Effect of chemical biological and physical purification on chitin recovery from exoskeletons of shrimp (Penaeus sp) and grasshopper (Sphenarium purpurascens)

Abstract

The aim of this study was to evaluate the effect of three methods: Chemical (hydrolysis by alkaline-acid reactants), solid-state fermentation (SSF) and physical (ultrasonication) treatments in grasshopper and shrimp exoskeletons for chitin recovery. In products derived from each method were evaluated the percentages of demineralization, deproteinization and color changes. The results showed that at 120 h of SSF with strain L. plantarum BG-112 were obtained 32.43% and 32.63% of deproteinization and 40.31% and 15.40% of demineralization with grasshopper and shrimp respectively. The alkaline-acid treatment produced 98.19% and 96.75% of deproteinization and 98.91% and 92.66% of demineralization with these substrates. Finally, using ultrasonication (40% of amplitude), the deproteinization achieved was 64.58% and 61.12% and presented a demineralization of 13.71% and 12.29% in grasshopper and shrimp exoskeletons. Chemical treatment showed a greater protein and mineral removal compared to other treatments with a process time of 5 h, and chitin yields achieved were 51.94% (grasshopper) and 47.68% (shrimp). However, the application of ultrasonic waves allowed the extraction of protein and minerals in a shorter time (2 h), and on wet basis chitin yields were estimated as 75.3% and 74.02% from grasshoper and shrimp exoskeletons.