔSM) of LFPP under a field change of 0–7 T are determined to be 4.6 J/kg·K (H⊥c) and 4.1 J/kg·K (H//c) at 4 K and 5 K, respectively. The slow decrease of −ΔSM around the phase transition temperature implies that LFPP has a large refrigeration temperature range.

High-precision temperature control of helium Joule–Thomson cryocooler: Long-term temperature stability

To meet the refrigeration requirements of scientific instruments for mK-level temperature stability over a long-time range in the liquid helium temperature, the temperature characteristics and high-precision control strategies of the helium Joule-Thomson cryocooler (JTC) have been experimentally investigated for the first time. Based on the Ideal Gas Law, the influencing mechanism of pre-cooling temperature, gas reservoir volume, and liquid phase volume fraction on refrigeration temperature were qualitatively analyzed and experimentally verified. An active control studies of pre-cooling temperature, low-pressure and heat load were carried out to verify the feasibility of active temperature control of helium JTC. Finally, a long-term temperature stability of ±1 mK/h was successfully achieved when a multi-stage active control strategy was adopted, which is the optimal long-term temperature stability of helium JTC that have been reported to date.

Analysis of forming mechanism and influencing factors of thermoacoustic plate end temperature difference

In order to explore the formation mechanism and influencing factors of the temperature difference between two ends of the plate stack, an expression of the temperature change of the stack with time was established based on the two-dimensional heat conduction equation. Based on this, the finite element model of heat transfer between a single thermoacoustic plate stack and the gas above it is established in Ansys, and the temperature of the plate stack is solved. When the sound field is constant, the variation law of the temperature of the stack with the working time and space is obtained, and the formation mechanism of the temperature difference between the two ends of the plate stack is revealed. From the calculation results, it is found that the net heat transfer between the gas and the plate stack is mainly reflected in the two ends of the plate stack, and the contribution of the air mass in the middle part is mainly the relay heat transfer. In the process of working, part of the sound work is converted into the internal energy of the air mass, which makes the gas temperature on the surface of the plate rise as a whole. The working frequency, stack length and stack thermal conductivity are taken as the influencing factors. When no load is added, the variation of the temperature of the high and low end of the stack with the working time under different working conditions is analyzed. And the theory of series between short plates is put forward to explain the formation mechanism of large temperature difference between the two ends of the plates. In order to further reduce the cooling temperature of thermoacoustic refrigerator, a new research method and exploration direction are proposed.

Stability of serum total cholesterol, triglycerides, and plasma glucose of healthy individuals at different storage conditions

Evaluation of the stability of serum and plasma analytes under different temperatures and time points is vital since it significantly affects the pre-analytical errors. The aim of the study was to determine the stability of serum total cholesterol and triglyceride and plasma glucose of healthy individuals under different storage conditions (25-30°C and 2-8°C) and at different time points (1-hour, 4-hour, 6-hour, and 24-hour). Venous blood samples were collected from healthy individuals aged between 20-50 years after a 12-hour fast. Plasma and serum were separated and stored at different temperatures (25-30°C and 2-8°C) and different time points (1-hour, 4-hour, 6-hour, and 24-hour). Results indicated a significant difference between the mean plasma glucose concentration at room temperature (25-30°C) and refrigerated temperature (2-8°C) at 1-hour (0.072%, p = 0.05). However, there were no significant differences in mean serum total cholesterol concentrations (p = 0.633) and mean serum triglyceride concentrations (p = 0.246) between these temperatures at 1-hour time point. Regarding time points (1-hour, 4-hour, 6-hour, and 24-hour), significant differences in plasma glucose concentrations occurred at 24-hour (10.03%, p = 0.001) at room temperature (25-30°C) and 6-hour (8.79%, p = 0.003) at refrigerated temperature (2-8°C) compared to the 1-hour reference values. Additionally, there were significant differences in serum total cholesterol concentration at 4-hour (12.55%, p = 0.000) and serum triglyceride at 24-hour (29.18%, p = 0.001) compared to the reference values obtained at 1-hour at room temperature (25-30°C). No significant differences were observed among the time points (1-hour, 4-hour, 6-hour, and 24-hour) for serum total cholesterol (p = 0.507) and serum triglyceride values (p = 0.761) at refrigerated temperature (2-8°C). Plasma glucose is unstable at both room temperature (25-30°C) and refrigeration (2-8°C), with recommended testing within 6 hours at room temperature (25-30°C) and stored in a refrigerator (2-8°C) if delayed. It is better to estimate serum total cholesterol within 1-hour of collection at room temperature (25-30°C) while serum triglyceride concentration within 6 hours at the same temperature to obtain accurate and reliable results.

