Inhibition of quality loss in chilled megrim (Lepidorhombus whiffiagonis) by employing citric and lactic acid icing

Effect of Vacuum Impregnation and High Hydrostatic Pressure Treatments on Shelf Life, Physicochemical, and Sensory Properties of Seabream Fillets

Marination is commonly used to preserve fish, which, in combination with other non-thermal technologies, such as vacuum impregnation and high hydrostatic pressure, may help to preserve freshness and extend shelf life. In addition, marination may mask changes in physicochemical properties and the sensory attributes of fish resulting from intense pressurization treatments. In this study, we evaluated the effects of vacuum impregnation (50 mbar for 5 min) alone or in combination with a moderate pressurization treatment (250 MPa for 6 min) on the physicochemical properties, microbiological and oxidative stability, and sensory properties of refrigerated seabream fillets. Compared to conventional marination, vacuum impregnation alone had no effect on the aforementioned properties, except for a higher perception of lemon aroma (0.9 vs. 1.6). However, vacuum impregnation with pressurization reduced the total viable mesophilic aerobic bacteria to counts below 4 log colony forming units (CFU)/g after 16 days of storage at ≤ 2 °C, compared to 6 log CFU/g with conventional marination. Additionally, the color and texture were affected by the pressurization treatment. However, color was more susceptible, and at the beginning of storage, lightness was higher in the pressurized samples than in the control (52 vs. 78). Regardless, this whitening effect and other minor changes in texture and sensory properties compared to conventional marination with vacuum impregnation with pressurization can be considered of little relevance considering the increase in shelf life, the lack of lipid oxidation (maintained at low and similar levels as those of the non-pressurized samples), and the intrinsic whitening effects of certain marinades.

Influence of corn starch based bio-active edible coating containing fumaric acid on the lipid quality and microbial shelf life of silver pomfret fish steaks stored at 4 °C

The present study aimed at assessing the impact of addition of fumaric acid (0.5%), as an active agent, in a corn starch (2%) based edible coating, on the lipid quality and microbial shelf life of silver pomfret (Pampus argenteus) fish steaks stored at 4 °C. Treating fish steaks with FA resulted in a bacteriostatic effect leading to reduced counts of total mesophilic and psychrotrophic bacteria, H2S producing bacteria and Pseudomonas spp. The total mesophilic bacterial count of uncoated control sample exceeded the permissible limit of 7 log cfu g-1 on 6th day and had the lowest microbial shelf life. FA incorporation in the CS coating improved the microbial stability of fish steaks resulting in a shelf life of 15 days. The outcomes of the study suggest that CS based coating is beneficial in delaying lipid oxidation as displayed by the lower TBA and PV values while FA is an effective agent for further increasing the preservative action of CS coating by significantly inhibiting microbial growth as well as lipid quality deterioration, which could be exploited by the seafood industry as an active packaging component.

Employment of Flake Ice Systems Including Natural Preservative Compounds for the Quality Enhancement of Chilled Seafood-A Review

Marine species deteriorate rapidly post-mortem as a consequence of a variety of biochemical and microbial breakdown mechanisms. Due to the increasing demand for high-quality fresh seafood, different strategies are now available to retard spoilage for as long as possible. The present study provides an overview of a recently proposed strategy based on the addition of natural compounds to marine species. In this strategy, different kinds of natural preservative compounds are included in the flake-ice medium that is commonly used for chilled storage. Natural sources tested for this purpose include low-molecular-weight organic acids and different kinds of extracts of plants, macroalgae, and by-products resulting from marine species commercialization. The preservative action of such treatments is analyzed according to the effect on different deteriorative mechanisms (i.e., lipid hydrolysis, oxidation, and microbial activity development), as well as on the resulting sensory acceptability and shelf-life time. The basic objective of this review is to provide an overview concerning the positive effect that the presence in an icing system of natural preserving compounds may have on the quality of chilled marine species. Furthermore, various potential avenues are proposed to develop the practical and commercial employment of this technological strategy.