22 March 24
Eben van Tonder

Introduction

Thawing chicken meat in Lagos brought renewed perspectives on muscle proteins. From an L of purge, I isolated at least 50%, possibly as high as 60% proteins. Muscle tissues contain a variety of proteins that contribute to their structure, function, and biochemical properties, including their interaction with various solvents. I review key muscle proteins, their solubility, presence in different meats and participation in curing processes.

Key Muscle Proteins

1. Myoglobin

Water-soluble and responsible for the red colour of meat. It can undergo colour changes and participate in curing by reacting with nitric oxide (NO) to form nitroso myoglobin, giving cured meats like ham their pink colour. It is the most abundant protein we see every day in the factory that leaches out as the meat thaws.

2. Actin and Myosin (Myofibrillar Proteins)

Salt-soluble. These proteins are primarily involved in muscle contraction and structure. They’re found in all meat types and can undergo slight colour changes but are less involved in curing reactions compared to myoglobin.

3. Collagen

Insoluble in water but can transform into gelatin in the presence of water when cooked for long periods. This transformation makes it soluble in water. Collagen is more abundant in beef and pork than in chicken and participates minimally in curing processes. However, its conversion to gelatin can affect the texture of processed meats.

4. Elastin

Similar to collagen, elastin is insoluble in water and does not play a significant role in curing. It’s found in connective tissues and contributes to the meat’s toughness.

5. Tropomyosin:

Salt-soluble, found in muscle tissues, and plays a role in muscle contraction by regulating the access of myosin to actin filaments. It has a minor role in meat curing processes.

6. Albumins and Globulins (Sarcoplasmic Proteins)

Water-soluble, these proteins are involved in various biochemical processes within muscle cells. They have limited participation in curing and colour change processes. Albumins are mainly found in blood, but they also appear in the cells’ sarcoplasm with proteins like myoglobin.

Presence in Beef, Chicken, and Pork

When thawing the chicken, albumin and globulin with some myoglobin with enzymes and nutrients. Without directly analyzing it, I sense that there is more myoglobin in chicken than one would expect. Still, the following general rules apply:

– Myoglobin: High in beef, moderate in pork, low in chicken.

– Actin and Myosin: Abundant in all three meat types, with slight variations.

– Collagen: High in beef and pork, especially in tougher cuts; lower in chicken.

– Elastin: Presence varies with the cut and age of the animal but generally follows collagen trends.

– Tropomyosin, Albumins, Globulins: Present in all meats but vary less between types compared to myoglobin and collagen.

Curing and Color Change Potential

1. Myoglobin: High potential for colour change and curing.

2. Actin and Myosin: Moderate ease of participation in curing, minor colour changes.

3. Collagen, Elastin, Tropomyosin, Albumins, Globulins: Low to negligible direct participation in curing and colour changes.

Conclusion

It is a strange thing how thawing chicken can make one review meat proteins and how this review can possibly lead to a breakthrough that eluded me for a few years now. Remarkable!