Farsi gum (zedo gum) coating incorporated with Lactobacillus sakei; a novel shelf-life extension for Turkey breast during refrigerated storage

Antioxidant and antibacterial coatings incorporated with biological agents are an emerging alternative for preserving meat products. In this study, Farsi gum-based coatings (FG) incorporated with Latilactobacillus sakei were used for the shelf-life extension of refrigerated turkey breast. The quality and safety properties of coated turkey breast were investigated during storage at refrigeration temperature. Results revealed that L. sakei loading into the FG coating could significantly (p < 0.05) improve the quality of turkey breast in a 16-day refrigerated storage. The increase in the values of pH (6.15–6.94), total volatile basic-nitrogen (TVB-N) (34.33–43.13 mg N/100 g), thiobarbituric acid reactive substances (TBARs) (2.27–3.67 mg MDA/kg), and protein carbonyl (PC) (1.62–2.14 nmol/mg protein) of samples during cold storage periods was as follows: FG 2% + L. Sakei < FG 1% + L. Sakei < FG 2% < FG 1% < uncoated (control). The microbial quality of turkey breast showed a significant (p < 0.05) improvement in the presence of the L. sakei coatings, ranging from 7.15 to 7.75 log10 CFU/g in different treatments. The texture, odor, color, and overall acceptability of the coated turkey breast samples were significantly (p < 0.05) more desirable than the uncoated turkey breast samples. The findings revealed that FG coating incorporated with L.sakei can improve turkey breast's shelf-life by reducing microbial growth and adverse chemical reactions.

Flow Patterns of Tetraflouroethane Refrigerant in Different Small Diameter Tubes Used for Vaccine Delivery Boxes

This study aims to determine the flow patterns of tetrafluorethane refrigerant in different small diameter tubes. It attempts to establish a relationship among the temperature, pressure drop, volumetric flow of tetraflouroethane refrigerant in a 900 mm long small diameter tube. Tests are conducted to determine the effect of varying hydraulic tube diameter to the temperature and pressure drop of tetraflouroethane refrigerant in different flow rate. A copper tube with hydraulic diameter of 0.20 mm, 0.25 mm, 0.30 mm, 0.35 mm, 0.40 mm and 0.45 mm were used in this study. For every known hydraulic diameter, there are six (6) test points located in every 150 mm interval. The experimental rig is composed of six (6) pieces of 900 mm long copper tubes for the given hydraulic diameters. Each tube is marked with 150 mm, 300 mm, 450 mm, 600 mm, 750 mm and 900 mm. The markings represent the length of capillary tubes in millimeters where test points are located. A pressure transducer is attached to every test point and is used to measure the pressure drop at every length of the small diameter capillary tube. The result shows that pressure drop increases as the tube hydraulic diameter decreases and attained an evaporator temperature as low as -5 oC. The smaller the diameter of the tube, the more it is effective to give pressure drop for the design of a handy vaccine delivery box refrigeration system.

