Résumé:
Our study aims to determine the effect of date syrup on the physicochemical, microbiological and organoleptic quality of a fermented type yoghurt steamed during the post acidification phase of preservation of samples at positive temperature at 4 ° C for 21 days. The experiment was carried out with date syrup at different concentration 0%, 2.5%, 5%, respectively in steamed fermented milks. Each parameter studied is represented by three pots of 100 ml, ie an overall number of 15 samples. For 21 days of storage, the following measurements and controls were carried out every 7 days on each processed product: acidity, pH. From the beginning to the end of the post-acidification period, the average values in the fermented milks are characterized by a remarkable decrease (4.25-4.17), that the acidity values of the fermented milks measured are proportionally decreased with the addition of date syrup. Overall average acidity levels between 78 ° D at the beginning of fermentation up to 82.34 ° D at the end of the post-acidification period. During the experiment, however, the acidity of the experiments did not exceed the commercially acceptable standards of 150 ° D. Moreover, the number of specific yogurt germs namely streptococcus thermophilus and lactobacillus bulgariccus proves to meet the standards required for parboiled yoghurt, 107 live germs / ml In general, the addition of date syrup in the fermented milk did not alter the main organoleptic criteria of the products namely: adhesiveness, sweet taste, acid taste, odor and color
