EFFECT OF PH, TEMPERATURE AND GLUCOSE ADDITION ON FLOW BEHAVIOR OF FRUIT PUREES - I - BANANA PUREE

The influence of pH (3.0 and 5.1) and addition of glucose to attain wa ter activities (a(w)) ranging from 0.89 to 0.97 on the flow behaviour of banana purees was evaluated in the temperature range 10-55 degrees C. All purees were shear-thinning fluids with appreciable yield stress values, the flow curves essentially following the Herschel-Bulkley mo del. Glucose addition generally decreased the apparent viscosities and increased the temperature dependence of the flow properties. There we re no patterns with respect to the effect of pH on flow characteristic s. The effect of temperature (10-40 degrees C) and concentration (21.4 -50.9 degrees Brix) on the consistency coefficient was represented by a single derived by combining an Arrhenius type relationship for the d ependence on temperature and an exponential relationship for the influ ence of concentration. (C) 1997 Elsevier Science Limited. All rights r eserved.