The hook is that Ettlinger was having ice cream with the kiddies one day, reading the wrappers, when his offspring asked him about polysorbate 60 and he had no freaking clue what it was either and decided to find out. Best of all, as a published author, he could plausibly (a) make money by doing this, if not while doing this and (b) tour lots of chemical plants which apparently for him is a bit of a thrill. The structure of the book is laid out as the wrapper -- a chapter per ingredient, in order (except the corn sweeteners are grouped, for example). He avoids details that might lead to the temptation to start showing chemical equations, for which I applaud him. Nothing quite like math, physics and chemistry notation to really slow a good read down.
Ettlinger does cover the process by which the ingredients in Twinkies are refined, extracted, mined and so forth. He describes the vehicles he travels in, the plants he tours, the big towering stainless steel things and the tanker trucks and the high temperatures and the blah blah blah. He ALSO explains why things get the names they do, and why they are designated artificial or natural, and whether they are kosher or not and why. He gets into the history of how these processes were developed, the economics of them and so forth. He explains the post 9/11 security situation that prevents him from getting access sometimes. He talks about the mergers and sales of plants between chemical conglomerates that leads to massive uncertainty as to who owns what in some cases.
In short, this bright, orange, goes-down-easy (if slowly, if you're reading to remember) volume packs a lot into a little. He's no advocate but he's got an overriding theme that we should all be thinking about: the Twinkie complex, which is a synecdoche (I really wanted to use that word) for the industrial food complex. He's not advocating trying to turn the clock back, or even attempts to opt out of it. But he points out along the way how other countries are making other regulatory decisions, and the incredible pervasiveness in our lives.
Great, great, great stuff. Ettlinger is a bit more blase about a lot of this stuff than I am, but it's possible that's just a rhetorical stance to avoid hacking off the mass market. Definitely worth a trip to the library or picking it up in paperback (not long now; February). Probably worth hardcover prices if you keep books around as reference.