Composition of major quinochalcone hydroxysafflor yellow A and anhydrosafflor yellow B is associated with colour of safflower (Carthamus tinctorius) during colour-transition but not with overall antioxidant capacity: A study on 144 cultivars

•Water-extraction of safflower yellow pigments was optimized by Response Surface Methodology.•Anhydrosafflor yellow B content decreases during colour-transition of safflower floret.•Hydroxysafflor yellow A content has a weak relationship with colour.•Antioxidant capacity of safflower yellow pigments remains constant regardless of colour.