Physicochemical Characteristics Research Articles

Production and characterization of yogurt formulated with ɑ-D-mannan produced by Kluyveromyces marxianus

Yogurt is a popular dairy product known for its flavor and nutritional value. Consumer acceptance of yogurt depends largely on its structural integrity, sensory properties, and rheological behavior, and certain additives are necessary to improve its texture. Natural skimmed yogurt, due to its low-fat composition, has a manufacturing defect reflected in the texture and runniness of the product, increasing the need for thickeners and stabilizers to give the product the desired appearance and texture. Alternative sources of stabilizers/thickeners have been tested to offer a viable additive for use. Thus, this study aimed to propose a yogurt formulated with mannan polysaccharide produced by the yeast K. marxianus, to evaluate its ability to improve the technological and functional properties of the product. Formulations were tested with mannan concentrations ranging from 0.1 to 0.5%. The result shows that the yogurt formulated with 0.1% ɑ-D-mannan exhibits better rheological characteristics. The analysis of the product during the 30-day storage period showed that the product prepared maintained its adequate texture, physicochemical and microbiological characteristics. Thus, the mannan produced by K. marxianus proved to be a possible thickener and stabilizer to be used in the food industry, mainly in the formulation of yogurt.

Effect of Different Formulations and Storage on the Physicochemical, Microbiological, and Organoleptic Characteristics of Dovyalis caffra Fruit Yogurt

This study investigated the effect of incorporating up to 15% (w/w) Dovyalis caffra fruit pulp into cow milk yogurt. Monitoring the physico-chemical, microbiological, and organoleptic properties of these formulations was performed weekly during refrigerated (4 °C) storage for 21 days. Compared to the control, formulations with added pulp recorded enhanced contents of ascorbic acid, total polyphenols, fiber, total titratable acidity (TTA), and yellowness, which is in line with increasing fruit pulp. This, however, corresponded to significantly lower contents in fat, protein, viscosity, pH, and overall sensory acceptability. Pulp incorporation had no significant effect on moisture, ash, and water-holding capacity (WHC) of formulations. Storage for up to 21 days indicated a significant increase in TTA and a corresponding decrease in pH but no significant change in WHC and viscosity of formulations. There was no detection of coliforms, yeasts, and molds in all samples throughout the storage period. This study demonstrates that Dovyalis caffra fruit has significant potential in the formulation of nutritious, desirable, and shelf-stable fruit-based yogurts. Further product optimization is, however, recommended to maximize the organoleptic quality of the formulations.

Sensitivity Analysis Study of Engine Control Parameters on Sustainable Engine Performance

With the increasing global concern for environmental protection and sustainable resource utilization, sustainable engine performance has become the focus of research. This study conducts a sensitivity analysis of the key parameters affecting the performance of sustainable engines, aiming to provide a scientific basis for the optimal design and operation of engines to promote the sustainable development of the transportation industry. The performance of an engine is essentially determined by the combustion process, which in turn depends on the fuel characteristics and the work cycle mode suitability of the technical architecture of the engine itself (oil-engine synergy). Currently, there is a lack of theoretical support and means of reference for the sensitivity analysis of the core parameters of oil–engine synergy. Recognizing the problems of unclear methods of defining sensitivity parameters, unclear influence mechanisms, and imperfect model construction, this paper proposes an evaluation method system composed of oil–engine synergistic sensitivity factor determination and quantitative analysis of contribution. The system contains characteristic data acquisition, model construction and research, and sensitivity analysis and application. In this paper, a hierarchical SVM regression model is constructed, with fuel physicochemical characteristics and engine control parameters as input variables, combustion process parameters as an intermediate layer, and diesel engine performance as output parameters. After substituting the characteristic data into the model, the following results were obtained, R2 > 0.9, MSE < 0.014, MAPE < 3.5%, indicating the model has high accuracy. On this basis, a sensitivity analysis was performed using the Sobol sensitivity analysis algorithm. It was concluded that the load parameters had the highest influence on the ID (ignition delay time), combustion duration (CD), and combustion temperature parameters of the combustion elements, reaching 0.24 and above. The influence weight of the main spray strategy was greater than that of the pre-injection strategy. For the sensitivity analysis of the premix ratio, the injection timing, EGR (exhaust gas recirculation) rate, and load have significant influence weights on the premix ratio, while the influence weights of the other parameters are not more than 0.10. In addition, the combustion temperature among the combustion elements has the highest influence weights on the NOx, PM (particulate matter) concentration, and mass, as well as on the BTE (brake thermal efficiency) and BSFC (brake specific fuel consumption). The ID has the highest influence weight on HC and CO at 0.35. Analysis of the influence weights of the index parameters shows that the influence weights of the fuel physicochemical parameters are much lower than those of the engine control parameters, and the influence weights of the fuel CN (cetane number) are about 5% greater than those of the volatility, which is about 3%. From the analysis of the proportion of index parameters, the engine control parameter influence weights are in the following order: load > EGR > injection timing > injection pressure > pre-injection timing> pre-injection ratio.

