title: Metabolite profiling of red and white pitayas (Hylocereus polyrhizus and Hylocereus undatus) for comparing betalain biosynthesis and antioxidant activity.
abstract: Metabolite profiling of red and white pitayas (Hylocereus polyrhizus and Hylocereus undatus) was performed using gas chromatography-time-of-flight-mass spectrometry and ultraperformance liquid chromatography-quadrupole-time-of-flight-mass spectrometry with multivariate analysis. Different species and parts of pitayas (red peel, RP; white peel, WP; red flesh, RF; and white flesh, WF) were clearly separated by partial least-squares discriminate analysis. Furthermore, betalain-related metabolites, such as betacyanins and betaxanthins, or their precursors were described on the basis of their metabolites. The results of antioxidant activity tests [1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS), and ferric reducing ability of plasma (FRAP)], total phenolic contents (TPC), total flavonoid contents (TFC), and total betacyanin contents (TBC) showed the following: RP ≥ WP > RF > WF. TPC, TFC, TBC, and betalain-related metabolites were higher in the peel than in the flesh and suggested to be the main contributors to antioxidant activity in pitayas. Therefore, peels as well as pulp of pitaya could beneficially help in the food industry.
authors.affiliation: Department of Bioscience and Biotechnology, Konkuk University , Seoul 143-701, Republic of Korea.
authors.forename: Dong Ho
authors.initials: DH
authors.lastname: Suh
authors.forename: Sunmin
authors.initials: S
authors.lastname: Lee
authors.forename: Do Yeon
authors.initials: do Y
authors.lastname: Heo
authors.forename: Young-Suk
authors.initials: YS
authors.lastname: Kim
authors.forename: Somi Kim
authors.initials: SK
authors.lastname: Cho
authors.forename: Sarah
authors.initials: S
authors.lastname: Lee
authors.forename: Choong Hwan
authors.initials: CH
authors.lastname: Lee
mesh_terms: D000975:Antioxidants / Q000737:chemistry* / Q000378:metabolism; D050858:Betalains / Q000096:biosynthesis*; D029421:Cactaceae / Q000737:chemistry / Q000145:classification / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D005419:Flavonoids / Q000737:chemistry / Q000378:metabolism; D005638:Fruit / Q000737:chemistry / Q000378:metabolism; D013058:Mass Spectrometry; D055432:Metabolomics; D010936:Plant Extracts / Q000737:chemistry* / Q000378:metabolism; D059808:Polyphenols / Q000737:chemistry / Q000378:metabolism
chemical_list: D000975:Antioxidants; D005419:Flavonoids; D010936:Plant Extracts; D059808:Polyphenols; D050858:Betalains