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

Abstract

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 (mu mol 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 L* and b* increased with the decrease in the fruit supplement in kefir production, and L* and b* 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. This study aimed to investigate the quality characteristics of kefir supplemented with fresh elderberry fruit mash and elderberry powder as a source of natural color and due to its rich nutritional content. Key findings show a positive association of some sensory properties, antioxidant activity, and total phenolic content with samples containing elderberry powder. The sample with 4% postfermentation elderberry mash received the highest total monomeric anthocyanin content at the beginning of storage. Elderberry powder could be used in kefir production successfully.image