Characterization of purple carrot germplasm for antioxidant capacity and root concentration of anthocyanins, phenolics, and carotenoids

Authors: PEREZ, MARIA - Consejo Nacional De Investigaciones Científicas Y Técnicas(CONICET); CARVAJAL, SOFIA - Consejo Nacional De Investigaciones Científicas Y Técnicas(CONICET); BERETTA, VANESA - Consejo Nacional De Investigaciones Científicas Y Técnicas(CONICET); BANNOUD, FLORENCIA - Consejo Nacional De Investigaciones Científicas Y Técnicas(CONICET); FANGIO, MARIA - Universidad Nacional Del Sur (UNS); BERLI, FEDERICO - Universidad Nacional Del Sur (UNS); FONTANA, ARIEL - Universidad Nacional Del Sur (UNS); SALOMON, MARIA - Instituto Nacional De Tecnologia Agropecuaria; GOZALEZ, ROXANA - Instituto Nacional De Tecnologia Agropecuaria; VALERGA, LUCIA - Consejo Nacional De Investigaciones Científicas Y Técnicas(CONICET); ALTAMIRANO, JORGELINA - Consejo Nacional De Investigaciones Científicas Y Técnicas(CONICET); YILDIZ, MEHTAP - Yildiz Technical University; IORIZZO, MASSIMO - North Carolina State University; Simon, Philipp; CAVAGNARO, PABLO - Consejo Nacional De Investigaciones Científicas Y Técnicas(CONICET)

Submitted to: Plants
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/24/2023
Publication Date: 4/27/2023
Citation: Perez, M.B., Carvajal, S., Beretta, V., Bannoud, F., Fangio, M.F., Berli, F., Fontana, A., Salomon, M.V., Gozalez, R., Valerga, L., Altamirano, J.C., Yildiz, M., Iorizzo, M., Simon, P.W., Cavagnaro, P.C. 2023. Characterization of purple carrot germplasm for antioxidant capacity and root concentration of anthocyanins, phenolics, and carotenoids. Plants. 12(9). Article 1796. https://doi.org/10.3390/plants12091796.
DOI: https://doi.org/10.3390/plants12091796

Interpretive Summary: Most carrots grown today are orange, but the first carrots, around 1100 years ago, were purple or yellow. The purple pigments in carrots and many food crops like blueberries or red apples, are anthocyanins; and the yellow and orange pigments, are carotenoids. Both carotenoids and anthocyanins are antioxidants, and the consumption of both pigment types has been associated with reduced risk of chronic diseases, including some types of cancers, cognitive decline, neurodegenerative and cardiovascular diseases, and age-related macular degeneration, among others. This study evaluated the antioxidant capacity, which is a measure of the antioxidizing power, of carrots containing both types of pigments. Antioxidant capacity, estimated by several methods, was moderately-to-strongly correlated with the content of anthocyanin pigments, but weakly correlated with the content of carotenoid pigments. These results provide insights for informing the development of nutritional databases that include carrots, and it may have application for assessing the nutritional value of other crops. It is of interest to nutritional scientists, carrot growers and researchers, seed companies, and consumers.

Technical Abstract: The present study characterized a genetically and phenotypically diverse collection of 27 purple-rooted and two non-purple (one orange and one yellow) carrot accessions for concentration of root anthocyanins, phenolics, and carotenoids, and antioxidant capacity estimated by four different methods (ORAC, DPPH, ABTS, FRAP), in a partially replicated experimental design comprising data from two growing seasons (2018 and 2019). Broad and significant (p<0.0001) variation was found among the accessions for all the traits. Acylated anthocyanins (AA) predominated over non-acylated anthocyanins (NAA) in all the accessions and years analyzed, with AA accounting 55.5-100% of the total anthocyanin content (TAC). Anthocyanins acylated with ferulic acid and coumaric acid were the most abundant carrot anthocyanins. In general, black or solid purple carrots had the greatest TAC and total phenolic content (TPC), and the strongest antioxidant capacities, measured by all methods. Antioxidant capacity, estimated by all methods, was significantly, positively, and moderately-to-strongly correlated with the content of all individual anthocyanins pigments, TAC, and TPC, in both years (r=0.59-0.90, p<0.0001), but not with the carotenoid pigments lutein and ß-carotene; suggesting that anthocyanins and other phenolics, but not carotenoids, are major contributors of the antioxidant capacity in purple carrots. We identified accessions with high concentration of chemically-stable AA, of value for the production of food dyes, and accessions with relatively high content of bioavailable NAA that can be selected for increased nutraceutical value (e.g., for fresh consumption).