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<p>This study evaluated the effects of classical and microwave-assisted (MW) infusion on the physicochemical, bioactive, and aromatic profiles of black tea. Samples were subjected to infusion in MW at different powers (300, 450, and 600&#xa0;W) and times (5, 10, and 15&#xa0;min), and total phenolic content (TPC), antioxidant activity, color attributes (L*, a*, b*), °Brix, and individual phenolic compounds were analyzed in the tea samples. MW-assisted infusion, especially at 600&#xa0;W for 10–15&#xa0;min, significantly enhanced antioxidant activity and TPC (up to 7613.73&#xa0;mg GAE/100&#xa0;g), compared to classical infusion (7900.61&#xa0;mg GAE/100&#xa0;g). HPLC analysis revealed higher gallic acid levels in the samples subjected to MW, while (−)-epicatechin was more abundant in the sample subjected to classical infusion. FTIR spectra showed similar functional group profiles, with MW-treated samples displaying slightly higher peak intensities in regions associated with phenolics and esters. PCA and PLS analyses confirmed distinct chemical profiles and predictive capacity of FTIR data for quality parameters. Aroma profile analysis revealed that MW-assisted infusion and freeze-drying significantly influenced the volatile compound composition of tea. While aldehydes dominated in liquid tea samples subjected to classical infusion, acids and ketones were more prominent in powdered samples. These findings highlight the potential of alternative processing methods in modulating tea aroma and sensory attributes. MW-assisted infusion was reported to be effective in reducing processing time while enhancing phenolic extraction and antioxidant properties, though it altered volatile composition compared to classical infusion.</p>

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FTIR spectroscopy coupled with chemometric analysis and aroma profiling to differentiate classical and microwave-assisted black tea infusions

  • 期刊论文

  • 发表日期：

    2025年9月29日

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  • Cem Baltacıoğlu

摘要

This study evaluated the effects of classical and microwave-assisted (MW) infusion on the physicochemical, bioactive, and aromatic profiles of black tea. Samples were subjected to infusion in MW at different powers (300, 450, and 600 W) and times (5, 10, and 15 min), and total phenolic content (TPC), antioxidant activity, color attributes (L*, a*, b*), °Brix, and individual phenolic compounds were analyzed in the tea samples. MW-assisted infusion, especially at 600 W for 10–15 min, significantly enhanced antioxidant activity and TPC (up to 7613.73 mg GAE/100 g), compared to classical infusion (7900.61 mg GAE/100 g). HPLC analysis revealed higher gallic acid levels in the samples subjected to MW, while (−)-epicatechin was more abundant in the sample subjected to classical infusion. FTIR spectra showed similar functional group profiles, with MW-treated samples displaying slightly higher peak intensities in regions associated with phenolics and esters. PCA and PLS analyses confirmed distinct chemical profiles and predictive capacity of FTIR data for quality parameters. Aroma profile analysis revealed that MW-assisted infusion and freeze-drying significantly influenced the volatile compound composition of tea. While aldehydes dominated in liquid tea samples subjected to classical infusion, acids and ketones were more prominent in powdered samples. These findings highlight the potential of alternative processing methods in modulating tea aroma and sensory attributes. MW-assisted infusion was reported to be effective in reducing processing time while enhancing phenolic extraction and antioxidant properties, though it altered volatile composition compared to classical infusion.