Garlic (Allium sativum L.) is an herbaceous plant and is recognised for its numerous medicinal and culinary properties, and it is used in diverse food preparations for its characteristic flavour and aroma. High alliin content increases the formation of allicin, a bioactive compound of garlic. Therefore, this research aimed to compare different extraction methods for garlic (Allium sativum L.) between subcritical water extraction (SWE) and Soxhlet extraction to obtain a high extraction yield and alliin content. The SWE conditions were 120 °C and 180 °C temperatures and 2 mL/min and 6 mL/min flow rates at a constant pressure of 15 MPa for a 10 min extraction time, respectively. In the meanwhile, the extraction time for Soxhlet extraction with various solvents, namely, distilled water, ethanol–water (1:1), and 100% ethanol, was two hours. High-performance liquid chromatography (HPLC) was used to analyse alliin. Soxhlet extraction had the best yield (1.96 g) using ethanol–water (1:1) as the solvent in comparison to SWE extraction (1.28 g) at 180 °C and 6 mL/min. In contrast, SWE yielded a greater concentration of alliin (136.82 mg/g) at 120 °C and 2 mL/min than the Soxhlet method when using distilled water as the solvent (65.18 mg/g). Therefore, SWE may replace Soxhlet extraction as the conventional method for extracting alliin from garlic at a high concentration, and SWE has advantages that favour garlic extracts.

This study investigates dynamic subcritical water extraction (SWE) as a novel, single-step, and environmentally sustainable method for the recovery of allicin from Allium sativum L. Unlike conventional extraction techniques, SWE extracts allicin and hydrolyse alliin simultaneously within a closed system, eliminating the need for organic solvents. Response Surface Methodology (RSM) was employed to optimize temperature (120–180 °C), flow rate (2–6 mL/min), and extraction time (10–30 min). The optimal conditions of 150 °C, 4 mL/min, and 30 min produced the highest allicin concentration (2.548 mg/g_sample) and extract yield (1.695 g). Solubility analysis revealed maximum values for extract yield (0.045 g/mL), alliin (6.841 mg·mL/g_sample), and allicin (0.082 mg·mL/g_sample), highlighting the influence of solvent polarity and mass transfer efficiency under subcritical conditions. Kinetic modelling using the Esquivel and Brunner models, selected as empirical and diffusion-based approaches commonly applied to solid–liquid extraction systems, showed excellent correlation (R² = 0.984–0.999), confirming diffusion-controlled extraction behaviour, with the Brunner model demonstrating superior predictive accuracy. SWE efficiently unifies hydrolysis and extraction within a single, eco-friendly, and scalable system, enabling effective recovery of allicin and other bioactive compounds.

The dumping of waste banana peels from local chip manufacturing has encouraged sustainable food trends to valorize these peels as pectin sources. In this study, soluble pectin from banana peels was extracted using a continuous subcritical water extraction system (SWE). This method was a promising fast extraction process with a water solvent that was environmentally friendly. Temperature (100 to 160 °C) and extraction time (5 to 50 minutes) were manipulated, with a fixed pressure of 15 MPa, a flow rate of 15 mL/min, and a particle size of 0.6 mm. The response surface methodology (RSM) was used to generate approximately 13 experimental trials from the central composite design. Based on linear and square models, the results revealed that the interaction of temperature and time to pectin yield had a significant effect. At 100°C for 5 minutes, an optimal condition for producing pectin yield was achieved, which risen the highest pectin yield by 26%. As a result, the SWE continuous system promoted increased pectin production in the shortest extraction time. In short, banana peel pectin is a powder that serves a primary function in numerous food, pharmaceutical, and cosmeceutical applications.

The rising complexity of wastewater due to industrial and municipal activities poses significant environmental challenges, particularly in Malaysia. This mini review explores the potential of horseshoe crab shell waste as an effective and sustainable adsorbent for wastewater treatment. Horseshoe crab shells, which contain high levels of chitin, can be processed into chitosan, a biopolymer with strong adsorption properties for various pollutants, including heavy metals, organic compounds, and dyes. Using horseshoe crab, shell-derived materials offer a green alternative to synthetic adsorbents, promoting circular economy principles by valorizing waste. This review examines different preparation techniques, including silver nanoparticle functionalization, deacetylation, and pyrolysis, each of which optimizes the material’s adsorption capacity for specific pollutants. Key benefits of these bio-based adsorbents include their biodegradability, cost-effectiveness, and the potential to reduce reliance on synthetic materials. The review also addresses challenges such as production scalability, resource sustainability, and material consistency, highlighting future directions for enhancing the applicability of horseshoe crab shell-based adsorbents in diverse wastewater treatment scenarios.

This study explores the green valorization of palm oil solid condensate (POSC) using supercritical CO₂–ethanol extraction. Temperature (40–80 °C) and pressure (10–30 MPa) were optimized to recover β-carotene, α-tocopherol, and phenolic-rich fractions. The optimum (80 °C, 13.6 MPa) produced 2.53 g extract with 9.34 mg/kg β-carotene and 15.44 mg/kg α-tocopherol. LC–MS/MS profiling revealed compositional evolution such as phenolic and lactone dominance at low severity; glycosides, flavonols, and alkaloids at intermediate; and triterpenoids and lignans at high severity. These compounds modulate NF-κB, MAPK, and Nrf2 pathways, supporting antioxidant and anti-inflammatory activities. The study confirms that controlled supercritical extraction can selectively tailor bioactive profiles from POSC, converting a palm oil by product into functional nutraceutical and pharmaceutical ingredients.