Effect of the lactic acid fermentation by probiotic strains on the sour cherry juice and its bioactive compounds

Nowadays, demand for products which beyond the overall nutritional value have a feature that protects the consumers health, have increased. Several studies have proved fruit juices can become suitable carrier or medium for probiotic organisms. Therefore the aim of our study was to investigate the possibility of the probiotication of sour cherry juice by lactic acid fermentation with probiotic starter culture. In the fermentation 9 Lactobacillus strains were used and two cultivars of sour cherry as raw material. The pH adjustment and supplement of nutrients were necessary and to reach the recommended probiotic cell count we also investigated the effect of dilution of sour cherry juice. Due to the optimized combination of the pH adjustment, supplementation and dilution, the investigated strains reached the desired 9 log cfu/mL cell density in sour cherry juices, however a significant difference was observed between the number of viable cells of some Lactobacillus strains. In the Újfehértói fürtös sour cherry L. acidophilus La-5 (9.43 log cfu/mL), while in the Petri species L. acidophilus 150 (9.60 log cfu/mL) resulted in the highest probiotic cell number. The lactic acid fermentation can increase the phenolic compounds, but in case of the bioactive compounds significant differences were not general between the strains.