How does storage time and processing affect the flavour of seaweed?
Oct 05, 2022

Matís have started with some of their trials in work package 3. Sophie Jensen, a reserach scientist at Matís, Iceland, gives us a summary of their latest trial where they analysed the odor components of seaweed and the effects of storage time and processing methods:

Perception of the flavour of foods is a complex process that involves the senses of smell and taste. The compounds in food and beverages that our noses can detect as smell are so called volatile organic compounds (VOCs) that are emitted as gases. Since different compounds will give a different smell, depending on the amount and combination of these compounds within a food it will provide a flavour fingerprint for that specific food. Different compounds smell differently due to differences in how they stimulate or react with the sensors we have in our nose cavity. Some of them we perceive as pleasant and others as unpleasant (e.g., ammonia). Depending on how sensitive we are to the different compounds, the same compound can smell different for different persons. Since food and beverages are a complex mixture of hundreds of such VOCs it is very difficult for a normal person to differentiate between them. To help identifying and quantifying certain “wanted” and “unwanted” chemical compounds present in a product, technology such as Head-Space SPME GC-MS can be used (showed in video below).

Video showing how volitile compounds can be analysed using HS-SPME coupled to GC-MS. Since the compounds are volitile, when heated they will start to vaporise, if they are caught in a small space they will concentrate there and it is possible to adsorb them onto an SPME fiber, when saturated, this fiber can then be injected into a GC where the volitile compounds are desorbed from the fiber by means of heating and helium gas flow.

This has been done for a few seaweed species and we know that different seaweed species can be separated according to selected VOCs associated with their odour characteristics. The VOCs composition can however be drastically changed by the processing procedure and storage of the seaweed, which in turn can affect the odour perception of the final product. For application in food, some seaweed odour components may be desirable in some applications but unwanted in others. In SusKelpFood the seaweed species Alaria esculenta have been harvested and processed in different ways by different commercial producers and have been analysed by Head-Space SPME GC-MS. Since the compounds are volatile, when heated they will start to vaporise, if they are caught in a small Head-Space they will concentrate there and it is possible to adsorb them onto an SPME fibre, when saturated, this fibre can then be injected into a GC (Gas Chromatograph) where the VOCs are desorbed from the fibre by means of heating and helium gas flow and can be identified by an MS (Mass Spectrometer).

These trials will tell us something about the effect of different storage times and processing methods on the VOC profile in the seaweed. This information can then be combined with studies on the odour characteristics of the seaweed to maybe identify the formation of compounds produced during processing that might be unsuitable for food applications.

For further reading, read the newly published article: