Effect of mash enzyme and heat treatments on the cellular antioxidant activity of black currant (Ribes nigrum), raspberry (Rubus idaeus), and blueberry (Vaccinium myrtillus) juices

Abstract

The aim of this study was to determine the effect of mash enzymatic maceration and heating treatments before pressing on the antioxidant activities in selected berry juices. Total phenolic contents were determined by the Folin–Ciocalteau assay, antioxidant activities were determined by means of the oxygen radical absorbance capacity (ORAC) assay, and the intracellular antioxidant potentials were determined through the cellular antioxidant activity (CAA) assay. Blueberry juices exhibited the highest antioxidant activity, followed by black currant and raspberry juices. The mash enzyme treatment with Pectinex® Ultra Color enzyme preparation, improved the antioxidant activities in vitro. ORAC values correlated with CAA values (R2 = 0.91) and a slightly positive correlation was observed between Folin–Ciocalteau and CAA assays (R2 = 0.56). The findings support the observation that the mash enzymatic treatment of macerated fruits enhances their antioxidant activity. Considering the chemical assays (ORAC and total phenolic content), a combined treatment with heating to 85°C followed by mash enzymatic treatment was the most effective. Considering a biological model through the CAA assay, however, a comparable improvement in antioxidant activity resulted from the enzymatic and the combined treatments. Overall, the data showed that maceration enzymatic treatment improves the intracellular antioxidant activity in HepG2 human cells. To the best of our knowledge, this is the first report on the effect of the antioxidant potential of mash enzymatic and heating treatments assessed by means of a cellular approach.

Keywords

• Mash maceration
• berry juices
• intracellular antioxidant activity
• CAA