Asian Journal of Physical and Chemical Sciences

Proximate, Mineral, and Vitamin Composition of Psidium guajava (Guava) Roots: Nutritional Profiling and Potential Applications as a Functional Food Ingredient

Goodness Oluwadamilola Kolawole — 2026-06-03

Medicinal plants are valuable sources of bioactive compounds with significant therapeutic potential. Psidium guajava (guava), a widely used tropical medicinal plant, is well-known for its phytochemical richness. However, while the leaves and fruits have been extensively studied, the roots remain underexplored. This study aimed to determine the proximate composition, mineral content, and vitamin profile of Psidium guajava root extract to evaluate its nutritional potential and applications as a functional food ingredient. Fresh guava roots were collected, air-dried, powdered, and extracted using methanol by maceration. Proximate analysis was carried out according to AOAC (2005) methods. Mineral contents (Ca, Mg, K, P, Fe, Zn, Cu, Mn) were determined using atomic absorption spectroscopy, while vitamin levels were analyzed using standard spectrophotometric and titration methods. Results showed exceptionally high crude fiber content (52.83 ± 0.21%), moderate carbohydrate (18.60 ± 0.14%) and protein (11.58 ± 0.44%), low fat (0.20 ± 0.01%), and ash (4.48 ± 0.14%). Mineral analysis revealed an extraordinarily high calcium level (11.148 ± 40.647 mg/100g), along with potassium (4.168 ± 0.083 mg/100g), phosphorus (2.162 ± 0.012 mg/100g), magnesium (0.792 ± 0.011 mg/100g), and trace amounts of iron, zinc, manganese, and copper. Vitamins detected include vitamin E (11.58 ± 0.44 µg/100g), vitamin C (0.454 ± 0.024 mg/100g), and vitamin A (1.036 ± 0.078 µg/100g). The findings demonstrate that Psidium guajava roots possess a unique nutritional profile rich in dietary fiber and calcium. This supports its potential use as a natural dietary supplement and functional food ingredient for promoting digestive and bone health, while providing baseline data for further nutraceutical development.

Space Weather Conditions Associated with Highly Perturbed Interplanetary Conditions and the Heliospheric Relaxation Phase During Solar Cycle 24

C.M. Tiwari — 2026-06-10

Space weather conditions are strongly influenced by variations in interplanetary parameters and Solar Cycle (SC) dynamics. SC 24 exhibited distinct phases of heliospheric relaxation and highly perturbed interplanetary conditions, providing a unique framework for analysis. Understanding these contrasting phases is essential for evaluating factors associated with geomagnetic activity and their impact on the near-Earth environment. This study aims to examine the relationship between solar activity, interplanetary parameters, and geomagnetic responses, and to identify the primary physical mechanisms governing space weather during this cycle.

A dataset (Annual average) covering SC 24 was analysed using solar activity indices (sunspot number and F10.7 flux), interplanetary parameters (IMF magnitude (Scalar B), solar wind speed, plasma temperature, and proton density), and geomagnetic indices (Dst, Kp, Ap, AE, AL, AU). The data were obtained from NGDC/NOAA, and WDC Kyoto. Statistical methods (correlation coefficient, regression analysis) were applied to evaluate parameter relationships

Solar activity proxies are strongly correlated with each other (r = 0.67) but exhibit weak correlations with geomagnetic indices. In contrast, interplanetary parameters, particularly IMF strength and solar wind speed, show stronger control over geomagnetic activity. During the deep minimum (2008-2009), IMF (Scalar B) decreased to 3.89 nT and solar wind speed to 360 km s^-1, while during the maximum phase, values increased only modestly (Scalar B = 5.71 nT, V = 420 km s^-1). The AE index increased significantly from 68 nT to 177 nT, whereas Dst remained relatively weak (-10 to -12 nT), indicating suppressed ring current activity. Additionally, proton density showed negligible correlation with geomagnetic indices despite a strong correlation with the Alfvén Mach number (r = 0.99).

The results suggest that coronal mass ejections during SC 24 were associated with propagation through a comparatively low-pressure heliospheric environment, a condition that may have contributed to enhanced expansion and reduced magnetic field strength at 1 AU. This interpretation is consistent with the observed reduction in CME geo-effectiveness during the cycle. Consequently, the relatively low occurrence of intense geomagnetic storms appears to be linked to weakened interplanetary magnetic conditions, while moderate and persistent geomagnetic disturbances were more strongly associated with recurrent corotating interaction regions and high-speed solar wind streams.

SC 24 demonstrates a shift in space weather dynamics, where interplanetary conditions dominate over solar activity proxies in controlling geomagnetic responses. These findings highlight the need to incorporate heliospheric background conditions into forecasting models. Future studies should focus on multi-point observations and advanced modelling approaches to improve space weather prediction under low solar activity conditions.

