Jewish World Review Jan. 29, 2002 / 16 Shevat, 5762
Dr. Ed Blonz
Dear W.: Color is a key factor in how appealing a meat product looks in the retail case. Meat is muscle, and it is normally dark red to purple. When exposed to oxygen, a chemical reaction takes place that causes the meat to turn bright red. This phenomenon is referred to as "bloom." Below the surface, or even on the bottom of the package, the color can be darker.
If a cut of meat that has bloomed is allowed to sit in the air, a second reaction can occur, causing the meat to turn brown. This is not necessarily a sign that the meat is of poor quality, but in time the flavor will begin to deteriorate. Interestingly enough, once meat has bloomed, the length of time it stays red depends on the antioxidant status of the meat. Studies have found that upping the vitamin E content of the animal's diet can increase the time the meat spends in bloom.
In general, butchers cut enough to satisfy turnover. They can also use an overwrap film to limit exposure, and some may even flush the package with a mixture of oxygen and carbon dioxide. These "treatments" cause the meat to bloom more slowly, and the process is coordinated with the time it takes to get the meat into the display case and sold.
Products that turn brown on the surface can be trimmed, allowing a new layer to bloom. In your case, the meat was red on the surface, but dark all the way through. The fact that it did not bloom once cut indicates that something went awry. It could very well have been due to stress, as you suggest, but there might have been other factors as well. In any event, it made perfect sense to take it back.
DEAR DR. BLONZ: Does tuna packed in water still have high levels of omega-3 essential fatty acids? If it has less than tuna packed in oil, how much less? -- M.M., Logan, Utah
Dear M.M.: With few exceptions, the oil used for canned tuna is either soybean or canola oil, not fish oil. As a result, the oil pack contains extra fat, but little in the way of extra amounts of the healthful omega-3 fats. A 3.5-ounce serving of light tuna in water (drained) contains 0.8 grams of fat, and 0.3 grams of omega-3 fats. Contrast that with light tuna in oil (drained), which contains 8.2 grams of fat, and 0.2 milligrams of omega-3 fats.
For higher levels of omega-3 fats, use the albacore (white) tuna. A 3.5-ounce serving of the water-packed albacore (drained) contains about 3 grams of fat, of which 1 gram is omega-3 fats. The difference is because of the fact that light tuna is made from the yellow fin and skipjack varieties, which contain less of the omega-3 fatty acids than albacore.
DEAR DR. BLONZ: I know one should try to avoid hydrogenated oils, but what about "fractionated vegetable oils?" What does "fractionated" mean? I've come across the ingredient several times, most recently in Dr. Soy Chocolate Peanut Soy Protein Bar. Thanks for your attention and your clearly written column. - L.S., San Diego, Calif.
Dear LS, Thanks for your kind comments. Fractionation is a process by which fats and oils are separated into various fractions, often based on melting characteristics. It is a preferable alternative to partial hydrogenation, because it does not lead to the formation of trans fatty acids. One example of the use of fractionated vegetable oil is as an ingredient in a coating or frosting. In this case, manufacturers might choose the "fraction" of the oil that would be solid at room
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