The effect of bark extract on the heat stability of unconcentrated milk is shown in Fig. 1; the effects of NDRWR, aloe vera and oak leaf extracts were essentially
similar (results not shown). The extracts markedly increased stability, particularly in the region of the minimum, pH 6.8-7.1, i.e. converted a type AHCT- pH profile
to a type B profille (Fox, 1982). Addition of coconut shell extract did not eliminate theminimum but did increase thestability of unconcentrated milk, principally by shifting the HCT- pH profile to more alkaline values, increasing stability at the maximum and diminishing the pH range over which the minimum occurred (results not shown)