Obtaining and characterization of olive (Olea europaea L.) pomace flour: An investigation on its applicability in gluten-free cake formulations added with xanthan

Olive pomace (OP) is a recognized cheap and abundant source of nutrients and gelling material. This study explored for the first time a total substitution of wheat flour by a mix of pulp-enriched flour derived from OP (OPF) with corn flour (CF) and/or rice flour (RF) for obtaining gluten-free (GF) cakes. OPF markedly increased lipid (9.37%-9.85%) and fiber (1.82%-3.16%) contents of GF cakes, which showed to have bioactivity in terms of total phenolic content (12.5-19.5 mg GAE/g) and antiradical activity (62.3%-90.1%). Xanthan gum (XG) addition (0.25% w/w) to GF cakes improved crumb structure, color, and helped to reduce crumb hardiness. A simplex centroid mixture design indicated interactions between OPF, CF, and RF affecting the firmness of GF cakes (1.97-7.48 N). Overall, F2 and F3 led to the best formulations with OPF, as this highly valuable and functional ingredient when associated with XG technologically improved GF cake formulations. Novelty impact statement The pomace obtained from olive oil extraction processing, a low commercial value by-product was freeze-dried and incorporated into gluten-free cake formulations as flour (OPF) to partially replace corn and rice flours. The performance of OPF with and without hydrocolloid (xanthan gum) was assessed, resulting in a highly nutritive, with pleasant appearance and acceptable texture cakes. This investigation highlights the potential application of bioactive-rich OPF as an alternative ingredient for incorporation in foods destined for celiac patients.