Depending on the time-temperature regime, blanching of whole carrots strongly affected trans–cis-isomerization of b-carotene in the corresponding unheated, pasteur-ized and sterilized juices (Table 1). In all samples, 13-cis-b-carotene was the predominant cis-isomer, whereas 9-cis-b-carotene could only be detected in sterilized jui-ces produced from extensively blanched carrots. Since 15-cis-b-carotene could not be completely separated from an unknown cis-isomer of a-carotene, quanti-tative data could not be obtained. In pasteurized juices, elevated heat load during blanching (80, 90, and 100 C for 30 and 60 min, respectively) led to the formation of 13-cis-b-carotene at levels between 1.8 and 10.0% (Table 1). Consistent with Bielig and Wolf (1971) who reported that mash texture affected carotene contents of decanter juices, a decrease of total car-otenes was observed for juices produced from exces-sively blanched carrots.