Wannabe foodsThe name on the jar in the baking goods shop I frequent says Persipan. So I grab it happily. Perispan is a cousin of marzipan and is made from apricot or peach kernels instead of almonds (no, the acid in the kernels doesn't turn into hydrogen cyanide as in an Agatha Christie novel, it's processed to stop that happening).Persipan might be marzipan's less posh relative, but that doesn't mean any old thing can be thrown in. It should be made of the kernels, sugar, liquid, and sometimes a flavour. But the container I hold contains the following: sucrose, lima beans, sorbitol, vegetable fat, thickener, TBHQ (basically butane) and then some other chemical crap besides. No kernels. In other words, it's not persipan (and by the way most marzipan is not, strictly speaking, marzipan either).The sushi counter is one place where you imagine that what you see is what you get. No mushed up processed fake foods, right? Sadly, very untrue. A crab maki is not what you think. Mainly because it has no crab-meat in it. Crabsticks have as much crab-meat in them as Fanta has orange in it. Yes that's right, big fat zero. Crabsticks are made from pulverised boiled fish mixed with starch, egg white and sometimes binding agents. Food colouring is added to the outside layer. The crab flavour is usually synthetic, less often natural, but actual crab meat? Nada. The technique was patented in 1973 and sushi roundabouts have never looked back. Crabsticks should really be much cheaper than they are, given that they're simply marine polony.And then there's mayonnaise. Of course most of us realise that mayonnaise off a supermarket shelf is not going to be the same concoction as real mayonnaise, which nowadays you'll only find in some households and a few good restaurants. But just how different the two are is pretty freaky. Actual, real, mayonnaise is made from oil - often olive - and eggs, with an acid such as vinegar or lemon to balance, and sometimes mustard too. Raw eggs are obviously not fit for a supermarket shelf. So the eggs are cooked, making a sort of industrialised sabayon or dairy-free custard. That's actually okay. It gets weird when mayonnaise doesn't even contain egg, and is made from only the vilest chemically extracted bleached vegetable oil, plus a cocktail of chemicals. Most curious (or perhaps most cunning, if you're a food technologist) is that many of the so-called mayonnaises out there contain water as a major ingredient (more water than oil even). It seems like a cheat, but to my mind these are the ones to go for. Yes, they're making you pay a lot for water, but it's by far the least offensive ingredient in the bottle...