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Research shows the possibility of repurposing fish industry-by products to generate fish flavours

21 October 2015

Recent research carried out by teams from the Universities of Northumbria and the West of England has explored the possibility of repurposing waste material in the fish industry. The study has centred on using what would otherwise be considered waste products (fish powder hydrolysates) as a starting point for manufacturing of flavour products.

The research team utilised a number of protease enzymes to derive amino acid rich ingredients from the waste products in order to generate higher value flavour components. These amino acid extracts, when combined with glucose or fish oil could then be sold back in to the industry sector. It was shown that a combination of peptidases (endo and exo) lead to the highest concentration in free amino acids, particularly for leucine, lysine and glutamic acid, with 4-heptenal and 2, 4-heptadienal being the main volatile/flavour compounds created. Some pyrazines and increased concentrations of the alcohols 1-octen-3-ol and 1-hepten-4-ol were also seen against controls, with these being compounds commonly seen in cooked seafood. The primary chemical components examined in the study, and those considered affecting the flavour profiles most, were pyrazines, sulphur, alcohols, ketones and aldehydes.

The analysis performed during the study involved the moisture, ash, total protein (by Kjeldahl method) and extractable fat content/fatty acid composition (by GC-FID) of the fish powder being determined by comparison to reference standards. The volatiles that were produced were analysed by using GC-MS and comparing their spectra to a database available through the National Institute of Standards and Technology 2008 as well as published literature for comparison. The quantification of the compounds was then carried out using external calibration curves.

This research is beneficial in that a source of sugar, fish oil and a variety of amino acids derived via peptidase enzymes from fish by-products have been shown successfully to produce volatiles that could become high value flavour precursors. This is potentially another business avenue for the fish industry as well as reducing wastage. Although various enzymes were shown to produce different amounts of amino acids the main differentiator was seen to be fish oil, which had a great impact on the volatile compounds being generated; its addition enhanced the concentration of lipid oxidation products such as hexanal, heptanal, 4-heptanal, 2, 4, - heptadienal, 1-penten-3-ol or 1-octen-3-ol, these being compounds in seafood identified in the flavour profile of cooked seafood as pleasant by sensory panellists.

Future research but with different types/concentrations of fish oil and combined with sensory evaluation, could allow investigation of consumer acceptance. This could then lead to a more precise procedure being identified for generating high value flavours from waste products. 

Our suite of state-of-the-art technologies and techniques including GC-MS means we can support with flavour analysis. Find out more.

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