What's In Your Gourmet Kitchen? - Part 4

Transcription

What's In Your Gourmet Kitchen? - Part 4

So what does that mean? How does that compare to other food? Well, if we look at this list of foods here provided by the FDA and the EPA, these are different quantities that have been found of lead in different types of food. I just highlighted a few of interest here. Wine, if you have that glass of wine, you’ll be getting about 0.8 µg serving of lead. If you have a can of apple sauce, you might have 0.85 µg of lead. And if you have this particular brand of, they tested a 2% milk, you’re gonna have about 0.95 µg of lead in your diet from that. So, how much lead is too much? Federal standards state tolerable total daily intake for adults is 75 µg a day. For pregnant women, it’s about 25 µg a day and for children, if they are over 7, it’s 15 µg and for children under 6, it’s 6 µg. In California, there’s Proposition 65 where they were trying to limit the total Lead intake to under 50 µg total. And they were also trying to further limit that any one product could not have more than 0.5 µg a day. So what did we find with our gourmet salts? Well, in our 1 teaspoon daily serving, we found between 2.4 and 8.1 µg, which would have clearly violated the California Proposition 65 for an individual product. What conclusions do we find about our gourmet salt? Each of the brands contained some of the toxic elements. It showed that the grey salts had the highest Lead level. The brown salts showed the highest Mercury level. And one pink salt that also showed some Cadmium levels. If you’re looking at one teaspoon serving, you could be up to 12% of you Mercury level and 16% of your Lead level. We also said that these salts have a lot of beneficial nutrients, macronutrients such as Iron, Magnesium and Potassium. Now we’re looking at everybody’s favorite product and our favorite gourmet product, chocolate. Here’s some fun facts about chocolate. Chocolate or cocoa has been in existence since 600 B.C. Mayans used cocoa beans as currency. So, if you were in the Mayan culture, you would probably never taste chocolate or very rarely ever taste chocolate in your life because it was usually reserved for the rich, the powerful and the rulers. Now, Carl Linnaeus was the father of modern taxonomy and he gave chocolate its name, cocoa, which meant “Food of the Gods”. And it’s of course, the number one favorite candy in the world. If we look at consumption in the world, Americans eat about 12 lbs a year. The British have a slightly bigger sweet tooth, which is quite surprising at 16 lbs a year. And finally, the Swiss eat 21 lbs a year of chocolate. In 2000, the chocolate industry reported sales of 8.6 billion dollars in the United States. So why study chocolate? Beside it being a really fun topic. It is very complex. The chemistry and physics of chocolate is a complex science which whole courses have taught us about and I’m pretty sure that any science teacher who has to show a class of students the concept of physics and chemistry will find chocolate a great way to get their students interested in chemistry and physics. In May of 2002, there was a suit brought against chocolate manufacturers for violating California Proposition 65. They claim that their labels did not disclose chemicals that can cause cancer or birth defects like Cadmium and Lead. So what is the science of chocolate? Chocolate has a crystal structure, that’s what gives it its rigidity and its snap. So when you open up a bar of chocolate, it has a good snap to it. Molten chocolate is tempered and this will produce seed crystals and there are more than 6 different types of seed crystals associated with chocolate. The most desirable form is Form 5. This is the form of chocolate that has a melting point of just about 33 °C, just under body temperature so you get that lovely melt-in-your-mouth when you put a piece of chocolate in your mouth.

There is another form that most consumers are familiar with, that’s Form 6. If you ever open up a chocolate bar and you see this kind of white haze on top of your chocolate bar and it kind of tastes a little stale, that’s probably Form 6. It’s a very dense, very stable form of chocolate, but it’s not really desirable. It happens when the fat is forced to the surface, and it causes its bloom. If you’ve ever heard somebody say that the chocolate has bloom, this is what happens, the fat has been forced to the surface.

Going on, it’s the chemistry of chocolate. Chocolate is a complex emulsion. It has cocoa, sugar, fat, minerals and over 800 different chemical compounds including metal and lecithin.

In our study of chocolate, we wanted to concentrate on the various metals. We had six chocolate varieties; we had three milk chocolates, three dark chocolates and the chocolate liquor, which we’ve studied. We examined them for major and trace elements by ICP and ICP-MS.

We took our chocolate pieces and we weighed them into flasks and Teflon beakers and digested them with nitric acid. Then we diluted with more nitric acid and ran them by ICP and ICP-MS. Again, we used our SPEX CertiPrep certified reference materials to tune and calibrate our system and again, here’s the list of the compounds.

So what do we find? We found a very large range of compounds in our chocolate, some desirable, some not so desirable. We have here magnesium, so chocolate is a very large source of magnesium here. We have 20,000 µg to 60,000 µg with the magnesium in our chocolate. There is a large source of potassium and calcium. There’s some Iron in some of our samples. There’s definitely phosphorus and sulfur and sodium. There’s also a few things that are not so good for us. There’s aluminum from 400 to 1200 µg and there’s nickel from 37 to 115 µg.

If we start looking at the toxic metals in chocolate, we’re talking about a 40g serving. We have three brands of chocolate, dark chocolate and three brands of milk chocolate and the chocolate liquor.

If we look at the dark chocolate, most of our high numbers for our toxic metals occurred in the dark chocolate. All three of the dark chocolate brands had high levels of Cadmium or had the higher value of Cadmium that we saw. Two of them had the higher values of Lead and two of them also had some significant values for Mercury.

If we look at the milk chocolate, there were one or two standouts. There was a fairly, actually the highest value of Mercury was in this one particular milk chocolate brand. And one of the higher value of Lead was in this one brand of milk chocolate. We look at the liquor though, all the values of the toxic metals were some of the lowest that we saw.

So how does this compare? Again, we bring back our allowable daily limit and if we look at the Cadmium level, we’re allowed 55 µg, and we found between 1 and 5 µg in our 40g sample. So that means in that 40g sample, you’ll be getting between 2 and 9% of your allowable daily limit of Cadmium. For Lead, again, we have 0.8 and 3 µg which would give between 2 and 6% of your allowable daily limit. For Arsenic, we’ve found a little bit better. Your allowable daily limit is 130 µg and we fell between 0.3 to 1 µg. You would have between 0.2 and less than 1 % of your allowable daily limit. Mercury has a very low allowable daily limit for an adult and again the results were compared for an adult. In some of our samples we were unable to detect Mercury, but in our highest sample we saw 4 µg of Mercury. So you could have between 0 and 50% of Mercury just from chocolate.

Dark chocolate has the most toxic metals. But we did find toxic metals in all of our brands.

There is CERCLA, the Comprehensive Environmental Response Compensation Liability Act which designates an order of toxicity and substances that are the most potential threat to human health. Among those are Arsenic, Lead, Mercury, Cadmium and Chromium which we did find in our samples.