**4. Conclusions**

Olive mill wastewaters (OMW) were explored as inexpensive, precious and valuable sources of bioactive molecules to be employed in the production of antioxidant-enriched milk-based products. In this regard, lyophilized OMW (LOMW) were involved in a radical grafting reaction to synthesize a tara gum conjugate, suitable as a thickening agen<sup>t</sup> in the preparation of pear puree-based pudding. Chemical composition of LOMW was evaluated by 1H-NMR and HPLC-MS/MS analyses and oleuropein aglycone derivative (5.8 μg mL−1) was detected as the main compound. Additionally, this olive process by-product was characterized by evaluation of the total phenolic content, flavonoids, phenolic acids and anthocyanins amount, providing a straight measure of its antioxidant features. LOMW was able to inhibit ABTS radical, displaying in the aqueous medium, scavenger properties almost one order of magnitude increased compared to the organic one. LOMW reactive species and tara gum chains were involved in an eco-friendly grafting reaction to synthesize a polymeric conjugate that was characterized by spectroscopic, calorimetric and toxicity studies. Antioxidant properties of the polymeric conjugate were also evaluated, suggesting its employing as a thickening agen<sup>t</sup> in the preparation of pear puree-based pudding. Milkbased foodstuff showed high performance of consistency and relevant antioxidant features over time (28 days) in comparison with its non-functional counterparts confirming LOWM as an attractive source for the development of functional foods.

**Supplementary Materials:** The following supporting information can be downloaded at: https: //www.mdpi.com/article/10.3390/foods11020158/s1, Table S1: Acquisition parameters for MRM HPLC-MS/MS analyses.

**Author Contributions:** Conceptualization: U.G.S., D.R., F.A. and M.L.C.; Data curation: U.G.S., P.C. (Pasquale Crupi), M.M., C.O.R. and V.R.; Formal analysis: U.G.S., P.C. (Paolino Caputo), M.M., P.C. (Pasquale Crupi) and R.M.; Funding acquisition: M.L.C., F.A., D.R. and C.O.R.; Investigation: U.G.S., P.C. (Paolino Caputo), P.C. (Pasquale Crupi), V.R. and F.A.; Methodology; U.G.S., P.C. (Pasquale Crupi), C.O.R., F.A. and V.R.; Supervision: M.L.C., C.O.R. and D.R.; Writing—original draft: U.G.S., P.C. (Paolino Caputo), P.C. (Pasquale Crupi), R.M. and F.A.; Writing—review & editing: D.R., C.O.R., U.G.S. and M.L.C. All authors have read and agreed to the published version of the manuscript.

**Funding:** This work was financially supported by AGER 2 Project, gran<sup>t</sup> n. 2016-0174, AGER Foundation—Olive Tree and Oil: Competitive-Claims of olive oil to improve the market value of the product, EU project 820587—OLIVE-SOUND—Ultrasound reactor—The solution for a continuous olive oil extraction process H2020-EU.2.1.—INDUSTRIAL LEADERSHIP-EIC-FTI-2018–2020-Fast Track to Innovation (FTI)—European Union's Horizon 2020 research and innovation program under gran<sup>t</sup> agreemen<sup>t</sup> No. 820587. University founds and POR Calabria FESR-FSE 2014/2020-Linea (B) Azione 10.5.12.

**Institutional Review Board Statement:** Not applicable.

**Informed Consent Statement:** Not applicable.

**Data Availability Statement:** Not applicable.

**Conflicts of Interest:** The authors declare no conflict of interest.
