ABSTRACT
Subcritical water hydrolysis was carried out to produce valued materials from squid viscera, the waste product of fish processing industries. The reaction temperatures for hydrolysis of raw and deoiled squid viscera were maintained from180 to 280oC for 5 min. The ratio of material to water for hydrolysis was 1:50. Most of the proteins from deoiled squid viscera were recovered at high temperature. The protein yield in raw squid viscera hydrolyzate decreased with the rise of temperature. The reducing sugar yield was higher at high temperature in subcritical water hydrolysis of both raw and deoiled squid viscera. The highest yield of amino acids in raw and deoiled squid viscera hydrolyzates were 233.25±3.25 and 533.78±4.13 mg g-1 at 180 and 280oC, respectively. Most amino acids attained highest yield at the reaction temperature range of 180-220oC and 260-280oC for raw and deoiled samples, respectively. The recovery of amino acids from deoiled squid viscera was about 1.5 times higher than that of raw squid viscera.
ABSTRACT
The oil in mackerel viscera was extracted by supercritical carbon dioxide (SCO2) at a semi-batch flow extraction process and the fatty acids composition in the oil was identified. Also the off-flavors removal in mackerel viscera and the storage improvement of the oils were carried out. As results obtained, by increasing pressure and temperature, quantity was increased. The maximum yield of oils obtained from mackerel viscera by SCO, extraction was 118 mgg(-1) (base on dry weight of freeze-dried raw anchovy) at 50 degrees C, 350 bar And the extracted oil contained high concentration of EPA and DHA. Also it was found that the autoxidation of the oils using SCO2 extraction occurred very slowly compared to the oils by organic solvent extraction. The off-flavors in the powder after SCO2 extraction were significantly removed. Especially complete removal of the trimethylamine which influences a negative compound to the products showed. Also other significant off-flavors such as aldehydes, sulfur-containing compounds, ketones, acids or alcohols were removed by the extraction.
Subject(s)
Alcohols/isolation & purification , Aldehydes/isolation & purification , Animals , Carbon Dioxide/chemistry , Chromatography, Supercritical Fluid/methods , Fatty Acids/isolation & purification , Fatty Acids, Omega-3/analysis , Fish Oils/chemistry , Food Handling/methods , Ketones/isolation & purification , Methylamines/isolation & purification , Perciformes , Pressure , Solvents/chemistry , Sulfhydryl Compounds/isolation & purification , Temperature , Time FactorsABSTRACT
The extraction of mackerel viscera using supercritical carbon dioxide (SCO2) was performed under the conditions of temperature range from 35 to 45 degrees C, and constant pressure 25 MPa. The digestive enzyme activities were determined in comparison of untreated and treated SCO2 and solvent treatment. Activities were maintained with high level compared to that of solvent extraction. Also from result of SDS-PAGE, the protein denaturation was minimized when using SCO2 extraction. The major amino acids in the mackerel viscera were determined as glutamic acid, aspartic acid, glycine, leucine, lysine and the free amino acids were taurine, L-alanine, L-leucine, 1-methyl-L-histamine, 3-methyl-L-histidine.