HPLC Analysis of Carotenoid Stability During Bread-Making: Esterification Strategies for Enhanced Retention

Carotenoids are antioxidants derived from plants which contribute to human health and signify key quality traits in wheat-based foods. They are highly unstable, however, and inclined to degrade during processing. Xanthophyll esterification has been recognized as a natural method of improving carotenoid stability during grain storage. A joint study conducted by The Institute for Sustainable Agriculture and The Institute of Fat (both part of the Spanish National Research Council)investigated carotenoid retention throughout the bread-making process, with particular focus on the potential protective effect of esterification. Six genotypes with contrasting carotenoid content and esterification capacity, including bread wheat, tritordeum, and Hordeum chilense-wheat chromosome substitution lines, were analyzed. Carotenoids were quantified by high-performance liquid chromatography (HPLC) at sequential processing stages: grain, flour, dough, freshly baked bread, and bread stored for 48 h. A paper based on this investigation was published in the Journal of the Science of Food and Agriculture.¹

Carotenoids are naturally occurring pigments that play key roles in human health by acting as potent antioxidants.^2-4 Their intake has been connected to a reduced risk of developing several chronic conditions, including cardiovascular disease, cancer, neurodegenerative disorders, obesity, and age-related macular degeneration.^4,5

Lutein (the most abundant carotenoid in the endosperm of grains) present in free form or esterified with fatty acids (mostly palmitic and linoleic acids)⁶, was found by the researchers to be the predominant carotenoid in all the genotypes evaluated, with slight genotype-dependent differences. Esterified carotenoids consistently showed higher retention compared to their free forms. Baking was identified as the most detrimental step for carotenoid degradation in the study, whereas storage after baking resulted in only minor additional changes. The researchers also reported that carotenoid esterification might continue during the early stages of bread-making.¹

“Carotenoid esterification,” write the authors of the study,¹ “represents a promising strategy to enhance carotenoid preservation during bread-making. This approach could complement both technological optimizations in processing and the genetic selection and improvement of wheat varieties with elevated carotenoid content. These optimizations should focus primarily on baking, as this was the step that had the most detrimental effect on carotenoid retention.”

In the opinion of the researchers, the improving of carotenoid retention during thebread-making process will likely require a combination of technological innovations in processing methods and genetic improvements in wheat germplasm. They believe that wheat lines with high total carotenoid content and low lipoxygenase activity are especially encouraging for developing wheat-based products with high carotenoid content and enhanced nutritional value.¹ “Carotenoid esterification,” they state, “represents an additional strategy to improve carotenoid retention during bread-making; however, it remains unclear whether its protective effect arises from reduced degradation or from continued de novo ester synthesis during the initial stages of bread-making.”¹ In the minds of the researchers, the clarification this mechanism will be vital for the optimization of both breeding and processing approaches which are aimed at preserving carotenoids in cereal-based foods.¹

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References

1. Requena-Ramírez, M. D.; Rodríguez-Suárez, C.; Hornero-Méndez, D. et al. Esterification Enhances Carotenoid Retention During Bread-Making. J Sci Food Agric. 2026.DOI: 10.1002/jsfa.70521
2. Eggersdorfer, M.; Wyss, A. Carotenoids in Human Nutrition and Health. Arch Biochem Biophys. 2018, 652, 18-26. DOI: 10.1016/j.abb.2018.06.001
3. Meléndez‐Martínez, A. J. An Overview of Carotenoids, Apocarotenoids, and Vitamin A in Agro‐Food, Nutrition, Health, and Disease. Mol Nutr Food Res. 2019, 63 (15), 1801045. 10.1002/mnfr.201801045
4. Swapnil, P.; Meena, M.; Singh, S. K. et al. Vital Roles of Carotenoids in Plants and Humans to Deteriorate Stress with its Structure, Biosynthesis, Metabolic Engineering and Functional Aspects. Curr Plant Biol 2021, 26,100203 (2021). DOI: 10.1016/j.cpb.2021.100203
5. Nishino, H.; Murakoshi, M.; Tokuda, H. et al. Cancer Prevention by Carotenoids. Arch Biochem Biophys. 2009, 483 (2), 165-168. DOI: 10.1016/j.abb.2008.09.011
6. Hornero-Mendez, D, in Carotenoid Esters in Foods; Mercadante, A. Z. Ed.; Royal Society of Chemistry, 2019.