Electrochemical Characterization of a Composite Material Based on Activated Carbon from Palm Shells and Graphene Oxide for Applications in Supercapacitors

Djako Oscar Eric Koutouan — 2026-06-13

Agriculture is an important pillar of economic development in Côte d'Ivoire. However, it generates significant amounts of waste, the recovery of which will help combat pollution. Palm nut shells in particular represent an abundant, low-cost resource and excellent precursors for activated carbon that can be used as electrode material in supercapacitors. The objective of this study is to convert palm shell waste into activated charcoal for the fabrication of electrodes that can be used as supercapacitor materials with energy storage capability. In this work, a composite material made from palm nut shell activated carbon and graphene oxide was prepared for use as electrode material. The study of electrochemical properties by cyclic voltammetry, galvanostatic charge/discharge and electrochemical impedance spectroscopy gives promising results for the PALM 75 composite (mass ratio of palm kernel shells/graphene oxide 75/25). Quasi-rectangular voltammograms were obtained, synonymous with electrochemical double-layer behaviour, a maximum specific capacity of 143 F g⁻¹ at a current density of 0.25 A g⁻¹, a maximum energy density of 19.8 Wh kg⁻¹, a maximum power density of 2500 W kg⁻¹, an equivalent series resistance of 0.539 Ω with 100% cyclic stability after 10,000 cycles. This work shows a new way of converting agricultural waste in Côte d'Ivoire.

Health Risk Assessment Associated with the Presence of Heavy Metals in Soils Around the Kalsaka Gold Mine, Burkina Faso

NIKIEMA Aloys — 2026-07-04

This study assessed heavy metal concentrations in soils around the Kalsaka gold mine in Burkina Faso and evaluated the associated human health risks for adults and children. Sixteen soil samples were collected from locations surrounding the mine and analysed for chromium, nickel, copper, zinc, arsenic, mercury, and lead using atomic absorption spectrophotometry. Human exposure was estimated through ingestion, inhalation, and dermal contact pathways using standard exposure parameters. The results showed that the mean concentrations of chromium, nickel, copper, arsenic, and mercury indicated contamination in the sampled soils, while zinc remained below the reference limit used in the study. Lead showed localised contamination, with the maximum concentration exceeding the reference value although the mean concentration remained below it. Arsenic showed the highest mean concentration among the measured elements, followed by chromium, copper, zinc, nickel, lead, and mercury. Estimated daily intake values indicated that ingestion was the major exposure pathway, particularly for children. Non-carcinogenic risk assessment showed that the combined risk index exceeded unity for both adults and children, suggesting potential non-carcinogenic health risks associated with exposure to contaminated soils. Children showed higher risk values than adults, indicating greater vulnerability. Chromium and arsenic were the main contributors to non-carcinogenic risk. The estimated carcinogenic risk values were low under the exposure assumptions used in this study. Overall, the findings indicate that soils around the Kalsaka gold mine contain elevated levels of selected heavy metals and that continued monitoring, exposure reduction, and environmental management measures are needed.

Comparative Analysis of Statistical and Machine Learning Models for Carbon Dioxide Fugacity in Vridi Canal

Yao Marcel Konan — 2026-07-06

This study compared the performance of Multiple Linear Regression (MLR), Multilayer Perceptron (MLP), and a hybrid MLR/MLP model for estimating carbon dioxide fugacity (fCO₂) in the surface waters of Vridi Canal. Measurements and supporting hydroclimatic data collected between May and September 2023 included redox potential, conductivity, dissolved oxygen content, cumulative rainfall, ambient temperature, and tidal coefficient. In the MLR framework, fCO₂ was treated as the dependent variable, while in the MLP model it was treated as the output parameter. For the hybrid model, the MLP was applied to the residuals obtained from the MLR predictions, using the relevant variable selected from the regression analysis. The MLR results showed weak linear association between fCO₂ and the selected variables, with redox potential being the only variable showing pseudo-linearity during the study period. The standalone MLP model also showed limited ability to reproduce the experimental fCO₂ values, with the best-performing 1-1-1 configuration remaining below the required validation threshold. By contrast, the hybrid MLR/MLP approach, particularly the MLR/1-7-1 configuration, produced substantially stronger predictive performance and accounted for 99.84% of the variance in the testing phase. These findings indicate that the hybrid framework can represent complex, partly nonlinear ecological behaviour in Vridi Canal more effectively than the individual statistical or neural-network models.

Phytochemical, Proximate and Mineral Analysis of Aqueous Leaf Extract of Irvingia gabonensis

Oyinbrakemi Collins Ogu — 2026-07-07

This study evaluated the phytochemical, proximate and mineral composition of the aqueous leaf extract of Irvingia gabonensis. The extract was prepared from authenticated leaves and analysed using standard qualitative and quantitative phytochemical procedures, proximate methods and mineral analysis. Proximate analysis showed that carbohydrate was the major component (42.87 ± 6.28%), followed by moisture (28.42 ± 2.87%) and crude fibre (14.74 ± 1.22%). Crude protein was present at 8.52 ± 0.68%, while ash and crude lipid were recorded at 2.98 ± 0.05% and 2.47 ± 0.02%, respectively. Mineral analysis showed that magnesium had the highest concentration (46.42 ± 2.86 mg/kg), followed by sodium, calcium, potassium, zinc and iron. Qualitative phytochemical screening indicated the presence of tannins, flavonoids, alkaloids, saponins, terpenoids, steroids, glycosides, proteins, reducing sugars and carbohydrates. Quantitative analysis showed measurable levels of saponins (296.34 ± 5.56 mg/g extract), tannins (248.66 ± 6.98 mg/g extract), flavonoids (245.83 ± 8.72 mg QE/g extract), total phenolics (137.75 ± 5.89 mg GAE/g extract) and alkaloids (128.46 ± 7.16 mg/g extract). These findings indicate that I. gabonensis leaves contain nutritional constituents and secondary metabolites of biochemical interest. However, biological activities were not assessed in this investigation; therefore, further antioxidant, toxicity and activity-based studies are required before medicinal relevance can be confirmed.