Exploring Bioactive Compounds in Brown Seaweeds Using Subcritical Water: A Comprehensive Analysis.

In this study, we characterized the bioactive properties of three important brown seaweed species, Sargassum thunbergii, Undaria pinnatifida, and Saccharina japonica, by subcritical water extraction (SWE), as these species are well known for their beneficial health effects. Their physiochemical properties, including potential antioxidant, antihypertensive, and α-glucosidase inhibitory activity, and the antibacterial activity of the hydroysates were also analyzed. The highest total phlorotannin, total sugar content, and reducing sugar content in the S. thunbergii hydrolysates were 38.82 ± 0.17 mg PGE/g, 116.66 ± 0.19 mg glucose/g dry sample, and 53.27 ± 1.57 mg glucose/g dry sample, respectively. The highest ABTS+ and DPPH antioxidant activities were obtained in the S. japonica hydrolysates (124.77 ± 2.47 and 46.35 ± 0.01 mg Trolox equivalent/g, respectively) and the highest FRAP activity was obtained in the S. thunbergii hydrolysates (34.47 ± 0.49 mg Trolox equivalent/g seaweed). In addition, the seaweed extracts showed antihypertensive (≤59.77 ± 0.14%) and α-glucosidase inhibitory activity (≤68.05 ± 1.15%), as well as activity against foodborne pathogens. The present findings provide evidence of the biological activity of brown seaweed extracts for potential application in the food, pharmaceutical, and cosmetic sectors.

Extraction of edible oils and amino acids from eel by-products using clean compressed solvents: An approach of complete valorization.

Green extraction methodologies using supercritical carbon dioxide (SC-CO2) and subcritical water were used to valorize Conger myriaster skin (CMS). The omega-3 fatty acid content in CMS oil extracted using SC-CO2 was 18.62 ± 0.08%, and vitamin A, D, E, and K2 contents were 467.38 ± 0.46 µg/100 g, 8.31 ± 0.02 mg/100 g, 143.42 ± 4.61 mg/100 g, and 1.27 ± 0.05 mg/100 g, respectively. De-oiled CMS was hydrolyzed using subcritical water at temperatures ranging from 160 to 280 °C. Total protein, total sugar, and Maillard reaction product contents reached maximum values of 409.31 ± 2.86 mg bovine serum albumin (BSA)/g at 190 °C, 8.31 ± 0.31 mg glucose/g at 280 °C, and 0.240 ± 0.003 (Abs420nm) at 220 °C, respectively. The highest antioxidant activity was observed at 280 °C. Free amino acids were abundant in the hydrolysates. Oil extraction from CMS using supercritical and subcritical fluids represents an effective and economical source of functional materials.

In vitro characterization of bioactive compounds extracted from sea urchin (Stomopneustes variolaris) using green and conventional techniques.

This study investigated the in vitro bioactivities of extracts obtained from viscera, spines, shells, and gonads of Stomopneustes variolaris using subcritical water extraction (SWE) at 110 °C, 150 °C, 190 °C, and 230 °C and Soxhlet extraction. The highest amounts of phenolics (22.68 ± 0.05 mg GAE/g), flavonoids (27.11 ± 0.10 mg RE/g), and proteins (40.25 ± 0.84 mg BSA/g) were recorded from gonads at 230 °C, whereas maximum sugar content (23.38 ± 1.30 mg glucose/g) was in viscera at 150 °C. Gonads at 230 °C exhibited the highest DPPH activity (78.68 ± 0.18%), whereas viscera at 150 °C exhibited the highest ABTS+ (98.92 ± 1.27%) and protein denaturation inhibition activity (37.13 ± 9.94%). Viscera at 110 °C claimed the highest amylase inhibition (42.46 ± 0.83%), and spines at 150 °C had the highest anticancer activity (IC50 = 767.47 µg/mL). SWE achieved superior results in bioactive compound recovery and detected higher levels of bioactivities (p < 0.05). Results suggest processing sea urchin extracts via SWE has potential application to the food and pharmaceutical industries.