Good eating and 'heathly' food seem to be topics that keep popping up in my life, so I thought I'd touch on my discoveries regarding wheat grains today...
I think I've wondered about the difference between wheat germ and wheat bran whenever I'm working on a recipe that requires one or the other. I always thought the authors were just being pretensions and that wheat germ and wheat bran were the same thing.Then, I ran out of my wheat germ and went to the local co-op to buy some. While searching through the bins of bulk goods for the wheat germ, I found bins of both wheat germ and wheat bran. Even more interesting, only the wheat germ was stored in the fridge, while wheat bran was stored at room temperature. This started me re-thinking my idea that the two grains were the same. (Perhaps some of you are wondering why this realization took me so long - it does seem rather obvious in retrospect.) The storage methods gave me my first hint - if wheat germ requires cool storage, it would suggest that it has higher fat content that wheat germ and the cool storage delays the fats going rancid.
My next step was to check out the ever trusty Joy of Cooking, which told me that wheat bran was ground-up version of the bran portion of the wheat kernels. This sent me in search of information of the parts of a wheat kernel (Wikipedia is my friend), and low and behold, wheat kernels have a bran, or outer sheath, an endosperm, making up the bulk of the kernel, and a germ, the portion of the kernel that will germinate and form a new plant. So, rather obvious now, wheat germ is made of ground-up germ while wheat bran is made up of ground-up bran. Interestingly, I've also found that most flour is made of ground wheat kernels after the bran and germ are removed.
Now to the question of why the wheat germ needs to be refrigerated while wheat bran does not. As I suspected, the fat content differs between these two cereal products. Wheat germ is relatively rich in omega 3 lipids. To keep the omega 3s fresh, you need to put the wheat germ in the fridge. Wheat bran is relatively rich in fiber - not surprising for the ground bits of a kernel husk. In addition, both wheat germ and wheat bran are good sources of vitamin B, iron, and other micro-nutrients. These nutrients are part of why whole wheat flour is better for you than regular flour - whole wheat flour includes the bran and the germ while regular flour does not.
In conclusion, wheat germ and wheat bran really are different. You need to store them differently, and that is because of differences in content - the wheat germ is richer in fats and the wheat bran is richer in fiber. However, I'm still not sure this means that I'll pay any more attention to my recipe directions than I have before. Both have some fiber, some protein, some lipids, and more nutritional value that all purpose flour. I'll make sure to pay attention to how I store them, and I'll probably put more wheat germ than wheat bran on my oatmeal in the morning since I'd rater add more omega-3s than fiber to my breakfast, but otherwise my cooking choices are unlikely to change very much. On the other hand, I'll now feel oddly informed when shopping in the bulk cereal section and when baking.
