Fig. 4

Interaction graph of phycocyanin stability with (a) pH (b) temperature, and c storage time (Tukey method and 95% confidence level); d standardized interaction; e interactions of Tukey HSD (honestly significant difference) (A: temperature; B: pH; C: storage time). Same letters in the column signify no significant difference between treatments; different letters signify statistical difference (a–c). PC, phycocyanin; dw, dry biomass weight