Use of Electro-Activated Whey as Ingredient in Fermented Milk Production: Proof of the Concept of the Technological Feasibility

Alkaline electro-activation of whey was previously reported to convert 25–45% of lactose into lactulose. Neutralization after electro-activation did not cause the loss of the lactulose yield. Lactulose is an established prebiotic and is used as an additive in fermented dairy products. The aim of this work was to study the behavior of electro-activated whey used as an ingredient in a fermented milk. To carry out this study, prior to fermentation, milk (0, 1, 2, and 3% fat) was supplemented with 3, 6, and 9% electro-activated whey. Different analyses were performed such as acidification kinetic, textural, rheological, syneresis, organic acids production, sensorial, and microbiological parameters were assessed. Furthermore, the effect of electro-activated whey on the fermented milk microstructure was analyzed by scanning electron microscopy. The obtained results showed that the addition of electro-activated whey prolonged the time of fermentation. Samples with electro-activated whey had more homogeneous and less porous microstructure and were characterized by a significantly reduced syneresis compared to milk or whey supplemented milk. The presence of electro-activated whey did not hinder bacterial growth and triggered the superior production of organic acids such as lactic, acetic, citric, propionic, and butyric acids. The analysis of residual lactulose during refrigerated storage showed that approximately 50% of lactulose remained in the fermented milk, suggesting that the consumption of such product will provide a sufficient amount of lactulose reaching the host colon. Finally, this study clearly demonstrated the feasibility of using electro-activated whey as a lactulose-containing ingredient in fermented milk manufacturing.