Oxidative stability of lipids from hepatopancreas of Pacific white shrimp (Litopenaeus vannamei) added with different essential oils at 200 ppm during 10 days of storage was studied. With increasing storage time, the progressive formation of hydroperoxide was found in all samples as evidenced by the increases in peroxide values (PV) (p<0.05). Amongst all essential oils tested, lemon essential oil exhibited the highest preventive effect against oxidation, followed by plai and basil essential oils, respectively. The increases in thiobarbituric acid reactive substances (TBARS) and ρ-anisidine value (AnV) of lipids were noticeable when storage time increased (p<0.05). The increases in TBARS and AnV were retarded in the presence of essential oils. Nevertheless, the effectiveness for prevention of lipid oxidation of all three essential oils was slightly lower than α-tocopherol when used at the same level. The formation of volatile compounds and rancid odour of samples were lowered when being incorporated with essential oils. Based on sensory evaluation, lipid containing lemon essential oil had a similar rancid odour to that added with α-tocopherol. Thus, essential oils could be used as natural antioxidants to retard lipid oxidation and rancidity of lipids from hepatopancreas during extended storage.
Practical applications: Shrimp hepatopancreas, a byproduct from shrimp processing industries, is an important source of lipids and astaxanthins, which are susceptible to oxidation. Their changes are associated with development of off-odour and loss of nutritive value. Therefore, the uses of natural antioxidants, especially essential oils, can be a potential means to retard lipid oxidation and rancidity of shrimp oil during extended storage.
Essential oils could be used as natural antioxidants to retard lipid oxidation and rancidity of lipids from hepatopancreas during extended storage.