Profiling Phytochemical and Nutritional Components of Potato
Type of funding scheme: Walsh Fellowship
| List of participants: | Partner no. | Partner Organisation |
|---|---|---|
| 1 | Dr Kim Reilly | Teagasc Kinsealy |
| 2 | Mr. Michael Gaffney | Teagasc Kinsealy |
| 3 | Dr Nigel Brunton | Ashtown Food Research Centre (AFRC) |
| 4 | Prof. Nora O'Brien | University College Cork (UCC) |
Aim and objectives
The term "phytochemical" is used to define "non-nutrient chemicals found in plants that have biological activity against chronic diseases". Phytochemicals found in cultivated vegetable and fruit crops show potent anti-carcinogenic and other health promoting properties. Most research has focused on fruit and field vegetable crops such as Brassica species. Potato (Solanum tubersosum) is one of the most important staple food crops globally. In Ireland there are 550 commercial potato growers and the value of the potato sector is estimated to be €162 million at farm gate. To date little research has evaluated the phytochemical content of potato. A recent study by the USDA has indicated that there is considerable variation in phytochemical content between potato varieties, and that some varieties accumulate significant levels of bioactive compounds such as phenolic compounds including flavonoids, quercetin and kukoamines. Such compounds have been implicated in reduction of risk for cardiovascular disease, high blood pressure and certain cancers. In addition levels of vitamins such as folate and ascorbate vary between cultivars. This project will evaluate the phytochemical and nutritional profile of a range of potato varieties with the objective of identifying those with optimal nutritional and phytochemical content. Levels of expression and allelic variation of key genes involved in synthesis of phytochemical and nutritional components of interest will be examined for cultivars showing contrasting levels of accumulation of nutritional or phytochemical metabolites.
Innovative aspects of the project
Traditional plant breeding approaches have focussed on yield, quality and disease resistance with less emphasis on nutritional and phytochemical content. Within existing potato germplasm there are likely to be a range of levels of health promoting bioactive compounds, however existing Irish varieties have not been characterised with respect to these components. Identification of potato varieties with higher levels of health promoting phytochemicals and nutritional components could potentially offer growers the opportunity for niche marketing of "value added" potato varieties and would serve a "public good" role in allowing consumers access to nutritionally superior varieties. Expression and allelic variation data should allow further characterisation of genes responsible for accumulation of phytochemical and nutritional components. Outputs would include a data set and generation of knowledge for plant breeders.
Methodology and associated work plan
The level of total phenolic compounds in a range of potato cultivars grown over two years will be assessed using the Folin Ciocalteu method. Profiles of individual phenolic compounds will be examined by standard TLC (Thin Layer Chromatography) and HPLC (High Performance Liquid Chromatography) techniques. The potential antioxidant capacity of various cultivars will be assessed. Levels of folate will be measured using a standard microbial assay using Lactobacillus casei. A high throughput HPLC method for the simultaneous measurement of ascorbic acid, glycoalkaloids and phenolics will be standardised and used to examine potato varieties. Where cultivars show contrasting levels of accumulation of nutritional and/or phytochemical metabolites, the levels of expression of biosynthetic genes will be examined by semi-quantitative RT-PCR in cultivars showing lowest and highest levels of accumulation. Since allelic variation can also contribute to differential activity of biosynthetic enzymes involved in metabolite accumulation, allelic variants of genes of interest will be identified and characterised using a PCR sequencing approach.
Evolution of the project
A PhD student - Mr Jesus Valcarcel Barros (jesus.barros@teagasc.ie) was recruited for the project in December 2009 and is based at Teagasc Kinsealy.
Contact person: Dr Kim Reilly (kim.reilly@teagasc.ie)
