Variations In Chemical Composition Research Articles

Water chemical formation mechanism and water quality analysis of Shichuan River under the influence of human activities

ABSTRACT It is necessary to analyze the characteristics of the water environment and factors influencing the basin in order to determine its current ecological status. This study aims to investigate the chemical properties in the Shichuan River Basin using Gibbs diagram, Piper triangle diagram, correlation analysis, factor analysis, and main ion ratio method. The enhanced Nemerow comprehensive index method and fuzzy comprehensive evaluation method are employed for river water quality assessment. The findings reveal that runoff water has a weak alkaline nature with low salinity. The hydrochemical type of river water includes Ca2++Mg2++Na+-SO4 2-, Ca2++Mg2+-SO4 2-+Cl-+HCO3 -, Ca2++Na+-SO4 2-+Cl-+HCO3 -. Silicite and dolomite weathering are identified as primary influencing factors, while evaporite weathering also contributes to variations in chemical composition within the basin's waters. Ca2+, Mg2+, SO4 2- and HCO3 - originate from carbonate rock and silicate rock weathering processes, whereas Na+, K+ and Cl-, are primarily derived from evaporite weathering influenced by domestic sewage and agricultural activities. Agricultural production practices along with discharge of domestic sewage have an impact on Na+, K+, Cl- and NO3 -concentrations in aquatic systems. Water quality at all three monitoring sections falls under level IV classification. Phosphorus emerges as a key limiting factor for eutrophication within this basin's watersheds.

Antioxidant activities and chemical composition of rhizome essential oil from Zingiber plicatum Škorničk. & Q.B.Nguyen from Vietnam

The Zingiber genus has been widely applied in food and pharmaceuticals due to its varied chemical composition and significant benefits. Zingiber plicatum Škorničk. & Q.B. Nguyễn was described in Vietnam in 2015, yet there has been no report on its phytochemicals and bioactivity. In this study, we first analyzed the chemical composition of essential oil and its antioxidant activities. Isolation of the rhizome essential oil was performed through hydrodistillation using a Clevenger apparatus for 3.5 h, then volatile compositions were determined using gas chromatography-mass spectroscopy (GC-MS). Additionally, the antioxidant activities were assessed using 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging and ferric reducing power assays. The GC-MS analysis showed a total of 54 volatile components, mainly belonging to monoterpene hydrocarbons (57.69%) and sesquiterpene hydrocarbons (28.98%). The main compounds were β-pinene (26.85%), α-pinene (11.73%), limonene (10.03%), and germacrene D (5.26%). The essential oil also showed antioxidant activities, with an IC50 of 84.53 mg/mL for DPPH scavenging activity and an EC50 of 17.3 mg/mL for ferric reducing power. These findings first provided data on the chemical components and antioxidant properties of Z. plicatum essential oil.

Symphytum genus—from traditional medicine to modern uses: an update on phytochemistry, pharmacological activity, and safety

AbstractWith around 34 recognized species, Symphytum genus (comfrey) has a noteworthy position within the Boraginaceae family. Comfrey species have been empirically used since ancient times as wound-healing and skin-regenerating agents in ulcers, wounds, bone fractures, and rheumatic complaints. This review aims to provide a thorough examination of recent scientific advances and challenges within the Symphytum genus, covering data published between 2013 and 2023. It delivers an updated overview of the taxonomy, ethnopharmacological uses, chemical composition, and pharmacological activities of the genus. Special emphasis is put on molecular identification methods for species taxonomy, emerging extraction technologies for comfrey phytochemicals, metabolomics techniques for mapping chemical complexity, modern bioassay platforms revealing its poly-pharmacology, formulation strategies, and remediation approaches for removal of toxic pyrrolizidine alkaloids (PAs). For instance, recent metabolomic studies employing advanced spectro-chromatographic techniques have revealed a diverse chemical composition of comfrey plants, including polysaccharides, allantoin, benzoic and cinnamic acid derivatives, flavonoids, fatty acids, and unsaturated necine-structure-based PAs. The mechanisms underlying their anti-inflammatory, analgesic, wound-healing, anti-irritant, and osteo-regenerative properties were targeted in modern pharmacological setups. Thus, key compounds like allantoin, rosmarinic acid, globoidnans A and B, rabdosiin, and comfreyn A, have been identified as significant contributors to the anti-inflammatory and wound-healing effects of Symphytum-derived preparations. Despite their well-established clinical use, concerns about PAs-induced toxicity have prompted the development of novel PA remediation strategies, enabling the production of comfrey extracts with enhanced safety profiles that can meet the regulatory standards imposed by authorities.

