Dr. habil Julia K. Keppler is Associate Professor (UHD) at the Laboratory of Food Process Engineering of Wageningen University & Research. Her research focuses on the targeted functionalization of proteins during extraction or processing in foods, encompassing dairy, plant, insect, mussel, and single cell proteins (including those produced by precision fermentation). The focus is on understanding protein-protein and protein-ingredient interactions during processing from the nanoscale (individual protein properties) to the mesoscale (protein aggregates such as fibrils, micelles) and macroscale (gels, emulsions, foams). The overall goal is to identify favorable protein sources (or mixtures of various sources) and processing conditions for producing meat and dairy alternatives of the future.

Julia Keppler (co-)authored over 60 scientific peer-reviewed papers and holds 3 patents. She obtained her PhD in 2014 at Kiel University (Germany) and her Habilitation in Food Technology in 2021. Since 2014, she was a junior research group leader at Kiel university and visiting post-doc at INRA (France). Since 2019, she is leading the protein functionalization group at the laboratory of Food Processing Engineering.

Cellular proteins: A sustainable source of food proteins

The aim of this project is to investigate sustainable production chains for cellular proteins based on the interrelationship between growth conditions, downstream processing and functionality for a range of selected microorganisms, including microalgae, bacteria, fungi and yeast. For each organism, three main areas will be investigated: Growing conditions, downstream processing and structure-function relationships.

This project is a collaboration with Wageningen University, NIZO and Wageningen Food and Biobased Research (WFBR) and will provide insights into the applicability, sustainability and feasibility of using microbial biomass and/or its fractions as functional protein-rich ingredients in food applications.

CO2-eating Microbes4Food  

Wanqing Jia

Our world is populated by microbes. Some of them are edible and contain valuable proteins. Others can grow on CO2 and thus actively contribute to reducing harmful climate gases. What if you could not only combine the two, but the proteins were also highly functional?  

Cupriavidus necator could be such a miracle microbe. It is one of few biotechnologically relevant hosts that can grow on hydrogen and formate, which both can be produced from renewable electricity - hence electro-microbial production. In addition, it produces high-quality proteins in high concentrations and can grow independently of seasonal variations and needs neither land nor antibiotics. However, not much is known about the use of this microbe for food protein production. That is why Wageningen researchers from different disciplines have joined forces to explore the potential of this microbe from production to food application.  

We will produce our miracle microbe in sufficient quantities, fractionate the proteins, categorise their techno-functionality, think about ways to improve the microbial food functionality and publish the results. Once we have demonstrated functionality, we can draw attention to the potential of these microbes and have a sufficient basis for a research proposal towards realizing efficient, large-scale production and food applications. 

This is a seed money project together with Nico Claassens (MIB) and Laurice Pouvreau (WFBR)

Plant protein modification by phenolic compounds and fibers: synergy between plant proteins, polyphenols and fibres inherent to plant materials

PhD student Iris Faber

This project aims to gain fundamental understanding of synergy between plant proteins, polyphenols and/or fibres that can improve structure formation in plant-based foods. Mildly fractionated plant protein ingredients are multicomponent systems. Possible synergistic interactions between minor constituents in plants (e.g. polyphenols and fibres) and plant proteins are not completely mapped out. For this reason, we aim to study potential synergistic interactions between these inherent minor constituents and plant proteins from yellow pea, soy and potato in order to form ingredients that can replace currently used structuring agents (e.g. modified starch, methylcellulose and gellan gum) in plant-based foods. Analyses methods such as SDS-PAGE, differential scanning calorimetry (DSC), protein surface hydrophobicity (ANSA), HPLC, HPSEC and FTIR are necessary to relate changes in physicochemical properties to depicted functional properties in emulsion and gel model systems.

This work is part of the project ‘Clean label solutions for plant-based foods’ co-financed by the Top Consortium for Knowledge and Innovation Agri & Food by the Dutch Ministry of Economic Affairs under contract number LWV20.68.

