Approximately 50 % of fruits and vegetables ends up being wasted during industrial processing, in the form of peels, cores, pomace, unripe or damaged fruits and vegetables. Given its relatively stable yield and controllable quality, this waste stream has high valorisation potential.
Valorisation of waste streams by for example turning these into high quality powdered ingredients can promote full crop use and close the cycle of our food production chain. This will bring economic, societal and environmental benefits. Conventionally, processing methods for ingredients in food industry are very much directed towards purification. However, purifying food ingredients often requires harsh and energy-consuming extraction conditions. This also negatively affects the nutritional properties and techno-functionality of the ingredients and moreover such purified ingredients are perceived as less natural by consumers. The focus of this PhD project will be on the design of mild and energy-efficient extraction procedures (e.g. aqueous extraction, dry fractionation) to produce nutritious and functional dietary fibre enriched concentrates from fruit and vegetable waste streams and apply those fractionated ingredients to prepare prototype healthy foods.
We will first select a typical and challenging argo-food by-stream as starting point. Then we will develop and evaluate different processing routes (for milling and fractionation) to obtain dietary fibre-enriched ingredient fractions that have high nutritional value and functionality. A mild, simple and energy-saving production process is preferred. We will analyse the influence of processing on the nutritional properties, e.g. how does processing affect presence of bioactives and functional properties of fibres? Subsequently, the processing approach and parameters will be optimized to reduce the loss of bioactive molecules, antioxidant capacity and to steer the functional properties of the dietary fibres. Finally, the ingredients obtained with the optimized procedure will be evaluated during preparation of few prototype foods. To further verify and promote the developed processing method, we will prepare dietary fibre concentrates from several other agro-food by-streams as well.