Influence of edible flowers on the physicochemical and oxidative stability of raw ground beef patties

This study investigates the antioxidant and physicochemical characteristics of raw ground beef patties and raw ground beef patties treated with varying percentages of roselle (Hibiscus sabdariffa L.) and rose (Rosa canina L.) powders during 7 days of storage at 4°C. The analysis included key parameters such as antioxidant activity using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, lipid oxidation through 2-thiobarbituric acid reactive substances (TBARS), protein oxidation markers (carbonyls, Schiff bases, and free thiols), water-holding capacity, pH, color, and texture. Both roselle and rose powders enhanced the antioxidant capacity of the patties, reducing oxidative markers (TBARS, carbonyls, Schiff bases, and free thiols) during storage. Additionally, improved water-holding capacity and reduced pH were observed across all treated patties, with minimal impact on texture. However, while roselle powder showed beneficial effects, patties treated with rose powder exhibited superior overall results. The more favorable outcomes in rose-treated patties, particularly in oxidative stability and physicochemical properties, can be attributed to the higher concentrations of bioactive compounds, such as phenolic acids and flavonoids, present in rose powder. These compounds likely contributed to enhanced free radical scavenging activity, providing stronger protection against lipid and protein oxidation. Furthermore, rose powder maintained more stable color and physicochemical properties, with patties showing acceptable color and minimal texture degradation by the 7th day of storage. These findings highlight the potential of rose powder as a highly effective natural additive for extending the shelf life and preserving the quality of ground beef patties, positioning it as a promising ingredient for future applications in the food industry.

Study of the Effect of NaOH Type Alkaline Catalyst on the Physicochemical Characteristics of Used Cooking Oil Biodiesel

Dependence on fossil fuels causes significant environmental damage and increases costs and scarcity in the future. To overcome this problem, a transition to renewable energy is needed, one of which is biodiesel which can be obtained from used cooking oil. This study aims to convert used cooking oil that cannot be reused into biodiesel products. Biodiesel synthesis can be carried out by the transesterification process, using NaOH catalyst with concentration variations of 0.5%, 0.75%, 1%, 1.25%, and 1.5% of the total mass of oil. The test parameters are calorific value, density, viscosity and flash point as well as yield on used cooking oil biodiesel products. The test results show that the use of a catalyst concentration of 1% produces more optimal density, viscosity, and calorific value and flash point. Each value is 0.859 g / cm³, 2.34 cSt, 10,356 cal / g, and 139°C. However, the use of a catalyst concentration of 0.5% shows that the biodiesel product is less than optimal. This can be shown by the highest density, viscosity and flash point values of the catalyst concentration variations used. Each value is 0.88 g/cm3, 3.16 cSt and 178°C, while the calorific value is also low with a value of 9,689 cal/g. However, when viewed from the yield, the catalyst concentration of 0.5% produces the highest value of all catalyst concentration variations used with a value of 88%.

