Investigation of betacyanins stability from peel and flesh of red-purple pitaya with food additives supplementation and pH treatments

Betacyanins are potential source of natural red dyes. Generally, natural plant pigments, such as betacyanins, are highly unstable and prone to degradation due to internal and external factors. Hence, this study investigated the stability of betacyanins extracted from peel and flesh of red-purple pitaya using alcohol/salt-based liquid biphasic partitioning system (LBPS) over a 10-days storage period. Various stability treatments, including addition of food additives, pH treatments and different storage conditions were conducted. Overall, the results reveal that the peel and flesh extract added with 0.5% (w/v) of ascorbic acid and without any pH adjustments showed an optimum betacyanins stability under all storage conditions. The betacyanins retentions of the peel and flesh extract at 4 °C dark storage (4 °C D) were the highest, as indicated at 114.98 ± 1.11% and 105.90 ± 1.59%, respectively. In addition, kinetic analysis of the degradation of betacyanins was studied, and the extracts at 4 °C D showed no degradation sign of betacyanins. Stabilised betacyanins with low degradation rate would be beneficial to be used in food science processing.