title: Effect of ultrasonic treatment on the polyphenol content and antioxidant capacity of extract from defatted hemp, flax and canola seed cakes.
abstract: The effectiveness of ultrasonic extraction of phenolics and flavonoids from defatted hemp, flax and canola seed cakes was compared to the conventional extraction method. Ultrasonic treatment at room temperature showed increased polyphenol extraction yield and antioxidant capacity by two-fold over the conventional extraction method. Different combinations of ultrasonic treatment parameters consisting of solvent volume (25, 50, 75 and 100 mL), extraction time (20, 30 and 40 min) and temperature (40, 50, 60 and 70 °C) were selected for polyphenol extractions from the seed cakes. The chosen parameters had a significant effect (p<0.05) on the polyphenol extraction yield and subsequent antioxidant capacity from the seed cakes. Application of heat during ultrasonic extraction yielded higher polyphenol content in extracts compared to the non-heated extraction. From an orthogonal design test, the best combination of parameters was 50 mL of solvent volume, 20 min of extraction time and 70 °C of ultrasonic temperature.
authors.affiliation: Department of Food Science, University of Otago, PO Box 56, Dunedin 9054, New Zealand. Electronic address: suesiang.teh@otago.ac.nz.
authors.forename: Sue-Siang
authors.initials: SS
authors.lastname: Teh
authors.forename: Edward John
authors.initials: EJ
authors.lastname: Birch
mesh_terms: D000975:Antioxidants / Q000302:isolation & purification*; D029688:Brassica napus / Q000737:chemistry*; D002188:Cannabis / Q000737:chemistry*; D019597:Flax / Q000737:chemistry*; D059808:Polyphenols / Q000302:isolation & purification*; D013010:Sonication; D013696:Temperature; D013997:Time Factors
chemical_list: D000975:Antioxidants; D059808:Polyphenols
keywords: Antioxidant capacity; Defatted seed cake; Flavonoids; Polyphenols; Total phenolic content; Ultrasonic