Evaluation of the Physicochemical and Antioxidants Properties of Freeze-Dried Beetroot Colourants Extract Using Different Levels of Citric Acid

Abstract

This research investigated freeze-dried beetroot colourants extracted using citric acid as green organic solvent at 1-5% citric acid concentration and water as the control. The physicochemical and antioxidants activities were determined using standard methods of analysis. Mineral investigation showed that phosphorus and potassium were predominant, though with a significant decrease from 150.98 mg/100g at 0 % citric acid to 101.28 mg/100g at 5 % citric acid for phosphorous. However, the potassium content ranged from 131.78 mg/100g at 0 % to 152.76 mg/100g at 3 %, the citric acid extracted beetroot colourants had higher potassium content. Also, as the concentration of citric acid increased, there was a significant (p<0.05) decrease in the pH, with increase in titratable acidity and lightness of the samples. The antioxidant properties showed a noteworthy radical scavenging ability with a strong IC50 values of DPPH (2,2-diphenyl-1-picrylhydrazyl), and ABTS (2,2’-azinobis (3-ethylbenzothiazoline-6 sulfonic acid) radical scavenging activity ranging between 48.60 to 85.63 µg/mL and 48.87 – 85.76 µg/mL respectively. This study reveals promising potentials in the freeze-dried extracts that could be utilized in the food product development and pharmaceutical industries to enhance life quality as well as the impact of different citric acid concentration in beetroot colourant extraction and its relevance as solvent in beetroots colourants extraction.