Stabilizing oils from smoked pink salmon (Oncorhynchus gorbuscha)

Unsaturated Fatty Acids and Their Immunomodulatory Properties

Oils are an essential part of the human diet and are primarily derived from plant (or sometimes fish) sources. Several of them exhibit anti-inflammatory properties. Specific diets, such as Mediterranean diet, that are high in ω-3 polyunsaturated fatty acids (PUFAs) and ω-9 monounsaturated fatty acids (MUFAs) have even been shown to exert an overall positive impact on human health. One of the most widely used supplements in the developed world is fish oil, which contains high amounts of PUFAs docosahexaenoic and eicosapentaenoic acid. This review is focused on the natural sources of various polyunsaturated and monounsaturated fatty acids in the human diet, and their role as precursor molecules in immune signaling pathways. Consideration is also given to their role in CNS immunity. Recent findings from clinical trials utilizing various fatty acids or diets high in specific fatty acids are reviewed, along with the mechanisms through which fatty acids exert their anti-inflammatory properties. An overall understanding of diversity of polyunsaturated fatty acids and their role in several molecular signaling pathways is useful in formulating diets that reduce inflammation and increase longevity.

Influence of smoking and packaging methods on physicochemical and microbiological quality of smoked mackerel (Scomber scombrus)

Flesh and fatty acid compositions, total volatile basic nitrogen (TVB-N), lipid oxidation and aerobic plate count, Enterobacteriaceae, psychrotrophic bacteria were determined in raw and smoked mackerel during cold storage (three groups differing in way of packaging; unpacked (UP), vacuum packaging (VP) and modified atmosphere (MAP) at 7, 14, 21, 28, 35, and 42 days. The protein, fat content and n-3 polyunsaturated fatty acids increased after smoking. The pH value and TVB-N were significantly higher in unpacked mackerel. Initial malondialdehyde concentration in raw mackerel was lowered after smoking and then lipid oxidation was the most pronounced in unpacked mackerel. Hot smoking, vacuum packaging, and modified atmosphere reduced bacterial growth, while the microbial contamination in all groups was below the limits during the whole period of storage. However, physicochemical properties of unpacked mackerel exceeded the limits from day 35 on. The present study indicates a lowering of products of secondary lipid oxidation after smoking followed by accelerated lipid degradation during cold storage of unpacked smoked mackerel. It is suggested that the smoking process and appropriate packaging method can protect lipids as well as valuable polyunsaturated fatty acids from oxidation. Vacuum packaging and modified atmosphere ensured microbial quality and protein and lipid stability. Their use is recommended for extending the shelf life of smoked fish considering the initial microbial and also chemical quality before and after smoking.

Bioprospecting for Antithrombotic Polar Lipids from Salmon, Herring, and Boarfish By-Products

Marine polar lipids (PLs) have exhibited promising cardioprotection. In this study, marine by-products such as salmon heads (SHs), their brain, eyes and main optic nerves (SBEON), and head-remnants after SBEON removal (RemSH), as well as herring fillets (HFs), herring heads (HHs) and minced boarfish (MB), were evaluated as potential sustainable sources of such bioactive PLs. The antithrombotic bioactivities of PLs derived from these marine by-products were assessed for the first time in human platelets against platelet-activating factor (PAF), thrombin, collagen, and adenosine diphosphate (ADP), while their fatty acid composition was evaluated by gas chromatography–mass spectrometry (GC-MS). PLs from all marine by-products tested possess strong antithrombotic activities against aggregation of human platelets induced by all platelet agonists tested. RemSH, SBEON, HHs, HFs, and MB exhibited strong anti-PAF effects, similar to those previously reported for salmon fillets. PLs from MB had the strongest anti-collagen effects and PLs from SHs and SBEON were the most active against thrombin and ADP. PLs from HHs had similar antithrombotic effects with those from HFs in all agonists. RemSH was less active in all agonists, suggesting that SBEON is the main source of bioactive PLs in SHs. All PLs were rich in omega-3 polyunsaturated fatty acids (ω3PUFA), such as docosahexaenoic acid (DHA) and eicosapentaenoic (EPA) acid, with favourable low values of the ω6/ω3 ratio. Salmon, herring, and boarfish by-products are rich sources of bioactive marine PLs with potent antithrombotic and cardioprotective properties.

Thermal and oxidative stability of Atlantic salmon oil (Salmo salar L.) and complexation with β-cyclodextrin

The thermal and oxidative stability of Atlantic salmon oil (Salmo salar L.) as well as its β-cyclodextrin (β-CD) complexation ability has been verified for the first time. The main omega-3 fatty acids, EPA and DHA, were significantly degraded, even at 50 °C. Their relative concentrations decrease from 6.1% for EPA and 4.1% for DHA to 1.7% and 1.5% after degradation at 150 °C, respectively. On the other hand, the relative concentrations of monounsaturated and saturated fatty acids remained constant or slightly increased by a few percent after degradation (e.g., from 10.7% to 12.9% for palmitic acid). Co-crystallization of ASO with β-CD at a host–guest ratio of 1:1 and 3:1 from an ethanol–water mixture and kneading methods has been used for the preparation of β-CD/ASO complexes. The analysis of the complexes by thermogravimetry, differential scanning calorimetry (DSC), and Karl Fischer titration (KFT) as well as the decrease of the “strongly-retained” water content confirm the formation of the inclusion compound. Furthermore, the DSC parameters correlate well with the KFT kinetic data for β-CD/ASO complexes.

Stabilizing smoked salmon (Oncorhynchus gorbuscha) tissue after extraction of oil

Alaska salmon oils are rich in n-3 polyunsaturated fatty acids and are highly valued by the food and pharmaceutical industries. However, the tissue that remains after oil extraction does not have an established market. Discarded pink salmon (Oncorhynchus gorbuscha) tissues were preserved using a combination of smoke-processing and acidification with lactic acid bacteria (LAB). All samples were analyzed for moisture, protein, ash, and lipid contents. Bacterial cell counts, pH, and lactic acid concentrations were recorded as a measure of LAB viability. Neither raw nor smoked salmon were free from spoilage during 60 d of storage. Only fermented samples successfully stabilized below pH 4.7, while retaining lactic acid concentrations over 15 g/L during storage. When smoked, fermented salmon head tissues were dried, the pH of the resulting high-protein "cracker" was significantly lower than when crackers were prepared only from the smoked (but not fermented) salmon material. Both cracker varieties retained valuable polyunsaturated fatty acids. This research suggests that salmon-head tissues discarded after oil extraction represent a good source of protein and high-value fatty acids in a shelf-stable form.

PRACTICAL APPLICATION

Alaska salmon oils are rich in n-3 polyunsaturated fatty acids and are highly valued by the food and pharmaceutical industries. However, the tissue that remains after oil extraction does not have an established market. Material produced from salmon tissue discarded after oil extraction may represent a valuable resource for preparing high-protein crackers and other fish-based food products. In addition to providing a unique smoke-flavoring, the smoked, fermented fish material may also impart antioxidant factors thereby extending the shelf life of the product.