Extraction and Storage Stability of Betacyanin from Red Amaranth Leaves

Kerk, Zi Ann (2024) Extraction and Storage Stability of Betacyanin from Red Amaranth Leaves. Final Year Project (Bachelor), Tunku Abdul Rahman University of Management and Technology.

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Abstract

Red amaranth (Amaranthus tricolour Linn) consists plentiful of bioactive compounds and phytochemicals, which is a good source of natural red colour pigment that can be an excellent substitute for synthetic azo-dyes and also bring health benefits to consumers. The objective of this study was to investigate the effect of extraction temperature (40 ℃, 50 ℃ and 60 ℃) and time (30 min, 60 min and 90 min) on the yield, colour, total betacyanin content (TBC), total phenolic content (TPC), total flavonoid content (TFC) and antioxidant activity (DPPH and ABTS) of natural pigment extracted from red amaranth leaves. Additionally, the storage stability of the red amaranth extract at 4 ℃ and 25 ℃ for a duration of 12 storage days was also evaluated. The results showed that the extraction temperature and time significantly affected (P < 0.05) the yield, colour, TBC, TPC, TFC and antioxidant activity (DPPH & ABTS). The optimal extraction parameters were determined as 50 ℃ of extraction temperature and 57 min of extraction time with the composite desirability of 0.8590, which contributed to 80.64 % of yield, 7.23 of colour L*, 10.20 of colour a*, 1.67 of colour b*, 8.04 of colour change, 52.99 mg/100 g of TBC, 1040.53 mg/100 g of TPC, 1703 mg/100 g of TFC, 1159 mg/ 100 g of DPPH, of 1633.31 mg/100 g of ABTS. The storage stability results showed that storage temperature and storage time significantly affected (P < 0.05) the colour, TBC, TPC, TFC, DPPH and ABTS. The degradation of colour, TBC, TPC, TFC, DPPH and ABTS was significantly lower (P < 0.05) at 4 °C than 25 °C. The degradation rate constant was lower, and half-life was higher at 4 °C than 25 °C. This study gives an insight of providing suitable process parameters for aqueous water extraction of natural pigments from red amaranth leaves and maintain its stability under suitable storage temperature.