Comparative analysis of physical, chemical, functional, and sensory properties of five amaranth ( Amaranthus spp.) varieties across two phenological stages

Abstract This study aimed to evaluate the physical, chemical, functional, and sensory profiles of five amaranth varieties (Amaranthus cruentus and Amaranthus hypochondriacus) harvested at two phenological stages: (A) early (7–8 true leaves) and (B) late (12–14 true leaves). The results showed a significant interaction (p ≤ .05) between variety and phenological stage for functional properties. The pigmented variety PQ2 (A. hypochondriacus), harvested at the late phenological state (height of 25–30 cm), exhibited the highest total phenolic content (TPC) of 302.8 mg gallic acid equivalents 100 g−1 f. w. and the highest antioxidant capacity (ORAC) of 8,773 μmol TE 100 g−1 f. w. A strong positive correlation (r = 0.94, p < .001) between TPC and ORAC exists, linking pigmentation with functional potential. The Areli variety showed the highest protein content (4.18 g 100 g−1 f. w.), while other varieties stood out for their mineral content, reaching up to 842 mg 100 g−1 f. w. of calcium and 10 mg 100 g−1 f. w. of iron. These results identify pigmented varieties, particularly PQ2, as high-value candidates for functional food applications due to their high ORAC and nutritional profile. Genotypic selection and harvest timing are crucial for maximising the bioactive potential of amaranth leaves.