General Effect of ensilage on the taste of Ulva sp.

To increase the storage of the harvested Ulva sp. but also to change/ameliorate their taste, VITO investigated the ensilage of this green seaweed.

In the first part of the project, the effect of different parameters on the ensilage of Ulva was tested. These first tests indicated that the bacterial inocula Holdbac Plus, Holdbac Listeria, Holdbac VEGE and Kefir resulted in a faster decrease in pH and higher concentrations of lactic acid compared to the Ulva to which no bacterial inocula were added. From these first tests it was also clear that Viscozyme, a mix of enzymes, had to be added to open the cell wall of the Ulva resulting in a better ensilage. It was not totally clear if washing of the Ulva to remove the salts was needed since the effect of washing depended from batch to batch of ensilage. It was not completely clear if washing the Ulva to remove the salts was needed since the effect of washing varied from batch to batch within the ensiled batches.

Sensory evaluation at the ILVO Food Pilot indicated that ensilage of Ulva completely modified the sensory profile of frozen/thawed Ulva (Figure). A strong sour taste and odor were detected in the ensiled Ulva. In addition, the grassy and seafood flavor of frozen/thawed Ulva was reduced (or masked by the sour flavor) because of the ensilage. Interestingly, both Kefir and Holdbac significantly increased the fruity odor of the ensiled Ulva.