Metabolomics reveals the effects of different storage times on the acidity quality and metabolites of large-leaf black tea

The Flavor Characteristics, Antioxidant Capability, and Storage Year Discrimination Based on Backpropagation Neural Network of Organic Green Tea (Camellia sinensis) during Long-Term Storage

“…However, as storage time extended, oxidative reactions, degradation, and transformations of amino acids took place, such as the Strecker and Maillard reactions [ 34 ], resulting in a substantial decrease in the total amino acid content. This finding aligns with the transformations observed in Liupao tea [ 35 ] and large-leaf black tea [ 8 ] throughout the storage process. Soluble sugar, a primary sweet component in tea, can mitigate the bitter taste associated with certain substances in tea infusion.…”

“…The freshness of tea samples stored for 15 and 16 years notably diminished compared to those stored for other durations ( p < 0.05), aligning with changes in the content of free amino acids, particularly theanine. Acidic compounds in tea infusions dissociated, yielding hydrogen ions that imparted acidity to the tea [ 8 ]. This acidity tended to decrease during the storage of organic green tea, consistent with the trend in oolong tea at different storage years [ 9 ] but contrasting with large-leaf black tea [ 8 ] at varying storage years.…”

“…Acidic compounds in tea infusions dissociated, yielding hydrogen ions that imparted acidity to the tea [ 8 ]. This acidity tended to decrease during the storage of organic green tea, consistent with the trend in oolong tea at different storage years [ 9 ] but contrasting with large-leaf black tea [ 8 ] at varying storage years. A moderate bitterness contributes to the mellow quality of tea [ 8 ].…”

“…In the aging process of Jinhua white tea over 5–10 years, the content of tea polyphenols, catechins, caffeine, and amino acids significantly decreased, while gallic acid and theabrownins increased [ 7 ]. Long-term storage of large-leaf black tea resulted in a decrease in theaflavins, catechins, and amino acids, and an increase in theabrownins and thearubigins [ 8 ]. Lipids and organic acids in oolong tea increased with storage years, while tannins, phenolic acids, amino acids, and their derivatives decreased [ 9 ].…”

The effects of tea plant age on the color, taste, and chemical characteristics of Yunnan Congou black tea by multi-spectral omics insight

“…An increasing body of evidence suggests that organic acids containing acidic groups are important color modifiers by regulating the pH value of tea infusions ( Yu et al, 2022 , Zhang et al, 2023 ). The pH values of DB, HB, and TB samples were measured within the range of 4.85–4.90, as displayed in Fig.…”