Abstract
In Tunisia, kaddid, a dehydrated salted and spiced meat product, is still prepared using traditional procedures. Nowadays, local industrials are interested by this native product, highly appreciated by Tunisian consumers, and the establishment of a mechanized and controlled process has become necessary to allow for kaddid production. The present work focuses on the meat-salting step, which is the first and critical stage of kaddid's elaboration. Kinetics and modelling of sodium chloride uptake and water loss were investigated for different salting experimental conditions of brine concentration (15%, 21% and 26.5% w/w) and salting modality (wet and dry salting). The results obtained show an effect of the brine concentration and salting method on water exudation and sodium chloride uptake during meat salting. Furthermore, Zuggarramundi and Lupin's and Peleg's models were satisfactorily tested for the description of water exudation and sodium chloride uptake by beef meat during salting process. Values calculated for sodium chloride apparent diffusivity (D (S)) varied between 4.08 x 10(-10) and 8.07 x 10(-10) m(2)/s and those of water (D (w)) were in the range of 1.04 x 10(-9) to 1.47 x 10(-9) m(2)/s depending on brine concentrations and salting method. In addition, meat quality changes i.e. protein and microbial characteristics, were explored during the salting step. Changes in protein characteristics due to salting process were confirmed by electrophoretic studies of sarcoplasmic and myofibrillar proteins. At the lower brine concentration tested (15%), myofibrillar proteins suffered solubilisation, while at high salt concentration (brining at 26.5% and dry salting), they underwent degradation. All salting cases studied have shown an inhibitor effect on microorganism proliferation either after 24 or 48 h of processing. Dry salting during 24 h is the most suitable salting method for kaddid meat elaboration since it allows the highest dehydration level, preserves microbial quality and induces proteolysis which could generate aromatic compounds.