Effect of lactic acid fermentation on phenolic composition and antioxidant capacity of caper bud (Capparis spp.)

In this study, caper bud samples belongs to Capparis ovata Desf. species were utilized in Kombucha production. Analyzes of green tea Kombucha (KC1), caper Kombucha (KC2), green tea-caper Kombucha (KC3) and as a raw material caper samples were conducted. In addition to the physico-chemical properties, antioxidant capacity (ABTS, CUPRAC, DPPH) and total phenolic content of samples were determined in terms of extractable, hydrolyzable and bioalinable phenolics. The dry matter, water-soluble dry matter, ash and total acidity and pH of the caper buds used in the Kombucha production were determined respectively as 25,99±1,12 (g/100g); 14,47±0,21, 1,74±0,06 (g/100g); 0,57±0,06 (g/100g); 5,30±0,12. Bioaccessible phenolic content of caper buds were found as 18,55±0,15; 15,68±0,65 and 8,38±0,50 µmole troloks/mL in terms of TEACABTS, TEACCUPRAC and TEACDPPH. In Kombucha samples, at the end of fermentation, the total acidity ranged between 0,74±0,02 and 1,43±0,04 (g/100g), while the pH was between 3,18±0,01 and 3,19±0,01. Although, caper buds did not contain any anthocyanin, KC1 sample was determined to have 2,30 mg/L (cyanidin-3-glycoside equivalent) anthocyanin and it was increaesed 52% and determined as 3,50 mg/L (cyanidin-3-glycoside equivalent) in KC3 sample by the support of caper buds. When the antioxidant capacity of Kombucha samples are evaluated, KC3 sample had the highest values in extractable (TEACABTS: 7,06 µmole trolox/mL; TEACDPPH: 7,12 µmole trolox/mL), hydrolyzable (TEACABTS: 7,59 µmole trolox/mL; TEACCUPRAC: 4,28 µmole trolox/mL; TEACDPPH: 3,03 µmole trolox/mL) and bioaccessible phenolics (TEACABTS: 5,70 µmole trolox/mL; TEACCUPRAC: 4,47 µmole trolox/mL; TEACDPPH: 2,36 µmole trolox/mL). In addition, according to sensory evaluation results, KC3 sample was the most preferred one by the panelists with 5.60 points (Overall acceptability). As a result of the study, by using a rich substrate capers bud, antioxidant capacity and total phenolic component content enriched, new healthy fermented beverage was produced.