Phytochemical characterization and sensory acceptability of sweet herbal tea blend I: moringa, yerba mate, and chamomile

Abstract

This study aimed to investigate sweet herbal tea blends commonly consumed in South American countries, focusing on sensory acceptability, sweetening properties, and phenolic compounds with antioxidant potential. The infusion blends studied included stevia (ST), yerba mate (YM), moringa (MO), and chamomile (CH) in various combinations and proportions. Moringa leaves from summer and winter harvests were used. Radical scavenging activity ranged from 10.3 to 42.8 µg/mL, from ST:YM to MO:CH infusions. Infusions prepared with summer-harvested MO showed significantly higher antioxidant activity (P < 0.001). Most blends exhibited synergistic effects on in vitro radical scavenging activity, although MO:YM and MO:ST:YM showed antagonistic interactions. Total phenolic content varied from 58.6 to 118.6 mg GAE/g DE, being lowest in MO:CH and highest in ST. The content of steviol glycoside sweeteners increased proportionally with the amount of ST in the blends. In general, the recovery of natural sweeteners and antioxidant compounds followed distinct patterns, but a strong correlation was found between total flavonoids (as quercetin equivalents) and radical scavenging activity. Sensory evaluation showed that the proportion of stevia (1:1 vs. 1:3) had little effect on acceptability, aroma, or perceived sweetness. Scores ranged from 6.5–7.0 for flavor, 6.0–6.4 for sweetness quality, and 4.4–6.1 for sweetness intensity; CH:MO:ST had the lowest sweetness scores. Sensory perception varied mainly by sex and stevia consumption habits. An ST concentration of 0.67–1.0 g per infusion was considered acceptable. These findings suggest that sweet herbal tea blends may offer a healthy, naturally sweet alternative to traditional herbal infusions.