New food ingredients for a sustainable and healthy diet: the case of apple pomace

A huge amount of apple “pomace” consisting of skins, seeds and stalks is produced every year from industrial processing worldwide. The recovery and re-use of these by-products in the food chain could increase sustainability of apple industry and contribute to a better nutrition. Indeed apple pomace contains valuable phytochemicals and fibers. The nutritional value of apple pomace is especially linked to its high content of phloridzin. This phenolic compound is known to inhibit competitively the Na+/glucose co-transporter and is recognized as an anti-diabetic agent. The aims of this study were: to 1) to summarize the state of art of apple pomace potential food uses, and 2) to present novel results on the stability of phytochemicals in dried apple pomace. For the experimental study, apple pomace and control apple pulp were dehydrated at different moisture levels. Major components were analyzed by AOAC procedures. Phytochemicals were analyzed by HPLC. Antioxidant and antiglycation properties were determined by spectroscopic and fluorescence techniques. Moisture properties were studied by 1H NMR. Storage was carried out at 30 °C for 9 months and kinetic models for phytochemical degradation were developed. Phytochemical contents were more than one order of magnitude higher in the pomace than in the pulp of apple. These compounds showed long-term stability in the dried apple pomace, which was related to moisture properties. The distinctive composition, properties and stability of dried apple pomace support its exploitation on industrial scale for new product development. Some uses of apple pomace as a food ingredient have resulted successful in terms of consumers’ liking, whereas apple pomace benefits in terms of health improvement still remain to be validated.