Impact of pretreatment and atmosphere on quality of lipids extracted from cephalothorax of Pacific white shrimp by ultrasonic assisted process

Impacts of different pretreatment conditions and atmosphere on yield and oxidative stability of lipids from Pacific white shrimp (Litopenaeus vannamei) cephalothorax using ultrasonic assisted extraction (UAE) process were studied. Cephalothorax was subjected to vacuum-microwave (VM) heating prior to UAE using a mixture of isopropanol/n-hexane (1:1) as solvent. Nitrogen gas was flushed at two flow rates; low (2.15 l/min) and high (4.35 l/min) into the system during ultrasonication. Vacuum-microwave heating resulted in the increase of lipid yield and highest yield was observed in the samples extracted by a combination of VM and UAE. Tannic acid (TA) was incorporated into cephalothorax at three different levels (0.05, 0.1 and 0.2%) in combination with VM, followed by nitrogen flushing. Nitrogen flushing during ultrasonication process resulted in the increased oxidative stability of lipids as confirmed by low PV, TBARS and FFA. Furthermore, astaxanthin content in the lipid was found to be increased by aforementioned treatments.