Enhancement of kefir functionality by adding black elderberry and evaluation of its quality during storage

The research explored the influences of 2% and 4% heat-treated fresh elderberry fruit mash supplement and 0.5% and 1% dried elderberry powder supplement before and after fermentation in kefir production on certain features of kefir beverage. Antioxidant activity, total monomeric anthocyanin, and total phenolic content were 16.69-75.67 (μmol TE/kg), 14.64-88.20 (mg cyn-3-gly/kg), and 167.94-531.33 mg GAE/kg in the samples during storage, respectively. Total phenolic content and antioxidant activity were higher in kefir samples produced with elderberry powder when compared to the other samples. It was determined that <i>L*</i> and <i>b*</i> increased with the decrease in the fruit supplement in kefir production, and <i>L*</i> and <i>b*</i> values were mostly higher in kefirs with fruit supplement before fermentation. The highest ACE inhibitor activity was observed in the kefir sample (1-DEPre sample) with 1% dried elderberry supplement before fermentation on the first day of storage. It was determined that the general appreciation scores were above 3, and the samples produced mostly with dried elderberry powder were appreciated more when compared to the samples produced with fresh elderberry.