Assessing chemical composition variations on vintage, vineyard location and grape ripeness: A regional study of red wines produced in the colorado river middle basin, La Pampa (Argentina)

This work aimed to characterize chemical composition of Malbec and Cabernet Franc red wines from two different regions of La Pampa’s province, which stands out as one of the youngest wine-producing regions in Argentina and has remained unexplored until now. These wines were produced from grapes of two consecutive vintages (2021 and 2022), and were harvested at two different ripeness levels. Global phenolic parameters, colour characterization and multi-elemental profile were evaluated. Multivariate statistical approaches were successfully implemented to investigate the vintage and ripeness effects on chemical profile of red wines and characterize them based on regional variations. Our results showed that vintage and ripeness affected both phenolic and multi-elemental profiles, and such chemical variables allowed the wines differentiation according to region. The results of this first study could form the basis for future research into optimizing the region’s winemaking potential.

Different surface treatments on recently introduced CAD-CAM resin-modified ceramics: Implications on bond strength

Statement of problemThe diverse chemical composition of recently introduced resin-modified ceramics complicates the establishment of a universally accepted clinical bonding protocol. PurposeThe purpose of this in vitro study was to evaluate the influence of different surface treatments of resin-modified ceramics on the bond strength to a resin cement. Material and methodsSixteen 10×12×3-mm resin-modified ceramic slices were obtained from each material (Cerasmart; GC, Shofu Block HC; Shofu, Vita Enamic; Vita, Evolux hybrid; BlueDent, Alium; Alium). Slices were assigned to 4 groups based on surface treatments: Control (no treatment), airborne-particle abrasion with Al2O3 (Al2O3), conditioning with 9% HF (HF), and Al2O3+HF. After treatments and silane coupling agent (Monobond N; Ivoclar) application, 7 resin cement cylinders (Choice 2 veneer; Bisco) were built on each slice and light polymerized for 20 seconds. Half of the specimens (n=14 cylinders) were stored for 24 hours, and the other half were thermocycled (20 000 cycles, 5 °C to 55 °C, 30-second dwell time). Microshear bond strength was tested and analyzed with 3-way ANOVA and the Tukey HSD test (α=.05), and failure patterns were classified. Surface morphology after treatments was observed with scanning electron microscopy and Raman spectroscopy. ResultsAfter 24 hours, all treatments induced higher bond strength (P<.05) than in the control in Evolux. Al2O3+HF caused higher bond strength (P<.05) than in the control in Cerasmart and Shofu, and higher bond strength than Al2O3 in Cerasmart. However, it resulted in lower bond strength (P<.05) than Al2O3 in Alium. After thermocycling, irrespective of the resin-modified ceramic, all treatments induced higher bond strength (P<.05) than in the control. HF induced lower bond strength (P<.05) than Al2O3 in Alium. Al2O3+HF caused the highest bond strength (P<.05) in Evolux and higher bond strength (P<.05) than HF in Vita Enamic. Adhesive failures were prevalent under control conditions, and mixed failures were common after treatments. Al2O3 induced surface alterations in all resin-modified ceramics. HF notably altered Vita Enamic, while it had no noticeable impact on the other resin-modified ceramics. Al2O3+HF caused a considerable alteration in Vita Enamic and modified the other resin-modified ceramics. Vita Enamic had the characteristic vibrational bands of inorganic compounds, while the other resin-modified ceramics exhibited distinct bands associated with organic compounds. ConclusionsAirborne-particle abrasion with Al2O3 followed by HF yielded the highest bond strength, regardless of the resin-modified ceramic, except for Alium, which demonstrated better bond strength after airborne-particle abrasion with Al2O3. 9% HF for 30 seconds caused notable surface alterations in Vita Enamic, negatively impacting its bond strength. Vita Enamic was the only resin-modified ceramic displaying both organic and inorganic composition, while the other resin-modified ceramics showed predominantly organic composition.

