This study aimed to investigate how the freshness before frozen storage affect the quality and sensory characteristics of seabream in different commercial presentations and to correlate the findings with free amino acids composition. The fish were slaughtered, allocated to three processing treatments (whole, gutted and filleted) and stored at refrigeration (0 ±1 °C) for different times (5, 9, 11 and 18 days) before one-month frozen storage (-30 °C). After this time, physicochemical (pH, TVB-N, TBARS and free amino acids), bacterial count and sensory evaluation (Torry Index & Quality Descriptive Analysis -QDA-) were studied. Significant differences were found among treatments over time for TVB-N, TBARS and bacterial growth. The quality index (Torry) exhibited a gradual decrease. QDA showed that fillets had the lowest assessment. Free amino acids contents varied significantly during frozen storage with a particular behavior that depended on the previous treatment applied and the fish freshness degree (elapsed days before frozen).

Fish provides a low-caloric content, polyunsaturated fatty acids, many essential trace elements and is also a rich source of protein, ranging from 10% to 25%. Therefore, the production of FPH (fish protein hydrolysates) is of great interest, as the resulting products exhibit a variety of important bioactive and technological properties, making them potential ingredients for new functional foods and supplements. The aim of this review was to compile and analyze information on enzymatic hydrolysates, with particular emphasis on those derived from fish by-products, as a potential ingredient in human nutrition. Their nutritional characteristics, food safety aspects, bioactive properties, technological attributes, key influencing factors, and applications in food products were evaluated. The findings revealed that these properties are influenced by several factors, such as the raw material, enzymes used, degree of hydrolysis, and the molecular weight of the peptides, which need to be considered as a whole. In conclusion, the gathered information suggests that it is possible to obtain high-value products through enzymatic hydrolysis, even when using fish by-products. However, although numerous studies focused on FPH derived from fish muscle, research on by-products remains limited. Further investigation is needed to determine whether the behavior of FPH from by-products differs from that of muscle-derived FPH.

The aim of this study was to characterize the spoilage microbiota of hake fillets stored under modified atmospheres (MAP) (50% CO₂/50% N₂) at different temperatures using high-throughput 16S rRNA gene sequencing and to compare the results with those obtained using traditional microbiology techniques. The results obtained indicate that, as expected, higher storage temperatures lead to shorter shelf-lives (the time of sensory rejection by panelists). Thus, the shelf-life decreased from six days to two days for Batch A when the storage temperature increased from 1 to 7 °C, and from five to two days—when the same increase in storage temperature was compared—for Batch B. In all cases, the trimethylamine (TMA) levels measured at the time of sensory rejection of hake fillets exceeded the recommended threshold of 5 mg/100 g. Photobacterium and Psychrobacter were the most abundant genera at the time of spoilage in all but one of the samples analyzed: Thus, Photobacterium represented between 19% and 46%, and Psychrobacter between 27% and 38% of the total microbiota. They were followed by Moritella, Carnobacterium, Shewanella, and Vibrio, whose relative order varied depending on the sample/batch analyzed. These results highlight the relevance of Photobacterium as a spoiler of hake stored in atmospheres rich in CO₂. Further research will be required to elucidate if other microorganisms, such as Psychrobacter, Moritella, or Carnobacterium, also contribute to spoilage of hake when stored under MAP.

A by-product from the filleting of sea bass (Dicentrachus labrax) was used to manufacture enriched pasta. The research aimed at achieving an increase of protein and unsaturated fatty acid contents, making innovative and healthy pasta products that are able to step up fish consumption. Two different kind of cereals were used to make fresh pasta, which were subjected to frozen storage with the addition or not of a rosemary antioxidant. The developed pastas were analyzed by physicochemical methods. Proximal analysis demonstrated an improvement of nutritional values on those of a common pasta. Fatty acid profiles, acidity indices, and TBARS (Thiobarbituric acid reactive substances) index confirmed the stability of fat and effective protection against oxidation, especially in pasta with added antioxidant. The cooking time for pasta was set at 90 s, and color parameters were modified due to the incorporation of fish in the pasta-making process. An enrichment in fatty acids ω-3 and ω-6 was also confirmed. The conversion of α-linolenic acid (ALA) in eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in frozen storage was detected, which remained stable during 90 days. Finally, sensory profiles of enriched pasta were found to be adequate and improved following the addition of an antioxidant due to a decrease of negative attributes associated with oxidation.

The study aimed at the development of fresh sausages using rabbit exclusively as raw material. The idea was to offer an innovative product to increase rabbit consumption. Also, to meet currently consumers' requirements, a low-fat version was made. Two final formulations, a control sausage and a low-fat version using konjac gum, were developed through an iterative process and stored in a MAP under refrigeration. Sensory, microbiological and physicochemical analyses were carried out on days 1, 6, 8 and 13 after packaging. The shelf-life of the sausages was determined according to a multivariate criterion. Results showed a significant reduction in fat content and energy value. Sensory analysis showed a decrease in characteristic aroma and flavour and an increase in rancid odour, while hardness and fragility decreased in the low-fat treatment. The shelf-life was 7 days for all treatments, concluding that the multivariate method was a powerful technique as physicochemical, microbiological and sensory criteria were considered.

The fish industry generates by-products that are still nutrient-rich. Its incorporation in pasta production could be an interesting option to get functional food. Therefore, the aim of this study was to compare the nutritional composition, technological properties and sensory quality of two pastas containing tuna and sea bass by-products, separately. Durum wheat semolina and fish by-product concentrates were used in pasta manufacturing. Fatty acids profile, optimal cooking time, texture profile analysis, color, weight gain, swelling index, cooking losses and moisture were determined and compared with a non-containing fish reference. A sensory analysis was also carried out. In general, results showed a higher content of fatty acids in tuna pasta than in sea bass pasta. The texture profile analysis (TPA) showed lower hardness and fracturability in the fish pasta. Cohesiveness was higher in the tuna pasta while sea bass pasta was brighter. Fish incorporation caused a decrease in weight gain and swelling index and an increase in cooking losses. Sensory analysis established differences in homogeneity, typical aroma, fish flavor, fish odor and elasticity. It was concluded that the use of these by-products results in a more nutritious pasta although tuna content should be reduced (<3%) to improve its sensory profile.