Monitoring of acid-induced coagulation of dromedary and cows' milk by untargeted and targeted techniques

Imène Felfoul (1) , Alia Bouazizi (1) , Hamadi Attia (1) , Romdhane Karoui (2)

1 Université de Sfax - University of Sfax
2 BioEcoAgro - Equipe 9 - Structure-function relationship at the service of the reasoned formulation of food and ingredients

The monitoring of acid-induced coagulation of dromedary and cow milk was investigated using both conventional (viscosity, conductivity, acidification kinetics) and non-destructive (turbidity, fluorescence spectroscopy) methods. Maximum of viscosity (36.66 +/- 0.01 mPa s) for dromedary milk was observed at a pH of 3.5. Throughout acid-induced coagulation, dromedary milk exhibited lower viscosity than cow milk (maximum 36.66 +/- 0.01 versus 57.67 +/- 0.05 mPa s, respectively). The addition of HCl induced an increase of the electrical conductivity reaching values of 9.49 and 6.16 mS at the end of coagulation for dromedary and cow milk, respectively. Results obtained by turbiscan showed that the change in Delta BS was more steady for dromedary milk than for cow milk allowing the formation of a uniform gel. The structural and conformational changes in casein micelles during acid coagulation induced a decrease in the fluorescence intensity of tryptophan as the gel formation progressed for both milk samples.

Domaines: Sciences du Vivant [q-bio]; Sciences de l'environnement

Imène Felfoul, Alia Bouazizi, Hamadi Attia, Romdhane Karoui. Monitoring of acid-induced coagulation of dromedary and cows' milk by untargeted and targeted techniques. International Dairy Journal, 2022, 127, pp.105300. ⟨10.1016/j.idairyj.2021.105300⟩. ⟨hal-03653068⟩