title: Microwave-Assisted Extraction of Phenolic Compounds from Almond Skin Byproducts (Prunus amygdalus): A Multivariate Analysis Approach.
abstract: A microwave-assisted extraction (MAE) procedure to isolate phenolic compounds from almond skin byproducts was optimized. A three-level, three-factor Box-Behnken design was used to evaluate the effect of almond skin weight, microwave power, and irradiation time on total phenolic content (TPC) and antioxidant activity (DPPH). Almond skin weight was the most important parameter in the studied responses. The best extraction was achieved using 4 g, 60 s, 100 W, and 60 mL of 70% (v/v) ethanol. TPC, antioxidant activity (DPPH, FRAP), and chemical composition (HPLC-DAD-ESI-MS/MS) were determined by using the optimized method from seven different almond cultivars. Successful discrimination was obtained for all cultivars by using multivariate linear discriminant analysis (LDA), suggesting the influence of cultivar type on polyphenol content and antioxidant activity. The results show the potential of almond skin as a natural source of phenolics and the effectiveness of MAE for the reutilization of these byproducts.
authors.forename: Arantzazu
authors.initials: A
authors.lastname: Valdés
authors.forename: Lorena
authors.initials: L
authors.lastname: Vidal
authors.forename: Ana
authors.initials: A
authors.lastname: Beltrán
authors.forename: Antonio
authors.initials: A
authors.lastname: Canals
authors.forename: María Carmen
authors.initials: MC
authors.lastname: Garrigós
mesh_terms: D000975:Antioxidants / Q000737:chemistry / Q000302:isolation & purification*; D005591:Chemical Fractionation / Q000295:instrumentation / Q000379:methods*; D002851:Chromatography, High Pressure Liquid; D008872:Microwaves; D015999:Multivariate Analysis; D010636:Phenols / Q000737:chemistry / Q000302:isolation & purification*; D010936:Plant Extracts / Q000737:chemistry / Q000302:isolation & purification*; D027861:Prunus / Q000737:chemistry*; D012639:Seeds / Q000737:chemistry*; D053719:Tandem Mass Spectrometry
chemical_list: D000975:Antioxidants; D010636:Phenols; D010936:Plant Extracts
keywords: HPLC-DAD-ESI-MS/MS; almond skin; antioxidant activity; linear discriminant analysis; microwave-assisted extraction; phenolic compounds