2025Journal articleFree to read
Zhu Zhixi
Journal of Sociology and Education
This study aimed to quantitatively investigate the effects of ultraviolet (UV) light exposure duration (0, 12, 24, 36, 48, and 60 hours) on the caffeine concentration in matcha powder (Camellia sinensis), as measured by UV-Vis spectrophotometric analysis, and to elucidate the associated photodegradation kinetics.A controlled experimental design was implemented. Uniform samples of matcha powder (0.05 g ± 0.002 g) were spread in quartz dishes and subjected to precise periods of UV light exposure. Caffeine was subsequently extracted using a standardized volume of dichloromethane (DCM, 50 mL). The concentration of caffeine in each extract was determined by measuring absorbance at 275 nm using a UV-Vis spectrophotometer and interpolating from a pre-established five-point calibration curve (1-5 ppm) of pure caffeine in DCM. All extractions and measurements were performed in triplicate to ensure statistical reliability. Key variables, including solvent volume, sample mass, ambient temperature (25 ± 1 °C), and filtration methodology, were rigorously controlled.The caffeine concentration exhibited a clear exponential decrease with increasing UV exposure time, described by the function y = 3.3099e^(-0.026x) (R² = 0.9865). The mean initial caffeine concentration (0-hour exposure) was 3.48 ppm, which declined to 0.79 ppm after 60 hours of irradiation. Qualitatively, a visible colour transition of the matcha powder from vibrant green to a brownish-yellow hue was observed, indicative of concurrent chlorophyll photodegradation. The calculated degradation rate constant (k = 0.026) was significantly higher than values reported for uncatalyzed caffeine photodegradation (k = 0.00036), suggesting a catalytic role of reactive oxygen species (ROS) generated from photo-sensitizers like…
Abstract shortened. Read the full abstract at the source.
Abstract text comes from PubMed, OpenAlex or Europe PMC and belongs to the authors and publisher.
Study type
Sensory / consumer
Taste, aroma, color and how people perceive matcha.
Assigned automatically from the title, abstract and subject terms.
Topics
Matcha is a main subject here (named in the title).
Zhu Zhixi. (2025). How Does Exposure Durations (0h, 12h, 24h, 36h, 48h, 60h) to Uv Light affect the Caffeine Concentration of Caffeine of Matcha Tea, Measured by Uv- Spectrophotometric Analysis?. Journal of Sociology and Education. https://doi.org/10.63887/jse.2025.1.8.11
DOI: 10.63887/jse.2025.1.8.11
Japanese matcha is a type of powdered green tea, grown in a traditional way. Shading of the plants during the growth period enhances the processes of synthesis and accumulation of biologically active compounds, including theanine,…
ReviewCognition, mood and stressAntioxidants and polyphenolsL-theanine and caffeineCited 321×Matcha green tea (Camellia sinensis), which originates from Japan, is commonly considered as particularly beneficial to health. A large content of polyphenols, amino acids (mainly tannins) and caffeine potentially increase the antioxidant…
Agronomy / cultivationAntioxidants and polyphenolsL-theanine and caffeineCultivation and shadingCited 124×Matcha tea is rich in taste and bioactive constituents, quality evaluation of matcha tea is important to ensure flavor and efficacy. Near-infrared spectroscopy (NIR) in combination with variable selection algorithms was proposed as a fast…
Chemical / analyticalAntioxidants and polyphenolsL-theanine and caffeineProcessing, milling and qualityCited 117×Abstract BACKGROUND The study reports a portable near infrared (NIR) spectroscopy system coupled with chemometric algorithms for prediction of tea polyphenols and amino acids in order to index matcha tea quality. RESULTS Spectral data were…
Randomized controlled trialAntioxidants and polyphenolsL-theanine and caffeineProcessing, milling and qualityCited 114×