Apple, grape or orange juice: Which one offers the best substrate for lactobacilli growth? — A screening study on bacteria viability, superoxide dismutase activity, folates production and hedonic characteristics

• Lactobacilli growth was higher in apple than in grape or orange juices.
• Compared to supplementation, fermentation improved lactobacilli viability.
• Folates were produced by L. plantarum and L. rhamnosus strains in apple juice.
• SOD activity was correlated to lactobacilli growth during fermentation.
• Fermented apple juices were scored as ‘like moderately’, by most of the panelists.

ABSTRACTFermentation can contribute to improve functional aspects of foods. The first goal of this study was to determine amongst apple, grape and orange juices, the one with the best bacterial growth performance during fermentation by Lactobacillus strains from commercial and artisanal food origins, at 40 °C for 48 h. The juice with the highest bacterial growth was evaluated for bacteria viability during 4 weeks of cold storage, superoxide dismutase (SOD) activity and folates production analyzed through HPLC/fluorimetry. Acceptability of fermented juice was appraised through hedonic analysis. Lactobacilli counts were the highest in apple and the lowest in orange juices at t = 48 h. In most cases, bacteria counts were higher in fermented (5.5 to 9.5 log CFU/ml) than in supplemented apple juices (4.2 to 5.7 log CFU/ml), at the 4th week of cold storage. SOD activity was significantly increased in all apple juices fermented by commercial Lactobacilli strains. Folates were produced in apple juices fermented by Lactobacillus plantarum and Lactobacillus rhamnosus. Apple juice was the best substrate for Lactobacillus growth and, considering bacterial viability and overall acceptance by the panelists, Lactobacillus acidophilus L10 was the most suitable strain for apple juice fermentation.