Nutritional and Antinutritional Evaluation of the Pulp and Seed of Terminalia catappa l. (Tropical Almond) Fruit and Physicochemical Properties of Its Seed Oil

Aims: This study aimed at determining the nutritional and antinutritional composition of the pulp and seeds as well as physicochemical characteristics of the seed oil of Terminalia catappa L. (tropical almond). Methodology: The analyses were done in the Agroecology and life science laboratory of the University of Buea between June 2023 and May 2024. The experimental design was employed. Oil was extracted using soxhlet method. UV-visible spectrophotometer was used for nutritional and antinutritinal analyses; while gas chromatography and titrimetry were used to analyse the fatty acid profile and physicochemical properties of the seed oil respectively. Results: Results revealed that the seeds recorded more concentrated energy (596.28 Kcal/100g) than the pulps (403.42 Kcal/100g). Total phenolic (133.70 ± 0.15 mg/100g), tannin (77.90 ± 0.01 mg/100g), oxalate (15.01 ± 0.01 mg/100g) and phytic acid (2.81 ± 0.06 mg/100g) contents were displayed by the pulp and 29.70 ± 0.25, 18.00 ± 0.07, 20.92 ± 0.07 and 1.88 ± 0.01 mg/100g, respectively for seeds. The abundant minerals in the pulp were K, Ca, Na, and P, those in the seeds were Mg, K, P and Fe. The Acid value, Saponification value, Iodine value, Peroxide value and P-anisdine value of the seed oil were 2.24 ± 1.16 mgKOH/g, 222.2 ± 3.11 mgKOH/g, 78.50 ± 0.54 gI2/100g, 5.50 ± 0.71 mEq/kg and 3.65 ± 0.23, respectively. Fatty acid profiling showed 66.68% unsaturated fatty acids of which 19.86% and 9.81% were linoleic and linolenic, respectively and 33.32% saturated. Conclusion: The pulps and seeds of T. catappa have a significantly high content of macro and micronutrients that can meet up the nutritional needs of a population and the quality assessment of the oil suggests that it can be recommended as suitable for industrial usage.

Enhancing oyster mushroom growth and yield using air gliding arc discharge

Abstract Oyster mushroom cultivation can be hindered by slow budding and low yield. This study explored the potential of atmospheric pressure gliding arc discharge plasma to address these challenges. Two types (direct and indirect) of plasma treatment methods were applied to the mushroom spawn and the growth environment in oyster mushrooms. Physicochemical characterization of plasma-activated water (PAW) revealed increased conductivity, oxidation-reduction potential, and nitrate/nitrite levels, and hydrogen peroxide with longer treatment times. Plasma-treated spawn exhibited faster budding and earlier colonization compared to others. The longest stem was observed in spawn exposed to plasma for 3 minutes, while the largest stem diameter was found in spawn treated with plasma-activated water for 4 minutes. Mushrooms produced with a 4-minute PAW treatment had the highest total fresh weight and biological efficiency. Therefore, compared to control spawn, the production of mushroom spawn treated with plasma increased by a factor of 1.5. Overall, plasma treatment enhanced mushroom development and yield, indicating its positive impact on oyster growth.

Impact of Thermal, Ultraviolet and Ultrasonic Treatment on Mechanical, Physicochemical and Sensory Characteristics of Pear Jelly

The purpose of this study is to evaluate the influence of thermal, ultraviolet, and ultrasonic processing by examining the mechanical, physicochemical, and sensory characteristics of pear fruit jelly. Samples were processed using thermal pasteurization (TP), ultraviolet light (UV-C,) and ultrasound (US) at 65°C/50 min for all methods. US increases the most mechanical performance values compared to TP and UV-C treatment which reduces them. TP does not statistically significantly alter most physicochemical characteristics except for sugars, where it exhibits a slight reducing effect. UV-C irradiation increases water activity and moisture content the most compared to other treatments and has the least reducing effect on sugars. The US treatment significantly reduces the glucose, fructose, and sucrose in the highest amount and increases total solids and soluble solids contents. In terms of color characteristics, TP treatment makes the color of the samples darker, UV-C irradiation more saturated, and US preserves the original colour best. The strongest correlations between physicochemical and colour parameters have positive and statistically significant Pearson coefficients. Different processing methods had different effects on the sensory characteristics, with UV-C improving aroma, US taste, and texture, and TP having no significant effect on these.

