AN INVESTIGATION INTO THE TEMPERATURE-DEPENDENCE OF THE RHEOLOGICAL SYNERGY BETWEEN XANTHAN GUM AND LOCUST BEAN GUM MIXTURES

The interaction between xanthan gum (XG) and locust bean gum (LBG) in water has been investigated using texture analysis, thermorheological analysis and high sensitivity differential scanning calorimetry. For t he batches of XG and LBG used in the present study and at a total poly mer concentration of 1% w/v, texture analysis indicated that the great est synergy occurred at approximately 10% w/w XG, while the technique also allowed measurement of the increase in strength resulting from he ating the mixes to 70 and 80 degrees C and cooling to room temperature . Thermorheological studies showed a maximum in viscosity for the xant han gum gels at approximately 45 degrees C; this maximum became less p ronounced as the concentration of XG decreased. High sensitivity diffe rential scanning calorimetry indicated that XG undergoes two transitio ns at approximately 30 and 80 degrees C on heating, but on cycling a s ingle transition is seen at approximately 74 degrees C. It was also no ted that the transitions were diminished or were absent in the presenc e of LBG.