Enhancement of the nutritional properties of apple pomace by fermentation with autochthonous yeasts

•Fermentation of apple pomace increases its levels of nutritional and functional properties.•The increase in nutritional properties is yeast-dependent.•The use of fermented apple pomace broadens the scope of application of apple pomace in the food sector.

This paper focuses on the enhancement of the nutritional composition and phenolic compounds of apple pomace by solid state fermentation with autochthonous cider yeasts. Under the tested fermentation conditions (7 days, 25 °C), 3 yeast strains (S. cerevisiae, ref: 32; S. bayanus, ref: C6; and H. uvarum, ref: 62) were able to deplete fermentable sugars. Significant increases in protein (23-49%), fat (17-39%) and dietary fibre (30-41%) were detected in all cases with respect to unfermented apple pomace. The biotransformation increased the content of phenolic compounds, mainly quercetin and phloretin derivatives, as well as that of oleic and linoleic acids. The information derived from this study is relevant to revalorize apple pomace as a nutritive and functional foodstuff allowing the production of enriched foods.