Obtention of Pelleted Kluyveromyces Marxianus Cidca 9121 with Immunomodulatory Properties: Selection of Protective Agents Using Plackett–Burman and Box–Behnken Experimental Designs

Probiotic yeasts are increasingly used in different animal production systems. Supply of feeding in the form of pellets provides productive advantages in several systems such as poultry production or aquaculture. The inclusion of viable yeast in the pellets has to overcome heat stress during palletization and also dehydration stress. We have worked with our previously characterized probiotic strain Kluyveromyces marxianus CIDCA 9121. We evaluated the resistance of this strain to a process dehydration and extrusion after pellet generation, conditions that were not analyzed for this genus of probiotic yeast. We determined the effects of different thermoprotective agents in order to maximize yeast viability over time and preservation of its probiotic traits. To this aim we used the single factor optimization method, Plackett-Burman central compound rotating design (P-B CCRD) and response surface methodology (RSM) for optimize survival conditions in a process performed at laboratory scale. We selected a combination of sucrose, maltose and maltodextrin and we have tested two different combinations of these agents in a pilot plant extrusion/dehydration process showing that one of them could increase yeast viability. Remarkably, we could observe that immunomodulatory capacity of this strain was not affected after dehydration in the presence of the different additives tested and subsequent rehydration, being the first report showing conservation of probiotic traits of K. marxianus strain upon pelleting opening new perspectives for product development.