Acidified Water Extraction and Stability of Anthocyanin from Tradescantia Spathacea Leaves

Chew, Ler Ying (2025) Acidified Water Extraction and Stability of Anthocyanin from Tradescantia Spathacea Leaves. Final Year Project (Bachelor), Tunku Abdul Rahman University of Management and Technology.

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Abstract

An efficient extraction procedure is essential to obtain high quality of the extracted anthocyanin to use as a natural food colourant possessing unique antioxidant effect. This study aims to investigate the effect of process parameters for acidified water extraction of anthocyanin from Tradescantia spathacea leaves and its stability. The effects of sample concentration (1.0%–5.0%, w/w) and pH (1.5–3.5) of acidified water on the yield, colour, total phenolic content (TPC), total flavonoid content (TFC), and antioxidant properties (DPPH, FRAP, ABTS radical scavenging activity) of Tradescantia spathacea leaves extract were studied using one-factor-at-a-time approach. The effects of extraction temperature (40–60 °C) and time (30–90 minutes) was investigated on the properties of leave extract through response surface methodology. The stability of crude extracts was analysed for heat (50 °C and 80 °C) and light (covered and uncovered). The results showed that the optimal sample concentration and pH were determined as 4% and 1.5, respectively. The extraction temperature and time significantly affected (P < 0.05) the yield, colour, TAC, TPC, TFC, DPPH, FRAP & ABTS of the leaves extract. The optimal extraction parameters were determined as 60 ℃ of extraction temperature and 30 min of extraction time with the composite desirability of 0.8254, which contributed to 85.03 ± 0.00% of yield, 35.2 ± 0.9 of colour a*, 11.53 ± 0.02 mg/100 mL of TAC, 568.99 ± 1.90 mg QE/100 mL of TFC, 5579.86 ± 16.03 mg GAE/100 mL of TPC, 2319.22 ± 4.50 mg AAE/100 mL of DPPH, 1261.18 ± 3.70 mg FeSO4E/100 mL of FRAP, and 587.74 ± 1.60 mg TE/100 mL of ABTS. Both heat and light exposure significantly affected (P < 0.05) the colour and TAC of the extracts. This study provides valuable insights into optimising process parameters for acidified water extraction of anthocyanin from Tradescantia spathacea leaves, which is potential to utilise as alternative to synthetic colourants in the food industry.