I’ve started looking into food science, because I see it as an excellent arena in which children can build the foundations for a science education. Positive experiences with food involve most of the skills and dispositions needed for quality science education. (They need to learn to observe closely, for example: to notice changes with all senses – sight, smell, taste, touch, even sound – as well as develop the art of patience, and they experience both failure and success through experimentation). On top of this, even those teachers who are the most nervous-around-science can usually build on their confidence in the kitchen.
My focus is narrower than that at the moment – I am beginning with bread science.
There is some really cool science happening when we bake bread… from the wheat to the flour to the dough to the loaf (and beyond), pretty much all the core science areas are covered, so I’ve decided to start there with my research…
On top of this, baking bread requires hands-on experiential learning that involves all the senses – and all the different memorising that using all your senses invokes.
It also invites mutliple cultural forays…not just because it invites us to consider different cultural approaches to food (and an anthropological perspective on why these differences come about), but because so many cultures have some form of bread or cereal-based meal: rewana / paraoa parai, naan bread, chapati / roti, ciabatta, pizza, bread and butter pudding, pita bread, corn bread, challah, and a million other bread bread bread recipes that date their traditions back from here to there… (then there are the other wheat-based foods, too – wagashi, for example, which I only just came across)
And it raises a million political discussions, which come together into a lesson on information/scientific literacy (by which I mean, learning to sieve out the information you wish to keep from that which doesn’t convince you of its validity and form your own opinion). Consider Isabel Pasch’s passionate love for bread (see her article, The Art of Slow Baking in Earth Matters 5, 2011) with this position on grains, for example… There is also the whole question of education for sustainability which enters this topic.
“A grain of wheat is a complete universe unto itself. It is 83 to 85 percent endosperm, 2.5 percent germ, and 12.5 to 14.5 percent bran. When harvested, a grain of wheat may appear dry and lifeless, but unless it is very old it is alive and can remain alive, in a dormant state, for several years! As in any seed, the germ is the ‘potential life,’ or embryo, of the grain, capable of germinating and producing more wheat, even after it is picked. When combined with water, it is awakened from dormancy and will begin to sprout. The endosperm, the starch/protein component, is the germ’s food and the bran is the protective layer that contains it. / When baking bread with flour ground from the whole wheat grain, it is necessary for the germ to still be alive when ground to make bread with good texture and flavour. The germ is viable for only a few weeks after grinding, which is why whole wheat flour over six weeks old is no longer good for baking bread.” (Levy Beranbaum (c2003), 545)
Yeast has its own interesting history (see http://www.h2g2.com/approved_entry/A2791820) and easy science experiments are out there to better understand yeast (see http://www.exploratorium.edu/cooking/bread/activity-yeast.html) … but much of the science of yeast (that results in good bread) is to be found in sourdough:
I’m a convert to sourdough, philosophically (and because I always loved the taste), but I confess, I’m still trying to work out the secrets of getting this right – my first loaf was sour as; the second tasted good, but was pretty solid… I’m back into it today. I want to get this right, so I can do it with the kids. Check out http://www.newsobserver.com/2011/01/31/957315/the-secret-life-of-yeast-bread.html
“…the sourdough process results from the fermentation reactions of two quite different classes of microorganisms: wild yeast and beneficial bacteria. For well over five thousand years, all breads were produced by the fermentation of these two essential microorganisms acting together. The yeasts are primarily responsible for leavening and bread texture, the bacteria for the sourdough flavor. …’traditional’ sourdough requires a ‘culture’, or ‘starter,’ containing both of these organisms.” (Wood, c2011, p.1)
“One of the most important differences between sourdough and other bread is that the sourdough bacteria helps digest all ‘phytic acids’, a naturally occurring substance in the bran of all wholegrains. This acid inhibits the minerals in the bran to be absorbed by the body. While in straight yeasted breads, about 90 per cent of the phytic acid remains.
Sourdough breads naturally have a low GI (glycemic index) of 50 or under, about half the GI of yeasted bread. This is due to the acidity of sourdough bread, which slows down the digestion of sugar in the bowel. This explains why you will feel substantially full for longer periods of time when you eat sourdough bread, compared to eating soft, spongy, yeasted commercial bread.” (Mardewi (2009) 17)
“Sourdough fermentation partly pre-digests gluten, allowing some people who are sensitive to gluten to enjoy eating properly fermented sourdough breads.”
