title: Rapid and Efficient Conversion of All-E-astaxanthin to 9Z- and 13Z-Isomers and Assessment of Their Stability and Antioxidant Activities.
abstract: An optimized isomerization method was developed by heating all-E-astaxanthin in ethyl acetate (70 °C) with I-TiO2catalyst, yielding 22.7% and 16.9% of 9Z- and 13Z-astaxanthin, respectively, in 2 h, with 92-95% purity after semipreparative HPLC purification. 13Z-Astaxanthin had higher antioxidant activity than all-E- and 9Z-astaxanthins in oxygen radical absorbing capacity assay for lipophilic compounds, photochemiluminescence, and cellular antioxidant activity (CAA) assays, and 9Z-astaxanthin was higher in DPPH radical-scavenging activity assay and lower in CAA assay. All isomers were relatively stable between pH 2.0 and 11.6, except 13Z- and 9Z-astaxanthins at pH 2.0, suggesting they may be converted after passing the gastric phase in vivo. Metal ions did not significantly (p < 0.05) affect the stability. Results of the current study provides a means for further study into the mechanisms related to in vivo transformation and bioavailability of Z-astaxanthins, and their application in the development of functional foods and nutraceutical products.
authors.affiliation: School of Food Science and Technology, Jiangnan University , 1800 Lihu Avenue, Wuxi, Jiangsu 214122, China.|Guelph Research and Development Centre, Agriculture and Agri-Food Canada , 93 Stone Road West, Guelph, Ontario N1G 5C9, Canada.
authors.forename: Cheng
authors.initials: C
authors.lastname: Yang
authors.affiliation: School of Food Science and Technology, Jiangnan University , 1800 Lihu Avenue, Wuxi, Jiangsu 214122, China.|State Key Laboratory of Food Science and Technology, Jiangnan University , 1800 Lihu Avenue, Wuxi, Jiangsu 214122, China.|National Engineering Research Center for Functional Food, Jiangnan University , 1800 Lihu Avenue, Wuxi, Jiangsu 214122, China.
authors.forename: Lianfu
authors.initials: L
authors.lastname: Zhang
authors.affiliation: Guelph Research and Development Centre, Agriculture and Agri-Food Canada , 93 Stone Road West, Guelph, Ontario N1G 5C9, Canada.
authors.forename: Hua
authors.initials: H
authors.lastname: Zhang
authors.affiliation: School of Food Science and Technology, Jiangnan University , 1800 Lihu Avenue, Wuxi, Jiangsu 214122, China.|College of Food Science, Heilongjiang Bayi Agricultural University , Daqing, Heilongjiang 163319, China.
authors.forename: Qingrui
authors.initials: Q
authors.lastname: Sun
authors.affiliation: Guelph Research and Development Centre, Agriculture and Agri-Food Canada , 93 Stone Road West, Guelph, Ontario N1G 5C9, Canada.
authors.forename: Ronghua
authors.initials: R
authors.lastname: Liu
authors.affiliation: School of Food Science and Technology, Jiangnan University , 1800 Lihu Avenue, Wuxi, Jiangsu 214122, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Li
authors.affiliation: College of Food Science and Engineering, Jiangxi Agricultural University , Nanchang 330045, Jiangxi China.
authors.forename: Leiyan
authors.initials: L
authors.lastname: Wu
authors.affiliation: Guelph Research and Development Centre, Agriculture and Agri-Food Canada , 93 Stone Road West, Guelph, Ontario N1G 5C9, Canada.
authors.forename: Rong
authors.identifier: http://orcid.org/0000-0001-6537-1820
authors.initials: R
authors.lastname: Tsao
mesh_terms: D000975:Antioxidants / Q000737:chemistry*; D007536:Isomerism; D015394:Molecular Structure; D010084:Oxidation-Reduction; D024341:Xanthophylls / Q000737:chemistry
chemical_list: D000975:Antioxidants; D024341:Xanthophylls; C005948:astaxanthine
keywords: 13Z-astaxanthin; 9Z-astaxanthin; all-E-astaxanthin; antioxidant activity; isomerization; metal ion; pH effect; semipreparative purification; stability