Charles N'Gatta (Thesis defended the 29th september 2022)

Beef is an important source of essential nutrients (amino acids, iron, zinc, and B-vitamins) for humans. However, it is often criticized for, on the one hand, its composition of fatty acids (FA), and on the other hand, for the strong variability of its sensory qualities, especially it tenderness, which is decisive for the consumer. In terms of nutritional interest, a grass-based diet, as practiced in mountain farming, leads to the production of a low-fat meat rich in conjugated lipid acids, FA potentially favorable to human health and polyunsaturated fatty acids n-3 (PUFA n-3). These PUFA have properties very beneficial for the growth and maintenance of cognitive functions. Ruminant livestock products are also important sources of B-vitamins that are essential in the human diet, but are likely to degrade depending on the way the products are processed.

The aim of this thesis work will be to better valorize the muscles of cattle currently difficult to market by transforming them into elaborate products. They will be consumed in pieces, guaranteed in terms of tenderness, have high nutritional value, and their flavor will remain optimal after long storage periods. To achieve a product meeting these specifications, the prospective muscles will be selected before cutting, treated mechanically, marinated and cooked. The marinating operation will aim to decrease the oxidation phenomena and improve the stability of the flavor of the product. The major challenges of this work will lie in the ability to: (1) take into account the structural and compositional variability encountered on unprocessed beef muscles, (2) mechanically tenderize the product, and (3) slow down its oxidation during phases of mechanical treatment, of cooking and preservation.

This thesis is co-directed by Pierre-Sylvain Mirade (QuaPA) and Dominique Gruffat (UMRH, INRA).