Polyamines in tea processing

The stress-induced metabolites changes in the flavor formation of oolong tea during enzymatic-catalyzed process: A case study of Zhangping Shuixian tea

To interpret the environmental stresses induced dynamic changes of volatile and non-volatile constitutes in oolong tea leaves during enzymatic-catalyzed processes (ECP), metabolomic and proteomic studies were carried out using the processed leaf samples collected at the different stages of ECP for Zhangping Shuixian tea manufacture. Non-processed leaves were applied as control. Out of identified 980 non-volatiles and 157 volatiles, 40 non-volatiles and 8 volatiles were screened out as biomarkers, respectively. The integrated analysis on metabolites-proteins showed that phenylpropanoid biosynthesis, flavonoid biosynthesis, and phenylalanine metabolism were significantly enriched and highly correlated to the dynamic changes of key metabolites during ECP stage. A biological pathway network was constructed to illuminate the enzymatic-catalyzed production of critical flavoring compounds, including carbohydrates, amino acids, flavonoids, and volatile phenylpropanoids/benzenoids. The electronic-sensory analyses indicated leaf dehydration and mechanical wounding occurred over the sun-withering and turning-over steps are indispensable to form characteristic flavor of Shuixian tea.

Heterologous Expression and Characterization of Tea (Camellia sinensis) Polyamine Oxidase Homologs and Their Involvement in Stresses

Polyamine oxidase (PAO) is a key enzyme maintaining polyamine homeostasis, which affects plant physiological activities. Until now, the gene members and function of PAOs in tea (Camellia sinenesis) have not been fully identified. Here, through the expression in Escherichia coli and Nicotiana benthamiana, we identified six genes annotated as CsPAO in tea genome and transcriptome and determined their enzyme reaction modes and gene expression profiles in tea cultivar 'Yinghong 9'. We found that CsPAO1,2,3 could catalyze spermine, thermospermine, and norspermidine, and CsPAO2,3 could catalyze spermidine in the back-conversion mode, which indicated that the precursor of γ-aminobutyric acid might originate from the oxidation of putrescin but not spermidine. We further investigated the changes of CsPAO activity with temperature and pH and their stability. Kinetic parameters suggested that CsPAO2 was the major PAO modifying polyamine composition in tea, and it could be inactivated by β-hydroxyethylhydrazine and aminoguanidine. Putrescine content and CsPAO2 expression were high in tea flowers. CsPAO2 responded to wound, drought, and salt stress; CsPAO1 might be the main member responding to cold stress; anoxia induced CsPAO3. We conclude that in terms of phylogenetic tree, enzyme characteristics, and expression profile, CsPAO2 might be the dominant CsPAO in the polyamine degradation pathway.

Extraction Efficiency of Different Solvents and LC-UV Determination of Biogenic Amines in Tea Leaves and Infusions

Biogenic amines (BAs), that is, spermine, spermidine, putrescine, histamine, tyramine, β-phenylethylamine, cadaverine, and serotonin, have been determined in several samples of tea leaves, tea infusions, and tea drinks by LC-UV method after derivatization with dansyl chloride. Different extraction solvents have been tested and TCA 5% showed better analytical performances in terms of linearity, recovery percentages, LOD, LOQ, and repeatability than HCl 0.1 M and HClO4 0.1 M and was finally exploited for the quantitative determination of BAs in all samples. In tea leaves total BAs concentration ranged from 2.23 μg g(-1) to 11.24 μg g(-1) and PUT (1.05-2.25 μg g(-1)) and SPD (1.01-1.95 μg g(-1)) were always present, while SER (nd-1.56 μg g(-1)), HIS (nd-2.44 μg g(-1)), and SPM (nd-1.64 μg g(-1)) were detected more rarely. CAD and PHE were determined in few samples at much lower concentrations while none of the samples contained TYR. Tea infusions showed the same trend with total BAs concentrations never exceeding 80.7 μg L(-1). Black teas showed higher amounts of BAs than green teas and organic and decaffeinated samples always contained much lower BAs levels than their conventional counterparts.

Health effects and occurrence of dietary polyamines: a review for the period 2005-mid 2013

This review continues a previous one (Kalač & Krausová, 2005). Dietary polyamines spermidine and spermine participate in an array of physiological roles with both favourable and injurious effects on human health. Dieticians thus need plausible information on their content in various foods. The data on the polyamine contents in raw food materials increased considerably during the reviewed period, while information on their changes during processing and storage have yet been fragmentary and inconsistent. Spermidine and spermine originate mainly from raw materials. Their high contents are typical particularly for inner organs and meat of warm-blooded animals, soybean and fermented soybean products and some mushroom species. Generally, polyamine contents range widely within the individual food items.