Project webpage:

https://www.wur.nl/en/project/clean-label-solutions-for-structuring-plant-based-foods.htm

Project link: Clean label solutions for structuring plant based foods.

LinkedIn: linkedin.com/in/iris-faber-09589859

Plant protein emulsion: Development of a vegan ketogenic supplement to support muscle health

PhD student Melissa Mosselman

In this multidisciplinary project we aim to develop a plant-based ketogenic supplement (high fat, protein and no carbohydrates) that, on top of the normal diet, can contribute to maintaining a better muscle health status during aging. During the development of the supplement, several factors will be taken into account: 1/ Physical and chemical stability of the emulsion, 2/ Digestibility of the plant proteins and lipids, and 3/ Organoleptic properties (i.e. taste and smell). The impact of the selected ketogenic supplement on ketosis, whole body energy metabolism, muscle function, and fatigue will be evaluated during a (long-term) human intervention study. This project is in collaboration with the laboratory of Food Chemistry and the laboratory of Human and Animal Physiology.

This research is funded by the VLAG Graduate School and a collaboration between FPE, FCH (Marie Hennebelle) and HAP (Jaap Keijer and Silvie Timmers).

Project link: Designing a ketogenic supplement for muscle health.

LinkedIn: http://linkedin.com/in/melissamosselman

Mussel protein processing: Modification and characterization of mussel myofibrillar proteins as a novel source of protein

PhD student Maryam Moghadam

As marine species have attracted the attention of researchers as a source of bioactive compounds with potential economic benefit due to their use as ingredients in functional food, cosmetics, nutraceuticals, and pharmaceutical industries, we put our focus on investigating the biosynthetic potential of Blue mussel proteins for the formation of tailored valuable bio compounds as well as an alternative source of protein.

In this project, we aim to explore the physicochemical and functional properties of mussel myofibrillar and sarcoplasmic proteins. Furthermore, the effect of ultrasound treatment to modify the protein characteristics will be assessed.

This research project is funded by The Federal Ministry of Education and Research (BMBF, Germany) and is in collaboration of Kiel University, GEOMAR Helmholtz Centre for Ocean Research in Germany and Wageningen University and research.

Precision fermentation: recombinant Casein aggregation

PhD student Laurens Antuma

In recent years, more and more consumers adopt a (partially) vegan or vegetarian diet. Consequently, the demand for dairy alternatives has grown. Current alternatives for dairy products are mainly present in the form of plant-based cheese or milk, which differ considerably from their dairy counterparts in many aspects. Since recently, caseins can be produced recombinantly by bacteria or yeasts through fermentation, paving the way for the production of a vegan dairy alternative of acceptable quality. This project aims to meet consumer demand for such alternatives by determining the functionality of recombinant caseins, studying their assembly into casein micelles and explore ways to produce cheese from them.

This project is part of the GOUDA project in collaboration with Formo, the University of Hohenheim, the Technical University of Berlin and Time-Travelling Milkman and is a Eurostar project (Eurostars - Project E! 114377 GOUDA) 

Project link:

GOUDA - Revolutionising the dairy industry by developing the first animal-free cheese

LinkedIn: https://www.linkedin.com/in/laurens-antuma/

Precision fermentation: recombinant Lactoglobulin aggregation

PhD student Loes Hoppenreijs

In this project, we investigate the use of recombinant proteins as a more sustainable alternative to animal-derived protein, and in particular we focus on the milk protein ß-lactoglobulin. Instead of cows, cell cultures (such as bacteria or yeasts) can be used as small factories to produce recombinant milk protein. We study the purification, characterization and functionality (i.e., gelling) of ß-lactoglobulin to work towards its use as a food ingredient. Besides, we use recombinant ß-lactoglobulin as a tool to study the self-assembly upon heating, by inducing mutations.

