9 Quality Of Fresh Meat.pdf n3r6c

Fresh Meat Quality

Aixa Rivera, MS Extension Beef Cattle Specialist Department of Animal Industry UPR - RUM - CCA

Production cycle

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Meat is define as: „

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animal tissues that are suitable for use as food. Includes processed or manufactured products that might be prepared from these tissues. It also includes: ‰ ‰ ‰ ‰ ‰ ‰

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Liver Heart Intestines Stomach Kidneys Other

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Fresh Meat: ‰

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Meat that has undergone the chemical and physical changes that follow slaughter and has only been minimally processed, Such as „

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fabrication into retail cuts, de-boning Grinding/ cubing

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Processed meat „

Meat whose fresh properties have been modified by one or various processes: ‰

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Adding of spices or curative salts, Color alteration Thermal treatment.

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Quality „

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Group of properties or attributes that gives meat products the necessary characteristics to be accepted. Principally : ‰ Nutritional quality – objective ‰ Acceptance or comsumtion quality – subjective „ „

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Sensory characteristics Safety

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Risk factors: „

Handling during the muscle to meat period: ‰ ‰ ‰ ‰ ‰ ‰ ‰ ‰ ‰

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Nutrition Transportation Stunning Bleeding Evisceration Washing Storing De-boning Packing

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Handling of fresh meat: ‰ ‰ ‰ ‰ ‰

Cutting/ retail cuts Grinding/ cubing Further process Packing Storage

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Characteristics of fresh meat: Quality

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Characteristics of fresh meat:

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Determines market use, Attractive for the consumer or buyer Determines its use for further processing

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Most important attributes of fresh meat:

a. b. c.

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Water Holding Capacity (WHC) Color Structure, firmness and texture.

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Water Holding Capacity (WHC): „

The meats ability (myofibril protein) of retaining its water or added water, during the application of external forces such as cutting, grinding or pressing.

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Importance due to its influence on: „ Color, texture and firmness of raw meat „ Palatability characteristics „ Juiciness and tenderness of cooked meat.

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Water „

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Principal component of meat, estimated close to 70 – 75% (muscle is 65 to 85 %) Most variable component Most of the meats water is in the free state. Affects juiciness.

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Color „

The color sensation varies with the observers vision, the quality and intensity of the light and the chemical and physical properties.

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Color is produced by pigments: „

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Components of the cell or tissue that produces color. (proteins) Absorbs some wave lengths and reflects others. ‰

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Affected by light conditions in place.

Texture and structure also affects: ‰ ‰

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Compact and firm – dark Soft and flaccid – pale

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Most important pigments: „

Myoglobin ‰ ‰

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Principal pigment of the muscle 80 – 90% of total muscular pigments (heme-pigment)

Hemoglobin pigment in red blood cells ‰ 20-30 % present ‰ Serves as oxygen transport from the lungs to muscle. In a well bled animal, 80-90 % of the color is due to Myoglobine, because it is the most abundant. ‰

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Color depends on: „

Type of muscular fiber: ‰ ‰

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White – less concentration of myoglobine Red – more concentration of myoglobine

Meat has a combination of these different types of fiber.

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The color intensity is affected by the amount of myoglobine. „ „ „ „

Age Specie Sexual category Muscle position and function

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Age Age

Myoglobine

Veal

2mg/g (1 – 3)

Calf

4mg/g (4 –6)

Heifer/bullock

Adult

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8mg/g (6 – 10)

18mg/g (16 – 20)

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Difference among species:

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Species

Color

Myoglobine

Pork

Pink/ gray

2mg/g 1-3

Lamb

Brick Red

6mg/g 4–8

Beef

Bright Red

8mg/g 4 – 10

Tuna

White/ gray

0.5 – 1 mg/g

Chicken

Light beige

1 - 2 mg/g

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Localization and function of the muscle: Localization / Function

Muscle name

Myoglobine

Locomotion

Extensor carpi radialis

12mg/g



Longissimus dorsi

6mg/g

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Localization / Function

Myoglobine

Leg

1.75 – 2.0mg/g

Heart

6mg/g

Gizzard

19.6 – 26.5mg/g 20

Color is affected by pre and post-management:

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Stress ‰

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Fight or flight

Conditions that can be produced: ‰ ‰

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Pale Soft Exudative Dark Firm Dry

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Pale Soft Exudative: „ „

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Common in Pork – Porcine Stress Syndrome – 5 – 10% Results in pale meat, lots of water loss (low WHC) and loss of firmness. May cause low yield % in process meats, increases loses while cooking, reduction of juices.

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Dark Firm Dry

„ „ „

More common in beef (3%) Cause by excess of ante-mortem physical activity Results in dark color meat, increase of WHC, very firm.

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Bacterial activity causes changes in color: Pigment

Catalysis

New pigment

Color

Oxymyoglobine

Oxidation + bacteria

Metmyoglobine (-OH)

Brown

Metmyoglobine

Bacteria produces H2O2

Coleglobine (-H2O2)

Green

Metmyoglobine

Bacteria produces H2S

Sulfmyoglobine (-SH)

Green

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Color changes during cooking: „

Changes in color due to: ‰ ‰

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increase of internal To. denaturalization of the pigments

When meat is cooked all the oxymyoglobine and myoglobine are changed to metmyoglobine. Once all reaction have been completed the protein is denaturalized. Surfaces changes: ‰

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Maillard Browning – carbonylamine browning (sugar amine browning) Surface Dehydration – crystallization

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Structure, firmness and texture:

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These properties are very difficult to measure objectively and are measured by the consumer through the use of his senses. Some factors that affect these properties are: ‰ Grade of firmness, ‰ Intramuscular fat content. ‰ Connective tissue content.

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Firmness grade : ‰

During chilling the carcass has developed firmness: „ Loss of extensibility „ solidification of intra and inter muscular fat ‰ „

High quantity of trapped water ‰

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Tissues of great firmness: sensation of a sticky and dry texture.

Non tender meats: „ Granulose structure „ Humid (poor WHC). Firm cuts with well defined muscles are preferred.

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Fat, meat and connective tissue: „

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Subcutaneous, Intermuscular, Intramuscular (marbling), Offal Solidification of fats ‰

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Helps maintain the cuts uniform and with their characteristic form.

Locomotion muscles: ‰

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Great quantity of connective tissue. Texture tend to be open coarse, less tender.

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Questions??

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