Biological and chemical characterization of shalgam juice

Shalgam juice is a traditional fermented beverage, mostly produced and consumed in the southern east parts of Turkey. The main ingredient of shalgam juice is black carrot which is known for its high antioxidant capacity due to the presence of anthocyanins. Although shalgam juice's composition is widely studied, further characterization is needed to determine its potential health benefits. In this study, shalgam juice's chemical and biological composition was characterized by determining its antioxidant capacity, identifying its microflora with species-specific PCR based on 16S rDNA and checking its anti-proliferative effects on Caco-2 cell lines using MTS assay in vitro. The antioxidant capacities of 11 different commercially available shalgam juices were investigated using DPPH, ABTS and FRAP assays and were found as 2.43-4.36 µmol TE/mL in ABTS, 3.53-5.96 µmol TE/mL in DPPH, 2.01-3.61 µmol TE/mL in FRAP assays. Comparison of the species-specific PCR targeting 16S rDNA gene sequences results with data from NIH by BLAST search program revealed twenty one Lactobacillus species and subspecies. Some of the identified LAB was previously reported as probiotics suggesting that shalgam juice may have probiotic potential in addition to its nutritional properties. The reconstituted lyophilized powder of shalgam juice inhibited the growth of Caco-2 cells in a dose dependent manner (50-6400 µg/mL) with 55.5-91.4% cell viability. In conclusion, although this study provided detailed information about the antioxidant and antiproliferative effects and microbial composition of shalgam juice in vitro, the mechanism behind health benefits of shalgam juice is still not clear and needs to be studied