STARTERS PRODUCED ON WHEY-PROTEIN CONCENTRATES

A whey(-) protein concentrate (WPC) was tested as a growth medium for the production of starter cultures, in comparison to milk and commerci al media products. The growth of two starters was examined, a mesophil ic culture of Lactococcus lactis subsp. cremoris composed of proteinas e positive (Prt(+)) strain E8(+) and proteinase negative (Prt(-)) stra in HP-, as well as a commercial yoghurt-culture. WPC could successfull y be used to prepare both mesophilic and thermophilic starters grown u nder external pH control. WPC-grown cultures produced with pH control had equivalent or higher populations than milk-grown starters produced in a classical fashion (without external pH control). Supplementation of WPC by a milk protein hydrolyzate (MH) stimulated the fermentation . Although supplementation of WPC with MH was satisfactory, bacterial populations were highest in commercial media. Ratios in the thermophil ic starters were not significantly different when produced on whey, mi lk or WPC-based media. However, with the mesophilic starters, there wa s a shift towards the E8(+) Prt(+) strain, when using milk as a growth medium. The thermophilic cultures obtained on milk showed a higher sp ecific acidifying activity than those produced on commercial media.WPC -grown starters could potentially be used as a vehicle to enrich milk with proteins and increase cheesemaking yields.