title: The identification of degradation products and degradation pathway of malvidin-3-glucoside and malvidin-3,5-diglucoside under microwave treatment.
abstract: Understanding the degradation of anthocyanins (Acys) during microwave treatment is required for the application of this novel technology to fruit and vegetable processing. The pH 3.5 buffer solutions containing 50mg/l malvidin-3-glucoside (Mv-3-glu) and malvidin-3,5-diglucoside (Mv-3,5-diglu), respectively, were treated with microwaves at 700 W. In comparison, the samples were heated at 98±2 °C in a water bath. In total, nine degradation products were detected (using LC-UV/Vis-MS/MS) for each Acys after microwave treatment. Anthocyanone A, hydroxycoumarins and dihydroxy phenylacetaldehyde were characterised as the main degradation products of both Acys under microwave conditions, which were not detected in the thermal treatment. In addition, syringic acid, 2,4,6-trihydroxybenzaldehyde, coumarin glucosides and 2,6-dimethoxyphenol were found simultaneously under the microwave and thermal treatments. During the microwave treatment, hydrogen peroxide was formed and resulted in the Baeyer-Villiger-type oxidation of the Acys, which was the main degradation pathway. At the same time, the conventional thermal degradation pathway of Acys also occurred.
authors.affiliation: College of Food Science and Nutritional Engineering, National Engineering Research Centre for Fruits and Vegetables Processing, Key Laboratory of Fruits and Vegetables Processing, Ministry of Agriculture, Engineering Research Centre for Fruits and Vegetables Processing, Ministry of Education, China Agricultural University, Beijing 100083, China.
authors.forename: Mengyao
authors.initials: M
authors.lastname: Zhao
authors.forename: Yinghua
authors.initials: Y
authors.lastname: Luo
authors.forename: Yuan
authors.initials: Y
authors.lastname: Li
authors.forename: Xin
authors.initials: X
authors.lastname: Liu
authors.forename: Jihong
authors.initials: J
authors.lastname: Wu
authors.forename: Xiaojun
authors.initials: X
authors.lastname: Liao
authors.forename: Fang
authors.initials: F
authors.lastname: Chen
mesh_terms: D000079:Acetaldehyde / Q000031:analogs & derivatives* / Q000032:analysis; D000872:Anthocyanins / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid; D003512:Cyclohexanones / Q000032:analysis*; D005960:Glucosides / Q000032:analysis* / Q000737:chemistry*; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D008872:Microwaves; D053719:Tandem Mass Spectrometry
chemical_list: C521179:8-glucopyranosyl-2,4-dihydroxy-6-oxocyclohexa-2,4-dienyl acetic acid; D000872:Anthocyanins; D003512:Cyclohexanones; D005960:Glucosides; C458419:malvidin-3-glucoside; D000079:Acetaldehyde; C502603:malvin; C013192:phenylacetaldehyde
keywords: Anthocyanins; Degradation; Identification; Malvidin-3,5-diglucoside; Malvidin-3-glucoside; Microwave