الخلاصة:
The yoghourt industry in Algeria is strongly dependent on the external markets of the raw
materials in particular the starters used for this purpose. The present study was related to the
assessment of technological performance of three autochthonous thermophilic starter
compared to an industrial one, followed by the optimization of fermentation by Box Behnken
model and finally the production of a natural yoghourt using the results of this optimization,
then the quality evaluation of the product during storage was done.
The results showed that these local starters have good proteolytic and lipolytic activities,
showed their ability to produce exopolysaccharides and flavors, and exhibited good
antagonistic activity, however acidifying activity was lower. The starter coded FTM 3
presenting the best technological traits.
After application of the optimal conditions obtained by the model Box Behnken, the
concentration in lactic acid obtained accounts for approximately 94% of the value envisaged.
The produced yoghourt is characterized by acceptable acidity and syneresis, the number of
viable cells is in the values of standards Algerian for all period of storage, thus a good
microbiological quality was obtained by the fact of the absence of all contaminants.
