Acta Scientiarum Polonorum Technologia Alimentaria

Background. Red beetroot is rich in bioactive compounds and antioxidants with numerous health benefits. However, its high moisture content makes it susceptible to decomposition. This study investigated the effects of different drying methods, following blanching pretreatments, on the quality of beetroot powder.
Material and methods. Beetroot samples were pretreated by either water or steam blanching and subse­quently dried using vacuum or oven drying. Freeze drying was performed for comparison. Proximate compo­sition, nitrate content, betalain concentration, antioxidant activity (IC50), and color parameters were analyzed using analysis of variance (ANOVA). Principal component analysis (PCA) was conducted to further evaluate the effects of treatments.
Results. Drying methods significantly influenced the bioactive properties of beetroot. Compared with con­ventional oven drying, vacuum drying yielded powder with higher betalain content (3,478.33 mg/100 g) and stronger antioxidant activity (IC50 = 541.73 ppm). Blanching pretreatment also had a significant effect. Steam blanching followed by oven drying produced powder with a nitrate content of 413.23 mg/kg. When steam blanching was combined with vacuum drying, the betalain content increased further to 3,996.81 mg/100 g, significantly higher than that obtained by oven drying, regardless of blanching type. This combination also produced powder with the strongest antioxidant activity (IC50 = 493.32 ppm). Blanching and drying treat­ments both increased the redness (a*) of beetroot powder. Steam blanching followed by vacuum drying re­sulted in the most intense red color, decreasing yellowness (b*) and lightness (L*) more than water blanching. Freeze-drying preserved high nitrate content, strong antioxidant activity, and good color retention.
Conclusion. Vacuum drying preceded by either steam or water blanching is an effective method for produc­ing beetroot powder with high bioactive compound content.