The Influence of Commercial Starter Cultures on the Quality of Telemea Cheese

The purpose of this scientific work was to study the influence that commercial starter cultures have on the quality of a traditional Romanian semi-hard cheese, namely Telemea. The starter cultures were thoroughly characterized prior to their application in the process, with particular attention to their impact on the food product both during and following processing. Different experimental types of cheese were obtained using two types of commercial starter cultures (MA11 and WHITE FLORA 1) in combination with a third commercial culture (MO536CRYO): MO536CRYO+MA11 and MO536CRYO+WHITE FLORA 1. The analysis focused on two factors that may influence cheese quality: the type of starter culture (mesophilic and thermophilic lactic acid bacteria) and the quantity of culture added to the milk. Starting from the same raw material, cow milk, and applying similar technological process, the cheeses inoculated with MO536CRYO+WHITE FLORA 1 exhibited superior physico-chemical, microbiological, and sensory characteristics compared to the other produced variants.

Comparative Analysis of Physico-Chemical and Potassium Sorption Properties of Sensitive Clays

The paper analyses physico-chemical and geotechnical characteristics of four Scandinavian sensitive soils formed under different environmental depositional conditions, with the main aims to contribute to the knowledge of sensitive soils and assess the potassium sorption capacity among the investigated soils, as a basic characteristic to evaluate the effectiveness of treatment with KCl and to analyse potassium migration in such soils. The results show that, although the chemical composition of the four soils is very similar, their sensitivity is significantly different. The correlation from literature linking the specific surface, mineralogy, and plasticity in sensitive clays of Eastern Canada, was found to be qualitatively valid for the investigated Scandinavian sensitive clays, too. The highest value of the sensitivity index among the tested soils was found to be related to the lowest cation exchange capacity and to a limited amount of amorphous minerals. These characteristics contribute to explaining the highly sensitive behaviour of that soil affecting the structure formation during the deposition stage. The potassium sorption capacity has been experimentally investigated through batch tests specifically performed on the sensitive soils, as the first step to quantify the maximum sorption capacity and identify the main factors affecting it. The maximum potassium sorption capacity was always lower than that estimated by the cation exchange capacity, and it increased with the cation exchange capacity, plasticity index, and activity of the soils, as well as with the amount of phyllosilicates and amorphous minerals.

Physicochemical, Structural, Thermal, and Rheological Properties of Mango Seed Starch from Five Cultivars

Large quantities of seeds are generated and discarded during agro-industrial mango processing. However, mango seeds still contain valuable components such as starch, which has applications in various industries. This study aimed to obtain and characterize starches from the seeds of five mango cultivars (Ataulfo, Manililla, Piña, Tapana, and Tommy Atkins). The isolated starches were evaluated for their physicochemical, morphological, structural, thermal, and rheological characteristics. The starches showed creamy white colorations, and their granules had spherical and oval shapes. This starch source contains a high percentage of apparent amylose, greatly influencing its thermal, rheological, and functional properties. Structural and molecular studies showed that all starches presented an A-type X-ray diffraction pattern, impacting their water absorption and viscosity. The transition temperatures were relatively high, which could be influenced by the length of the amylopectin chains and their intermediate components, the apparent amylose content, and other components such as lipids and anomalous amylopectin. The starches evaluated behaved as pseudoplastic materials, while oscillatory tests revealed that the pastes formed with mango starches are more elastic than viscous. In conclusion, research on the seed starch properties of different mango cultivars provides interesting results for their potential application in foods. It could contribute to the value-added processing of mango seeds as a potential starch source.

Amphiphilic self-assembling peptides: formulation and elucidation of functional nanostructures for imaging and smart drug delivery.

