Improved viability of Lactobacillus plantarum embedded in whey protein concentrate/pullulan/trehalose hydrogel during freeze drying.

In this study, trehalose (TRE) was added to prepare whey protein concentrate (WPC)/pullulan (PUL)/TRE hydrogel and the hydrogel was used as the wall material to improve the viability of encapsulated L. plantarum during freeze drying and storage. The optimum conditions were 5.0 % TRE concentration and 1:4 (v:v) of the ratio of L. plantarum suspension to the hydrogel. Under these conditions, the survival rates of L. plantarum were 94.36 ± 1.06 % after freeze drying and 97.02 ± 0.30 % after storage for 240 d at 4 °C. Interactions and rheological properties of WPC/PUL/TRE hydrogel were also studied. The results showed TRE reduced storage modulus (G') of the hydrogel and weakened hydrophobic interactions, disulfide and hydrogen bonds between proteins and polysaccharides, which was not conducive to hydrogel formation. In addition, the excellent water-holding capacity of WPC/PUL/TRE hydrogel was found by the drying kinetic experiment.