Analysis of the Variation in Antioxidant Activity and Chemical Composition upon the Repeated Thermal Treatment of the By-Product of the Red Ginseng Manufacturing Process.

Steamed ginseng water (SGW) is a by-product of the repeated thermal processing of red ginseng, which is characterized by a high bioactive content, better skin care activity, and a large output. However, its value has been ignored, resulting in environmental pollution and resource waste. In this study, UHPLC-Q-Exactive-MS/MS liquid chromatography-mass spectrometry and multivariate statistical analysis were conducted to characterize the compositional features of the repeated thermal-treated SGW. The antioxidant activity (DPPH, ABTS, FRAP, and OH) and chemical composition (total sugars, total saponins, and reducing and non-reducing sugars) were comprehensively evaluated based on the entropy weighting method. Four comparison groups (groups 1 and 3, groups 1 and 5, groups 1 and 7, and groups 1 and 9) were screened for 37 important common difference markers using OPLS-DA analysis. The entropy weight method was used to analyze the weights of the indicators; the seventh SGW sample was reported to have a significant weight. The results of this study suggest that heat treatment time and frequency can be an important indicator value for the quality control of SGW cycling operations, which have great potential in antioxidant products.

Resilience of anodic biofilm in microbial fuel cell biosensor for BOD monitoring of urban wastewater

Efficient wastewater treatment monitoring is vital for addressing water scarcity. Microbial fuel cells (MFCs) have emerged as real-time biosensors for biochemical oxygen demand (BOD) in urban wastewater. Discrepancies in signal generation may arise due to changes in the composition and metabolism of mixed-culture electroactive biofilms stemming from different wastewater compositions. In this study, 3D-printed MFC-based biosensors were employed to assess the BOD of sterile complex artificial wastewater and untreated urban wastewater. Alterations in the microbial composition of the anode were evaluated using 16S rRNA sequencing and metagenomics analysis. Results show that MFC-based biosensors can be effectively recalibrated for diverse types of wastewater, maintaining consistent sensitivity (0.64 ± 0.10 mA L mg−1 m−2 with synthetic wastewater and 0.78 ± 0.13 mA L mg−1 m−2 with urban wastewater) and limit of detection (49 ± 8 mg L−1 for synthetic wastewater and 44 ± 7 mg L−1 for urban wastewater). Crucially, pre-sterilization, conductivity adjustments, and nitrogen purging of wastewater are not required before its introduction into the biosensor. However, the presence of native aerobic microorganisms in the wastewater might affect the current output. Metagenomics and taxonomic analyses revealed that the alterations in biofilm composition are predominantly in response to the varied chemical and microbiological compositions of different substrates. Despite variations in anodic biofilm composition, the MFC-based biosensor maintains a relative error comparable to the standard BOD test. This highlights the resilience and flexibility of the biosensor when directly used with a variety of wastewater types before full biofilm adjustment.

