Physicochemical and functional properties of alkali‐soluble nonstarch polysaccharide‐rich fraction from selected edible flowers

Polysaccharides represent a major carbohydrate fraction in edible flowers and are recognized as potential functional food ingredients; however, their compositional and structure–function relationships remain poorly understood. This study investigates the chemical composition, structural, and functional properties of polysaccharides extracted from broccoli ( Brassica oleracea var. italica ), hibiscus ( Hibiscus sabdariffa ), marigold ( Calendula officinalis ), and rose ( Rosa centifolia ) flowers by alkaline treatment. The extracted fractions contained 52.7%–65.2% carbohydrates, along with varying levels of protein and ash, indicating co‐extraction during alkaline processing. Fourier transform infrared spectroscopy identified characteristic functional groups, whereas scanning electron microscopy revealed distinct morphological features among samples. X‐ray diffraction patterns confirmed predominantly amorphous structures with contributions from residual crystalline salts. Structural analysis shows that the polysaccharide consisted of cellulose and pectin. Functional properties varied with floral variety, with swelling capacity (6.43–12.61 mL/g), water‐holding capacity (2.59–8.09 g/g), and oil‐holding capacity (1.86–3.57 g/g). These findings establish clear composition–structure–function relationships and highlight how compositional factors, including protein content, uronic acid presence, and residual salts, influence functional behavior. The results support the potential application of edible flower polysaccharides as value‐added functional ingredients in food systems.