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Signe Hjerrild Nissen

PhD Fellow, PhD Student

Signe Hjerrild Nissen


PhD project: Underlying mechanisms behind biochemical changes in green and blue biomasses during processing and storage

University: Aarhus University

Department: Department of Food Science

Main supervisor: Trine Kastrup Dalsgaard, Associate Professor, AU-FOOD

Project supervisors: Morten Ambye-Jensen, Associate Professor, AU-ENG, Lene Stødkilde, Assistant Professor, AU-ANIS and Annette Bruhn, Senior researcher, AU-BIOS

Project term: April 15 2021 – April 14 2024

Master’s degree: MSc in Engineering (Sustainable Biotechnology), Aalborg University Copenhagen


Green and blue biomasses are promising sustainable substitutes for generating ingredients for human consumption as they contain valuable components. Several processing methods have been investigated, especially for generating a protein fraction. So far, the emphasis has mainly concerned protein profile and yield. However, different processing methods affect the composition of the outcome. Some of the affected constituents might include the concentration and composition of protein, amino acids, vitamins, fatty acids, and minerals. Moreover, the oxidative stability of the protein can be affected, which can compromise the nutritional value and functional properties. Although it is well recognized that the selection of processing methods is important, the fundamental understanding of the underlying mechanisms behind chemical changes is limited in novel alternatives as seaweed and leafy legumes. Thus, additional investigation in this area is imperative to gain a broader understanding concerning processing methods and the related outcome. This can provide essential knowledge for further investigation on these biomasses to obtain nutritional products for human consumption.


The aim of this project is to investigate biochemical changes and oxidative stability upon different processing methods of green and blue biomasses to gain knowledge about the underlying mechanisms related to these changes.

Research outline

This project investigates a green biomass (Alfalfa) and a blue biomass (Ulva sp.), which are promising sources of protein. The focus of the project is an insight into product composition and process-induced changes in terms of nutritional content and storage stability, where different processing techniques (e.g. heat and acid precipitation and membrane filtration) will be investigated. This will lead to fundamental knowledge that can describe the relationship and underlying mechanisms between biochemical changes and the oxidative stability when applying different processing techniques. Furthermore, the outcome will be a tool to optimize processing parameters regarding product quality.

Partners of collaboration

Aarhus University Centre for Circular Bioeconomy (CBIO)

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