Carrot pomace powder: a promising source of polyphenols and prebiotics for improving gut health

This study aimed to evaluate the properties of carrot pomace, including its nutritional composition, physiochemical attributes, change in polyphenols and prebiotic potential during in vitro gastrointestinal digestion and fermentation.

The study involved evaluating the nutritional and physiochemical properties of carrot pomace. It also assessed an in vitro gastrointestinal digestion model to evaluate changes in polyphenol levels and antioxidant properties at different digestive stages. The study also examined the prebiotic potential by analysing the growth of Lactobacillus acidophilus and short-chain fatty acid production by in vitro fermentation assay. High-resolution liquid chromatography mass spectrometry analysis was used to identify polyphenolic compounds before and after digestion.

The findings demonstrated that carrot pomace powder contained 43.59% dietary fibre. During in vitro digestion, polyphenol content (total phenolic and flavonoid content) and antioxidant properties (ferric-reducing antioxidant power (FRAP) assay, 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay, and 2,2-azinobis-ethylbenzothiozoline-6-sulphonic acid (ABTS) assay) were significantly different at each digestive stage, with strong correlations observed among polyphenols and antioxidant. Notably, polyphenol recovery percentages were significant throughout the digestion phases. Carrot pomace also exhibited prebiotic properties by promoting the growth of L. acidophilus and enhancing short-chain fatty acid production. High-resolution LC–MS analysis revealed eight polyphenolic compounds and their metabolites found in carrot pomace powder (CPP) before and three polyphenolic compounds present after in vitro gastrointestinal digestion.

This research indicated that polyphenols from carrot pomace could potentially play a role in gastrointestinal and colonic health. The valorisation of carrot residues into useful functional ingredient is a novel approach for developing more sustainable food systems as well as the concept of sustainable food.