Figure 6. Time course of inactivation of proteinase activity of pineapple extract incubated at 60ºC in the absence (O-O-O) or presence (Δ-Δ-Δ) of 9.8 mM sodium carbonate. 1.0 mL aliquots of the pineapple extract were withdrawn at different time intervals, cooled to and maintained at 30ºC, and the proteinase activity was assayed as in Proteinase assay given in the text.