Most books on sourdough will advise you to use organic, unbleached flour… here is why: “Flour, being the major ingredient of your bread, is so vital to the taste of your bread. Use the best quality unbleached flour you can afford, preferably organic/biodynamic. Bleaching, apart from its toxicity, destroys (oxidises) beta-caretenoids in the flour, causing the bread you make to be tasteless.” (Mardewi (2009) 19)
Similarly, they will advise that you use filtered water: “Always use filtered non-chlorinated, non-fluoridated water, especially for your starter culture. Chlorinated water will kill your wild-yeast starter/culture.” (Mardewi (2009) 21) Allow water to stand for 6 hours if chlorinated. (I’m thinking of the water cycle and the water crisis and the water system in modern urban settings, and the Treaty discussions over current discussions going on around the government’s decision to sell assets such as this…
Salt is another ingredient used in sourdough… and it also comes with a science lesson:
Mardewi writes: “It is important to add salt because:
- Salt controls your fermentation, allowing you to have a long fermentation period.
- Salt increases the strength of the gluten by tightening the gluten structure. A salt-less dough will be slack and sticky and the bread volume will be poor.
- Salt enhances the colour of your crumb and increases its moistness.
- You can reduce the amount of salt to a minimum of 1 per cent. That is about 2 teaspoons of sea salt per kilogram of flour.” (Mardewi (2009) 22)
- Salt also has its own cultural and political history – see Mark Kurlansky’s book, Salt, for example.
Books I have found/looked at
Helen W Atwater (1900) Bread and the Principles of Bread Making
Emily Buehler Bread Science: The Chemistry and Craft of Making Bread
Zen Master Edward Espe Brown, How to Cook Your Life (DVD)
Ed Wood (c2011) Classic Sourdoughs: a Homebaker’s Handbook. Berkeley : Ten Speed Press
Rose Levy Beranbaum (c2003) The Bread Bible. W. W. Norton & Company: New York & London.
Yoke Mardewi (2009) Wild Sourdough: the natural way to bake. New Holland Publishers: Sydney, Auckland, London, Cape Town
The Accidental Scientist: the Science of Cooking website has a list of reccommended books too (http://www.exploratorium.edu/cooking/books.html)
The politics of food…
Julian Cribb, The Coming Famine: The Global Food Crisis and What We can do to avoid it [NB his interview on Radio NZ National and YouTube videos: eg1, eg2, eg3, eg4]
Michael Pollan, The Omnivore’s Dilemma: A Natural History of Four Meals
Michael Pollan, In Defence of Food
Barbara Kingsolver, Animal, Vegetable, Miracle: A Year of Food Life
Ruth Ozeki, My Year of Meats
Richard Ellis, Tuna: A Love Story
Books for kids:
There aren’t actually so many as I would have thought – and some seem to miss the point with the science, to my view… but:
Melba George (c2006) Food Science FAQs. Macmillan Education Australia, South Yarra, Vic. [I really liked this – clear, simple, arranged for literacy and science in the classroom, but also answers interesting questions]
Bill Slavin and Jim Slavin (c2005) Transformed: How everyday things are made. Kids Can Press: Toronto.
The Science in a loaf of Bread, by Andrew Solway, in contrast, did not float my boat. It talked down to children from the start and listed yeast as a raw ingredient of bread (along with flour, water, salt and oil)… I did not like this approach.
Useful websites I have used:
Index of concepts
Allergic reactions (coeliac vs mild…)
Bleach (see chlorine????)
– commercial bread
– traditional bread
– chemical change
– physical change
– reversible (and irreversible) change
There are also some cool artistic possibilities: check out the windmills above, or this stationery/print… I’m also thinking you could do something similar to the Unit Plan for taewa/Maori potatoes (Design a label for a taewa product) put out by the Biotechnology Learning Hub, through which students come to “Understand the attributes and benefits of new taewa products and their potential impact on society. Understand the purpose and function of a label in marketing and communicating information about a product. Design an appropriate label for a taewa product.” Also useful for such an activity is the Biotechnology Learning Hub‘s ‘Student activity: What’s on a label?’
Wheat has its connections with religious education as well… several religions in fact, …and a number of sites on the net deal with this… eg1