title: Extraction and neoformation of antioxidant compounds by pressurized hot water extraction from apple byproducts.
abstract: There is a great interest in searching for new environmentally sustainable techniques to enhance the use of agricultural byproducts. In this work, a response surface methodology was used to study the influence of the two independent variables, temperature (25-200 °C) and extraction time (3-17 min), in the extraction of antioxidants by pressurized hot water extraction (PHWE) from industrial apple byproducts. The optimized extraction method for determination of flavonols was at 120 °C and 3 min, giving a predicted total yield of flavonols of 1.3 μmol/g dry apple byproduct. Results obtained suggest that new antioxidant compounds were formed at the higher extraction temperatures. A desirability function response surface, considering maximum antioxidant capacity and minimal formation of brown color, was calculated and gave an optimum of 125 °C and 3 min. This latter PHWE method correlates well with the obtained results for flavonols; thus, a desirability function is a simpler alternative method for finding optimal conditions.
authors.affiliation: Department of Chemistry, Centre for Analysis and Synthesis, Lund University, PO Box 124, SE-221 00, Lund, Sweden. Merichel.Plaza@chem.lu.se
authors.forename: Merichel
authors.initials: M
authors.lastname: Plaza
authors.forename: Victor
authors.initials: V
authors.lastname: Abrahamsson
authors.forename: Charlotta
authors.initials: C
authors.lastname: Turner
mesh_terms: D000975:Antioxidants / Q000032:analysis / Q000302:isolation & purification*; D005591:Chemical Fractionation / Q000295:instrumentation / Q000379:methods*; D002851:Chromatography, High Pressure Liquid; D006358:Hot Temperature; D007220:Industrial Waste / Q000032:analysis; D027845:Malus / Q000737:chemistry*; D010936:Plant Extracts / Q000032:analysis / Q000302:isolation & purification*; D011312:Pressure; D014866:Waste Products / Q000032:analysis*
chemical_list: D000975:Antioxidants; D007220:Industrial Waste; D010936:Plant Extracts; D014866:Waste Products