Edible Rose and Roselle: A Critical Review of Nutritional Composition, Safety, and Regulatory Considerations for Product Development.

The growing demand for sustainable and health-promoting products has increased scientific and industrial interest in edible flowers as functional ingredients. Rose (Rosa spp.) and roselle (Hibiscus sabdariffa L.) have gained attention for their traditional use, diverse phytochemical composition, and emerging applications in functional foods, nutraceuticals, and cosmetics. Much existing literature treats these species descriptively, reporting compositional data without critically addressing the safety, regulatory, and standardization barriers constraining industrial adoption. This review evaluates their nutritional composition, phytochemical profiles, and techno-functional properties, while critically addressing cultivar-level compositional variability, food safety (natural toxic compounds, microbial risk, pesticide residues), allergenicity, extraction methodology standardization, regional regulatory frameworks, and post-harvest industrial standardization. Rose petals are characterized by volatile terpenoids, flavonol glycosides, and phenolic acids linked to sensory quality and antioxidant activity; documented safety concerns centre on pesticide residue risk from dual ornamental/food-crop cultivation and oil adulteration. Roselle calyces are rich in anthocyanins, organic acids, polysaccharides, and minerals, supporting use as natural colorants, acidulants, and stabilizers, though cyanogenic glycoside variability, microbiological surveillance gaps, and an almost complete absence of allergenicity data warrant attention. Roselle seed protein, proposed as a functional ingredient, lacks allergenicity characterization. Applications in beverages, bakery products, gels, and cosmetics demonstrate commercial potential, but broader adoption remains limited by compositional variability, bioactive instability, and a persistent gap between demonstrated technical feasibility and adopted, food-relevant standards for extraction, quality control, and regulatory harmonization. Future research should prioritize dose-specific toxicological and allergenicity data, validated extraction protocols, and deliberate prioritization of edible flowers within regulatory and standardization mechanisms.