The rational design of self-assembled peptide-based nanostructures for theranostics applications requires in-depth physicochemical characterization of the peptide nanostructures, to understand the mechanism and the interactions involved in the self-assembly, allowing a better control of the objects' physicochemical and functional properties for theranostic applications. In this work, several complementary characterization methods, such as dynamic light scattering, transmission electron microscopy, circular dichroism, Taylor dispersion analysis, and capillary electrophoresis, were used to study and optimize the self-assembly of pH-sensitive short synthetic amphiphilic peptides containing an RGD motif for active targeting of tumor cells and smart drug delivery. The combined methods evidenced the spontaneous formation of nanorods (L = 50nm, d = 10nm) at pH 11, stabilized by β-sheets. To complement with imaging properties for diagnosis, a new strategy was developed by designing an optimized peptide sequence to allow for efficient functionalization with a contrast agent, while preserving the self-assembling properties. Co-assemblies of the peptide and its derivatives, after peptide modification with a gadolinium complex, exhibited similar nanorod structures and required properties for drug delivery and imaging applications in vivo.

Advances in polysaccharide-based materials for biomedical and pharmaceutical applications: A comprehensive review.

Polysaccharides, the most abundant biopolymers in nature, have attracted the attention of researchers and clinicians due to its practicality in biomedical and pharmaceutical sciences. These biomaterials have high bioavailability and play structural and functional roles in living organisms. Polysaccharides are classified into several groups based on their origin, including plant polysaccharides and marine polysaccharides (like chitosan, hyaluronic acid, dextran, alginates, etc.) with specific applications. These biopolymers possess unique physicochemical (such as surface functional groups, solubility, and stability), mechanical (like mechanical strength and tensile), and biomedical (such as antioxidant activity, biocompatibility, biodegradability, renewability, and non-immunogenicity) characteristics which have made them excellent platforms for a wide variety of biomedical and pharmaceutical applications. Ease of extraction and different preparation approaches are mentioned as other potential properties of polysaccharides that further improved their practicality in biomedical sciences. They have high drug/bioactive encapsulation capacity and sustained/controlled release manner in in vivo microenvironments. The anti-inflammatory and immunomodulation, stimuli-responsive drug/bioactive release, and passive and active drug/bioactive delivery are considered the potential features of these biopolymers in pharmaceutical sciences. Polysaccharides have indicated practical applications in biomedical sciences, including biosensors, tissue engineering, implantation, wound healing, vascular grafting, and vaccines. This review highlights the advances of polysaccharide-based materials in biomedical and pharmaceutical sciences.

Characterization of rice noodles fortified with different levels of stabilized rice bran

The study aimed to evaluate the effects of stabilized rice bran (SRB) on the functional, physicochemical, nutritional, and sensory characteristics of rice noodles. This study assessed the influence of SRB on the cooking quality and functional and nutritional properties of rice noodles. A total of five different levels of SRB (0, 2, 5, 10, and 15% w/ w) were incorporated into the rice noodles. Compared to control rice noodles (0% SRB), those incorporating 10 and 15% SRB demonstrated significant differences (p < 0.05) in cooking time (CT) and cooking loss (CL). As the level of SRB increased, the water absorption index (WAI), water solubility index (WSI), hardness, adhesiveness, springiness, and chewiness values of rice noodles decreased, respectively. The incorporation of SRB influenced (p < 0.05) the colour, proximate constituents (moisture, ash, carbohydrate, protein, fat, and crude fibre), antioxidant activity, and total phenolic contents of rice noodles. Noodles with 10% SRB showed the highest score for overall acceptability (7.86±1.14), while noodles with 15% SRB received the lowest score (6.31±0.81) in all sensory elements tested. Therefore, SRB can be used as a functional ingredient to enhance the nutritional and physicochemical properties of rice noodles with improved acceptability.

Effect of high hydrostatic pressure on the physicochemical characteristics of low sodium mortadella containing a high level of mechanically deboned poultry chicken meat.

