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Highly Sensitive and Selective PANI/Ag Nanocomposites-Based Gas Sensors for Room-Temperature NH3 Detection
Get PDFHighly sensitive gas sensors for detection of hazardous gases at room temperature is a critical research area. This study presents the fabrication of NH3 gas sensors based on polyaniline (PANI) and Polyaniline/silver nanocomposites (PANI/Ag NCs). PANI and Ag NPs were prepared by chemical oxidation and polyol methods, while PANI/Ag NCs were prepared using an ultrasonic-assisted method. XRD analysis confirmed the crystallinity of Ag NPs and the amorphous nature of PANI. SEM images revealed the porous structure of PANI and the uniform distribution of Ag NPs within the PANI matrix. UV–Vis analysis displayed the characteristic absorbance peaks and FTIR analysis confirmed the purity of the synthesized materials. The PANI/Ag (80/20) NC sensor notably displayed significantly improved gas-sensing properties over pristine PANI in terms of higher capacitive and resistive responses, superior sensitivity up to 1047.2%, and faster response/recovery times of 20/6 sec at 36 ppm. The enhanced performance would be ascribed to the enhanced surface area with the incorporation of AgNPs and better electron mobility. The results suggest that PANI/Ag NC-based sensors have excellent potential for efficient room-temperature gas detection
Evaluation of the Antioxidant Activity of Honey
Get PDFAntioxidant activity of honey highly correlates with its total phenol content. The antioxidant capacity is attributable to various components, and there are several measurement methods for evaluating all of these components; hence, integration of measurement methods is important. Therefore, the aim of this study was to evaluate the antioxidant activity of honey by examining correlations among the total polyphenol content, color values, melanoidin content, 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging activity, and iron-reducing capacity. Fourteen honey samples were collected from different nectar sources. Total polyphenol content was measured using the Folin–Ciocalteu method. Color values and melanoidin content were measured using the absorbance values of samples. The antioxidant capacity was evaluated by measuring DPPH radical-scavenging activity and iron-reducing ability using the ferric-reducing antioxidant power method. Substantial correlations were observed between the total polyphenol content and iron-reducing capacity, total polyphenol content and color value, color value and iron-reducing capacity, melanoidin content and total polyphenol content, melanoidin content and iron-reducing capacity, and melanoidin content and color value. Among all honey samples, buckwheat honey had the highest values for all parameters. These findings indicate that the antioxidant effect of honey should be evaluated based on not only its total polyphenol content and DPPH radical-scavenging activity but also its iron-reducing capacity, color value, and melanoidin content
Effect of High Protein Formulation on Rheological, Sensory and Microstructure of Cookies
Get PDFThis study investigates the impact of high-protein formulations on the rheological, sensory, and microstructural properties of cookies, with an emphasis on using plant- and dairy-based protein sources. Protein plays an essential role in the diet, providing amino acids necessary for muscle, healthy bone, tissue repair, growth in children, adolescents, and pregnant women. Despite the known benefits of plant-based proteins, limited research has focused on their effect in high-protein bakery products, particularly cookies. In this study, three cookie formulations were developed using pea protein isolate, soy protein isolate, and a combination of whey protein isolate with skim milk powder, along with almonds for enhanced nutritional value. Control cookies were prepared with wheat flour. Proximate analysis showed a significant increase in protein content with 53.22% in the pea protein isolate cookies, 46.76% in the soy protein isolate cookies, and 49.92% in the whey and skim milk powder cookies in comparison with control which was 12%. Farinograph analysis indicated increased breakdown times for the experimental doughs, ranging from 13.2 to 19.1 minutes compared to 9 minutes for the control, suggesting improved dough stability. Microstructural analysis revealed a porous structure in the cookies, likely resulting from trapped air during baking, which enhances texture and lightness. Observations showed that interactions between protein isolates and starch granules create structural diversity, contributing to the cookie’s crispness and chewiness. Sensory evaluation favored the whey protein isolate and skim milk powder formulation, which scored the highest in appearance, flavor, and texture attributes. Overall acceptability ratings were favorable across all samples, with the cookie containing whey protein + Skim milk powder receiving the highest score (8.5) among the high-protein cookies. This study demonstrates the potential of high-protein cookie formulations as nutritionally valuable food products. Further research is recommended to examine the effects of varying protein proportions on the sensory and rheological properties of these formulations
Proximate Composition and Fatty Acid Profiling of Five Species of Fish Caught from Kerala Coast, India
