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This research aimed to evaluate the effect of sun drying, hot air drying, vacuum drying, and freeze drying on moisture, water activities (a w ), dry matter, energy consumption, proximate composition, chlorogenic acid, total phenolic compounds (TPCs), and 2,2-diphenyl-1-picrylhydrazyl (DPPH) of coffee pulp. Coffee pulp was collected from Thailand. Samples were placed under the sun for 15 and 18 h, hot air drying at 60 and 90°C for 14 and 16 h, freeze drying at −18°C for 15 h, or vacuum drying at 40°C for 15 h. Moisture and a w of freeze-dried samples were 5.48% and 0.53%, respectively.Freeze drying consumed 7.69 kW/kg lower than sun drying and hot air drying (p ≤ 0.05).Freeze drying produced more crude ash and crude fiber than sun drying (p ≤ 0.05). Sun drying samples contained higher crude protein than freeze drying samples (p ≤ 0.05).The 12.64 mg GAE/DW TPCs, 4.94 mg/DW chlorogenic acids, and 2.84 mg TE/DW DPPH were detected in freeze drying samples. Freeze drying efficiently preserved bioactive compounds. Novelty impact statement:The high content of antioxidant capacity of coffee pulp was found in vacuum and freeze drying. Regarding its ability to highly preserve bioactive compounds, freeze drying was recommended for producing a higher quality of dried coffee pulp.

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