Magnesium Supplementation Alters Leaf Metabolic Pathways for Higher Flavor Quality of Oolong Tea

Jiuliang Xu, Liangquan Wu, Bingxin Tong, Jiaxu Yin, Zican Huang, Wei Li and Xuexian Li
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Jiuliang Xu: The Key Plant-Soil Interaction Laboratory, Department of Plant Nutrition, Ministry of Education, China Agricultural University, Beijing 100193, China
Liangquan Wu: International Magnesium Institute, Fujian Agriculture and Forestry University, Fuzhou 350002, China
Bingxin Tong: The Key Plant-Soil Interaction Laboratory, Department of Plant Nutrition, Ministry of Education, China Agricultural University, Beijing 100193, China
Jiaxu Yin: International Magnesium Institute, Fujian Agriculture and Forestry University, Fuzhou 350002, China
Zican Huang: International Magnesium Institute, Fujian Agriculture and Forestry University, Fuzhou 350002, China
Wei Li: Fujian Key Laboratory of Agro-Product Quality and Safety, Fujian Academy of Agricultural Sciences, Fuzhou 350003, China
Xuexian Li: The Key Plant-Soil Interaction Laboratory, Department of Plant Nutrition, Ministry of Education, China Agricultural University, Beijing 100193, China

Agriculture, 2021, vol. 11, issue 2, 1-12

Abstract: Oolong tea, one of the most famous tea beverages in China, contains specialized metabolites contributing to rich flavors and human health. Accumulation patterns of such metabolites and underlying regulatory mechanisms significantly vary under different growth conditions. To optimize quality and yield while minimizing environmental effects, three treatments were designed in this study: Conventional fertilization, optimized fertilization, and optimized fertilization supplemented with magnesium (Mg). We investigated the yield, taste quality, primary and secondary metabolites of oolong tea, and found that a substantial reduction in chemical fertilizers (nutrient optimization by reducing 43% N, 58% P 2 O 5 and 55% K 2 O) did not affect the tea yield in this study. Interestingly, Mg fertilization is an important factor influencing amino acid and sugar accumulation in oolong tea, resulting in higher concentrations of total free amino acids and a lower ratio of tea polyphenols (TP) to free amino acids (FAA). Gas chromatography-time-of-flight mass spectrometry (GC-TOF-MS) and liquid chromatography-high resolution mass spectrometry (LC-HRMS) combined multivariate analyses revealed distinct features of metabolite accumulation in leaves of three different treatments, as indicated by 34 differentially accumulated characteristic compounds. The levels of serine, aspartic acid, isoleucine, phenylalanine, theanine, and proline were reduced by fertilizer optimization and increased by Mg supplementation. Mg particularly promoted theanine accumulation favoring a stronger umami taste of oolong tea, while decreasing astringency and bitter metabolites. Thus, Mg application paves a new path for tea quality improvement in Southern China where Mg deficiency in the soil is a frequent limiting factor for crop production.

Keywords: oolong tea; optimized fertilization; magnesium; taste quality; metabolomics (search for similar items in EconPapers)
JEL-codes: Q1 Q10 Q11 Q12 Q13 Q14 Q15 Q16 Q17 Q18 (search for similar items in EconPapers)
Date: 2021
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (1)

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