Damage growth characteristics on the exit surface of fused silica by the low-temporal coherence light irradiation

The growth of fused silica surface damage poses a high risk in operating high-power laser devices, with complex physical mechanisms related not only to the wavelength, pulse width, fluence of incident pulse lasers, but also to initial damage size and material properties. With low-temporal coherence light (LTCL) increasingly applied in high-power laser-driven inertial confinement fusion (ICF), LTCL-induced damage growth has become a bottleneck limiting output power improvements. This paper analyzes LTCL damage growth characteristics and mechanisms on fused silica surfaces, obtaining its damage growth coefficient and threshold. By analyzing chemical composition variation, electric field of initial damage, and comparing the damage growth threshold of artificial initial damage, the mechanism of surface damage growth is investigated. This research provides reliable information for estimating fused silica lifetime in high-power LTCL devices and contributes to understanding LTCL properties.

Exploring the use of averaged thermal kinetic parameters in luminescence thermochronometry

In luminescence thermochronometry, the thermal stability of feldspar minerals is conventionally constrained from isothermal decay experiments. However, despite recent refinement of the measurement protocol, measurements take several days and are routinely done for each individual sample. Following that most other thermochronometric methods usually use only a single reference set of thermal kinetic parameters, and that recent studies on direct physical probing of feldspar sample properties have shown that trap depth and band-tail width are broadly similar despite large variations in chemical composition, we sought to optimise luminescence thermochronometry measurements by exploring whether a single set of thermal kinetic parameters can describe luminescence thermal decay in feldspar. We explored the effect of using averaged thermal kinetic parameters rather than sample-specific thermal kinetic parameters to model luminescence signal accumulation under different thermal conditions. A set of K- and Na-feldspar minerals extracted from all over the world were analysed after being measured with a multi-elevated temperature protocol, comprising four different IRSL signals at 50, 100, 150, and 225 °C. Comparisons were done between the thermal kinetic parameters of each IRSL signal depending on different variables such as geographic region, transect, lithology, or mineralogy of the analysed feldspar grains. Even though it is not possible to generalise the thermal kinetic parameters between IRSL signals measured at different temperatures, the variance between the thermal kinetic parameters of different samples measured at the same IRSL temperature is consistent with the uncertainties on the individual parameters (i.e., <2–10%), suggesting that averaged, rather than sample-specific values may be appropriate. We then explored the effect of using these averaged parameters to model luminescence signal accumulation under different synthetic and natural thermal conditions. For our dataset, results show minimal impact on the obtained cooling histories and exhumation rates. We therefore propose the use of averaged rather than sample-specific thermal kinetic parameters for rapid investigation of luminescence thermochronometry samples. Based on careful initial characterisation of a few samples to verify the validity of using averaged thermal kinetic parameters, this would reduce measurement times by ca. 50% (i.e., 3–4 days per sample), allowing higher resolution sampling and measurement.

Beyond Pharmaceuticals: Harnessing the Potential of Plant-based Compounds for Anti-inflammatory Therapy

Abstract: A complicated biological reaction of vascular tissues to damaging stimuli like infections, harmed cells, or irritants is called inflammation. Symptoms include redness, inflamed joints, stiffness, discomfort in the joints, and loss of joint function. NSAIDs are frequently used to treat inflammation. Sadly, these drugs raise the possibility of blood clots, which can result in heart attacks and strokes. Consequently, there is ongoing research focusing on developing potent anti-inflammatory drugs using natural ingredients. Natural products, due to their diverse chemical composition, offer a rich source for the development of novel medications. The treatment of various inflammation- related disorders heavily relies on a natural substance derived from medicinal plants. The objective of the present study is to assemble information on potential parts of the plants or phytochemicals derived from medicinal plants used on inflammatory models, employing state-ofthe- art scientific methodologies. In this study, state-of-the-art scientific methodologies are utilized to investigate the effects of phytochemicals derived from medicinal plants. Relevant data is collected, focusing on the examination of these phytochemicals in experimental models of inflammation. The study aims to collect thorough data on potential plant parts or promising phytochemicals derived from medicinal plants that have been evaluated using advanced scientific techniques in the realm of inflammation models. This compilation will offer valuable insights into their potential as anti-inflammatory agents. The findings have the potential to contribute to the development of new and improved anti-inflammatory medications with fewer or no adverse effects compared to current treatments. While many of these studies hold academic interest only a few are accepted into clinical trials. Numerous phytoconstituents have been identified for exhibiting diverse pharmacological actions.

