Chemical changes during the chilled storage of Chilean jack mackerel (Trachurus murphyi): Effect of a plant-extract icing system

Chilean jack mackerel (Trachurus murphyi) is an underutilised medium-fat fish species, captured in large volumes but commercialised in the fish meal and surimi industries. This study provides a first approach including a novel technology for the commercialisation of this fish species as a chilled product for human consumption. Ice prepared from aqueous extracts of oregano (Origanum vulgare) and rosemary (Rosmarinus officinalis) leaves was applied as chilling system and compared to traditional ice. Chemical changes related to quality criteria were analysed throughout a 23-day chilling period. A marked antioxidant effect (p < 0.05) could be detected with fish kept under both plant-extract icing systems, according to peroxide and thiobarbituric acid reactive substance formation; meanwhile, the employment of such icing systems led to lower (p < 0.05) scores for pH value and total volatile amine formation. Additionally, the plant extract presence in the chilling medium provided a lower (p < 0.05) lipid hydrolysis (free fatty acid formation) development. According to the preservative effect observed for both plant extract systems, further research is envisaged concerning their optimal employment, this including the qualitative and quantitative analysis of active molecules present in the extracts.