Get PDFIn this comprehensive study, we investigated the proximate composition and fatty acid profiles of five distinct species of fish: Epinephelus diacanthus, Johnius glaucus, Scatophagus argus, Alepes djedaba, and Stolephorus commersonnii, all sourced from the vibrant waters along the Kerala coast. The proximate composition of these fish was meticulously analyzed, focusing on key nutritional components: moisture, protein, fat, and ash content. Among these species, S. commersonnii exhibited the highest moisture content, showcasing its fresh and succulent nature, while A. djedaba displayed the lowest moisture levels. In terms of protein, S. argus stood out with the highest concentration, indicating its potential as a rich source of this essential nutrient, whereas E. diacanthus came in at the lower end of the spectrum. When we examined fat content, S. argus again excelled with the richest levels of fat, contributing to its flavor and caloric density, while S. commersonnii contained the least fat, offering a leaner option for health-conscious consumers. Delving deeper into the fatty acid profiles, we classified the fatty acids into three categories: saturated fatty acids (SFA), monounsaturated fatty acids (MFA), and polyunsaturated fatty acids (PUFA). Significantly, our findings revealed that S. commersonnii had the highest percentage of docosahexaenoic acid (DHA), a vital n-3 fatty acid known for its numerous health benefits, while S. argus recorded the lowest DHA level. On the other hand, eicosapentaenoic acid (EPA) was most abundant in Alepes djedaba presenting an excellent option for consumers seeking the benefits of n-3s, with Scatophagus argus trailing behind in EPA content. Furthermore, the analysis highlighted the impressive levels of polyunsaturated fatty acids in Stolephorus commersonnii, making it a standout choice for those looking to enhance their diet with essential fats. Overall, this study enhances our understanding of the nutritional profiles of these fish species, providing valuable insights for both consumers and the fishing industry
Shelf-life Determination of Dried Onion (Allium cepa) and Tomato (Lycopersicon esculentum) Products
Get PDFThe role of nutrient-rich vegetables in promoting good health has resulted in an increase in their demand over the past decade, but they are highly seasonal, causing lower prices and heavy losses at peak season. The objective of the study was to determine the shelf life of dried onion and tomato products. The study was conducted in Mekelle University’s food science and post-harvest technology laboratory. Four treatments (sun, shade, solar, and oven drying methods) were used to dry onion and tomato products, and shelf life was determined using CRD at a 5% level of significance. Data such as microbial counts, time and temperature of drying, moisture content, rehydration ratio, and sensory characteristics were recorded and analyzed using analysis of variance. The highest microbial load obtained was for shade-dried onion (6.06 log10cfu/g) and sun-dried tomato (5.83 log10 cfu/g). For dried onion, significant differences were observed among the driers on the microbial population of coliform (p<0.05) and total bacterial count (p<0.01) but not on yeast and mold count. The maximum rehydration was achieved in the oven-dried products (3.64) followed by solar drying (3.28). Dried onion and tomato remained organoleptically acceptable, except for sun-dried tomatoes for color and appearance (4.75) and aroma (4.75) in the first month of storage. The oven-drying method was the best method of dehydration of freshly dried onions and tomatoes. Further research should be carried out to determine the effect of drying on the extended storage time of the dried products
Evolution of Microstructure During Stress Relieving Heat Treatment of 1S Aluminium
Get PDFAluminium and its alloys are extensively used in nuclear research reactors due to its low neutron absorption coefficient, good heat transfer properties, excellent corrosion and oxidation resistance in air and water environment combined with desirable mechanical properties along with considerable radiation stability. The thin walled tubes are normally manufactured through port hole die extrusion route and used in 'O' tempered condition. The thin tubes in 'O' tempered condition are undergone canning operation which may alter the microstructural features to some extent which may affect mechanical properties. The paper describes the extent to which microstructural and subsequently mechanical properties are altered due to the simulated canning process and further requirements of stress relieving heat treatment to restore the microstructural features and mechanical properties. The following studies are carried out with 1S aluminum tube in 'O' tempered state, simulated canning condition and stress relieved at different temperature, - hardness measurement, X ray line profile analysis for dislocation density measurement, tensile properties measurement using ring tensile testing, electron back scattered diffraction (EBSD) analysis for recrystallization fraction determination and changes in texture components. It is found that the canning operation changes dislocation density, micro-strain, coherent domain size which are well reflected in hardness and ring tensile testing. Subsequent stress relieving at 350°C for 2 hrs. leads to improvement of mechanical properties appreciably
Morphological, Phytochemical and Pharmacological Properties of Carum carvi (Caraway) and Bunium persicum (Black Caraway) Seeds: A Review
