Culture medium based on whey permeate for biomass production of lactobacilli with technological aptitudes

The objective of this study was to formulate a culture medium to produce lactobacilli biomass using cheese whey permeate, as well as to study its effect on the metabolic activity of both Lacticaseibacillus rhamnosus 73 (L73) and Lacticaseibacillus paracasei 90 (L90) when grown under controlled or free pH conditions. The optimised media demonstrated to be efficient in obtaining high levels of L73 and L90, being also suitable to grow other lactobacilli strains with great potential as adjunct cultures for cheeses. The pH control enhanced biomass production for L73 but not for L90. In general, the peptidase activities and the metabolism of lactose and organic acids were influenced by the control of pH. Similarly, both L73 and L90 showed different volatile compound profiles depending on the pH condition. The diverse flavour-forming abilities of these strains might be of great value to cheese industries, by providing cheese with novel flavour profiles. •The optimised medium was effective to produce high biomass levels of lactobacilli.•The pH control during growing enhanced biomass production for L73 but not for L90.•L73 grown under controlled pH conditions showed improved uptake of minerals.•Lactose and organic acid metabolism by L73 and L90 were influenced by pH control.•The flavour-producing capacity of the strains depended on the pH condition during growing.