Saying "Hi" to Breakfast, Part II

Yesterday I began looking at what it was I was eating for breakfast.  I learned a bit about the USDA grading of eggs, and about the Colorado Proud logo on the egg carton.  I also had an interesting experience with respect to the old eggs.  Later in the day, I found a wikipedia article stating that old (floating) eggs should not be eaten because the enlarged air cell inside the egg is a result of bacterial activity.  I feel fine after eating the three eggs yesterday, but would rather not take my chances eating more bacteria (and their waste) than I have to.

Moving on to the next item in my breakfast, I had a piece of German rye bread with "Country Crock Shedd's Spread" and avocado, shown below:

I was introduced to German bread during my week visiting Berlin in early December.

So, let's check out the ingredient list for German "Whole Rye Bread" and see which ingredients I know and which are strangers.

Ingredients: whole kernel rye, water, wholemeal rye flour, salt, oat fiber, yeast.  This looks like a pretty simple ingredient list; 6 items and no names requiring a PhD in chemistry to understand.

Whole kernel rye and wholemeal rye flour both come from rye grain with various amounts of grinding, crushing, or other mechanical manipulation.  Water and salt, like them or not, are what they are.

Oat fiber is made from oat hulls, which are separated from the groats by centripetal acceleration (the hulls and groats are dropped onto a spinning surface, where the less dense hulls are separated from the more dense groats).  That sounds pretty cool, and a form of food processing that seems reasonably harmless to me.

Finally, yeast is a eukaryotic micro-organism from the Fungi kingdom that is commonly used as a leavening agent in bread.  From the wikipedia article, the 1,500 known species of yeast (as of 2006) were thought to be only 1% of the total existing species of yeast.  In addition to being used for baking and alcohol production, yeast are used for bioremediation and industrial ethanol production.

A little bit of reading on wikipedia revealed that most rye is grown in the European Union and consumed locally.  So, the rye in my bread was most likely grown in Germany, where the bread was produced.  Germany is the world's 3rd largest producer of rye, behind Russia and Poland.

The bread package declaires it contains no preservatives and no wheat.  Rye, though, is a close relative to wheat.  They are so close that the species can interbreed.  Whoa, interesting!

In reading about rye bread, I found another term which I had heard of before but not yet taken the time to understand: glycemic index.  The glycemic index of a food is a unitless ratio of two integrals.  Thinking back to high school calculus, an integral gives us the area under a curve.  In the case of glycemic index, the curve is a relationship of blood glucose versus time for a two hour duration, for a fixed amount of digestible carbohydrate.  This curve (and the corresponding area underneath the curve for a two hour duration) tells us something about the body's response ingesting a given carbohydrate.

Earlier I said the glycemic index is a ratio of two integrals.  The numerator of the ratio is the integral of the blood glucose response for the food in question, while the denominator is the integral for a control carbohydrate source (either pure glucose or white bread).  When glucose is used as the control carbohydrate, the ratio gives a value between 0 and 1.  The ratio is multiplied by 100, such that glycemic index values range from 0 to 100 when glucose is used as the control carbohydrate.  Using glycemic index with white bread as the control value can lead to ambiguity because there is no uniform definition for white bread, so the GI values can vary depending on the type of bread used.

Whole Rye Bread has a glycemic index in the mid to high-50's, which means it is a Medium GI food according to the wikipedia article on glycemic index.