Chemical Compositions of Fruit and Vegetable Pomaces from the Beverage Industries

Purpose To determine the chemical composition of fruit (apple and orange) and vegetable (carrot) pomaces in order to assess their potential use in value-added products. Methods A range of bromatological and mass spectrometry-based metabolomic analyses were employed to chemically characterise apple, orange, and carrot pomaces. Results Dietary fibre was the most abundant component of the substrates, comprising most by cellulose and pectin. Another major component of the pomaces were soluble sugars. Nevertheless, all pomaces showed low levels of lipids (below 5%) with most of the fatty acids being unsaturated. Besides, each pomace was found to have a more diverse metabolomic composition than earlier described, and the variation between batches was not significantly different for most parameters tested. Conclusion This study shows that these food-grade pomaces have good potential for bioconversion into high-value-added products via microbial fermentation, and not solely for the extraction of a small number of chemical compounds. In addition, untargeted metabolomic tools showed great potential in providing a more comprehensive analysis of waste biomass composition, as well as potentially being useful in food and feed safety assessment. Graphical Abstract