Beta-carotene

Golden/Orange tomatoes can either contain Tetra-cis-lycopene or Beta-carotene, as both these compounds produce tomatoes in the golden to orange colour spectrum. Chemical analysis will confirm which compound is present reflected in the skin pigmentation.

Beta-carotene is an anti-oxidant and may protect against free radical damage (1). Beta-carotene converts to vitamin A in the human body and is an essential nutrient for humans. Vitamin A deficiency affects a staggering percentage of the population, especially in the developing world. (2) It is the leading cause of blindness in children. and is also associated with increased burden of infectious disease. (3) (4)

For several years we have grown a high Beta-carotene selection of ours that we named ‘Golden Eye’ with the hope that it may be able to reduce the incidence of childhood blindness. In 2020 we found that two separate plants had morphed and produced bigger tomatoes – these we named ‘Golden Eye Improved’ and ‘Oracle’. Both new varieties are very high in Beta-carotene and may contain the highest levels of any tomatoes, as well as containing interesting levels of several polyphenolic compounds.

For our 2020 year data analysis of our tomatoes please click here.

Golden Eye Original

Golden Eye Improved

‘Oracle’ (Golden Eye version 3)

Comparison Golden Eye Original (left) with Golden Eye Improved (right)

2021 Progress

The ‘Oracle’ Tomato Selections

Several years ago, we had a ‘volunteer’ tomato that grew for us and it tested with the highest level of beta-carotene that we had seen. We named it ‘Golden Eye’. In 2020 we made two selections from this variety and named them ‘Golden Eye Improved’ and ‘Oracle’. Then in 2021 these plants morphed into a wider range and a few of the notable selections are ‘African Oracle’; ‘New Oracle’; ‘Optical’; and ‘Oracle 1 SBO’’.

‘African Oracle’ is an anomaly in that it has flipped from being high in beta-carotene to being higher in tetra-cis-lycopene as well as still containing a relatively high level of beta-carotene. In theory this is not possible because if you look at the biosynthesis pathway for carotenoids, what you see is this:                           Tetra-cis-lycopene -> all-trans-lycopene -> beta-carotene

The first step is converted by carotenoid isomerase, and the second two steps by lycopene beta cyclase (to make two rings on beta-carotene). Tangerine type tomatoes have non-functional carotenoid isomerase, or get stuck and don’t proceed to all-trans-lycopene, so it is hard to understand how you would get beta-carotene, unless you had only a partially functional carotenoid isomerase, but to our knowledge that is not something that has been seen before. (1)

‘New Oracle’ – This strong growing disease-resistant plant produced abundant golden cherry tomatoes that contained very high levels of beta-carotene as well as excellent levels of folate. (The folate levels were considerably higher than a standard red supermarket tomato). Naturally occurring folate, such as in these tomatoes is more bioavailable than the synthetic form of folic acid.

‘Optical’ – This version produced larger cherry tomatoes that contained high levels of beta-carotene.

‘Oracle 1 SBO’ – Small bright orange currant-sized fruit that tested with the highest level of beta-carotene and significant polyphenol concentrations for ten out of thirteen of the polyphenol compounds tested for.

  • Our thanks to Dr Jessica Cooperstone, Assistant Professor, The Ohio State University for her assistance with helping us understand the biosynthesis pathway for tomato carotenoids.
  1. Stommel John R, USDA 97L63, 97L66, and 97L97: Tomato Breeding Lines with High Fruit Beta-carotene Content. HortScience 36(2):387-388. 2001
  2. World Health Organization (WHO). Global prevalence of vitamin A deficiency. Micronutrient Deficiency Information System (MDIS) Working Paper 2 [on the Internet]. Geneva: WHO. 1995 [cited 2012 Sept 13].Available from: http://whqlibdoc.who.int/publications/2009/9789241598019_eng.pdf.
  3. West KP Jr. Vitamin A deficiency disorders in children and women. Food Nutr Bull 2003;24:S78–90.
  4. Kopec Rachel E, Cooperstone Jessica L, Schweiggert Ralf M, Young Gregory S, Harrison Earl H, Francis David M, Clinton Steven K, Schwartz Steven J, Avocado Consumption Enhances Human Postprandial Provitamin A Absorption and Conversion from a Novel Hihh-B-Carotene Tomato Sauce and from Carrots. The Journal of Nutrition, June 4 2014 as doi:10.3945/jn.113.187674