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Turkey, the normal festive chicken options as quantity three on the “meals consumed at Christmas” checklist, after roast potatoes and carrots. But not all components of a turkey are created equal when it comes to style and dietary goodness. The explanation for these distinction are present in how turkeys sometimes transfer round their surroundings.

Wild turkeys (Meleagris gallopavo) can fly moderately quick distances, are competent swimmers and have good acceleration and floor velocity – a real triathlete! That is in distinction to the turkeys which might be farmed for consumption. They’re typically unable to fly, so their muscle composition and look is considerably totally different from their wild relative.

What makes a muscle darkish?

The muscle protein of any consumed meat is damaged down by the digestive system into its principal constructing blocks: amino acids. The proteins sometimes include three totally different protein varieties. The primary are myofibrillar proteins, which allow the muscle to contract. Sarcoplasmic proteins embody issues akin to enzymes (that are important for oxygen metabolism) and myoglobin, which comprises the haeme pigment that offers meat its color. Lastly are collagen proteins, which maintain every little thing collectively.

Because the protein parts counsel, myoglobin performs a key function in whether or not meat is taken into account darkish or white. The myoglobin content material can be an indicator of what sort of work the muscle did.

Darkish meat has excessive ranges of myoglobin. It helps bind oxygen within the muscle to be used by the mitochondria of the cells, which is important for ensuring the physique’s cells operate correctly. The extra the muscle is used, the extra myoglobin it wants and the higher blood provide it depends on, thus giving it a darker color.

Myoglobin is what offers turkey thighs their darkish color.

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So, for instance, turkeys (and chickens) consistently roam round on the bottom, which means their leg muscle groups are performing train for lengthy durations of time. Because of this leg muscle groups are also referred to as “sluggish twitch fibres”, as a result of they’re in a position to carry out for extended durations of time with out fatigue.

Whereas these muscle groups have totally different names within the turkey, they’ve related features as these in human legs (though their knees bend the opposite means).

The breast and wings, however, are thought-about “white” meat. These muscle groups are not often utilized in turkeys (notably farm-reared turkeys). Which means that the breast and wings don’t want to have the ability to retailer or use giant quantities of oxygen over a chronic interval. These muscle groups are also referred to as “quick twitch” fibres, as they’re designed for fast bursts of power however tire rapidly. The breast is identical muscle because the pectoralis main muscle in people.

Which bit is finest?

Turkey is leaner, so it has much less fats than rooster. Turkey breast has about 160 energy per 84g serving, of which 60 energy come from fats and comprises 24g of protein. The remaining energy come from protein and different sources akin to blood and collagen within the meat. The wing has 190 energy per 84g serving, of which 90 energy come from fats with 23g of protein. The leg however has 170 energy per 84g serving, with 70 energy coming from fats and comprises 23g of protein.

In order a proportion of energy from protein, the breast is one of the best. Energy from protein are preferable as they require extra power to breakdown in comparison with fat or carbohydrates. This course of additionally takes longer and subsequently retains the physique feeling fuller for longer.

Darkish meat sometimes has extra fats in it, which can be utilized as an power retailer for these lengthy length actions, akin to going for a run. Fats can be the explanation the darkish meat often has extra flavour. So, if it’s style you’re after, the leg is finest – although the darkish meat comprises extra energy (and fats) than chicken. With this in thoughts, the underside of the turkey, which acts as the bottom throughout cooking, equally has a few of the most flavourful meat. It’s because all of the fats and juices soak into this darkish meat.

Darkish meat comprises a higher proportion of an individual’s advisable each day quantity of iron in it. Iron is an important aspect within the physique. About 70% of it’s in your blood and muscle groups, and it’s vital for carrying oxygen spherical your physique. Too little iron may end up in anaemia, which may scale back the quantity of oxygen that may be carried by haemoglobin inflicting shortness of breath, tiredness and a scarcity of power. So whereas darkish meat is likely to be fattier and better in energy, it could even have another advantages over chicken.

Adam Taylor is affiliated with the Anatomical Society.