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
Whole-mounted Malpighian tubules of larvae from two meliponid bee species fixed in acetic acid-ethanol showed apositive cytoplasmic staining with Schiff reagent when submitted to the Feulgen reaction in which acid hydrolysiswas done in 4 M HCl at room temperature. The ability of various treatments applied before the Feulgen acid hydrolysisto abolish this cytoplasmic staining was examined. The aldehyde groups of phospholipids present in the cytoplasm ofthe Malpighian tubules were blocked or removed by sequential treatment with 5% sodium borohydride and acetonechloroform(1:1, v/v) for 15 min each prior to HCl hydrolysis. This treatment is recommended in order to abolish thecytoplasmic (plasmal) reaction and to allow the reliable quantification of DNA by the Feulgen reaction and thediscrimination of nuclear phenotypes in the Malpighian tubules of meliponid bees.