Lutein has several benefits for human health, playing an important role in the prevention of age-related macular degeneration (AMD), cataracts, amelioration of the first stages of atherosclerosis, and some types of cancer. In this work, the Scenedesmus almeriensis microalga was used as a natural source for the supercritical fluid (SF) extraction of lutein. For this purpose, the optimization of the main parameters affecting the extraction, such as biomass pre-treatment, temperature, pressure, and carbon dioxide (CO₂) flow rate, was performed. In the first stage, the effect of mechanical pre-treatment (diatomaceous earth (DE) and biomass mixing in the range 0.25–1 DE/biomass; grinding speed varying between 0 and 600 rpm, and pre-treatment time changing from 2.5 to 10 min), was evaluated on lutein extraction efficiency. In the second stage, the influence of SF-CO₂ extraction parameters such as pressure (25–55 MPa), temperature (50 and 65 °C), and CO₂ flow rate (7.24 and 14.48 g/min) on lutein recovery and purity was investigated. The results demonstrated that by increasing temperature, pressure, and CO₂ flow rate lutein recovery and purity were improved. The maximum lutein recovery (~98%) with purity of ~34% was achieved operating at 65 °C and 55 MPa with a CO₂ flow rate of 14.48 g/min. Therefore, optimum conditions could be useful in food industries for lutein supplementation in food products.

Olive oil is a core component of the Mediterranean diet known for its nutritional properties and health benefits. Olive industry is moving to novel extraction systems for higher oil yield and quality and for waste reduction, which is a relevant problem in the process due to its toxicity and high disposal costs. Multi-Phase Decanter (DMF) is a modern two-phase system performed without adding water during the process. Using DMF, a wet by-product indicated as pâté and consisting of the fruit pulp and vegetation water (VW) is recovered. The pâté has a high content of potentially bioactive molecules that may be exploited to promote plant resistance against microbial pathogens. In this work, to identify by/products of biological interest, the VW recovered from the pâté by centrifugation was subjected to fractionation by tangential-flow membrane filtration (TFMF), combining microfiltration (MF) and ultrafiltration (UF). High-resolution NMR spectroscopy indicated the presence of bioactive molecules such as flavonoids, hydroxytyrosol and oleuropein with known antimicrobial activity. High-Performance Anion Exchange Chromatography with Pulsed Amperometric Detection (HPAEC-PAD) was performed to detect the presence of pectic oligosaccharides in the fractions, showing the enrichment, in the UF-concentrate fraction, of oligogalacturonides (OGs), well known for the ability to elicit defense responses and protect plants against pathogen infections. Arabidopsis thaliana plants treated with TFMF fractions displayed induction of defense responses and exhibited resistance against microbial pathogens without adverse effects on growth and fitness. This study shows that pâté by-products can potentially be exploited in agriculture as sustainable plant phyto-protectant. Graphical (image created with BioRender)

The growing demand for sustainable protein sources has increased interest in edible insects and their potential role within circular bioeconomy strategies. This study evaluated the suitability of brewer’s spent grain (BSG), cocoa bean shell (CBS), and banana peel (BP) as alternative substrates for Tenebrio molitor rearing and assessed the valorization of the resulting biomass through pilot-scale supercritical CO₂ extraction (CO₂-SFE). Larvae reared on BSG-based and BP-based diets achieved growth performances comparable to those obtained with a conventional wheat bran diet, whereas CBS-based diet resulted in lower weight gain and feed intake. No significant differences in feed conversion ratio were observed among diets. Substrate composition also affected biomass nutritional quality, with larvae reared on the BSG-based diet exhibiting the highest protein content (60.4%), whereas larvae reared on CBS-based diet exhibited the highest lipid content (29.3%). CO₂-SFE generated protein-enriched meals and lipid-rich extracts, yielding 12.9–15.4% oil depending on the substrate. Following extraction, protein content increased to 68.5%, 50.3%, and 60.2% in BSG-, CBS-, and BP-derived meals, respectively. The extracted oils were characterized by high levels of unsaturated fatty acids, with oleic acid (42.4–47.6%) as the predominant component. Overall, the results demonstrate that agro-industrial by-products can be effectively converted into valuable insect-derived ingredients and highlight the potential of integrating substrate selection with green extraction technologies within insect biorefinery systems.

Almond blanched skins (BS) and blanch water (BW) are underutilized agro-industrial by-products, despite their richness in polyphenols and other bioactive compounds. This study investigates the reuse of BW as an extraction solvent to recover polyphenols from BS, avoiding the need for additional water or organic solvents. BW showed a total polyphenol content (TPC) of 475.2 ± 10.7 µg GAE/mL and a Total Antioxidant Capacity (TAC) of 840.4 ± 41.8 µM TE. Thermal extraction at 115 °C and 1.7 atm for 1 h (1:10 BS/BW w/v) produced an enriched blanch water (EBW) with a TPC of 809.2 ± 12.1 µg GAE/mL and a TAC of 2188.8 ± 3.6 µM TE. Subsequent microfiltration and nanofiltration further concentrated the bioactive fraction, with the nanofiltration retentate exhibiting a 2.8-fold increase in TPC and a 2.1-fold increase in TAC compared to the EBW feed. Spray-drying generated a fine, homogeneous, and storage-stable powder without loss of antioxidant capacity. UHPLC-QqTOF-MS/MS analysis identified catechins and their derivatives, procyanidins, and flavanol glycosides as the main polyphenols contributing to the strong antioxidant capacity of the powder. Overall, this workflow provides a scalable and water-saving strategy to convert almond-processing residues into high-value functional ingredients for food, cosmetic, and pharmaceutical applications.

The integration of sustainable insect rearing with green downstream processing is essential for the development of circular biorefineries. This study investigated the fractionation of Tenebrio molitor biomass obtained from larvae reared on diets containing agro-industrial by-products by bench-scale supercritical CO₂ (SC-CO₂) extraction. Larvae were reared on diets containing brewer’s spent grain (BSG), cocoa bean shell (CBS), or banana peel (BP). A preliminary process screening identified 40 °C and 200 bar as the most suitable extraction conditions, providing efficient fractionation under mild operating conditions. Lipid extraction yield depended on the initial composition of the insect meals, ranging from 6.47 ± 0.26% for BSG-derived biomass to 23.02 ± 1.52% for CBS-derived biomass. SC-CO₂ extraction simultaneously produced protein-enriched meals, increasing protein content up to 69.4 ± 0.7%, with protein enrichment ranging from 14.9% to 33.4%. The recovered oils exhibited a favorable fatty acid profile, with more than 72% unsaturated fatty acids, predominantly oleic and linoleic acids. These findings show that differences in the composition of insect biomass obtained under different rearing conditions are reflected in the yield and characteristics of the fractions recovered under identical extraction conditions. Integrating rearing substrate selection with SC-CO₂ extraction represents an effective strategy to produce high-value protein-enriched meals and oils from agro-industrial by-products, supporting the development of sustainable insect biorefineries.