molecules Article Metabolic Profiling of Pitaya (Hylocereus polyrhizus) during Fruit Development and Maturation Yawei Wu 1,2 , Juan Xu 3, Yizhong He 4, Meiyan Shi 3, Xiumei Han 2, Wenyun Li 2,3, Xingwu Zhang 2 and Xiaopeng Wen 1,* 1 Key Laboratory of Plant Resource Conservation and Germplasm Innovation in Mountainous Region, Institute of Agro-Bioengineering/College of Life Sciences, Guizhou University, Guiyang 550025, Guizhou, China;
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[email protected] (X.Z.) 3 Key Laboratory of Horticultural Plant Biology, Huazhong Agricultural University, Wuhan 430070, Hubei, China;
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[email protected] (M.S.) 4 Citrus Research Institute, Southwest University/National Citrus Engineering Research Center, Chongqing 400712, China;
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[email protected]; Tel./Fax: +86-851-882-98-514 Received: 7 February 2019; Accepted: 18 March 2019; Published: 20 March 2019 Abstract: Pitaya (Hylocereus polyrhizus) has attracted much interest from consumers as it is a novelty fruit with high nutrient content and a tolerance to drought stress. As a group of attractive pigment- and health-promoting natural compounds, betalains represent a visual feature for pitaya fruit quality. However, little information on the correlation between betalains and relevant metabolites exists so far. Currently, color (Commission International del’Eclairage, CIE) parameters, betalain contents, and untargeted metabolic profiling (gas chromatography-time-of-flight-mass spectrometry, GC–MS and liquid chromatography tandem mass spectrometry, LC–MS) have been examined on ‘Zihonglong’ fruits at nine different developmental stages, and the variation character of the metabolite contents was simultaneously investigated between peel and pulp.