The report investigates using vegetable side streams, treated using a thermophysical technique known as steam explosion, as food ingredients and tests their functionality in model food products.
The incorporation of added fibre is of interest to food manufacturers to enable high fibre claims to be made about products. Food processing residues from vegetables offer scope for improved functionality of existing food products as well as a route for reducing ingredient waste and improving process sustainability.
Results and conclusions
Mild thermophysical processing produced insoluble fibres with stronger textural properties. The increase in colour after processing was sufficiently slight. These processed insoluble fibres were incorporated into food products, by drying and milling for bakery products and by blending the undried fibre for use in a breakfast drink. At 2% of the flour chicory fibre could be incorporated as a milled product into bread without adverse effects i.e. no loss of loaf volume and no impairment of taste or texture.
With respect to the application of undried chicory pulp in a breakfast drink an optimum recipe could be determined. Based on consumer sensory trials, an optimal recipe was determined for a particle size of 7,5 mm – 10 mm and a percentage addition of 7,6%; the resulting overall score was 6,6, which is objectively considered an acceptable score for the palatability of insoluble chicory root fibre inside a prototype breakfast drink. Based on these results a business model, including a production process and different commercial scenarios will be established.
The results demonstrate a technologically feasible route for the utilisation of defined, traceable residues from the food manufacturing industries to impart functional characteristics when reformulating existing product recipes. In both the bread product and the breakfast drink, it was possible to add chicory fibre to produce a high-fibre product with no adverse effect on product quality when compared against a conventional equivalent product.
Two candidate vegetable side-streams were chosen: carrot fibre from a vegetable juice production facility and chicory fibre from an inulin factory. Both side-streams represent a source of pectic-polysaccharide-rich fibre. Carrot fibre has many applications as a binder or extender in meat products such as sausages and pates, to reduce water purging in canned meats and to improve textures in bakery products such as breads, cakes and tortillas. Chicory pulp is largely used as an animal feed (Maertens et al. 2014) though there have been some applications in food for human consumption (Cardoso et al. 2007).
Pulp residues from carrot juice and chicory inulin manufacturers were subjected to thermophysical processing using microwaves, steam-explosion and pressure cooking to assess the potential to improve their properties for incorporation into foods.
This case study sits within Work Package 6 (WP6) (Valorisation of waste streams and co-products) of the EU H2020 funded REFRESH project. One of the key objectives of WP6 is to increase the exploitation of food and packaging waste by helping business stakeholders to identify waste streams appropriate for valorisation regarding a) their robustness of supply, quality and composition and b) for which products and outputs might be realised that are technologically feasible, economically viable, legislatively compliant and environmentally sustainable / beneficial.
Peter Ryden, Graham Moates, Keith Waldron, Matthe de Roode (2018) Report of the REFRESH Project, D6.4 Impact assessment texture processing