Application of lactic acid fermentation to elderberry juice: Changes in acidic and glucidic fractions

In the present work, the changes in sugar and organic acid profiles of elderberry juice fermented by lactic acid bacteria were reported for the first time. Twelve different LAB strains belonging to Lactobacillus plantarum, Lactobacillus paracasei, Lactobacillus casei and Lactobacillus rhamnosus species were applied for fermentation. All the samples obtained were analysed by GC-MS technique, after fermentation and cold storage. Lactic acid was the main end product: its concentration ranged between 10287 +/- 585 mg/kg (juice started with L. easel 2246) and 27261 +/- 4089 mg/kg (juice fermented with L. rhemnosus 1019), increasing its amount of about 40 fold compared to the unstarted product. Malic and citric acids were extensively metabolized by LAB, while glucose and fructose (27080 +/- 4062 mg/kg and 27338 +/- 4101 mg/kg respectively) were almost unaffected suggesting a switch in the microbial metabolism with the use of organic acids instead of sugars, probably due to the hostile environment represented by elderberry juice. To better highlight the differences among the samples, Discriminant Analysis was performed revealing differences between L. casei and all the other species tested especially due to the organic acid concentrations.