Page 53 - FoodFocusThailand No.174 September 2020

STRATEGIC R&D
STRATEGIC R&D

Muscle Proteins

and Enhancement of

Meat Texture Properties

Protein is an essential nutrient for human, we require protein for building and repairing body tissues. Almost all
kinds of food contain protein, more or less. However, the most popular source of protein is meat because of its
textures and flavors while the choice of meat for each person mostly depends on the meat texture.

Focusing on the meat composition, meat is mainly composed of called the Maillard reaction, simmer gives soft texture with rich flavor
water (70 – 80%), protein (20 – 25%) and fat (1 - 2%) while the main from slow cooking and evaporating process, etc.
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textural characteristics of meat are firmness, cohesiveness and
juiciness. The juiciness plays an important role for tenderness of cooked Enhancement of meat texture properties
meat which is directly related to muscle proteins. Besides selecting high quality young aged meat and proper cooking
method, pretreatment is another effective way to enhance meat texture
Muscle Proteins properties. Pretreatment involves cutting technique, marination or even
There are 3 basic muscle proteins that comprise skeletal muscle; storage condition. In this article, two kinds of pretreatment in margination
1. Stromal Proteins They constitute the connective tissue which category will be shared;
provides mechanical support and protection to the muscle. The • Marination by Acid/ Base When muscle turns into meat, Glycogen
connective tissue is composed mainly of Collagen (90%) along with is broken down to lactic acid causes the pH of meat can range from 5.2
other fibrous proteins including elastin, laminin and fibronectin, and to 7.0. At pH about 5.3, the isoelectric point of muscle, the protein repulsion
proteoglycans. Stromal proteins form the harness that holds together is at the lowest point indicating the equal amounts of positive and negative
the muscle cells. charges causing roughness in meat.
2. Sarcoplasmic Proteins They are involved in various metabolic As the pH becomes more acidic or basic, the balance of charges is
functions such as protein metabolism, fatty acid oxidation, electron disrupted by an increase in positive charges (acidic side) and negative
transportation. Sarcoplasmic proteins contain the proteolytic enzymes charge (basic side) on the myofibrillar protein, causing repulsion. The
that are involved in the post-mortem muscle tenderization process, shear force decreases when muscle pH is lowered to 3.5 because the
and Myoglobin that is responsible for meat color. accumulation of the net positive charges resulting in greater repulsive
3. Myofibrillar Proteins consist of many individual proteins that forces that pushing the myofibrils apart and causing better water-holding
perform different functions. Two basic functional categories of capacity .
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myofibrillar proteins are structural and contractile proteins. Some • Marination by Enzyme Protease is an enzyme that catalyzes
common structural proteins are titin (connectin), desmin (skeletin), and proteolysis, it breaks proteins into smaller polypeptides or single amino
Z-protein. The important contractile proteins are actin, myosin, acids. Aside from animal proteases, there are also plant and bacterial or
actomyosin and troponin. fungal proteases.
Most of plant proteases effect to both stromal and myofibrillar proteins.
Some factor affects the tenderness of cooked meat Some plant protease is able to develop characteristic called “Mushiness”
• Animal Age As the animals age, the divalent reducible cross- e.g. Papain in papaya, Bromelain in pineapple. On the other hand,
linkages in Collagen interact to form mature trivalent, non-reducible, bacterial proteases effect either on stromal or myofibrillar proteins which
more heat-stable cross-links, which further enhances their stability and give more preferable texture to the consumer .
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mechanical strength. The meat toughness increases as the animal In addition, in a soy sauce production process, traditional fermentation,
aged due to an increase in collagen cross-linking and decrease in proteases are produced naturally by Koji mold during Koji making process.
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collagen solubility . Nowadays, thanks to an advance technology, the undersigned
• Cooking Methods Different cooking method results in different microorganism can be removed while enzyme can be maintained.
meat textures and flavors. For example, deep-frying creates crispy/ Therefore, the special-technique-treated soy sauce containing active
dry texture at the outer layer and keeps juiciness inside, grilled meat protease can be a novel pretreating tool for enhancing meat texture
acquires a distinctive roast aroma and flavor from a chemical process properties as a meat tenderizer.

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