_Applied_  
_sciences_  
_Article_  
**A Quick, Green and Simple Ultrasound-Assisted Extraction for the Valorization of Antioxidant Phenolic Acids from Moroccan Almond Cold-Pressed Oil Residues**  
**[PERSON] 1,2,3,t(r)**, [PERSON] 4,t, [PERSON] 4, [PERSON] 1,2,**  
**[PERSON] 5, [PERSON] 1,6, [PERSON] 7(r), [PERSON] 4,*,t(r)** and  
[PERSON][PERSON] 1,2,*,t(r)**  
1 Laboratoire de Biologie des Ligneux et des Grandes Cultures, INRA USC1328, Orleans University, 45067 Orleans CEDEX 2, France; [EMAIL_ADDRESS] (D.T. ); [EMAIL_ADDRESS] (S.D. ); [EMAIL_ADDRESS] (L.G.) 2 Bioactifs et Cosmetiques, CNRS GDR 3711 Orleans, 45067 Orleans CEDEX 2, France  
3 Department of Pharmaceutical Botany, Faculty of Pharmacy, Mahidol University, Bangkok 10400, Thailand  
4 Laboratoire de Biologie des Plantes et des Micro-Organismes, Faculte des Sciences, Universite Mohamed Ier, Oujda 60000, Maroc; [EMAIL_ADDRESS] (A.E. ); [EMAIL_ADDRESS] (M.A.) 5 Department of Protticultural Sciences, College of Agriculture & Natural Resources, University of Tehran, P.O. Box 4111, Karaj 3158777871, Iran; [EMAIL_ADDRESS]  
6 Institut de Chimie Organique et Analytique (ICOA) UMR7311, Universite d'Orleans-CNRS, 45067 Orleans CEDEX 2, France  
7 School of Pharmacy, Raffles University, Neemrana, Alwar 301705, Rajasthan, India; [EMAIL_ADDRESS]  
* Correspondence: [EMAIL_ADDRESS] (M.A. ); [EMAIL_ADDRESS] (C.H. ); Tel. : +212-536-500-601 (M.A. ); +33-237-309-753 (C.H.) \(\dagger\) These authors have equal contribution of the first authors. \(\ddagger\) These authors have equal contribution of the senior authors. Received: 16 April 2020; Accepted: 6 May 2020; Published: 10 May 2020  
**Featured Application: A quick, green, and simple ultrasound-assisted microextraction was here developed and validated for a quick and simple evaluation of total phenolic content from almond oil residues for their valorization as a source of antioxidant compounds. **  
**Abstract:** Almond (_Prunus dulcis_ (Mill.) [PERSON]) is one of the most important nut crops both in terms of area and production. Over the last few decades, an important part of the beneficial actions for health associated with their consumption was attributed to the phenolic compounds, mainly accumulated in almond skin. Interestingly, after cold-pressed oil extraction, most of these antioxidant phenolic compounds are retained in a skin-enriched by-product, a so-called almond cold-pressed oil residue. In Morocco, the fifth highest ranking producer in the world, this production generates an important part of this valuable byproduct. In the present study, using a multivariate Box-Behnken design, an ultrasound-assisted extraction method of phenolic compounds from Moroccan almond cold-pressed oil residue was developed and validated. Response surface methodology resulted in the optimal extraction conditions: the use of aqueous ethanol 53.0% (_v/v_) as a green solvent, applying an ultrasound frequency of 27.0 kHz for an extraction duration of 29.4 min. The present ultrasound-assisted extraction allowed substantial gains in terms of extraction efficiency compared to conventional heat reflux extraction. Applied to three different local _Beldi_ genotypes growing at three different experimental sites, the optimal conditions for ultrasound-assisted extraction led to a total phenolic content of 13.86 mg/g dry weight. HPLC analysis revealed that the main phenolic compounds from this valuable byproduct were: chlorogenic acid followed by protocatechic acid, _p_-hydroxybenzoic acid, and _p_-coumaric acid. The accumulation of these phenolic compounds appeared to be more dependent on the genetic background than on the environmental impact here represented by the three experimental culture sites. Both in vitro cell free and cellular antioxidant assays were performed, and revealed the great potential of these extracts. In particular, correlation analysis provided evidence of the prominent roles of chlorogenic acid, protocatechuic acid, and \(p\)-hydroxybenzoic acid.