The Effects of Ascorbic Acid on Lipid Oxidation during the Processing of Mytilus edulis chilensis in the Beagle Channel (Tierra del Fuego)

Abstract

The peculiarity of membrane lipids with high polyunsaturated fatty acids content in mollusks, suggests a special pattern for the development of lipid oxidation, decreased organoleptic characteristics and loss of product value for sale. In the Puerto Almanza area, Tierra del Fuego, mussel extraction is carried out for fresh commercialization in local cities. The antioxidants application in different marine resources at any stage of processing has been effective for the oxidative control. Our objective was to evaluate the level of lipid oxidation (tiobarbituric acid reactive species content, TBARS) and non-enzymatic antioxidants content in mussel (Mytilusedulischilensis) for commercialization, after the treatment with ascorbic acid (AH-). Mussels extracted from offshore batch culture, were exposed to different treatments: T1: dry control, T2: control in seawater without antioxidant, T3: exposed to AH- (10 mM) and T4: exposed to AH- (5 mM). Subsamples of each treatment were taken at 0, 6 and 24h, for analysis. A TBARS increase of 36% and ascorbyl radical content (A●) were observed during the first 24h on T1. The AH-incorporated by the mussels showed an antioxidant activity avoiding lipids oxidation during the first stage of processing (24h of exposure) comparing T1 and T4. These results showed the generation of oxidative stress in mussels during dry condition. The AH- content in frozen mussels decreased significantly after 24h of exposure to the antioxidant in T1 and T4, probably due to consumption. In addition, both A● as the A●/AH- index, increased significantly comparing T1, T3 and T4 treatments. This indicates that the manipulation conditions, transfer and cold storage generated an oxidative stress situation.Overall, our results indicated that the maintenance in water for 24h and that the addition of AH- (5 mM) after the mussel extraction, are beneficial during the transfer period and avoid the stress generated by manipulation of M. edulischilensis. Higher concentrations of the AH- could produce an effect contrary (pro-oxidant) in 24h. Further, cold storage (-20 ºC) for 5 days, regardless of the addition of antioxidants, does not prevent the oxidative lipid damage nor improve product quality.