Monday 28 November 2011

Choose one or all of these food stuffs from the menu in Have You Eaten Rice Yet? by Doc Elizabeth Stevenson. Read and follow them through to remind yourself of her talk.

Tight lipped mussels in a curdled sauce.
Problems with your mussels? Like all marine creatures, they are susceptible to red tides. Some humans can also be allergic to tropomyosin, a protein that helps the mussel shell contract.

Protein is made up of a long chain of amino acids arranged into coils. Cooking disturbs these chains, and this is denaturing. The amino acids stay linked together, but their arrangement changes. Denaturing can be reversible, but often with cooking, it is not. (People have built a whole subculture from modelling protein chains by computer. Watch this one for the graphics.)

As an example of protein 'unfolding', add vinegar to soya milk and see what happens. The proteins come together and form curd.

Roast meat.
The Maillard Reaction is the chemical process that is responsible for the colours and flavours of food. The reaction is between proteins (chains of amino acids) and sugars.

For us vegetarians, the same applies. We can have fried onions on toast.

Unnaturally green veg.
Soaking plants in copper sulfate to gain a greener colour then cooking them is a bad idea says the Doc. Why? Because at the centre of chlorophyll - the part that makes plants green - is the element magnesium. Heating copper sulfate plus magnesium produces a compound that is toxic in large doses.

Side salad.
No, you can't have lettuce from the freezer. A lettuce leaf is 95% water. Freezing the water causes the water to expand and burst out of the cell wall. So your lettuce leaf loses structure and goes all floppy.

Haggis.
Basically, don't eat haggis. Just don't. Offal, onion and spices cooked in an animal's stomach has nothing to recommend it. It's not the Doc saying that, it's me.

Incidentally, if you want at this point to research the history of the microwave, then start with Percy Spencer. The first microwave was the size of a small car and the weight of a baby elephant.

Microwaves are increasingly used by chemists to cook their haggises and heat their waters. But bear in mind that microwaves will heat polar compounds, but not non-polar compounds!

A polar compound is where there is an unequal sharing of electrons.

Water is polar, you can heat that. In water, the oxygen has a greater pull on the electrons in the bond than the hydrogens. See? Polar. Hmm. Nope, I'm not really getting this.

Except don't eat haggis and don't cook it in any means at all.

Neeps and tatties.
Starchy foods? Test for starch! With the iodine test!

You did this already. Exciting. Yesindeedy.

Fast ice cream.
With liquid nitrogen. How else.

Your choice of fizzy drink.
Except that the standard is Coca Cola with a Menthos mint. You can do that.

Outside, please, not in the front room. And don't tell your sister to stand over it 'to get a better view'.