Production and Evaluation of Some Bioactive Compounds Extracted from Squilla (Oratosquilla massavensis) Shells

Abstract

This work was performed to investigate the production and physicochemical properties of some bioactive compounds (chitin, chitosan and astaxanthin) extracted from squilla (Oratosquilla massavensis) shells. Chemical composition of squilla shells and chitin yield were determined. Results showed that pre-treated squilla shells contained 68.11% moisture, 12.88% true protein, 4.79% crude fat and 44.59% ash content (on dry weight). Chitin yield and its ash content ranged between 15.75–16.08% and 0.81–1.26%, respectively. The physicochemical properties of chitosan at different times and temperatures showed that chitosan composed 8.73–11.19% moisture, 0.66–0.83% true protein, 0.14 - 0.25% ash content. Viscosity of chitosan at higher temperatures (120°C and 130°C) for different times (30 min and 60 min) were significantly (P˂0.05) lower (80-111cps) than the lower temperatures (100°C and 110°C) for 60 min (138-130cps). At 120°C and 130°C, for 30 min, solubility was significantly lower (93.5-95.6%) than all other temperatures and times used. The degrees of deacetylation (DD) were significantly different at 130°C for 30 min and 60 min than all other temperatures and times used being higher than 70 % and ranged 73.11%-84.68%. Average molecular weight (MW) of chitosan at 120°C for 30 min was significantly different than all times and temperatures used except 120°C for 60 min and as high as 130°C for 60 min. Thus, it is obvious that MW ranged 180-189 Kilo Dalton was significantly different than lower Mw value (134.8 KD). A high value of water binding capacity (WBC) was found at 120°C for 60 min while fat binding capacity was found at 120°C for 30 min and 60 min compared with other treatments. Concerning the carotenoids, it was found that the astaxanthin in female gonads exhibited higher carotenoid concentration (14.01µg\g) than the shells (10.10µg\g on wet weight). In conclusion, squilla shells are highly prized as an inexpensive market value which could be converted into a valuable expensive chitosan and female gonads are considered a good source for carotenoids, particularly astaxanthin.