Impact of previous active dipping in Fucus spiralis extract on the quality enhancement of chilled lean fish

Preservative Effect of Aqueous and Ethanolic Extracts of the Macroalga Bifurcaria bifurcata on the Quality of Chilled Hake (Merluccius merluccius)

This work addressed the preservative behaviour of different icing media containing extracts from the alga Bifurcaria bifurcata. A comparative study of the antimicrobial and antioxidant effects of aqueous and ethanolic extracts of this macroalga was carried out. Whole hake (Merluccius merluccius) pieces were stored in ice containing either kind of extract and analysed for quality changes throughout a 13-day storage period. A progressive loss of microbial and biochemical quality was detected in all batches as chilling time increased. A significant inhibitory effect (p < 0.05) on microbial activity could be observed as a result of including the aqueous (lowering of psychrotrophic and lipolytic counts and pH value) and ethanolic (lowering of psychrotrophic and lipolytic counts) extracts. Additionally, both kinds of extract led to a substantial inhibition (p < 0.05) in the lipid hydrolysis rate (formation of free fatty acids), greater in the case of the batch containing ethanolic extract. Concerning lipid oxidation, a similar inhibitory effect (p < 0.05) on the formation of secondary compounds (thiobarbituric acid substances) was noticed in fish specimens corresponding to both alga extracts; however, more (p < 0.05) peroxide formation was detected in fish corresponding to the ethanolic extract batch. A preservative effect can be concluded for both kinds of extract; this effect agrees with previous studies reporting the presence of hydrophilic and lipophilic bioactive compounds in B. bifurcata.

High-CO2 Modified Atmosphere Packaging with Superchilling (-1.3 °C) Inhibit Biochemical and Flavor Changes in Turbot (Scophthalmus maximus) during Storage

The effects of modified atmosphere packaging (MAP) in combination with superchilling (−1.3 °C) on the physicochemical properties, flavor retention, and organoleptic evaluation of turbot samples were investigated during 27 days storage. Results showed that high-CO₂ packaging (70% or 60% CO₂) combined with superchilling could reduce the productions of off-flavor compounds, including total volatile basic nitrogen (TVB-N) and ATP-related compounds. Twenty-four volatile organic compounds were determined by gas chromatography–mass spectrometry (GC/MS) during storage, including eight alcohols, 11 aldehydes, and five ketones. The relative content of off-odor volatiles, such as 1-octen-3-ol, 1-penten-3-ol, (E)-2-octenal, octanal, and 2,3-octanedione, was also reduced by high-CO₂ packaging during superchilling storage. Further, 60% CO₂/10% O₂/30% N₂ with superchilling (−1.3 °C) could retard the water migration on the basis of the water holding capacity, low field NMR, and MRI results, and maintain the quality of turbot according to organoleptic evaluation results during storage

Potential Use of Marine Seaweeds as Prebiotics: A Review

Human gut microbiota plays an important role in several metabolic processes and human diseases. Various dietary factors, including complex carbohydrates, such as polysaccharides, provide abundant nutrients and substrates for microbial metabolism in the gut, affecting the members and their functionality. Nowadays, the main sources of complex carbohydrates destined for human consumption are terrestrial plants. However, fresh water is an increasingly scarce commodity and world agricultural productivity is in a persistent decline, thus demanding the exploration of other sources of complex carbohydrates. As an interesting option, marine seaweeds show rapid growth and do not require arable land, fresh water or fertilizers. The present review offers an objective perspective of the current knowledge surrounding the impacts of seaweeds and their derived polysaccharides on the human microbiome and the profound need for more in-depth investigations into this topic. Animal experiments and in vitro colonic-simulating trials investigating the effects of seaweed ingestion on human gut microbiota are discussed.

Shelf Life Extension and Improvement of the Nutritional Value of Fish Fillets through Osmotic Treatment Based on the Sustainable Use of Rosa damascena Distillation By-Products

The objective of this work is the comparative study of different osmotic treatments at 37 °C on the quality and shelf life of chilled sea bass fillets. Fish fillets were treated using osmotic solutions consisting of oligofructose (40%–50%–60%) and 5% NaCl with (BP/OT) and without (OT) former antioxidant enrichment by using Rosa damascena distillation by-products. Water activity decreased to approximately 0.95 after 330 minutes of osmotic treatment. Untreated and osmotically treated fish fillets (BP/OT) and (OT) were subsequently stored at 5 °C and their quality was evaluated based on microbial growth and lipid oxidation. Osmotic treatment extended significantly the shelf life of fish in terms of microbial growth; however, it also accelerated its lipid oxidation. The impregnation of Rosa damascena phenolics not only counterbalanced this negative effect, but led to a more than four-fold increase of the shelf life of sea bass, as compared to the untreated samples.

Antimicrobial Carvacrol Incorporated in Flaxseed Gum-Sodium Alginate Active Films to Improve the Quality Attributes of Chinese Sea bass (Lateolabrax maculatus) during Cold Storage

The objective of this research was to explore the antimicrobial activity and mechanism of carvacrol against Vibrio Parahemolyticus, Shewanella putrefaciens, Staphylococcus aureus and Pseudomonas fluorescens and evaluate the effect of the addition of carvacrol/β-cyclodextrin emulsions to flaxseed gum (FSG)-sodium alginate (SA) edible films on the preservation of Chinese sea bass (Lateolabrax maculatus) fillets during refrigerated storage. The minimum inhibitory concentration (MIC) of carvacrol against V. parahemolyticus, S. putrefaciens, S. aureus and P. fluorescens were 0.5, 0.5, 0.125, and 0.5 mg/mL, respectively. Alkaline phosphatase activity assay, nucleotide and protein leakage, and scanning electron microscope demonstrated that carvacrol damaged the external structure of the tested bacterial cells causing leakage of cytoplasmic components. At the same time, when FSG-SA films containing carvacrol used as coating agents for Chinese sea bass fillets cold storage, FSG-SA films containing 1.0 or 2.0 mg/mL carvacrol could significantly reduce TVB-N content, K-value, the degree of microbial deterioration and maintain quality of sea bass fillets according to organoleptic evaluation results.

Coating Effects of ε-Polylysine and Rosmarinic Acid Combined with Chitosan on the Storage Quality of Fresh Half-Smooth Tongue Sole (Cynoglossus semilaevis Günther) Fillets

The study was to evaluate the effects of chitosan-based coating combined with rosmarinic acid (RA) with different concentrations of ε-polylysine (ε-PL) on flavor retention and sensorial properties of half-smooth tongue sole fillets during storage at 4 °C. Results showed that chitosan-based coatings combined with ε-PL and RA contributed to the reduction of off-flavor compounds, such as total volatile base nitrogen (TVB-N), trimethylamine (TMA), and ATP-related compounds, and accumulation of free amino acids (FAAs). Nineteen volatile organic compounds were analyzed by gas chromatography-mass spectrometer (GC/MS) during storage, including seven alcohols, six aldehydes, and six ketones. The coating treated fresh half-smooth tongue sole (HTS) fillets significantly reduced the relative content of off-odor volatiles, such as 1-octen-3-ol, propanal, hexanal, and octanal. According to sensory evaluation results, chitosan-based coating combined with ε-PL and RA was an effective way to maintain quality of HTS fillets during refrigerated storage.