Statistics-based optimization of the extraction process of kelp polysaccharide and its activities

► The extraction process of kelp polysaccharide was optimized using RSM. ► Effect of factors on the polysaccharide yield is depicted by a mathematical model. ► Kelp polysaccharide displays a strong antioxidative ability in vitro. ► Kelp polysaccharide of 0.25% increases the collagen biosynthetic activity by 86%. ► This study provides insight into further development of kelp polysaccharide.