High hydrostatic pressure (HHP) is an emerging technology that can be applied to improve the functional properties of emulsified meat products. The aim of this study was to evaluate the effect of HHP (100 and 200 MPa) on low-sodium mortadella produced with high content of mechanically deboned poultry meat (MDPM). Seven treatments were produced: FC (2.5% NaCl - control 1), F1-C (1.25% NaCl - control 2), F1-100 (1.25% NaCl and 100 MPa), F1-200 (1.25% NaCl and 200 MPa), F2-C (1.25% NaCl, 1.60% KCl), F2-100 (1.25% NaCl, 1.60% KCl, 100 MPa), and F2-200 (1.25% NaCl, 1.60% KCl, 200 MPa). Proximate composition, sodium content, emulsion stability, extraction yield of myofibrillar proteins, instrumental color, texture profile, and microstructure of the samples were evaluated. Pressurization and salt reduction did not affect chemical composition (moisture, fat and protein) of the samples, while HHP increased protein extraction, forming a more compact, homogeneous and better distributed gel, improving emulsion stability and increasing mortadella hardness. Therefore, this technique could effectively compensate the deterioration in the protein gel matrix caused by salt reduction. Studies are necessary to investigate the effects of HPP on sensory properties and lipid oxidation of mortadella.

In Situ Growth of Ag-ZnO Nanorods on Graphitic Carbon Nitride for SERS Detection of Rhodamine 6G

Abstract Sensing azo dyes has received significant attention due to their environmental impact and harm to human health. A cellulose-paper-based surface-enhanced Raman scattering (SERS) substrate with a hierarchical Ag-ZnO@GCN nanorod composite was successfully prepared by hydrothermal method. The intended hierarchical nanocomposite was prepared using a facile and economically feasible method. The optical, functional group, structural profile, phase formation, and surface morphology of the prepared AZCN-80, AZCN-120, and AZCN-160 were characterized using UV-Vis, Fourier transform infrared spectroscopy, Raman, X-ray diffraction, scanning electron microscopy, and energy-dispersive X-ray analysis. The physicochemical characterization results demonstrated that this ubiquitous nanorod composite considerably enhanced the SERS sensing performance for detecting harmful organic molecules, specifically rhodamine 6G (R6G). In addition, the fabricated paper-based AZCN-160 substrate exhibited good linearity with a range of 10-5 to 10-15 M, with an R2 value of 0.96 compared to that of AZCN-80 and AZCN-120. Therefore, the paper-based SERS substrate developed in this study is a “proof-of-concept” strategy for designing and constructing efficient and effective molecular sensors for real-time sensing and monitoring.

Combination of Biochar and Advanced Oxidation Processes for the Sustainable Elimination of Pharmaceuticals in Water

The presence of pharmaceuticals in aquatic ecosystems is an issue of increasing concern. Regardless of the low concentration of pharmaceuticals in water, they can have a toxic effect on both humans and aquatic organisms. Advanced oxidation processes (AOPs) have been described as a promising technique for eliminating pharmaceuticals due to their high efficiency. However, the cost associated with the application of these processes and their high reagents and energy requirements have affected the implementation of AOPs at large scales. Biochar has been suggested to be used as a catalyst in AOPs to overcome these limitations. Biochar is considered as an alternative heterogeneous catalyst thanks to its physicochemical characteristics like its specific surface area, porous structure, oxygen-containing functional groups, electrical conductivity, persistent free radicals (PFRs), modifiable properties, and structure defects. This carbonaceous material presents the capacity to activate oxidizing agents leading to the formation of radical species, which are needed to degrade pharmaceuticals. Additionally, AOP/biochar systems can destroy pharmaceutical molecules following a non-radical pathway. To enhance biochar catalytic performance, modifications have been suggested such as iron (Fe) impregnation, heteroatom doping, and supporting semiconductors on the biochar surface. Although biochar has been efficiently used in combination with several AOPs for the mineralization of pharmaceuticals from water, further research must be conducted to evaluate different regeneration techniques to increase biochar’s sustainable applicability and reduce the operational cost of the combined process. Moreover, operational conditions influencing the combined system are required to be evaluated to discern their effect and find conditions that maximize the degradation of pharmaceuticals by AOP/biochar systems.

