Unlocking the Alkaloid Biological Potential of Chili Pepper ( spp.), Cacao ( L.), and Coffee ( spp.) Byproducts: Characterization, Non-Conventional Extraction, Applications, and Future Perspectives.

Chili peppers ( spp.), cacao ( L.), and coffee ( spp.) are important crops worldwide. Nearly 35%, 80%, and 45% of the respective fruits are underutilized or discarded, representing a considerable economic loss. This work reviews and analyzes the environmental factors that influence the concentration of the main alkaloids in these crops, including capsaicin, theobromine, and caffeine. Their reported anti-inflammatory, cardioprotective, neuroprotective, and cytotoxic properties are also reviewed. This work explores strategies for the revalorization of these crops, comparing alkaloid extraction methods that use non-conventional techniques, including supercritical fluid extraction (SFE), ultrasound-assisted extraction (UAE), high-pressure and -temperature extraction (HPTE), pressurized liquid extraction (PLE), pressurized hot water extraction (PHWE), enzyme-assisted extraction (EAE), and pulsed electric field-assisted extraction (PEFAE), and their combination to enhance the recovery of capsaicin, theobromine, and caffeine, leading to sustainable and innovative uses of these crops' byproducts. Capsaicin, theobromine, and caffeine alkaloids are promising ingredients for the development of functional foods, cosmeceuticals, and pharmaceuticals.