Variation in chemical composition and fruit morphometric traits of almond-leaved pear (Pyrus spinosa Forssk.) natural populations

Variation in chemical composition and fruit morphometric traits of almond-leaved pear (Pyrus spinosa Forssk.) natural populations

Co-modification of chrysocolla with ammonia and 1,2-diaminopropane and its response to flotation

Chrysocolla is a typical copper oxide with unique structural characteristics and a variable chemical composition, which make its recovery by flotation considerably challenging. A novel ammonia-1,2-diaminopropane-xantahte (NH3·H2O-1,2-DAP-xanthate) flotation method was proposed in this study for its effective recovery. Compared with the 1,2-DAP-xanthate system, the recovery of chrysocolla was substantially increased from 73.43 % to 95.26 % using the NH3·H2O-1,2-DAP-xanthate system. X-ray photoelectron spectroscopy, zeta potential, Fourier transform infrared spectroscopy, xanthate adsorption capacity, and time-of-flight secondary ion mass spectrometry analyses showed that the increase in the chrysocolla flotation recovery was attributed to an increased in the effective xanthate adsorption on the chrysocolla surface. The additional adsorption of xanthate could be attributed to the alteration of the surface properties of the chrysocolla by NH3·H2O, which exposed more copper sites and reduced the hydrophilic component of the surface. This promoted the effective adsorption of more 1,2-DAP on the mineral surface. Thus, more chelated copper formed, which improved the mineral surface activity and increased the number of active sites interacting with the xanthate.

Essential oils used against zucchini powdery mildew: evaluation of variability in chemical composition and bioactivity

Essential oils used against zucchini powdery mildew: evaluation of variability in chemical composition and bioactivity

Detection Strategies for Volatile Fragrance Released from Agricultural Products: Progress and Prospects

AbstractThe volatile aroma released from agricultural products is closely related to the health status and quality of their growth, thus endowing the related detection with great significance. For example, the dynamic variation of the volatile chemical composition of a banana during the growth process can reflect its ripeness. Also important for quality monitoring and storage is to precisely and swiftly identify volatile compounds produced by mildew in rice and wheat. In this endeavor, the current detection technologies such as gas chromatography‐mass spectrometry method (GC‐MS) cannot meet the pressing needs of smart agriculture in terms of real‐time monitoring, cost‐effectiveness, sensitivity, and detection speed, thereby necessitating alternative strategies to simultaneously satisfy these requirements. Aiming to provide an overall development trend in this field, this paper summarizes the existing detection technologies including GC‐MS, E‐nose, and sensory analysis with their respective shortcomings and challenges, and then proposes the application prospects. This work can effectively enrich the reliable monitoring methods for volatile agricultural fragrance while promoting the long‐run development of smart agriculture.

Laser-assisted electrohydrodynamic jet printing of hierarchical nanostructure

The hierarchical nanostructures had the advantages of large available space, specific surface area, low density, variable chemical composition, and controllable porosity, and have been widely used in energy, sensor, and catalysis. Traditional methods for preparing hierarchical nanostructures had limitations of a long process, few available materials, and un-customizable size. Electrohydrodynamic jet (E-Jet) printing is a competitive strategy for high-resolution printing. In this paper, a novel laser-assisted E-Jet printing employed a transient high-energy laser effect instead of a traditional continuously thermal effect for printing hierarchical nanostructure. The colorless ZnO ink was prepared with zinc acetate, diethanolamine, PVP, and ethanol. The transient thermal effect of laser irradiation focused a fine jet and induced Taylor cone expansion. The heat accelerated the solvent evaporation and increased the viscous force of the jet. The effects of laser on jet velocity, electric field, and jet behavior were analyzed theoretically. Characterization and 3D morphology of printed nanostructures with and without laser were investigated. The hierarchical nanostructures with size down to 180 nm could be laser-assisted E-Jet printed and its surface area increased multiply. The laser-assisted E-Jet printing method provides a simple, efficient, and low-cost strategy for preparing hierarchical nanostructure, having potential applications in high-performance devices.

