Journal Pre-proofs Upcycling of Belgian endive (Cichorium intybus var. foliosum) by-products. Chemical composition and functional properties of dietary fibre root powders Anna Twarogowska, Christof Van Poucke, Bart Van Droogenbroeck PII: S0308-8146(20)31306-6 DOI: https://doi.org/10.1016/j.foodchem.2020.127444 Reference: FOCH 127444 To appear in: Food Chemistry Received Date: 10 January 2020 Revised Date: 24 June 2020 Accepted Date: 26 June 2020 Please cite this article as: Twarogowska, A., Van Poucke, C., Van Droogenbroeck, B., Upcycling of Belgian endive (Cichorium intybus var. foliosum) by-products. Chemical composition and functional properties of dietary fibre root powders, Food Chemistry (2020), doi: https://doi.org/10.1016/j.foodchem.2020.127444 This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. © 2020 Elsevier Ltd. All rights reserved. 1 Upcycling of Belgian endive (Cichorium intybus var. 2 foliosum) by-products. Chemical composition and functional 3 properties of dietary fibre root powders. 4 Anna TWAROGOWSKA*, Christof VAN POUCKE, Bart VAN DROOGENBROECK 5 ILVO (Flanders Research Institute for Agriculture, Fisheries and Food), Technology and 6 Food Science Unit, Brusselsesteenweg 370, BE-9090 Melle, Belgium; 7 [email protected], [email protected], 8 [email protected] 9 *Corresponding author; [email protected]; 10 mobile: +32 494 40 26 23, Brusselsesteenweg 370, BE-9090 Melle, Belgium 11 Abstract 12 By-products of Belgian endive represent an interesting yet underutilised source of dietary 13 fibre (DF). Dietary fibre concentrates (DFC) that are low in sugar and neutral in taste are 14 sought by the food industry to increase DF content and improve texture in food products. The 15 aim was to set up a biorefinery process to produce DFC from forced roots of Belgian endive 16 (DFC-BE) and characterise the resulting product. As a control, non-treated forced roots 17 powder (FRP-BE) was tested. Water extraction significantly (p<0.05) decreased the content 18 of sugars, phenolic acids (PA) and sesquiterpene lactones (SL) in DFC-BE. In contrast, total 19 dietary fibre concentration (TDF) was higher in DFC-BE (81.82 g/ 100g DW) in comparison 20 to FRP-BE (49.04 g/100g DW). DFC-BE offers an excellent water holding capacity (WHC) 1 21 of 14.71 g water/g DW and a swelling capacity (SWC) of 23.46 mL water/g DW, suggesting 22 possible use as a functional food ingredient. 23 Keywords 24 Belgian endive, By-products, Hydration properties, Phenolic acids, Sesquiterpene lactones, 25 Dietary fibre, Dietary fibre concentrates, Biorefinery 26 27 1. Introduction 28 Rising challenges for food security and environmental issues have led to increasing interest in 29 bio-economy and more sustainable production. A circular economy and its goal of “zero 30 waste” is gaining attention. In the agri-food sector, which generates substantial amounts of 31 underutilised biomass fractions, this has spurred research into using these by-products and 32 waste fractions as raw material for new products and applications (Faustino et al., 2019). One 33 of the possible approaches for effective utilisation of biomass is the biorefinery concept, 34 which aims to obtain multiple products by applying cost-efficient fractionation technologies. 35 It focuses on the recovery of different types of valuable biomolecules which can be used, e.g. 36 as functional ingredients, food additives and nutraceuticals (Carciochi et al., 2017). 37 Besides the transition to bio-economy, a growing number of consumers are shifting their diets 38 to plant-based foods and clean labels, i.e. minimally processed, natural products. This trend is 39 forcing the food industry to look for new sources of natural ingredients (Aschemann-Witzel, 40 Varela, & Peschel, 2019). 41 In Europe, crops from the Cichorium genus (Asteraceae) are economically important, 42 especially in Belgium, the Netherlands, France, and Italy. The most valuable and well-known 43 leafy vegetables on the European market are Belgian endive (Cichorium intybus var. 2 44 foliosum), Radicchio rosso (Cichorium intybus var. foliosum) and endive (Cichorium endivia). 45 At the same time, industrial chicory (Cichorium intybus var. sativum) is grown for the 46 extraction of inulin (Barcaccia, Ghedina, & Lucchin, 2016). Unavoidably, food waste and by- 47 products are generated during the production of the edible Belgian endive crop. White 48 Belgian endive heads are forced during a 21 day period in the dark at 16-20°C. Each year in 49 the EU, approximately 300,000-400,000 tons of forced roots are produced but they currently 50 have no high-value use, often with a fate as compost or animal feed (Eurostat, 2020). 