Performances of different protocols for exocellular polysaccharides extraction from milk acid gels: Application to yogurt

Thi Binh An Nguyen (1) , Michael Nigen (1) , Luciana Jimenez (2) , Hassina Ait-Abderrahim (2) , Sylvie Marchesseau (1) , Laetitia Palmade (1)

1 UMR IATE - Ingénierie des Agro-polymères et Technologies Émergentes
2 Chr Hansen AS

Dextran or xanthan were used as model exocellular polysaccharides (EPS) to compare the extraction efficiency of EPS from skim milk acid gels using three different protocols. Extraction yields, residual protein concentrations and the macromolecular properties of extracted EPS were determined. For both model EPS, the highest extraction yield (∼80%) was obtained when samples were heated in acidic conditions at the first step of extraction (Protocol 1). Protocols that contained steps of acid/ethanol precipitation without heating (Protocols 2 and 3) show lower extraction yields (∼55%) but allow a better preservation of the EPS macromolecular properties. Changing the pH of acid gels up to 7 before extraction (Protocol 3) improved the extraction yield of anionic EPS without effect on the macromolecular properties of EPS. Protocol 1 was then applied for the quantification of EPS produced during the yogurt fermentation, while Protocol 3 was dedicated to their macromolecular characterization.

Mots clés: Exocellular polysaccharides (EPS); Extraction protocols; EPS production; Yogurt; Milk acid gelation; HPSEC-MALS; yoghurt

Mots clés: procédé d'extraction; polysaccharide extracellulaire; yaourt

Domaines: Ingénierie des aliments

Thi Binh An Nguyen, Michael Nigen, Luciana Jimenez, Hassina Ait-Abderrahim, Sylvie Marchesseau, et al.. Performances of different protocols for exocellular polysaccharides extraction from milk acid gels: Application to yogurt. Food Chemistry, 2018, 239, pp.742-750. ⟨10.1016/j.foodchem.2017.06.121⟩. ⟨hal-01607382⟩