Optimization of extraction process of Gelidium amansii agar by response surface methodology

In this paper,high temperature and high pressure were used to extract Gelidium amansii agar.Extraction rate and gel strength were used as index of extraction process. Based on single factor experiments,BBD central composite design and Design- Expert software were used to build a mathematical model.The optimum extraction parameters of agar were determined as follows: citric acid 0.03%,extraction time 33 min,solid- liquid ratio 1 ∶ 36,extraction temperature 110 ℃.Under these conditions,the extraction rate of agar was 37.85%.Agar's organoleptic properties,physical and chemical properties met the standard.The strength of gel was 873 g / cm~2,which belonged to a high strength products for the industry. The extraction rate of high- quality agar was improved,and research base was provided.