Effect of salted-drying on bioactive compounds and microbiological changes during the processing of karasumi-like Chinook salmon (Oncorhynchus tshawytscha) roe product

The physicochemical, biochemical and microbiological changes of karasumi-like Chinook salmon (Oncorrhynchus tshawytscha) roe were determined during 20 days of salted-drying processing. Colour parameters (L*, a*, and b*), water activity (aw) and the pH value decreased at the end of the processing. Total bacterial and LAB counts (log CFU/g) varied over the processing period. Saturated fatty acids, such as palmitic acid (C16:0) and stearic acid (C18:0), and unsaturated fatty acids such as palmitoleic acid (C16:1), oleic acid (C18:1), and arachidonic acid (C20: 4), were significantly decreased (p < 0.05), but conversely, gamma-linolenic acid (C18:3), and eicosapentaenoic acid (C22:5) were increased (p < 0.05) by salted-drying time. Cholesterol and tocopherol contents were reduced, while the astaxanthin and lutein contents were increased (P < 0.05) during the salted-drying process. Salmon karasumi-like product is a high nutrition product that contains a substantial content of functional compounds.

Digestibility in the gastrointestinal tract and migration to blood of β'-component (Onk k 5), a major salmon roe IgE-binding protein

The major allergen of chum salmon (Oncorhynchus keta) roe is the β'-component (Onc k 5, β'-c), which is a yolk protein and a fragment of vitellogenin. When yolk content containing β'-c was orally administered to mice, β'-c passed through the gastrointestinal tract and was excreted in feces without marked degradation. The direct administration of β'-c to ligated jejunal and ileal loops showed that β'-c was absorbed through the small intestine and transferred into the blood. Immunohistochemical staining showed that orally administered β'-c was distributed from the apical side to the basal side of intestinal epithelial cells, suggesting that endocytosis may be involved in the intestinal absorption of β'-c. In conclusion, β'-c is absorbed along a large portion of the small intestine and circulates in the blood stream without significant digestion. The resistance of β'-c to gastrointestinal digestion seems to contribute to its strong allergenicity.