The southern coast of Peru presents a wide diversity of seaweed, which could be used as a new sustainable source of nutritional and bioactive compounds. For the first time, we chemically characterized two species of brown (Macrocystis pyrifera) and red (Chondracanthus chamissoi) Peruvian seaweed. Both species contained significant amounts of proteins (5–12%), lipids (0.16–0.74%), carbohydrates (43.29–62.65%) and minerals (1300–1800 mg kg⁻¹ dw: dry weight). However, the profiles of amino acids, fatty acids and minerals were highly dependent on species type. C. chamissoi had a higher content of essential amino acids and minerals than M. pyrifera (170% and 45%, respectively), while the presence of polyunsaturated fatty acids (ω 6) as well as the content of tocopherols was higher in M. pyrifera (15.77 g 100 g⁻¹ and 2.37 μg 100 g⁻¹, respectively). Additionally, both species presented significant concentrations of total polyphenols (39–59 mg GAE g⁻¹) and a high antioxidant capacity (67–98 µM TE g⁻¹). Although M. pyrifera and C. chamissoi seem to be excellent raw materials for the food and nutraceutical industry, both species contained toxic heavy metals (cadmium: Cd and nickel: Ni) which could affect the safety of their direct use. Therefore, new separation strategies that allow the selective recovery of nutrients and bioactive compounds from Peruvian seaweed are required.

The use of water–ethanol mixtures in hot pressurized liquid extraction (HPLE) to recover phenolic compounds from agro-industrial waste has been successfully investigated. However, the unresolved challenge of reducing solvent costs associated with the process hinders the scaling of this eco-friendly technology. This study evaluated the use of isopropanol as an alternative, lower-cost solvent for recovering polyphenols from discarded blueberries through the HPLE process. HPLE was carried out using water–isopropanol mixtures (0, 15 and 30%) at 70, 100, and 130 °C. The total polyphenol content (TPC), antioxidant capacity (DPPH and ORAC), glucose and fructose contents, and polyphenol profile of the extracts were determined. HPLE extracts obtained using high isopropanol concentrations (30%) and high temperatures (130 °C) presented the highest TPC (13.57 mg GAE/gdw) and antioxidant capacity (IC50: 9.97 mg/mL, ORAC: 246.47 µmol ET/gdw). Moreover, the use of 30% water–isopropanol resulted in higher yields of polyphenols and removal of reducing sugars compared to atmospheric extraction with water–acetone (60%). The polyphenolic profiles of the extracts showed that flavanols and phenolic acids were more soluble at high concentrations of isopropanol (30%). Contrarily, flavonols and stilbenes were better recovered with 15% isopropanol and pure water. Therefore, isopropanol could be a promising solvent for the selective recovery of different bioactive compounds from discarded blueberries and other agro-industrial residues.

Olive leaves are agro-industrial waste that pose an environmental management problem. However, they contain polyphenolic compounds with important bioactive properties beneficial to human. This study aimed to evaluate the effectiveness of two extraction technologies (pressurized liquid extraction and ultrasound-assisted extraction) combined with green solvents (pure water, 15% ethanol, and 15% glycerol) at 50 °C and 70 °C. The goal was to obtain extracts with both antioxidant capacity and antihyperglycemic properties from olive leaves. Pressurized liquid extraction with 15% glycerol at 70 °C was the most effective method for obtaining extracts rich in total polyphenols (19.46 mg GAE/g dw), with an antioxidant capacity of 4.11 mg/mL (inhibition capacity: IC50) and 500.26 µmol TE/g dw. For both extraction methods at 70 °C, glycerol was more effective at recovering phenolic acids, stilbenes and secoiridoid; while ethanol was more effective for recovering flavonols and phenylethanoids. Oleuropein was the most important polyphenol extracted from both pressurized liquid and ultrasound-assisted extractions, with concentrations of 171.48 µg/g dw and 246.70 µg/g dw, respectively. The extract obtained from pressurized liquid extraction with 15% ethanol at 70 °C exhibited significant inhibition (70%) of α-glucosidase enzymes, similar to the reference drug acarbose. In contrast, these extracts showed low inhibitory activity against the α-amylase enzyme. These findings can be applied to the development of functional foods and nutraceutical supplements aimed at managing postprandial glycemic response, offering a natural alternative for supporting type 2 diabetes management.