Variability of antioxidant properties, catechins, caffeine, L-theanine and other amino acids in different plant parts of Azorean Camellia sinensis

Lisete Paiva; Elisabete Lima; Madalena Motta; Massimo Marcone; José Baptista

doi:10.1016/j.crfs.2020.07.004

Variability of antioxidant properties, catechins, caffeine, L-theanine and other amino acids in different plant parts of Azorean Camellia sinensis

Curr Res Food Sci. 2020 Aug 15:3:227-234. doi: 10.1016/j.crfs.2020.07.004. eCollection 2020 Nov.

Authors

Lisete Paiva^{1

2}, Elisabete Lima^{2

3}, Madalena Motta¹, Massimo Marcone⁴, José Baptista^{2

3}

Affiliations

¹ Gorreana Tea Plantation, Gorreana, 9625-304 Maia, São Miguel, Azores, Portugal.
² Department of Physics, Chemistry and Engineering (DCFQE) and Biotechnology Centre of Azores (CBA), University of Azores, 9500-321 Ponta Delgada, São Miguel, Azores, Portugal.
³ Institute of Agricultural and Environmental Research and Technology (IITAA), University of Azores, 9700-042 Angra do Heroísmo, Terceira, Azores, Portugal.
⁴ Department of Food Science, University of Guelph, Guelph, Ontario, N1G 2W1, Canada.

Abstract

During Camellia sinensis tea processing, manufacturers usually remove the internodes, which are classified as waste. This study presents the first determination of plant part contribution, particularly internodes, to green tea quality, in order to find the best blend to maximize impact on human health. Catechins, caffeine and free amino acid (FAA) profiles were determined by RP-HPLC/DAD, total phenolics (TPC) and total flavonoids (TFC) by Folin-Ciocalteu and colorimetric methodologies, respectively, and antioxidant activities by free radical-scavenging activity (FRSA), ferric-reducing antioxidant power (FRAP) and ferrous ion-chelating (FIC) methods. Individual esterified catechins content decreased as follows: epicatechin-3-gallate > epigallocatechin-3-gallate ≫ gallocatecin-3-gallate, and epicatechin derivatives content ranged from 63.91 to 91.22% of total catechins. Caffeine content was higher in internodes. L-theanine, histidine, asparagine, phenylalanine, glutamic acid and methionine were the major FAAs, and internodes contained the highest amounts of L-theanine and histidine (17 and 13.73 mg/g of sample, respectively). TPC ranged from 201.51 to 265.48 mg gallic acid equivalents/g dry extract (DE) and TFC ranged from 23.84 to 72.02 mg rutin equivalents/g DE. Internodes presented the lowest FRSA (EC₅₀ = 6.10-13.50 μg/mL), FRAP (EC₅₀ = 5.70-11.40 μg/mL) and FIC activity (36.96-79.21%). Bud presented the highest FRSA and FRAP, and bud+1st+2^ndleaves + internodes the highest FIC activity. The results revealed the potential contribution of the internodes to green tea quality and, consequently, to human health.

Keywords: Catechin profiles; Free amino acid profiles; Internode waste valorization; L-theanine/caffeine content; RP-HPLC analysis; Tea antioxidants; Total flavonoids; Total phenolics.

Publication types

Review