Photo (and chutney) by Stephen Heard.
Jim Croce would like to save time in a bottle, but I can save time in a jar. I mentioned recently that I make a mean mango chutney (with a connection, and I swear there was one, to public belief in vaccinations and global warming). Not long before that, I’d posted about the Plant Gastrodiversity Game. Putting the two ideas together made me think about the evolutionary history in every jar in my chutney. It’s easy to calculate such things these days, and I’m a world-class nerd, so of course I didn’t waste much time getting started. I’ll share my chutney recipe, and some things I learned from my analysis.
|8 mangoes, peeled and chopped (or 2 kg frozen mango, which saves a lot of time and likely has a lower carbon footprint)||Mangifera indica (Anacardiaceae)|
|4 tart apples (e.g. Granny Smith), chopped||Malus domestica (Rosaceae)|
|2 c chopped onion||Allium cepa (Amaryllidaceae)|
|6 cloves garlic, minced||Allium sativum (Amaryllidaceae)|
|1 c chopped carrots||Daucus carota (Apiaceae)|
|1 c raisins||Vitis vinifera (Vitaceae)|
|1 medium habeñero pepper, minced||Capsicum chinense (Solanaceae)|
|1 T ginger, minced||Zingiber officianale (Zingiberaceae)|
|4 tsp black pepper||Piper nigrum (Piperaceae)|
|½ tsp salt|
|1 ½ tsp cinnamon||Cinnamomum cassia (Lauraceae)|
|½ tsp cloves||Syzygium aromaticum (Myrtaceae)|
|2 tsp allspice||Pimenta dioica (Myrtaceae)|
|2 tsp mustard seed||Synapis alba (Brassicaceae)|
|1 T cumin||Cuminum cyminum (Apiaceae)|
|1 tsp fenugreek||Trigonella foenum-graecum (Fabaceae)|
|2 c white sugar||Beta vulgaris (Amaranthaceae)**|
|2 c brown sugar||Saccharum officinarum (Poaceae)|
|2 T lemon juice||Citrus ×limon (Rutaceae)|
|4 c apple cider vinegar||Malus domestica (Rosaceae)|
Combine everything in a very large pot and simmer until (1) the house smells wonderful, and (2) it’s as thick as you want it. Getting to (1) happens very quickly, but be warned that getting to (2) can take several hours. Then package the result in canning jars (no need for a fork). The chutney is terrific on samosas, on scrambled eggs, or in cheese-and-chutney sandwiches – just as a start.
So how much evolutionary history is represented in each jar of chutney? Ah, here comes the nerdy part. I used the Phylomatic program in the Phylocom package to extract, from the Davies et al. (2004) consensus angiosperm phylogeny, the evolutionary tree represented by the 19 botanical ingredients in my chutney. Here it is:
Adding up the lengths of all the branches (in millions of years) gives us our answer: 1,788 million years (or 1.8 billion) of evolutionary history in every jar of my mango chutney***. (You can do actual science with tools like this too).
1.8 billion years is a big number – but is it unusually big? I’m not quite nerdy enough to do this calculation for everything I cook, but I suspect the evolutionary history in my chutney is pretty respectable. Two things pack more evolutionary history into a jar: using more ingredients, and using ingredients derived from plants that are more distantly related. More technically: the set of ingredients is well dispersed across the plant phylogeny they’re sampled from (in contrast, a recipe combining tomatoes, eggplant, peppers, and potatoes, all in Solanaceae, would be phylogenetically clustered). My chutney rates highly on ingredient count (19), and not badly on phylogenetic dispersion (those 19 ingredients come from 15 families, with some fairly deep splits in the tree)****. So now my chutney tastes even better, because I know it took natural selection working in 19 different lineages nearly two billion years to get all those flavours right. It’s amazing what selection can do, given only time and variation.
Thinking about this leads me to suspect there’s a whole field of evolutionary gastronomy waiting to be explored. Human diets aren’t (I suspect) randomly assembled from available ingredients, and I have a set of hypotheses about this:
H1: Culinary ingredients are phylogenetically clustered, compared to all available plants. While we eat do plants from a lot of families, a few families seem likely to be overrepresented. Poaceae, Solanaceae, and Rosaceae spring to mind.
H2: Modern diets are more phylogenetically dispersed than ancient, or even historic, ones. Exploration, modern agriculture, and especially modern shipping, have made it possible for us to include plant families in our diet that simply wouldn’t have been available before (e.g., Musaceae (bananas) anywhere temperate; or Bromeliaceae (pineapple) in the Old World).
H3: Individual recipes tend to be phylogenetically overdispersed compared to the ingredients available in our cupboards or grocery stores. That is, I suspect we prefer dishes including contrasting flavours and textures (which we achieve by using distantly related ingredients) rather than more homogenous sets of related ingredients.
H4: Phylogenetic dispersion varies across cuisines. It will be lower in cuisines of temperate origin (accustomed to ingredient lists limited, pre-shipping, by the narrower set of plants that are cold-hardy), and higher in cuisines of tropical origin.
Each of these hypotheses is testable, although to my knowledge none has actually been tested. Of course, I might be the only person who thinks they’re interesting. If so, you probably stopped reading a while ago. If not, there might be several graduate theses lurking in this post.
So help yourself to the hypotheses. You’ll have to make your own chutney.
© Stephen Heard (firstname.lastname@example.org) January 14, 2016
- Vaccinations, global warming, and the fork in the canning jar
- The Plant Gastrodiversity Game
- Phylogenetic diversity of rock barrens plants
- Science fiction, stone plants, and the certainty of improbable things
*^I’ve been making this for many years and no longer remember the source for this recipe, so I can’t acknowledge it here.
**^I can’t be sure here, because sugar processors don’t tell you, but the majority of North American sugar is now from beet rather than cane. Brown sugar is often made from refined white beet sugar to which cane molasses is added (because beet molasses is apparently inedible). The things you learn…
***^I’m excluding here the evolutionary history back from the common ancestor of all these ingredients (140 million years ago) to the origin of life on Earth (3.5 billion years ago). Including this “root branch” would boost my estimate to 5.1 billion years. But excluding the root branch is standard in this sort of analysis, and anyway, my jars are only so big. I should also acknowledge that this is a quick-and-dirty analysis: the Davies tree is conveniently available but is no longer our most recent estimate of angiosperm phylogeny, and there are a couple of polytomies I probably could have resolved with a bit of literature searching. I don’t think our final answer would change that much, though.
****^Pesto, which combines basil and olives (angiosperms) with pine nuts (gymnosperm), packs an evolutionary punch out of proportion to its simplicity.