Résumé:
The main objective of this work is to study the tenderizing effect of plant proteases; papain (papaya) and ficin (tree fig) and animal proteases; pepsin (chicken proventriculi), purified by three phase partitioning system on hard spent meat and compare the impact of the different enzymatic artificial tenderizing treatments on the meat texture. This work describes the applied three phase partitioning system (TPP) for the purification of these proteases. Protocols were set up and the purified enzymes were characterized, before their applications on meat. Then we studied the tenderizing effect of these enzymes on down-graded meat, of several species, namely: the meat of aged camels, spent hens and cull cows. Our results show that pepsin has a tendency to concentrate in the middle phase of the TPP system, with a purification yield and purification fold of 86% and 3.26, respectively. The optimized parameters of the system are 40% ammonium sulfate (NH4) 2SO4, (1.0: 0.75) (v: v) a ratio of crude extract / t-butanol and pH 4. In parallel, papain was recovered, in the aqueous phase with a purification fold of 11.45 and a recovery of 134%, by the optimized parameters of the TPP system: 40% (NH4) 2SO4, the crude extract to t-BuOH ratios of (1.0: 0.75) (v:v), pH 6.0 and 25°C. while ficin was exclusively distributed, in the intermediate
phase, after saturation with 40% (w / v) ammonium sulfate, and 1.0: 0.75 (v / v) of extract crude: t-butanol ratio at pH 7.0, thus giving a purification fold of 6.04 and a yield of 167%. After application of the purified proteases on the meat, the results obtained demonstrate that papain and ficin have a considerable effect on the texture of the meat, in fact, these two proteases have degraded the muscle structure in contact with the enzyme, mainly the myosin and laminin, but having no effect on collagen. Electrophoretic analysis by Glycine-SDS PAGE revealed the degradation of various muscle proteins, which strongly indicates the considerable potential of using chicken pepsin, for tenderizing meat. From our results, we can affirm that the three purified enzymes show great potential, in their applications, on tough meats. This enzyme can be easily applied to these meats, to improve its tenderness, both on an industrial or domestic scale.
