A very Happy British Tomato week to you!
Looking at your supermarket and farm shop shelves this summer you will see a huge and colourful array of tomatoes: from the little cherry, via the cute plum to the giant beefsteak. Some organic, some on vine and many of the classic varieties.
Between each there will be some variation in nutrients and bioactive compounds (such as lycopene) due to the variety, growing conditions (outside, under glass), country grown in, time of year, type of fertiliser and storage. But for nutritional purposes what people most often want to know is the average composition of a tomato. Ever wondered how we know that?
We in Food Databanks National Capability (part of Quadram Institute Biosciences) can answer that question, because we have produced the figures used in the UK composition of foods database. To do it we had to make many trips to purchase copious fruits (or vegetables if you prefer) to combine into a single sample for laboratory analysis. We had to think about where the tomatoes were grown (UK or imported), how they were packaged and the market share of the supermarkets.
Here are just some factors we had to consider to produce the nutrient data for a standard tomato:
Then we had to think about where to buy our tomatoes. We visited 10 different major supermarkets as well as independent market stalls. We sampled tomatoes grown in the UK, the Netherlands, Spain and Portugal. We did all this twice to get make sure we covered different seasons.
After purchase, we took a few tomatoes, of equal amounts, from each source, blended them together, until they were an homogenous gloop, and froze them before they were analysed in a lab. That’s quite an undertaking just for one foodstuff eh?
Here are some of the results, we have a lot more data on vitamins and minerals in our database. The figures we have produced are used all over the place; for national intake surveys, for food product labelling and for research. All thanks to our supermarket shopping and thorough planning.
All data per 100g of standard raw tomatoes:
Energy 14 kcal
Energy 61 kJ
Total sugars 3g
Vitamin C 22mg
We also have the analytical results for the nutritional composition of raw cherry tomatoes, standard grilled tomatoes and canned tomatoes (whole and chopped). Not to mention tomato juice, chutney, ketchup, soup and pasta sauce. But not Bloody Mary, perhaps we should add that to our list, for research only.
P.S. You will find a load more information on tomatoes on the British Tomato Growers website http://www.britishtomatoes.co.uk/.