S. Aubert, I. Babic, M.J. Amiot, C. Nguyen-The
Phenolic compounds contribute to the organoleptic properties of fresh or processed fruits and vegetables. In the case of carotts, these oxidizable compounds are involved either directly (bitter compounds like cournarin) or indirectly, resulting in brown products due to the action of an oxidoreductase (polyphenoloxydase, peroxidase) subsequent to cellular traumatism. These phenolic compounds also seem to play a role in resistance to various fungal and bacterial attacks.

Extracts from several varieties of carrot were analyzed using high-pressure liquid phase chromatography followed by detection using either a photocell and U.V., or mass spectroscopy, to identify phenolic compounds. The most prevalent of these is chlorogenic acid (representing 60 to 70% of the total phenolics content). Other phenols must also be classified as hydroxycinnamic acid derivates (cis-chlorogenic acid, para-coumaroylquinic acid, dicaffeic acid).

When the plant is subjected to stress (cold,cutting,ethylene,etc.), chlorogenic acid accumulates in the root, couples with a simultaneous rise in the activity of phenylalanine ammonia lyase (PAL). Peeled, grated carrots stored in air at 4°C exhibit a significant rise in chlorogenic acid content from the first days of storage. At the same time, polymers appear to play a part in the suberization and lignification phenomena, namely by offering protection against microbiological attacks. Moreover, the coumarins (6-methoxymellein) located in the bitter epidermis of the roots, the synthesis of which is promoted by ethylene and/or storage in moist, cold conditions, appear to enhance this anti-microbial effect.

Phenolic compounds thus appear to be good indicators of varietal suitability for cold storage of carrots as well as for industrial transformation into fresh, ready to-use (pre-cut) vegetables.

Aubert, S., Babic, I., Amiot, M.J. and Nguyen-The, C. (1994). LES COMPOSES PHENOLIQUES MARQUEURS DE LA QUALITE DE CAROTTES CONSERVEES AU FROID.. Acta Hortic. 354, 201-214
DOI: 10.17660/ActaHortic.1994.354.21

Acta Horticulturae