Effect of plant extracts on quality characteristics and shelf-life of cold-marinated shrimp (Parapenaeus longirostris, Lucas, 1846) under refrigerated storage

The effects of rosemary (Rosmarinus officinalis), lemon balm (Melissa officinalis), lavender (Lavandula angustifola), oregano (Origanum vulgare) and savory (Satureja montana) extracts, alone and in mixtures, on lipid oxidation in cold-marinated shrimp (Parapenaeus longirostris) were studied. During the two-month screening period using the thiobarbituric reactive substances assay (TBARS) the most effective extract mixture (rosemary:oregano:lavender extracts in 3:2:1 ratio, ROL) was selected for the shelf-life study in pilot production of marinated shrimp to determine its effects on the quality characteristics of the final product. Degradation of the omega-3 fatty acids, eicosapentaeonic acid (EPA) and docosahexaenoic acid (DHA) during 8 months of refrigerated storage, was inhibited in shrimp marinated with ROL compared to control samples. In addition, lower levels of total volatile basic nitrogen (TVB-N) and trimethylamine nitrogen (TMA-N) were observed in shrimp treated with extracts while the TBARS values remained below the limit of 3 μmol malondialdehyde (MDA)/100g during the 8-month shelf-life study period, whereas the control sample exceeded this value in the third month. The total number of aerobic mesophilic and psychrophilic microorganisms was reduced after marinating with extracts. The obtained results are promising with regard to the application of plant extracts, especially the tested ROL mixture, to extend the shelf-life of food products and to reduce lipid oxidation and microbial load in the food model.