Characteristics of Novel Fermented Cloudy Fruit Juices Produced Using Lactiplantibacillus plantarum and Lactic Acid-Producing Lachancea spp. Yeasts.

Fermented fruit juices are considered functional beverages because they contain bioactive compounds derived from plant materials and produced by the microorganisms involved in fermentation. The composition of these beverages can vary depending on the strain used. This study aimed to determine the effect of different microorganisms conducting lactic acid fermentation on the chemical composition and bioactive component content of naturally cloudy fermented pear and plum juices. The process used Lactiplantibacillus plantarum K7 bacteria, which were isolated during sauerkraut fermentation, as well as Lachancea thermotolerans PYCC6375 and Lachancea fermentati PYCC5883 yeast cultures, which have poor ethanol fermentation capabilities. The pH, acidity, sugars (HPLC), free amino nitrogen, selected organic acids (HPLC), color (CIELAB), polyphenols (HPLC), volatiles (GC-MS), aroma-active volatiles (GC-MS-O), and sensory characteristics were analyzed. The fermented juices obtained were rich in organic acids (of plant and microbial origin), polyphenols, and had a reduced sugar content (with polyols replacing glucose and fructose), as well as a low alcohol content (<0.2%). At the same time, all three microorganisms significantly enhanced the fruity aroma of the juices. Lachancea yeasts proved to be a viable alternative to lactic acid bacteria for producing fermented juices and were significantly better suited to fermenting plum juices. The highest polyphenol content and highest consumer preference rating were obtained with plum juices fermented with L. fermentati yeast.