ENEA, CREA and the Ohio State University team up to improve the nutritional value of potatoes

A collaboration among ENEA (the Italian Agency for New technologies, Energy and Sustainable Economic development), CREA (the Italian Council for Agricultural Research and Economics) and the Ohio State University opens new prospects for enriching potatoes with important vitamins and antioxidants as resulted in two papers published on the journal PLOS One.

In the first paper¹,  classical breeding methods have been used to enrich potatoes with lutein and zeaxanthin, two carotenoids that accumulate in the ‘macula lutea’ of the human eye and have been shown to prevent  ‘Age-Related Macular Degeneration’, the leading cause of irreversible blindness in developed countries. Lutein is also the predominant carotenoid in human brain tissue, and high lutein diets have been associated with improved cognitive performance in infants and elderly people. Lutein is usually found in green leafy vegetables, while zeaxanthin dietary sources are rare. Among the results of this research is the new lutein-enriched potato variety Melrose, as well as the discovery that lutein-enriched potatoes also show reduced sprouting and weight loss during long-term storage, resulting in substantial reduction in the use of chemicals or refrigeration used to prevent sprouting during storage.

In the second one², the Ohio State University team joined the Italian institutions ENEA and CREA to study how much vitamin A can be provided from potatoes enriched in beta-carotene (“golden potatoes”), that were previously produced through a collaboration between ENEA and the University of Freiburg  (http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0000350). Beta-carotene is the main vitamin A source from plant foods, Vitamin A deficiency is one of the leading causes of children blindness and mortality in the developing world, because people from these countries mainly eat plant-based foods that are rich in energy, but not in several vitamins, including vitamin A. By enhancing the beta-carotene content of these crops through a process named “biofortification”, the vitamin A status of these populations can be improved, saving lives. Beta-carotene biofortification of staple crops is one of the top priorities in  the 2008 Copenhagen Consensus Report (http://www.copenhagenconsensus.com/guide-giving/gtg-micronutrient-fortification-and-biofortification-challenge) .

One main question, after the biofortification is achieved, is to verify the “bioaccessibility” of beta-carotene, i.e. how much of it survives after cooking and during digestion, and is efficiently taken up by cells lining the small intestine and subsequent absorbed for conversion into vitamin A. The Ohio State University team provided a simulated digestion system to study the bioaccessibility of beta-carotene from golden potatoes. The study also revealed that golden potatoes contain more than 10-fold the vitamin E levels than their non-transgenic counterparts. The bioaccessibility study suggests that a 150 gram serving of boiled golden potatoes may contribute as much as 42% and 23% of the daily vitamin A and 34 and 17% of the daily Vitamin E requirements for children and women of reproductive age, respectively.

Giovanni Giuliano, ENEA, coordinator of the studies, explained: “Carotenoid biofortification has proven itself with “golden” rice and maize. Potato was the third crop to join this group. The technology to use is highly dependent on the crop: for enriching maize and cassava with beta-carotene traditional breeding works well, while for rice and potatoes transgenic strategies seem to be the only viable option. We have to keep an open mind, remembering that nutritional requirements differ in different countries and that our final goal is to provide safe, nutritious food to 9 billion people worldwide”.

Dr. Mark Failla, who led the study at OSU added: “In addition to the finding that golden potato seems to represent a source of bioavailable vitamins A and E, it contains higher amounts of lutein and phytoene than conventional potatoes. These two carotenoids possessing health promoting properties also were stable during simulated digestion and had similar bioaccessibility as vitamin E and beta-carotene, respectively.  The provocative results support the importance of now testing the nutritional efficacy of golden potato in an appropriate animal model.”

Dr. Giuseppe Mandolino, who led the study at CREA, concluded: “The detailed characterization of high-carotenoid containing potato germplasm led to the discovery of new gene variants of the carotenoid biosynthetic pathway; these variants are potentially useful for breeding non-GMO, biofortified potato varieties, enriched with high-added value carotenoids such as zeaxanthin. During the collaborative project, the high carotenoid variety Melrose was released as a first example of such new varieties”.

Potato is the third most widely consumed plant food by humans. It was domesticated in South America by pre-Colombian populations and its present global production stands at 360 million tons/year. It is a staple food for over 800 million people worldwide and contributes significantly to the diet of some Asian, African, and South American countries with significant incidence of vitamin A and vitamin E deficiencies.

Carotenoids are pigments synthesized by all photosynthetic organisms, including plants, and contribute to the yellow, orange and red color of many flowers and fruits. Their cleavage products (apocarotenoids and retinoids) include signaling molecules important for plant and animal physiology. Dietary carotenoids act as vitamin A precursors, as modulators of visual and cognitive development and in the prevention of chronic disease.

¹ http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0184143, a collaboration between ENEA and CREA

² http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0187102

For further information:

Giovanni Giuliano, ENEA, giovanni.giuliano@enea.it

Mark Failla, Ohio State University, failla.3@osu.edu

Giuseppe Mandolino, CREA, giuseppe.mandolino@crea.gov.it