Lonicera caerulea L. as a Source of Biologically Active Compounds for the Enrichment of Fermented Milk Product

Lonicera caerulea L., also known as honeysuckle berries, are rich in biologically active compounds, which makes them a valuable raw material for the development of functional foods. The objects of the research were three honeysuckle cultivars (‘Zoluška’, ‘Siņaja Ptica’, ‘Goluboje Vereteno’), four genotypes (No 2A; No 3; No 5; No 8) and kefir, enriched with various amounts (3–10%) of fruit puree. Physical and chemical analyses to determine the qualitative indicators of raw materials and products were performed. The degree of liking of kefir was assessed using sensory analysis: hedonic and line scales. The results obtained showed that among the cultivars the highest content of anthocyanins (1103.5 mg·100 g⁻¹), total phenols (693.3 mg·100 g⁻¹), flavonoids (753.9 mg·100 g⁻¹), and tannins (1.6 mg·100 g⁻¹), were found in ‘Siņaja Ptica’ berries, while among the genotypes, berries of No 8 had the highest concentration of the aforesaid compounds. Both samples also showed the highest antiradical activity: ABTS^+• on average by 71.7% and DPPH⁻ by 43.7%. According to the sensory evaluation, kefir with 10% honeysuckle puree was rated the highest. Honeysuckle berries could be used as a promising source of natural anti-oxidants in future research aimed at developing different new products that could meet consumer expectations.