Valorization of Beetroot Pomace as a Flour Fortifier, Functional Ingredient and Dietary Supplement

The aim of this study was to evaluate the potential of minimally processed beetroot pomace (BP), obtained from an industrial juice producer selected as a case study, converted into a stable beetroot pomace flour (BPF) at an industrial scale level, for flour fortification, functional confectionery development, and dietary supplementation. It was characterized by a high dietary fiber content (~27 g/100 g) and a very low carbohydrate-to-fiber ratio (1.9). High level of total phenolics and flavonoids (14.1 ± 0.1 mg GAE/g and 1.43 ± 0.1 mg QE/g), betacyanins and betaxanthins (898 ± 54 and 960 ± 65 µg/g), as well as pronounced antioxidant (FRAP 31.5 ± 1.1 and DPPH 25.8 ± 2.9 µmol TE/g), anti-hyperglycemic and anti-inflammatory activity (27.3 ± 1.3% and 41.0 ± 3.4%) remained upon in vitro digestion. Replacing 14–28% of cereal and pseudo-cereal flour with BPF reduced the carbohydrate-to-fiber ratio to the recommended 10:1, while incorporation of 20% BPF into cookies reduced this ratio by 2.5-fold and the glycemic index from ~56 to ~30. Furthermore, long-term supplementation of standard and high-fat/high-sucrose diet with BPF (0.5% w/w) reduced feed efficiency by 1.7 and 2.6-fold respectively, and improved glucose tolerance in C57BL/6J mice. Findings show the effectiveness of the by-product in bridging the fiber intake gap and body weight regulation.