Preparation of chitin with puffing pretreatment

Explosive puffing and microwave puffing were used in crab shell pretreatment to produce porous structures. The pretreatment is expected to increase the reaction rate of chitin purification, reduce the reaction time, conserve energy and avoid adulteration. These pretreatments also help to create a green and environmentally friendly chitin purification process. The crab shells had endocuticles with ribbon-like tubules which became filamentous when subjected to explosive puffing at 4 and 14 kg/cm(2) (EP4 and EP14). Furthermore, the ribbon-like tubules became more fragmented and the distance between the Bouligand layers increased as the puffing pressure increased. The reaction rate constant (k) of calcium removal, magnesium removal and deproteinization increased from 0.0641, 0.0483 and 0.0688 min(-1) in the untreated group to 0.0843, 0.0694 and 0.1514 min(-1) in EP14, respectively. However, the structure of crab shell puffed by microwave (1500 W) displayed insignificant changes compared to the untreated group. Moreover, the k values of demineralization and deproteinization were also less than the untreated group. The crystallinity and chemical structure of the chitin prepared from the puffed crab shell were insignificantly different from the untreated group. The reaction times for demineralization and deproteinization in EP4 and EP14 were shorter than in the untreated group: there was a reduction of 24.5 and 15.8% in EP4 and 25.5 and 21.4% in EP14, respectively. Compared to the untreated group, EP4 and EP14 conserved energy of 1903 and 2574 kJ, respectively.