Abstract:
«Khliaa Ezir », a typical Algerian meat product, prepared according to a traditional process based on empirical observations and traditional recipes, consisting of steps of trimming /marinating, cooking/ripening and ageing in earthenware jar (Ezir). The objective of this thesis is to characterize the changes occurring in Khliaa Ezir during the preparation process, and to describe the mechanisms that govern the sensorial and technological qualities of the final product. In this context, twenty two (22) controlled manufacturing were used to characterize Khliaa Ezir in various stages of preparation. The overall composition of Khliaa Ezir at 21 days of storage (Khliaa Ezir ready for consumption) showed that it presented an intermediate moisture content (54, 83% ± 3,97) and high contents of fat (27,42% ± 3,86) and proteins (43.75% ± 0.53). Regarding sensorial characteristics, Khliaa Ezir showed high values for global tenderness and intensity of flavour due mainly to the spices and garlic used. A
principal component analysis (PCA) revealed the influence of some sensory attributes on the overall liking of the product. A proteomic characterization of myofibrillar and sarcoplasmic protein extracts of the product during preparation and ripening in earthenware jar out with 1- DE electrophoresis coupled with peptide mass fingerprinting analyses LC-MS/MS was carried. A comparison of the proteome of the two extracts at different days and steps showed quantitative difference in several bands. Some bands might be potential markers of the proteolysis that takes place during the preparation steps. However, cooking step seems to affect considerably the textural properties of the product, by significant changes on the structural proteins. In addition, the results of structural and microstructural characterization confirmed clearly the relationship by between proteolysis, structure and texture during the various stages of Khliaa Ezir manufacture. Khliaa Ezir could be considered as ‘‘shelf stable meat product”. The microbiological stability of the final product depends on the combination of several factors, mainly on i) the action of salt and spices, water activity reduction, ii) temperature and time of cooking and iii) the conditions of storage. Finally, findings from this thesis provide new insights in the biological mechanisms underlying the development of tenderness, flavor and microbiological stability of Khliaa Ezir. However, the recovery and industrial exploitation of Khliaa Ezir is strongly encouraged; especially for its technological proprieties and its sensory and nutritional acceptability.
