The use of High Pressure Processing as an extraction method was studied by evaluating the yield of astaxanthin from shrimp carapace as a model. Previous studies have demonstrated the antioxidant and antimicrobial properties of astaxanthin. The aim of this research was to compare these properties of astaxanthin as a surrogate for its yield from High Pressure Processing (HPP) extraction with the effect of hydrostatic pressure, holding time and amount of solvents versus chemical extraction method. A solvent mixture of acetone and methanol 7:3 (v/v) was used in both methods. The pressure treated was at 238 MPa with 16.29 min of holding time and 6.59 ml of solvents for HPP method. Antioxidant activity was evaluated using scavenging activity of DPPH radical, the reducing activity of Ferrum redox reaction and oxygen radical absorption capacity. Antimicrobial activity was evaluated using a zone of inhibition test against four strain of bacteria: E. coli, E. aerogenes, S. aureus and B. subtilis. The sample of astaxanthin demonstrated a significant increase in DPPH radical scavenging activity (25.47% to 87.90%), reducing activity of Ferrum redox reaction (2.86 µmol TE/g to 8.13 µmol TE/g) and oxygen radical absorption capacity (2,000 µmol TE/100 g to 4,000 µmol TE/100 g) compared to the chemical extraction sample. The antimicrobial activity of the astaxanthin from the HPP sample produced a greater zone of inhibition against all four strains of bacteria when compared to the chemically extracted sample. A higher quality of astaxanthin was achieved with the HPP extraction method compared to chemical extraction.
Bacillus amyloliquefaciens B7 was isolated from the fermented fish sauce and identified as protease producer. Generally, in downstream processing, purification of enzymes consumes higher cost regarding reagents and equipment used. Moreover, harsh purification methods used might cause denaturation of the enzymes. Therefore, there is a high demand for efficient and lowcost extraction and purification methods. Aqueous two-phase system (ATPS) is an alternative method that should be considered as it is simple, rapid separation yet cause little denaturation. Protease produced by B. amyloliquefaciens B7 was partitioned using two different ATPS, which were PEG/potassium phosphate and PEG/sodium citrate. Results showed the highest enzyme activity was found in interface phase with the ATPS system of 27% (w/w) PEG1500/ 34% (w/w) sodium citrate. Later, the ATPS conditions (pH, temperature, the concentration of selected salt and PEG) were optimized by using response surface methodology. The optimum conditions for ATPS purification were observed in ATPS conditions at pH 7 and 35°C with the enzyme activity of 0.20± 0.01 U/ml.