Abstract
In order to ensure continuous supply of seaweed materials for processing or final use as food or feed the appropriate preservation technique to keep the quality is required. Freezing or drying technologies are applied, but both are relative expensive as they demand significant energy supply. Ensiling technologies with the reduction of storage pH is an alternative preservation method and very few reports on acid preservation or ensiling are available. In addition, most of the published data focuses on the quality and changes of carbohydrates leaving proteins and amino acids without deserved attention. The objective of our studies was to characterize and study the quality changes of S. latissima during different storage conditions. The preservation effect of addition of acid, or by addition of acid producing bacteria, and different storage temperatures were evaluated. Quality of the preserved seaweeds was estimated by microbiological status, chemical composition including changes in amount and composition of amino acids formation of desirable and unwanted degradation products. Furthermore, the effect of preservation method on protein extractability was assessed. Proteins were extracted with an ultrasound assisted alkali extraction. 1H NMR spectroscopy was applied for a non-targeted profiling of biochemical changes due to enzymatic – and microbial activity during the preservation.
It was observed that storage temperature can play a key role for seaweeds preserved with lactic acid bacteria. Amount of total amino acids were slightly reduced in acid preserved seaweed, but quality of protein defined by percentage of essential amino acids and protein efficient ratio (PER) were similar to seaweeds preserved with acid producing bacteria. Preservation with acid producing bacteria enhanced the protein extractability in comparison to acid preservation, as well as fresh S. latissima biomass. The results indicate that preservation with acid producing bacteria is a potential preservation method for S. latissima promoting the further use for protein-rich food and feed ingredients.
It was observed that storage temperature can play a key role for seaweeds preserved with lactic acid bacteria. Amount of total amino acids were slightly reduced in acid preserved seaweed, but quality of protein defined by percentage of essential amino acids and protein efficient ratio (PER) were similar to seaweeds preserved with acid producing bacteria. Preservation with acid producing bacteria enhanced the protein extractability in comparison to acid preservation, as well as fresh S. latissima biomass. The results indicate that preservation with acid producing bacteria is a potential preservation method for S. latissima promoting the further use for protein-rich food and feed ingredients.