Examples of high-impact sensory and functional by-products
Several agri-food by-products offer strong valorisation potential:Citrus peels
Rich in essential oils, flavonoids and carotenoids, citrus peel by-products can be used to obtain aromatic extracts or antioxidant fractions.Almond, walnut or hazelnut press cakes
These by-products contain valuable lipid and phenolic fractions, making them an excellent base for developing protein ingredients, functional oils or natural antioxidants.Rosemary, thyme or sage residues
These aromatic plant by-products are used to obtain antioxidant and antimicrobial extracts of interest for natural preservation or cleaner formulation strategies.Which valuable compounds are concentrated in plant by-products?
| Compound | Where it is concentrated | Functional value |
|---|---|---|
| Polyphenols | Fruit peels, seeds and oilseed press cakes | High antioxidant potential |
| Carotenoids | Outer layers of fruits and vegetables (carrot, citrus, pumpkin) | Intense, stable colours |
| Essential oils | Citrus peels and aromatic plant residues | Rich in limonene, linalool or thymol |
| Phenolic compounds | Fruit peels, winery residues, olive sector residues, nut press cakes | Bioactive fraction with industrial interest |
| Natural pigments | Peels, leaves and stems | Anthocyanins or chlorophylls |
| Aromatic and volatile fractions | Leaves and stems of rosemary, thyme, sage and other aromatic species | Antioxidant and antimicrobial activity |
Benefits of valorising plant by-products
Valorising plant by-products delivers benefits on three levels:- Waste reduction, lowering environmental impact and the costs associated with by-product management.
- Raw material savings, by using resources already present within the processing plant.
- New revenue streams, turning low-value side streams into ingredients with rising demand in areas such as healthy foods, beverages, plant-based, nutraceuticals or spices.
How to replace solvents when obtaining bioactive and aromatic fractions
Many conventional processes rely on organic solvents to recover aromatic or bioactive fractions. While effective, they generate residues, require removal steps and may affect sensitive compounds. Moving towards cleaner processes means prioritising technologies based on natural fluids, such as supercritical CO?. Because it operates without solvents, helps preserve volatile compounds and delivers purer fractions, supercritical CO? is a key tool for developing more sustainable, stable and technically consistent ingredients from plant by-products. The result is a cleaner, more stable extract aligned with market expectations for naturalness.What is supercritical CO? used for in the valorisation of plant by-products?
Supercritical CO? supports a wide range of technical applications:- Obtaining essential oils and aromatic extracts from citrus peels, aromatic herbs, spices or nuts.
- Producing antioxidant extracts and natural pigments with high sensory stability.
- Defatting protein-rich ingredients, reducing lipid content in products such as cocoa, seeds or cereals.
- Removing unwanted compounds such as caffeine in coffee and tea, residual odours, pesticide traces or oxidation products.
- Reducing microbial load in heat-sensitive ingredients while preserving functional activity.
