JUVEN, B.J., Division of Food Technology, Agricultural Research Organization, The Volcani Center, P.O. Box 6, Bet Dagan, 50-200, Israel
KANNER, J., Division of Food Technology, Agricultural Research Organization, The Volcani Center, P.O. Box 6, Bet Dagan, 50-200, Israel
WEISSLOWICZ, H., Division of Food Technology, Agricultural Research Organization, The Volcani Center, P.O. Box 6, Bet Dagan, 50-200, Israel

The increased heat resistance of yeasts in orange concentrates as compared with single‐strength juices cannot be accounted for on the basis of sugar contents only. Citric acid is demonstrated to play a role in the heat resistance of spoilage yeasts in concentrated orange juices. Other major chemical constituents of citrus juices, namely, ascorbic acid and pectin, did not exhibit any significant effect. A model system, based on sucrose, glucose, fructose, citric acid and tripotassium citrate, is pro‐posed for the evaluation of the thermal resistance of yeasts in citrus concentrates. Copyright © 1978, Wiley Blackwell. All rights reserved