Tengiliður
Sophie Jensen
Verkefnastjóri
sophie.jensen@matis.is
Samantekt:
Hákarl is a unique Icelandic product obtained by fermenting and drying Greenland shark (Somniosus microcephalus), produced for centuries. However, little is known about the chemical and microbial changes occurring during the process. In this study, on a small industrial scale, fresh and frozen shark meat was fermented for eight and seven weeks, respectively, and then dried for five weeks. During the fermentation, trimethylamine N-oxide levels decreased to below the limit of detection within five weeks and pH increased from about 6 to 9. Simultaneously, trimethylamine and dimethylamine levels increased significantly. Total microbiological viable plate counts, and specific spoilage organisms increased during fermentation but decreased during drying. Culture-independent analyses revealed gradual shifts in the bacterial community structure as fermentation progressed. During the first three weeks of fermentation, Photobacterium was dominant in the fresh group, compared to Pseudoalteromonas in the frozen group. During the end of the process the groups became more alike with Atopostipes, Pseudomonas and Tissierella being dominant. The results indicate the possibility to reduce the duration of the fermentation period and since the bacterial composition in ready-to-eat hákarl was similar to other fermented products there might also be a potential to standardize the microbial community with starter cultures to gain an optimal fermentation procedure.