Physico-chemical changes in developed probiotic chicken meat spread fermented with Lactobacillus acidophilus and malted millet flour

This study was envisaged to develop a probiotic chicken meat spread fermented with Lactobacillus acidophilus (Lactic acid bacteria-LAB) and malted sorghum flour as a substrate and evaluation of its quality. Chicken meat spread was prepared by incorporating malted sorghum flour at 0, 2, 4 and 6 % (w/w) levels as a substrate in the product's formulation, along with Lactobacillus acidophilus at a concentration of 1 million cfu/g of the product. The product prepared with different formulations i.e. C (meat spread only), C1 (meat spread with 0 % malted sorghum flour + LAB), T1 (meat spread with 2 % malted sorghum flour + LAB), T2 (meat spread with 4 % malted sorghum flour + LAB) and T3 (meat spread with 6 % malted sorghum flour + LAB) were assessed for fresh product study and the storage stability at refrigeration temperature for 16 days when the physico-chemical parameters were analyzed. The fresh product study revealed significantly (p ≤ 0.05) higher moisture content in the T3 group. However, lower protein, ether extract, and ash content in T2 and T3 samples compared with the control, whereas a higher emulsion stability and cooking yield in the T2 group were observed when compared with the control. Free fatty acid, thiobarbituric acid, and titratable acidity values significantly (p ≤ 0.05) increased for the fermented samples in comparison to the control, and the same trend continued during the entire storage period. This study showcases the potential of using malted sorghum flour and Lactobacillus acidophilus to enhance the functional properties of chicken meat spreads, making them more nutritious and appealing to health-conscious consumers. Future research should focus on optimizing ingredient proportions and exploring alternative substrates to further improve these functional meat products.

Impact of microbial milk quality on mesophilic starter culture metabolism: A metaproteomics approach

Using a metaproteomics approach, we showed that the initial milk quality impacts the proteome allocation of starter cultures used in cheese production and can be considered a fundamental source of cheese quality batch-to-batch variation. Raw milk was spiked with a highly proteolytic strain of Pseudomonas trivialis, previously isolated from raw milk, and incubated for 1, 3, and 6 days at refrigerated temperature. After incubation, the milk was heat-treated and then fermented with a mesophilic starter culture commonly used to produce Gouda-type cheeses. The development of metabolites was analyzed and a taxonomical and functional characterization of the starter culture was performed. Milk storage time impacted both the metaproteome of the starter culture, consequently affecting metabolite levels after fermentation and the level of protein expressed by the different taxa; Lactococcus protein was more abundant in samples made from milk stored longer with Pseudomonas while proteins expressed by Leuconostoc spp. decreased in abundance.

Physiological and Technological Properties of Probiotic Lacticaseibacillus rhamnosus GG Encapsulated with Alginate-Chitosan Mixture and Its Incorporation in Whole Milk.

This study developed and evaluated chitosan-sodium alginate capsules containing the probiotic Lacticaseibacillus rhamnosus GG using extrusion and emulsification techniques. The encapsulated L. rhamnosus GG cells were also evaluated for technological and probiotic-related physiological functionalities, as well as when incorporated in UHT and powdered milk. Extrusion (86.01 ± 1.26%) and emulsification (74.43 ± 1.41%) encapsulation techniques showed high encapsulation efficiency and high survival rates of L. rhamnosus GG during 28days of refrigeration and room temperature storage, especially emulsification capsules (> 81%). The encapsulated L. rhamnosus GG cells showed high survival rates during exposure to simulated gastrointestinal conditions (72.65 ± 1.09-114.15 ± 0.44%). L. rhamnosus GG encapsulated by extrusion and emulsification performed satisfactorily in probiotic-related physiological (pH and bile salts tolerance) and technological properties (positive proteolytic activity, diacetyl and exopolysaccharides production, high NaCl tolerance (> 91%), besides having high heat tolerance (> 76%)). L. rhamnosus GG in extrusion and emulsification capsules had high survival rates (> 89%) and did not significantly affect physicochemical parameters in Ultra-High Temperature (UHT) and powdered milk during storage. The results demonstrate that L. rhamnosus GG can be successfully encapsulated with alginate-chitosan as a protective material through extrusion and emulsification techniques. UHT and powdered milk could serve as appropriate delivery systems to increase the intake of this encapsulated probiotic by consumers.

