The influence of whey protein concentrate on growth and survival of probiotic bacteria in whey

U radu je istražen utjecaj dodatka koncentrata proteina sirutke (KPS) na rast i aktivnost probiotičkih sojeva Lactobacilus acidophilus La-5 i Bifidobacterium animalis subsp. lactis BB-12 u slatkoj rekonstituiranoj sirutki te na njihovo preživljavanje tijekom 28 dana hladnog čuvanja (4 °C) fermentirane sirutke. Praćena je fermentacija sirutke pri 37 °C bez i sa dodatkom 1,5 i 3% KPS. Fermentacija sirutke s Lactobacilus acidophilus La-5, kojoj je dodano 3% KPS, bila je oko 1 sat kraća (~14 sati ) u odnosu na fermentaciju sirutke bez dodatka KPS (~15 sati). Porast broja živih bakterijskih stanica Lactobacilus acidophilus La-5 u sirutki s 3% KPS bio je bolji (Δlog CFU/mL = 2,1 ) u odnosu na sirutku bez KPS (Δlog CFU/mL = 1,7 ). Dodatak koncentrata proteina sirutke nije značajno utjecao na rast probiotičkog soja Bifidobacterium animalis subsp. lactis BB-12 u sirutki, kao ni na preživljavanje oba probiotička soja tijekom 28 dana hladnog čuvanja (pri 4 °C). Sirutka obogaćena s KPS imala je nešto veću titracijsku kiselost tijekom fermentacije i čuvanja u odnosu na sirutku bez dodatka KPS.This research examines the influence of whey protein concentrate addition (WPC) on growth and activity of probiotic species Lactobacilus acidophilus La-5 and Bifidobacterium animalis subsp. lactis BB-12 in sweet reconstituted whey and their survival during 28 days of fermented whey cold storage (4 °C). The fermentation of whey at 37º C with and without 1.5 and 3% of WPC addition has been observed. Fermentation of whey with Lactobacillus acidophilus La-5 to which 3% WPC was added, was about an hour shorter (~14 hours ) compared to the fermentation of whey without WPC addition (~15 hours ). The viable cells count of Lactobacilus acidophilus La-5 was better in whey with 3% of WPC addition (Δlog CFU/mL = 2.1 ) compared to whey without WPC addition (Δlog CFU/mL = 1.7 ). Addition of whey protein concentrate did not influence significantly on growth of Bifidobacterium animalis subsp. lactis BB-12 in whey, and also it did not influence the survival of both probiotic species during 28 days of cool storage (at 4 °C). Whey enriched with WPC had slightly higher titratable acidity during fermentation and storage compared to whey without WPC addition