Polifenoli i antioksidativna aktivnost Kombuha napitka obogaćenog Coffeeberry® ekstraktom

Abstract

Kombuha je tradicionalni napitak koji se dobija fermentacijom zaslađenog crnog ili zelenog čaja aktivnošću čajne gljive, koja predstavlja konzorcijum bakterija sirćetnog vrenja i autohtonih vrsta kvasaca. CoffeeBerry® proizvod se dobija od celog ploda kafe i sadrži komponente koje imaju nutritivnu vrednost i zdravstveni značaj. U radu su ispitani uzorci fermentativne tečnosti tokom pripremanja Kombuha napitka na tradicionalan način, kao i oni dobijeni obogaćenjem te fermentativne tečnosti CoffeeBerry® ekstraktom. Fermentacija se odvijala u bioreaktoru na 28±1°C u trajanju od 9 dana do postizanja optimalne konzumne kiselosti. Rezultati su pokazali da CoffeeBerry® ekstrakt doprinosi bržoj fermentaciji medijuma za kultivaciju. HPLC analizom uzoraka fermentativnih tečnosti identifikovana su i kvantifikovana pojedina polifenolna jedinjenja i katehini, a takođe i kofein. U fermentativnoj tečnosti obogaćenoj CoffeeBerry® ekstraktom detektovana je hlorogenska kiselina u visokom sadržaju (188,94-458,56 μg/ml). Ispitana je antioksidativna aktivnost fermentativnih tečnosti na DPPH i hidroksil radikale elektron-spin rezonantnom (ESR) spektroskopijom. Antioksidativna aktivnost na DPPH i hidroksil radikale povećava se tokom trajanja fermentacije. U fermentativnoj tečnosti obogaćenoj CoffeeBerry® ekstraktom, izračunate IC50 vrednosti za DPPH i hidroksil radikale iznosile su 26,33-170,13, odnosno 11,33-102,22 μL/mL.

Kombucha is a traditional beverage obtained by fermenting sweetened black tea with tea fungus, which represents a consortium of acetic acid bacteria and yeasts. Also, CoffeeBerry® products, derived from the whole fruit of the coffee plant, are valuable ingredients with nutritional and health-enhancing potential. Samples of fermentation broths enriched with CoffeeBerry® extract and traditional Kombucha were analysed. The fermentation was performed in a bioreactor at 28±1°C for nine days. The results showed that the CoffeeBerry® extract contributed to a faster fermentation of cultivation medium. Some individual polyphenolic compounds and catehins in fermentation broth samples were identified and quantified by high performance liquid chromatography (HPLC). Among the bioactive compounds present in investigated samples obtained during Kombucha fermentation of the sweetened black tea enriched with CoffeeBerry® extract, chlorogenic acid (188.94-458.56 μg/mL) was the predominant. The antioxidant activity of investigated samples was tested by measuring their ability to scavenge DPPH and reactive hydroxyl radicals by electron spin resonance (ESR) spectroscopy. The scavenging activities on DPPH and hydroxyl radicals were increased with the duration of fermentation. IC50 values for Kombucha fermentation broth enriched with CoffeBerry®, based on DPPH and hydroxyl radical scavenging activities, were in the ranges 26.33- -170.13 and 11.33-102.22 μL/mL, respectively.