Phytochemicals
Current trends in food and agriculture, such as the protein transition, are creating a growing interest in natural plant-based food products and ingredients. As a result, phytochemicals (phyto meaning ‘plant’ in Ancient Greek) are becoming increasingly prevalent and important in food.
The term ‘phytochemicals’ describes a bewildering number of small molecules from plants. Common phytochemicals that occur in food include: flavonoids and isoflavonoids (e.g. in tea & liquorice), stilbenoids (e.g. in peanuts & grapes), hydroxycinnamic acids and their derivatives (e.g. in cocoa & potato), phenolamides (e.g. in oat & barley), and saponins (e.g. in soy & pea). Many of these phytochemicals are phenolic compounds, which are molecules that are particularly reactive and are prone to structural changes during plant growth, and during processing and storage of plant-based food products or ingredients. These structural changes modulate phytochemicals’ molecular and functional properties, consequently affecting the properties (e.g. colour and taste) of plant-based food products or ingredients.
The aims are to:
- Characterize phytochemicals in plant materials, agricultural or industrial by-products, food ingredients, and food products using advanced analytical techniques;
Example: Analysis of phenolamides present in barley rootlets to explore the potential of this by-product to prevent spoilage of alcohol-free beer. - Monitor changes in phytochemical composition during plant growth, and during processing and storage of plant-derived food products or ingredients;
Example: Study the reactions of flavonoids that cause browning during storage of ready-to-drink green tea. - Modify phytochemicals with chemical, enzymatic, or microbial approaches, to improve their properties;
Example: Exploiting enzymes as tools to modify phenolic compounds for the development of new antibiotics and natural food preservatives. - Study reactions and interactions of phytochemicals with proteins and micronutrients;
Example: Investigate whether the interaction of oat proteins with phenolic compounds can be used to increase the protein content of oat milk.
Focus
Advanced phytochemical analysis
Analysis and structure elucidation of phytochemicals is at the core of our work on these compounds, as it is essential in studying phytochemical reactivity. Due to the high structural diversity of phytochemicals, their analysis can be quite challenging. We develop analytical approaches to obtain structural information on individual phytochemical molecules, as well as overall compositional data of phytochemicals present in plant-derived materials (including industrial waste streams or by-products). To this end, we employ a diverse array of advanced analytical techniques, including ultra-high performance liquid chromatography (UHPLC), high-resolution mass spectrometry (HRMS), ion mobility spectrometry (IMS), and nuclear magnetic resonance (NMR) spectroscopy.
Oxidation of phenolic compounds
One of the most well-known examples of the oxidation of phenolic compounds is the enzymatic browning reaction that leads to formation of brown colour upon cutting or bruising of fruits. Besides undergoing enzymatic oxidation, phenolic compounds can auto-oxidise to form brown and insoluble reaction products. Phenolic oxidation reactions are often considered to be undesirable, as they can negatively affect the attractiveness of foods or ingredients. On the other hand, controlled (enzymatic) oxidative coupling may also be used as a tool to modulate the structure and properties of phenolic compounds, which can lead to improved bio- or techno-functionality. We study these reactions to tackle challenges associated with undesired oxidation as well as exploring the potential of controlled oxidation as a valuable universal tool to modify phenolic compounds.
Interactions of phytochemicals with other food molecules
Phytochemicals are known to interact covalently and non-covalently with various other food molecules, including proteins and metals. Protein-phenolic interactions can impact sensory, techno-functional, and bio-functional properties in plant protein products. Similar to our work on phenolic oxidation, we investigate how these interactions can be prevented or how they may be exploited to enhance the functionality of both plant proteins and phenolic compounds. With regards to metal-phenolic interactions, we study the resulting formation of dark discolouration (e.g. in iron-fortified food products) and explore opportunities related to the complexation of metals by phenolic compounds.
Research Projects
Current:
- Oxidation of green tea phenolics. Junfeng Tan
- Bio-purification of plant proteins: elimination of off-flavours, anti-nutritional compounds and phytoestrogens. Pauline Damhof
- ProTip – Understanding protein-phenolic interactions: Tipping the scales in our favour! Solange Ha
- Unlocking the antioxidant potential of co-passengers of plant protein ingredients in emulsions. Quirine Hafkamp
Completed:
- Fungal prenyltransferases as tools to produce antimicrobial prenylated phenolics. Pimvisuth Chunkrua, defence date: 15-04-2026
- In-depth characterization of food lipids and phytochemicals with ion mobility mass spectrometry. Carlo de Bruin, defence date: 04-12-2025
- Tapping into oxidative coupling of barley phenolamides. Annemiek van Zadelhoff, defence date: 28-10-2024.
- Discolouration by iron-phenolic interactions – Colourful insights into the mechanisms and proposed solutions for food fortification. Judith Bijlsma, defence date: 14-09-2023.
- Prebiotic potential of green and black tea phenolics – Metabolite and microbiota profiling, and green biorefinery for sustainable production. Zhibin Liu, defence date: 07-04-2021.
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Research themes
Food Chemistry
The chair group Food Chemistry, led by Jean-Paul Vincken, is engaged in research and education about food chemistry.