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

Statistics-based response surface methodology (RSM) was used to optimize the extraction process of kelp polysaccharide and its activities were evaluated. Single factor experiment was first designed for determining the optimal range of each of four factors and these factors were further optimized using RSM with a CCD design. The optimal conditions were as follows: pH 3.4, temperature 83 °C, extraction time 3.95 h and ratio of water to kelp 1:23. Under the above conditions, the yield of kelp polysaccharide obtained was 1.26%. Scavenging percentages of free radicals OH, O(2)(-) and DPPH by kelp polysaccharide were up to 90.8% (1.6 mg/mL), 85% (1 mg/mL) and 23.8% (1 mg/mL), respectively. An increase of 86% in the biosynthetic activity of collagen was obtained at a kelp polysaccharide concentration of 0.25%. All these results indicate that kelp polysaccharide may be a good candidate as an effective ingredient of cosmetics for future use.