Annual variation in yield, chemical composition, antioxidant and antibacterial activity of rockrose (Cistus ladanifer L.) essential oils

The fluctuation in yield, composition, antibacterial and antioxidant activity of the essential oil (EO) of rockrose (Cistus ladanifer L.) obtained from two locations in central Spain was analysed and compared over the course of one year. Fifteen kilograms of C. ladanifer, collected monthly or fortnightly from two sites with different plant age (7 and 12 years), underwent steam-distillation. GC (FID)-MS analyses were done to determine the volatile profile of EOs. Obtained EO yields varied significantly (P < 0.001) throughout the year, ranging between 0.03 and 0.19% w/d.w. (±0.05) with the highest yields (>0.1%) observed from September to February. The younger population exhibited higher EO yields that the older one. Both rockrose populations displayed a high content of α-pinene (40.4–62.0%); the other predominant constituents included allo-aromadendrene + trans-pinocarveol, limonene, bornyl acetate and viridiflorol. The higher EO yields coincided with a higher content of α-pinene and a lower content of the other components. Furthermore, EOs’ antibacterial potential was tested against Bacillus cereus. Only a weak antibacterial potency (512–1024 μg/mL) was revealed, with stronger potency in case of older rockrose population. In vitro antioxidant capacity, evaluated by ORAC method, showed similar results for both populations, with its stronger potential between February and May.

A versatile, rapid Agrobacterium-mediated transient expression system for functional genomics studies in cannabis seedling.

We have developed and optimized a rapid, versatile Agrobacterium-mediated transient expression system for cannabis seedlings that can be used in functional genomics studies of both hemp-type and drug-type cannabis. Cannabis (Cannabis sativa L.) holds great promise in the medical and food industries due to its diverse chemical composition, including specialized cannabinoids. However, the study of key genes involved in various biological processes, including secondary metabolite biosynthesis, has been hampered by the lack of efficient in vivo functional analysis methods. Here, we present a novel, short-cycle, high-efficiency transformation method for cannabis seedlings using Agrobacterium tumefaciens. We used the RUBY reporter system to monitor transformation results without the need for chemical treatments or specialized equipment. Four strains of A. tumefaciens (GV3101, EHA105, LBA4404, and AGL1) were evaluated for transformation efficiency, with LBA4404 and AGL1 showing superior performance. The versatility of the system was further demonstrated by successful transformation with GFP and GUS reporter genes. In addition, syringe infiltration was explored as an alternative to vacuum infiltration, offering simplicity and efficiency for high-throughput applications. Our method allows rapid and efficient in vivo transformation of cannabis seedlings, facilitating large-scale protein expression and high-throughput characterization studies.

Sound velocities in lunar mantle aggregates at simultaneous high pressures and temperatures: Implications for the presence of garnet in the deep lunar interior

Recent experimental and theoretical studies on lunar magma ocean crystallisation have suggested the presence of significant proportions of garnet in the deep lunar interior. While phase relation studies indicate a deep lunar mantle consisting of olivine, pyroxene, and garnet, the compatibility of such an assemblage with seismic models of the lunar interior is yet untested. In this study we report compressional and shear wave velocities in an iron-rich assemblage consisting of olivine, orthopyroxene, clinopyroxene, and garnet up to ∼8 GPa and 1300 K, by means of ultrasonic interferometry measurements combined with synchrotron techniques using the multi-anvil press apparatus. Sound velocity and density models of lunar mantle rocks along a selenotherm based on our experimental results find good agreement with the seismic and density profiles at lunar interior depths of 740–1260 km. Further models are constructed, allowing for the variation of chemical composition, phase proportion, and temperature; these suggest that a garnet-rich deep lunar mantle is compatible with present-day lower lunar mantle temperatures of between 1400–1800 K. Our results show that lunar mantle rocks with up to 33 wt.% garnet may provide an explanation for the observed high velocities of the lower lunar mantle. The presence of garnet in the lowermost part of the Moon's mantle has significant implications for the depth and temperature of the Moon's magma ocean as well as the composition, structure and internal dynamics of the solid Moon.