Get PDFCarum carvi and Bunium persicum belongs to Apiaceae family. Both the species are medicinally important and has been used as antimicrobial, antioxidant, anticarcinogenic, antidiabetic, to treat heart problems, spice, condiments and breath freshener or lotions industries etc. Due to morphological similarities, the adulterations are being observed, so it is essential to understand the morphological, phytochemical and pharmacological properties of both the seeds. The plants look similar with approximately similar flower colour. Most prominent difference is in root structure. The roots of C. carvi are fleshy, fusiform tap while that of B. persicum is tuberous. C.carvi seeds are larger than that of B. persicum, with comparatively lighter brown colour. The seeds of C. carvi are sickle shaped while the seeds of the B. persicum are cylindrical in shape. Chemical composition of essential oil is approximately similar with variation in the percentage content of various compounds. Both the seeds are used for food preparation with some variation in their utilization due to difference in their aroma
Preservation Techniques to Increase the Shelf Life of Seafood Products: An Overview
Get PDFCurrently, humanity is facing many types of diseases with various origins and the high costs of chemical drugs for treatment. Therefore, the consumption of healthy and nourishing foods such as seafood products to treat these diseases should be considered in the human diet. However, seafood products are subject to high spoilage owing to their high-water content, rich composition of unsaturated fatty acids, susceptibility to oxidation, near-neutral pH, presence of non-protein nitrogenous compounds, and microorganism activity. Therefore, appropriate storage methods are required to prevent spoilage. This review was done with the aim of providing preservation methods and increasing the shelf life of seafood products. In general, the results of this research stated that common and traditional techniques of seafood products preservation including salting, canning, chilling, freezing, fermentation, super chilling, drying, smoking, frying, pickling/marinating and pasteurization and also modern techniques for seafood products preservation such as microwave processing, ultrasound, pulsed electric field (PEF), irradiation, high hydrostatic pressure (HHP), micro fluidization, usage of natural preservatives (plants and algae extracts, biodegradable polymers, bioactive polysaccharides and biopeptides extracted from marine resources/ seafood by-products), packaging ((MAP), (AP), (IP), (VP), (RP)), nanotechnology and other new methods can preserve the product for a period of time efficiently, also significantly increase the desired sensory and organoleptic characteristics of the product and as a result, they increase quality, safety and shelf life. However, improving the weaknesses of traditional methods by using modern techniques can improve and maintain the nutritional value of the product
Effect of Distance of the Flame’s Inner Cone from Substrate Surface on Diamond Films Synthesized on Ti Substrate for Dental Implants by Flame Combustion
Get PDFFlame combustion enables the synthesis of diamonds via acetylene-oxygen gas flame combustion in ambient air. Recently, titanium has been used for dental implants in the dental industry. In this study, diamond films were synthesized on a Ti substrate using the flame combustion method to improve the strength, wear resistance, and biocompatibility of dental implant surfaces. Moreover, to obtain high-quality diamond films and various synthesized diamond crystallites sizes and to achieve good adhesion on the Ti substrate, as a condition of the synthesis to prevent delamination, the distance of the flame’s inner cone from the substrate surface was varied by 1.0, 1.5, 2.0, 3.0, 4.0, and 5.0 mm. Based on the results, diamond films were synthesized on a Ti substrate surface via flame combustion. The surface morphology of the synthesized films was altered by varying the distance between the inner cone of the flame and the substrate surface. This distance affected the surface morphology of the synthesized diamond films. The delamination of the synthesized films was prevented completely. To investigate the factors causing this result, nuclei were generated on the substrate during the initial stages of synthesis. The effect of the distance between the inner cone of the flame and the substrate surface on the diamond films synthesized by flame combustion was investigated. The relationship between this distance and the state of the diamond nuclei on the substrate in the initial stages of synthesis was verified
Evaluation of Rice-based Alternatives to Titanium Dioxide for Colour-masking in Iron-Fortified Salts
Get PDFTitanium dioxide (TiO2) is a common whitening agent used in the food industry, used in candies, baked goods and confectionaries. Several food regulatory agencies have banned or severely restricted TiO2 use due to potential carcinogenic/ genotoxicity. Rice starch and rice flour were investigated as alternatives to TiO2, since they are cheap, opaque, white and are widely used in industry. Due to its amorphous granules and resulting low electrostatic forces, the adhesion of rice starch to extruded materials was much weaker than that of TiO2. Adhesives were synthesized from crosslinking citric acid with rice starch and rice flour through esterification reaction pathways. The results were tested on extruded ferrous fumarate cylinders used in salt fortification and compared with TiO2 was as control. The results show that rice starch as a whitening agent with a modified rice starch adhesive was a promising option for replacing TiO2 as a colour masking/whitening agent. It was observed that higher mass fractions of citric acid in the adhesive produced better results. Rice flour performed comparably to the rice starch in adhesives however, the ease of use was poorer due to higher viscosity and clumping. The cost for using rice starch was a cost-effective alternative to TiO2 as rice starch is a cheaper, widely available food additive