The good chicken in technical control

The quality of the meat brings together different characteristics. Intrinsic, such as carcass and sensory and nutritional qualities, and extrinsic, which include interactions between animal production and the environment, local food resources, animal welfare, and drug use. If the creators take into account all these qualities, the second category is presented more to attract and convince the end consumer.

carcasses

Carcass quality is the proportion of meat in relation to fat and bone tissue, as well as viscera. This is what determines the business value. A good proportion of muscle guarantees a respectable weight. Research in recent decades has focused on improving carcass quality. The criteria for evaluating them depend on the degree of maturity of the animal at slaughter. Carcass composition is related to growth rate. Globally, broiler production is based on the creation of fast-growing standard genotypes, slaughtered at 40 days, with low fillet yield and belly fat. The more resistant and slow-growing lines are more suitable for extensive agriculture (a low-input cultivation method that does not seek high individual productivity per animal or per unit of area).

Fillet or fat? A balance to be found

In poultry, carcass fattening is most often assessed at the abdominal level. The increase in chicken weight leads to an increase in the intramuscular lipid (IML) content of the fillets. When this fattening is done with maize, as is customary in Réunion, the meat is consequently marbled with a yellowish color (see elsewhere).
Regardless of the genetic type, the later the chicken is slaughtered, the better the breast, thigh and abdominal fat yield. And this is even more true of women. Standard chicken lines have fillet yields above 20% and abdominal fattening close to 2%. The opposite is observed in the slow-growing strains produced outdoors: less fillets, more fat. The body composition of birds depends on energy and protein intake. Lipid deposition in adipose and muscle tissues is affected by the amount ingested, the energy/protein ratio and the composition of the ingested lipids. A high ambient temperature would also influence the chicken’s fat intake, impairing the development of the loin. But like humans, a chicken that exercises loses fat. If these parameters are taken into account, it is quite obvious that chickens raised in the cold of the highlands and outdoors have different characteristics from their cousins ​​in the lowlands, which are more exposed to the heat.

Technological quality

The ability of meat to be processed into raw or cooked products, whole or divided is called technological quality. In short, it’s about seeing how the meat behaves when preparing it. The technological quality is particularly visible, for example, when comparing foie gras that loses more or less volume after frying (melts the fat).
This quality is linked to muscular properties and, therefore, to the level of energy reserves that depend on the breeding conditions. The heavier and later slaughtered a chicken, the larger the size of the muscle fibers. This results in a higher PHu (final pH) of the fillet, a darker color and less water loss.
The measurement of PHu, water loss and meat color in fact determine the technological quality.
The PHu (or final PH) defines the magnitude of the PH drop before and after slaughter. It comes from muscle glycogen reserves at the time of slaughter. (Note to shine in society: glycogen is a complex carbohydrate that stores energy in reserve and releases glucose into the blood in case of physical exertion). Intramuscular chemistry that confirms that stress can affect meat quality. Yohan De Lort of Ferme Yann is very careful when slaughtering his animals. “To minimize stress as much as possible, we pick up the chickens early in the morning, when it’s still dark, when they’re napping. . They don’t have time to notice anything.”
Measurement of water loss is also used to assess meat quality and meat yield. This involves predicting the behavior of meat during storage, its losses during thawing or cooking.
Meat color is determined by four components: the structure of the muscle and its degree of acidification (PH), the amount of red muscle pigment, the signal of the presence of iron, the chemical form of the muscle pigment, and the growth of bacteria. on the surface of the meat.

The sensory quality

This is obviously linked to technological quality. It depends on objective observations (appearance, color, marbling, tenderness, succulence), the genetic and sexual type of the animals, age, breeding conditions, but also the slaughter and processing of the meat. Chicken meat contains more unsaturated fatty acids than beef or pork. When heated, partial oxidation of linoleic and arachidonic acid occurs and compounds with green, citrus and fatty fruit odors are formed. Broth-like sulfur compounds are among the main aromas in cooked chicken meat.
Sensory quality is also subjective because it is subject to the appreciation of tasters who are themselves influenced by their training and sensitivity.

Alexandre Begue

Source: Meat qualities, influences of animal characteristics and their breeding condition. Product INRA Anim. 2015
Dr. Hedwig Schlichtherle-Cerny, a state-certified food chemist.

> Taste and color
According to studies released by INRA, “access to an open-air field in slow-growing lines of poultry can influence the color of carcasses and meat, which would become more yellow”, but with “moderate effects”.
Corn has a lot to do with it. “In northern France, chickens are fed more cereal,” explains Jack-Olivier Fort of Ferme des Merles, so they are whiter than chickens in the south, which are raised more on corn.” This is also the case in Réunion, where the color of the chicken is almost “cultural”. This consumer appetite for yellow has led manufacturers to offer more golden chickens.
But how to give them that color when they remain locked up and are slaughtered at 40 days?
According to Jack-Olivier Fort, this color is not necessarily the result of a dye that has been incorporated into the birds’ feed. In fact, it can be produced by a small flower, marigold (calendula), associated with paprika. However, a study conducted in 2005 as part of the sixth Days of Poultry Research in Saint-Malo, which proposed experimenting with other pigment sources besides the controversial canthaxanthin (a pigment that exists in its natural state), established a higher efficiency of protein concentrate. of alfalfa combined with corn gluten, with an interesting economic result.


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