Determining Organic Versus Conventional Planting Tea with HPLC, ICP, and MS

Research conducted by Yunnan Agricultural University, Yunnan Characteristic Plant Extraction Laboratory Co., Ltd., and the Yunnan Academy of Agricultural Sciences (Kunming, China) yielded a proposal for a model to differentiate between organic tea and conventional planting tea. The team initially determined the main characteristic components of organic and conventional planting teas (including water extracts, free amino acids, tea polyphenols, caffeine, flavonoids, catechins, mineral elements, and heavy-metal elements), followed by the substances that differed between the two groups. Then, through correlation analysis and linear discriminant multivariate statistical analysis methods, the characteristic different substances of organic and conventional planting teas were identified. Researchers compared tea samples in both groups using high performance liquid chromatography (HPLC), inductively coupled plasma–mass spectrometry (ICP-MS), and mass spectrometry (MS) analysis. A paper based on this research was published in Food Chemistry: X (1).

Originating in China and made from the tender leaves or buds of Camellia sinensis, a plant in the Camellia family, tea has become one of the three most popular non-alcoholic beverages in the world. Rich in chemical compounds and trace elements, it offers significant medicinal and health benefits (2,3). According to the planting mode, it can be divided into organic and conventional planting teas; organic tea is produced without synthetic pesticides, fertilizers, or growth regulators, is processed without synthetic food additives, and has been approved by a certification body (4), conventional planting tea can use pesticides, fertilizers, and growth regulators in production (5).

The authors of the study state that the market for organic tea is better than that for conventional planting tea, with the organic tea output increasing from 17.3 ten thousand tons in 2017 to 29.4 ten thousand tons in 2021. In addition, the production of organic tea also increases yearly to keep up with market demand. However, many illegal traders are taking advantage of the fact that distinguishing between the two groups visually is difficult, and conventional planting tea is being sold as organic tea. This deception causes major economic losses to consumers and disruption to the market, as well as affects trust in the quality of organic tea products. Therefore, an effective strategy must be developed to differentiate organic tea from conventionally grown tea, serving as the motivation for this study (1).

The results of the study showed that organic tea had higher ratings in sensory evaluation, appearance, taste, and aroma than conventional planting tea. From a sensory standpoint, the organic tea's color was yellow and green, the taste was fresh and sweet, and the aroma was rich and lingering. The organic tea contained significantly more free amino acids, flavonoids, and various minerals (including calcium, iron, potassium, magnesium, and sodium) than the conventional planting tea, while the content of epigallocatechin gallate, epicatechin gallate, epigallocatechin, catechin, gallocatechin, and cadmium was significantly lower. In addition, organic tea contains fewer heavy-metal components and more essential minerals, which makes it safer for human health. Also, the study identified valine, methionine, lysine, isoleucine, tyrosine, arginine, glycine, leucine, kaempferol, titanium, cystine, gallocatechin, cadmium, proline, and aluminum as markers to differentiate organic tea from conventional planting tea. The authors of the paper believe that these results can serve as a valuable reference for objectively evaluating the quality of organic tea (1).

Large assortment of tea on a white background. © butenkow - stock.adobe.com

References

1. Zhou, D.; Hu, Y.; He, X.; et al. Quality Analysis and Characteristic Difference Identification of Organic Tea and Conventional Planting Tea Based on ICP, HPLC and Machine Algorithm. Food Chem. X 2025, 26, 102299. DOI: 10.1016/j.fochx.2025.102299

2. Li, N.; Yao, Z.; Ning, J.; et al. Comparison of Different Drying Technologies for Green Tea: Changes in Color, Non-Volatile and Volatile Compounds. Food Chem. X 2024, 24, 101935. DOI: 10.1016/j.fochx.2024.101935

3. Ponder, A.; Hallmann, E. The Effects of Organic and Conventional Farm Management and Harvest Time on the Polyphenol Content in Different Raspberry Cultivars. Food Chem. 2019, 301, 125295. DOI: 10.1016/j.foodchem.2019.125295

4. Manzoor, Ma, L.; Ni, K.; Ruan, J. Influence of Organic and Inorganic Fertilizers on Tea Growth and Quality and Soil Properties of Tea Orchards’ Top Rhizosphere Soil. Plants 2024, 13 (2), 207. DOI: 10.3390/plants13020207

5. Giampieri, F.; Mazzoni, L.; Cianciosi, D.; et al. Organic vs Conventional Plant-Based Foods: A Review. Food Chem. 2022, 383, 132352. DOI: 10.1016/j.foodchem.2022.132352