This PhD project is funded by the german research foundation (DFG) priority programme DiSPBiotech (SPP1934), investigating dispersity-, structural- and phase-changes of proteins and biological agglomerates in biotechnological processes.

Project link:

 (Amyloid) aggregation behavior of structurally modified recombinant beta-lactoglobulin

Project publication

• Engineering amyloid and amyloid-like morphologies of ß-lactoglobulin. https://www.sciencedirect.com/science/article/pii/S0268005X21007177

Linkedin: linkedin.com/in/loeshoppenreijs/

Milk protein modification by phenolic compounds: Effect on allergenicity

PhD student Kerstin Schild

Food allergies are a growing global health problem with a significant socio-economic impact on individuals, families and society. However, there is not yet an effective causal therapy for manifest allergy, so the treatment is to avoid the concerned foods as much as possible. In my work I deal with one of the main allergens of milk: ß-lactoglobulin. What exactly is responsible for the allergenic potential of a protein is still largely unknown. Therefore, by modifying ß-lactoglobulin with secondary plant compounds, we are trying to find out possible properties of the protein that are related to its allergenic potential. We start in a very simple matrix, only ß-lactoglobulin and a phenolic compound. Step by step, we approach a more complex system by adding further milk components (caseins, fatty acids, etc.) so that we can study the modification process under food conditions.

The main work is done at the chair Food Technology at Kiel University (Germany) (https://www.foodtech.uni-kiel.de/de). In corporation with the Research Center Borstel, we are conducting the immunological tests for the project (https://fz-borstel.de/index.php/de/sitemap/programmbereich-asthma-und-allergie/klinische-und-molekulare-allergologie-prof-dr-uta-jappe/mission#innercontent).

This project is founded by the Federal Agency of Food and Agriculture (Germany)

Project link: Genetic and chemical modification of ß-lactoglobulin: Investigation of correlations between the allergenic potential and functional and structural properties.

LinkedIn: https://de.linkedin.com/in/kerstin-schild-01b79621a

Insect protein processing: Biofractionation and mild processing of edible insect protein

PhD student Luc Sweers

 Insects are a promising alternative protein source. Currently, the industrial processing of insects severely impairs the native protein functionality. Mild alternative methods are expected to retain these properties to a larger extent. However, the scientific knowledge about the effects of these mild alternative methods on the insect proteins is currently limited. The aim of this project is therefore to study the effects of mild alternative methods that retain to a larger extent the physicochemical and functional property of the insect proteins in comparison to traditional processing methods.

This project is a collaboration of Food Process Engineering (FPE) and Food Quality and Design (FQD) 

Project link: Biofractionation and mild processing of edible insect protein.

Link to WUR FQD: https://www.wur.nl/en/Research-Results/Chair-groups/Agrotechnology-and-Food-Sciences/Food-Quality-and-Design-1.htm

LinkedIn: https://nl.linkedin.com/in/luc-sweers/en

Project Publications: https://www.sciencedirect.com/science/article/pii/S0260877421002855 (Dry fractionation for protein enrichment of animal by-products and insects: A review)

Oxidative milk protein modification

PhD student Laura Fitzner

The aim of this project is to investigate the influence of (oxidative) modifications through physical or chemical treatments on functionality of the whey protein ß-lactoglobulin. In this context, we will focus on the temperature-induced aggregation for the formation of certain functional aggregate structures. The structural and physicochemical protein alterations and oxidative modifications through the pre-treatment as well as during the aggregation process will be followed. Furthermore, aggregation kinetics and aggregate morphology will be investigated. This knowledge can be used to design protein aggregates for specific applications as well as to control process-related aggregation of protein-based ingredients.

This research is part of the priority program SPP1934 - Dispersity, structure and phase changes of proteins and biological agglomerates in biotechnological processes – of the German Research Foundation (DFG). The main research part takes place at Kiel University in close cooperation with Wageningen University (FPE).