IMPACT OF HEATING ON CARROT FIRMNESS - CHANGES IN CELL-WALL COMPONENTS

The impact of heating in boiling water on tissue firmness retention of the carrot genotypes Danvers and B9304 was measured. Both genotypes showed a rapid early loss in firmness that was followed by a slower, more prolonged, softening. Softening was greater in Danvers carrots. Cell wall carbohydrate compositions of the two varieties were similar, but wall component dissolution (solubilization and depolymerization) was more extensive in Danvers. The breakdown of soluble and wall-bound pectins involved beta-elimination reactions. A survey of several carrot genotypes indicated that those carrots with chelator-soluble pectins of relatively lower molecular weight tended to soften more extensively during heating.