Abstract This study investigated the effects of incorporating dried sumac and cold atmospheric plasma treatment on the quality of smoothie. The combined approach effectively preserved microbiological and colloidal stability while enhancing the content of bioactive compounds. The 10-min treatment reduced microbial counts by 4.17 log CFU/mL and yielded the most stable formulation, outperforming the control in vitamin C retention (15 % higher on day 0; 46 % after 24 h) and total polyphenols (56 % higher initially; 63 % after storage), indicating gradual release of bioactives. In vivo assays using zebrafish larvae revealed toxicity at higher sumac concentrations, attributed mainly to lowered pH rather than plasma exposure. Locomotor disturbances observed after prolonged plasma treatment highlight the need for process optimization. Overall, this non-thermal method shows strong potential for producing functional smoothies with extended shelf life and improved nutritional value, warranting further safety assessments and optimization of processing parameters in mammalian models.