Wine lees as functional ingredient to produce biscuits fortified with polyphenols and dietary fibre

Wine lees, a by-product of winemaking process, still contains bioactive molecules (especially fibres and polyphenols) with potential functional properties. Considering the high frequency of consumption and high versatility of biscuits, the purpose of this work was to replace wheat flour with 10% (F10) and 20% (F20) of wine less flour (WLF) to produce biscuits with an improved nutritional profile. This study assessed the impact of substituting 10 and 20% of WLF on the physico-chemical, nutritional, textural, sensory, and volatile aroma compound characteristics. These results were compared with those of a control biscuit exclusively made with wheat flour (F0). The statistical comparison allowed for demonstrating how the fortified biscuits (F10 and F20) had significantly higher values of fibres, proteins, phenolic compounds, antioxidant activity, and higher oxidative stability than the control (F0). Different flavonoids and anthocyanins were detected in F10 and F20, such as ellagic acid and malvidin-3-acetil glucoside with a concentration greater than 200 mg/kg. The increased fibres and polyphenols in the F20 led to a significant lowering in glycaemic index (pGI) and starch hydrolysis (HI). Based on simulated colonic fermentation, F20 also exhibited a slight prebiotic effect supported by the significant increase in lactic acid bacteria cell density compared to F0.