51 However, these forced roots are a very interesting feedstock for the biorefinery concept: they 52 are available year-round and they have an attractive chemical composition, being rich in 53 sugars, dietary fibres (DF) and bioactive compounds such as phenolic compounds (PC) and 54 sesquiterpenes lactones (SLs). 55 According to the European Food Safety Authority (2010), the recommended daily intake of 56 dietary fibres should be around 25-38 g/day for adults. Chemical composition of DF and its 57 preparation influences its functional properties, which are vital in food applications. The most 58 common properties are water holding capacity (WHC), oil holding capacity (OHC) and 59 swelling capacity (SWC) (Garcia-Amezquita, Tejada-Ortigoza, Serna-Saldivar, & Welti- 60 Chanes, 2018). The inclusion of DF with these qualities in food products can improve quality 61 parameters such as texture, viscosity and shelf-life (Elleuch et al., 2011). 62 Plants defence mechanism against predators is related to a bitter taste, which is associated 63 with the presence of phenols and terpenes (Drewnowski & Gomez-Carneros, 2000). A high 64 concentration of these compounds can significantly affect consumer acceptance of plant- 65 based foods. However, in some cases such as beer and tonic water, a bitter taste is appreciated 66 (Drewnowski & Gomez-Carneros, 2000). 3 67 PC are present in the plant kingdom as a broad diversity of structures, from simple phenolic 68 acids to highly complex flavonoids. These bioactive compounds are known for their 69 antioxidant activity (Cheynier, 2012). 70 SLs are characteristic secondary metabolites for plants from the Asteraceae family. Besides 71 being responsible for the typical bitter taste of crops in the Cichorium genus, they also possess 72 a wide range of biological activities (anti-bacterial, anti-fungal, and anti-inflammatory). This 73 had led to their popularity as an active ingredient in traditional medicines to cure diarrhoea, 74 burns and influenza (Chadwick, Trewin, Gawthrop, & Wagstaff, 2013). 75 The aim of the present work was to set up a simple, cost-efficient biorefinery process to 76 prepare dietary fibre powders from forced roots of the Belgian endive and to assess their 77 potential as a fibre-rich functional food ingredient. The chemical composition, bioactive 78 compounds and dietary fibre profile of the obtained powders were characterised, and their 79 functional properties were evaluated. Additionally, sugars and short-chain carbohydrates, 80 phenolic acids and sesquiterpene lactones in the aqueous extracts were characterised to 81 estimate its potential for further valorisation in food and drink applications. 82 2. Material and Methods 83 2.1. Plant material 84 In total, 20 kg of forced roots of Belgian endive (Cichorium intybus var. foliosum), var. 85 ‘Sweet Lady’ were provided by NPW (National Proeftuin Voor Witloof, Herent, Belgium). 86 Sweet Lady was chosen as Belgian endive variety for this proof-of-concept study as this 87 relatively new variety which shows good quality and has a long production period. 88 2.2. Production of fibre rich powder from Belgian endive forced roots 4 89 Forced roots of Belgian endive were washed in cold water to remove remaining soil. Next, the 90 outer ends of the roots were removed at the top and bottom (±1 cm each end). Further, the 91 roots were cut into julienne form, about 5 cm long and 2.5 x 2.5 mm width, using a Robot 92 Coupe (CL50 Ultra, Mont-Sainte-Geneviève, France). The cut roots were soaked in water at 93 60 °C and stirred (120 rpm) at the ratio 1:4 (roots: water) during 3 h. Once per hour the water 94 was changed and collected for further analyses. After 3 h the roots were separated from the 95 water via a strainer and placed in a hot air oven (60 °C, 6-8h) to dried to a moisture content 96 below 10%. Dried samples were milled by using a ring sieve size 0.5 mm (Ultra centrifugal 97 mill ZM 200, RETSCH, Haan, Germany) to obtain dietary fibre preparations. Powders were 98 stored at room temperature in an aluminium coated plastic bags until further analysis. 99 The powder obtained after washing, cutting and drying the forced roots of Belgian endive 100 (without the soaking step) was called forced root powder (FRP-BE). The powder obtained 101 after an extra soaking step was called dietary fibre concentrate (DFC-BE) (see Figure 1.). 102 2.3. Chemical composition 103 2.3.1. Moisture, protein and ash content 104 Moisture content (MC) was measured by use of halogen moisture analyser (HB43-S, Mettler 105 Toledo, Schwerzenbach, Switzerland).