Fermentation of Murta (Ugni molinae) Juice: Effect on Antioxidant Activity and Control of Enzymes Associated with Glucose Assimilation

Abstract

Berries are rich in bioactive compounds, including antioxidants and especially polyphenols, known inhibitors of starch metabolism enzymes. Lactic acid fermentation of fruits has received considerable attention due to its ability to enhance bioactivity. This study investigated the effect of fermentation with L. mesenteroides of juice from the Chilean berry murta on antioxidant activity, release of polyphenols, and inhibitory activity against alpha-amylase and alpha-glucosidase enzymes. Three types of juices (natural fruit, freeze-dried, and commercial) were fermented. Total polyphenol content (Folin-Ciocalteu), antioxidant activity (DPPH and ORAC), and the ability to inhibit alpha-amylase and alpha-glucosidase enzymes were determined. Fermented murta juices exhibited increased antioxidant activity, as evidenced by higher levels of polyphenols released during fermentation. Inhibition of alpha-glucosidase was observed in the three fermented juices, although no inhibition of alpha-amylase was observed; the juice from freeze-dried murta stood out. These findings highlight the potential health benefits of fermented murta juice, particularly its antioxidant properties and the ability to modulate sugar assimilation by inhibiting alpha-glucosidase.