Roasted Fruit-Seed Coffee Alternatives: Processing-Induced Phytochemical Changes, Antioxidant Potential, Bioaccessibility, and Safety

Growing demand for caffeine-free beverages and the valorization of fruit-processing residues has increased interest in roasted fruit seeds as coffee alternatives. This review evaluates seed composition, processing-induced transformations, antioxidant-assay responses, gastrointestinal bioaccessibility, biological evidence, sensory performance, and safety of beverages derived from date, açaí, baobab, avocado, tamarind, durian, snake fruit, papaya, ampalaya, and talisay. Fruit seeds contain diverse phenolic acids, flavonoids, procyanidins, tannins, tocopherols, phytosterols, lipids, and polysaccharides. However, their profiles vary markedly with species, cultivar, maturity, anatomical seed component (e.g., whole seed, seed coat, or kernel), and processing history. Roasting exerts bidirectional effects: it can degrade native phenolics and lipophilic antioxidants while enhancing the release of bound compounds and generating Maillard reaction products with antioxidant activity, including melanoidins. Simulated digestion and selected cell-based studies provide preliminary evidence of phytochemical release during digestion and cytoprotection, but efficacy in humans and long-term beverage safety remain insufficiently established. Future studies should quantify compounds and contaminants in standardized brews, report exposure per serving, distinguish chemical from biological endpoints, and integrate sensory acceptance with safety.