title: The optimization of phenolic compounds extraction from cactus pear (Opuntia ficus-indica) skin in a reflux system using response surface methodology.
abstract: OBJECTIVE
  To extract, quantify, and evaluate the phenolic content in Opuntia ficus-indica skin for their antioxidant capacity with three different methods (ABTS, DPPH, and lipid oxidation) and to optimize the extraction conditions (time, temperature and ethanol concentration) in a reflux system.
  
  
  METHODS
  The extraction process was done using a reflux system. A San Cristobal II experimental design with three variables and three levels was used. The variables evaluated were time of extraction (h), concentration of ethanol (%, v/v) and temperature (°C). The extraction process was optimized using a response surface methodology.
  
  
  RESULTS
  It was observed that at higher temperature more phenolic compounds were extracted, but the antioxidant capacity was decreased. The optimum conditions for phenolic compounds extraction and antioxidant capacity mixing the three methods were as follows: 45% of ethanol, 80 °C and 2 hours of extraction. Values obtained in our results are little higher that other previously reported.
  
  
  CONCLUSIONS
  It can be concluded the by-products of Opuntia ficus-indica represent a good source of natural antioxidants with possible applications in food, cosmetics or drugs industries.
authors.affiliation: Food Research Department, School of Chemistry, Universidad Autónoma de Coahuila, Saltillo, 25280, Coahuila, México.
authors.forename: Aguirre Joya
authors.initials: AJ
authors.lastname: Jorge
authors.forename: De La Garza Toledo
authors.initials: de LG
authors.lastname: Heliodoro
authors.forename: Zugasti Cruz
authors.initials: ZC
authors.lastname: Alejandro
authors.forename: Belmares Cerda
authors.initials: BC
authors.lastname: Ruth
authors.forename: Aguilar Cristóbal
authors.initials: AC
authors.lastname: Noé
mesh_terms: D000975:Antioxidants / Q000032:analysis* / Q000737:chemistry; D001713:Biphenyl Compounds / Q000737:chemistry; D015227:Lipid Peroxidation; D029747:Opuntia / Q000737:chemistry*; D010636:Phenols / Q000032:analysis* / Q000737:chemistry; D010851:Picrates / Q000737:chemistry; D010936:Plant Extracts / Q000032:analysis* / Q000737:chemistry; D013451:Sulfonic Acids / Q000737:chemistry; D013844:Thiazoles / Q000737:chemistry
chemical_list: C000594526:2,2-azinobis-3-ethylbenxothiazoline-6-sulfonic acid; D000975:Antioxidants; D001713:Biphenyl Compounds; D010636:Phenols; D010851:Picrates; D010936:Plant Extracts; D013451:Sulfonic Acids; D013844:Thiazoles; C004931:1,1-diphenyl-2-picrylhydrazyl
keywords: Antioxidants; Opuntia ficus-indica; Prickly pear; Reflux, Phenolics; Response surface methodology