HoDyGdCoAl high-entropy amorphous alloys working at full temperature range for hydrogen liquefaction with large magnetocaloric effects

Cryogenic magnetic refrigeration materials based on magnetocaloric effect can be used for hydrogen liquefaction. In this work, glass formation ability (GFA), magnetocaloric effect (MCE), refrigeration performance of melt-extracted HoDyGdCoAl amorphous ribbons have been investigated. Amorphous ribbons undergo a second order magnetic phase transition which achieve a table-like behavior broaden the range of magnetic transition temperature in hydrogen liquefaction.The maximum magnetic entropy change (-ΔSmaxM), the δTFWHM and the refrigeration capacity (RC) achieved 10.9 J/ (kg K), 84.2 K and 742.4 J/ kg (x = 5) and 11.2 J/ (kg K), 69.8 K and 643.0 J/ kg (x = 20) under a magnetic field change of 7 T, respectively. Combining wide magnetic transition temperature and large refrigerant capacity, the present amorphous ribbons can be used as potential magnetic refrigerant materials in hydrogen liquefaction temperature region.

Nutritional, physicochemical, and chemical characterization of carbonated sugarcane juice

ABSTRACT The research aimed to enhance the shelf life of sugarcane juice through carbonation, employing different concentrations of juice mixed with syrup. Treatments included T0 (100% juice), T1 (80% juice), T2 (60% juice), T3 (40% juice), and T4 (20% juice). Physicochemical analyses encompassed color, pH, total soluble solids, and titratable acidity, with T0 (pH: 5.2, total soluble solids: 18.5°Brix) showing significant values. However, T4 exhibited the most significant (p ≤ .05) results, suggesting its potential for shelf-life extension. Additionally, bioactive compounds such as ascorbic acid, total phenolic, and flavonoid contents were measured, with T4 demonstrating noteworthy levels. Antioxidant assays (DPPH: 65% inhibition, TFC: 45 mg QE/100 ml, TPC: 130 mg GAE/100 ml, and FRAP: 320 µmol Fe2+/L) highlighted T4 the most effective, showcasing robust antioxidant activity. Sensory evaluation, conducted at refrigeration temperatures of 4–10°C, favored T4, indicating its superior acceptability. In conclusion, Carbonated sugarcane juice (20% T4) extends shelf life, preserves quality, and boosts antioxidants.

Blockchain-Based Cold Chain Traceability with NR-PBFT and IoV-IMS for Marine Fishery Vessels

Due to limited communication, computing resources, and unstable environments, traditional cold chain traceability systems are difficult to apply directly to marine cold chain traceability scenarios. Motivated by these challenges, we construct an improved blockchain-based cold chain traceability system for marine fishery vessels. Firstly, an Internet of Vessels system based on the Iridium Satellites (IoV-IMS) is proposed for marine cold chain monitoring. Aiming at the problems of low throughput, long transaction latency, and high communication overhead in traditional cold chain traceability systems, based on the Practical Byzantine Fault Tolerance (PBFT) consensus algorithm, a Node-grouped and Reputation-evaluated PBFT (NR-PBFT) is proposed to improve the reliability and robustness of blockchain system. In NR-PBFT, an improved node grouping scheme is designed, which introduces a consistent hashing algorithm to divide nodes into consensus and candidate sets, reducing the number of nodes participating in the consensus process, to lower communication overhead and transaction latency. Then, a reputation evaluation model is proposed to improve the node selection mechanism of NR-PBFT. It enhances the enthusiasm of nodes to participate in consensus, which considers the distance between fishery vessels, data size, and refrigeration temperature factors of nodes to increase throughput. Finally, we carried out experiments on marine fishery vessels, and the effectiveness of the cold chain traceability system and NR-PBFT were verified. Compared with PBFT, the transaction latency of NR-PBFT shortened by 81.92%, the throughput increased by 84.21%, and the communication overhead decreased by 89.4%.