Annual Variation in Proximate Chemical Composition of Fish Sold in Ludhiana Market: Punjab, India

A study was carried out to investigate the nutritional composition of four different fish species (Wallago attu, Labeo rohita, Pangasianodon hypophthalmus, and Rastrelliger kanagurta) sourced from the inland and marine sector comprising both culture and capture fisheries marketed in Ludhiana fish market from September 2021 to August 2022, encompassing four distinct seasons: post-monsoon, winter, pre-monsoon, and monsoon. The proximate parameters including protein, lipid, carbohydrate, ash and moisture content were analysed following the standard methods. The moisture content across the four species ranged from 72.48% to 81.08% in selected fish. Lowest moisture content was recorded during the pre-monsoon season, contrasting with their highest levels during the monsoon season. Protein levels ranged from 9.72% to 18.36% across different seasons. Specifically, P. hypophthalmus displayed the lowest protein content (9.72±0.18%), while R. kanagurta exhibited the highest (18.36±0.18). W. attu, L. rohita, P. hypophthalmus, and R. kanagurta exhibited their lowest lipid content in flesh during the monsoon season, measuring at 0.69%, 1.59%, 9.33%, and 2.47%, respectively, contrasting with their highest levels during the winter season at 1.07%, 2.05%, 11.04%, and 4.05%, respectively. Across different seasons, carbohydrate content varied from 0.23% to 2.04%. R. kanagurta exhibited the lowest carbohydrate values; while L. rohita displayed the highest. Across different species, ash content varied from 1.62% to 4.34%, with the lowest observed in P. hypophthalmus and the highest in W. attu. Overall in fish muscle, water content reached its peak levels while muscle protein content decreased during the monsoon. The decline in protein and the rise in water content of the muscle were attributed to gonadal development and maturation, which depleted muscle protein reserves during the monsoon season. Inverse relationship between moisture and fat content in fish were observed, suggesting that fatty fish typically exhibit relatively lower moisture content. Lower levels of carbohydrate content are found in the total proximate composition of fish muscle, indicating that most of the glycogen in freshwater fish does not significantly contribute to body reserves.

Chemical compositions and nutritional profiles of two edible tunicate species (Halocynthia roretzi and Halocynthia aurantium)

As an abundant marine bioresource, tunicates could be exploited in the food industry. However, limited knowledge of their chemical composition and nutritional profiles prohibited further application. In this study, two common edible tunicate species, Halocynthia roretzi (HR) and Halocynthia aurantium (HA), were subjected to comprehensive composition analysis in terms of moisture, protein, lipids, cellulose, ash, amino acids, fatty acids, non-cellulose carbohydrates and minerals. Reddish HR was much bigger than purple HA with respect to body length and weight, and their moisture fell within 82.98 %–90.92 %. The non-edible outer shell part (OS) and edible internal organs part (IO) had a dry weight ratio of around 3:2 for both two species. Generally, for both HR and HA, IO was more abundant in protein and lipids. In contrast, OS had much higher cellulose contents, confirming the better suitability of IO as a nutritional seafood. IO was richer in essential amino acids and unsaturated fatty acids, while OS had more abundant saturated fatty acids. The detected non-cellulose monosugars ranged from 0.47 % to 1.18 % and indicated the presence of some sulfated glycans. IO of HR had higher contents of essential minerals, such as Cu, Zn, and Fe, while IO of HA showed a higher K content. To sum up, this study identified the chemical composition and nutritional profile variations among different tunicate species and various dissected parts, guiding the development of specific strategies to exploit tunicates for proper food applications.