Abstract: Citric acid was used to extract chitin by decalcifying shrimp heads and shells of Penaeus vanmamei. The optimal extraction conditions were explored by single factor and response surface tests. The results showed that the ash content in chitin was 1.0 g/100g, which met the requirement of food grade. The optimal extraction process parameters were citric acid concentration of 12.00 g/L, material-liquid ratio of 1:2.00, and extraction time of 3.88 h. The utilization of citric acid for removing calcium salts from shrimp heads or shells could result in food grade of chitin and mild reaction conditions as well less pollution. In addition, the by-product of calcium citrate could be used as the calcium addition agent, thus enhancing the resource availability of shrimp heads or shells.

Key words: Penaeus vanmamei, citric acid, shrimp waste, decalcification