Multiscale structural characterization, physicochemical properties, and in vitro digestibility of pea starch produced by two different processes

AbstractBackground and ObjectivesDry grinding pea starch (DG) and wet grinding pea starch (WG) are two primary industrial starches with significantly different structures, physicochemical properties, and application potentials. To date, there have been no detailed studies examining these differences. Therefore, the aim of this study was to (i) investigate the effects of dry grinding and wet grinding on the structure of pea starch, and (ii) examine how the structure of pea starch influences its physicochemical properties and digestibility.FindingsThe crystallinity (35.75%), medium and long amylopectin (AP) chains (22.00%), swelling power (17.23 g/g), gelatinization temperature (76.4°C), and gelatinization viscosity (5585.0 cP) of WG were higher than those of DG (24.29%, 20.36%, 16.90 g/g, 75.9°C, and 5196.3 cP). In contrast, the average particle size (APS) (24.31 μm), resistant starch content (45.80%), and gel hardness (509.70 g) were lower than those of DG (25.68 μm, 52.13%, and 617.53 g).ConclusionsSignificant structural differences exist between WG and DG, with APS and AP chain length distribution being the primary factors contributing to the distinct physicochemical characteristics of the two pea starches.Significance and NoveltyThis is the first detailed comparison of the properties of commercial pea starch produced by two different processes. The results provide theoretical insights that underpin the use of pea starch in functional foods and promote the development of new starch‐based products.

Effect of Lime Solution Soaking on Physicochemical Characteristics of Catfish Bone Powder (Arius thalassinus)

Fish bone powder is one of the fisheries by product processing that has a high nutritional content, especially calcium and phosphorus content. In the processing of fish bone powder, the fishy odor is still detected due to organic compound such as protein and lipid which produce volatile compounds yielded unpleasant odor. The use of lime can eliminate fishy odors, improve color, shape, taste, texture, and extend shelf life. This study aimed to determine the difference of lime solution concentration on the physicochemical characteristics of catfish bone powder and to determine the best lime concentration used on the volatile compound content of catfish bone powder. The method carried out in this study was a laboratory experimental method and used a Complete Random Design (CRD) with 4 treatments (0%, 15%, 20%, 25%) and carried out in triplicate. Data analysis from physical and chemical tests were analyzed using ANOVA, while hedonic tests were performed using the Kruskal-Wallis test followed by the Mann-Whitney test. The results showed that soaking lime solution had a significant effect (P<5%) on moisture content, protein content, fat content, ash content, calcium content and color. Catfish bone powder with the best treatment of soaking in lime solution of 20% contained a calcium of 25.17%.The results of the hedonic test showed that the best treatment (20%) had a confidence interval of 3.95 < μ < 4.19 from 5 scale. The volatile compound of 4-[4-(dimethylamine) Benzaldehyde associated with fishy odor was detected in fish bone powder without lime solution, but it could not be detected in sample soaked in 20% lime solution showing the capability of lime solution to reduce fishy odor in fishbone powder.

Unveiling the green synthesis of WO3 nanoparticles by using beetroot (Beta vulgaris) extract for photocatalytic oxidation of rhodamine B.

Tungsten oxide (WO3) nanoparticles (WO3NPs) were prepared using beetroot (Beta vulgaris) extract. The synthesis was optimized by evaluating the effect of pH during the reduction of the WO3 precursor and sintering temperature. Physicochemical characterization of the formed nanoparticles was performed using X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and UV-visible diffuse reflectance UV-visible spectroscopy. Furthermore, the prepared WO3NPs were employed as photocatalyst for rhodamine B removal over the photocatalytic oxidation mechanism. Synthesis optimization revealed that a single phase of WO3NPs obtained by reduction at pH 4 and a sintering temperature of 550°C. XRD and XPS measurements revealed that the single-phase WO3NPs was obtained with a crystallite size of 26.4 nm. SEM and transmission electron microscopy (TEM) indicated polymorphic forms, predominantly as nanorods, with a mean particle size of 24 nm. The WO3NPs have a band gap energy of 2.9 eV, supporting their performance as a photocatalyst. Evaluation of the photocatalytic activities of WO3NPs represents high activity and reusability of the material. A removal efficiency of 99.67% was achieved during 30 min of treatment under UV light illumination. A study on the effect of scavengers revealed the important role of hydroxy radicals in the photocatalysis mechanism. WO3NPs can be recycled and reused for photocatalysis, maintaining photoactivity for five cycles.