Abstract:
Astaxanthin (AST) is a natural pigment that is responsible for the pink-red
color of crustaceans and fish. Astaxanthin is widely used in food, medical,
cosmetic and biotechnological and ornamental fish industries. Discarded
shrimp waste from processing industries could be a good source of AST.
Present study compared the efficiency of extraction of AST from shrimp
shell wastes by two methods; direct autolysis and autolysis of microwaved
shrimp waste samples. In both methods of autolysis, shrimp waste samples
were mixed with fresh crab wastes according to the following shrimp: crab
ratios of weights in grams; 20:20, 40:20, 60:20, 80:20, and 100:0. All the
samples were autolyzed at 600C for 20 min. and filtered. Filtrate and
residue were dried. AST in all filtrates and the residues were extracted
using hexane, and quantified by measuring absorbance at 470 nm.
Concentration of extracted AST by the two methods were compared by
analysis of variance (ANOVA) (p<0.05). Maximum (38.45 ± 0.94μg/g) and
minimum (9.31 ±0.65μg/g) AST concentration of the dried filtrate were
recorded in 40:20 and 20:20 autolyzed fresh shell fish samples respectively.
Concentration of AST is significantly different in two methods in all
shrimp: crab ratios studied. In both methods AST concentration increased
up to shrimp: crab ratio 40:20 and then with further increment of shrimp
content it gradually decreased except 80:20 ratio of microwaved method.
AST concentrations of all the residue samples were zero. Results indicate
that fresh sample autolyzed method gives higher concentration of AST than
microwaved autolyzed method. The ratio of 40:20 shrimp: crab waste is the
best combination to obtain high amount of AST yield.