Centrifugal Cryoconcentration of Prickly Pear Juice: Effect on the Polyphenolic Content and their Antioxidant Activity

Abstract

Centrifugal cryoconcentration has been shown to be effective in the desalination of seawater, concentration of proteins, and liquid foods, mainly fruit juices; in the latter, it is particularly interesting to be a non-destructive technology on various bioactive compounds, such as polyphenols, which have been found in several fruit juices such as prickly pear. An important issue is related to centrifugation's effect on the concentration efficiency of cryoconcentration. The present work's main objective was to study the Block cryoconcentration assisted by centrifugation (BCCC), their effects on the polyphenols, and antioxidant activity applied to prickly pear juice. Prickly pear juice was obtained, Bx, pH, titratable acidity, color, total reducing sugars, total phenolic content (TPC), flavonoids, FRAP, DPPH, and process parameters (efficiency (η), concentration index (CI), and solute yield (Y)) were evaluated. Data obtained for physicochemical parameters showed high values of °Bx in cryoconcentrated samples, pH values decreased in treated samples, and total titratable acidity increased, total reducing sugars were higher in samples treated at the lower time of centrifugation, all experimental samples showed noticeable color changes. Higher total phenolic and flavonoid content were observed in samples treated at 15 min of centrifugation; DPPH and FRAP tests were highly correlated with TPC and flavonoid content (R2> 0.96). High efficiency and concentration index were observed; however, a low value of solute yield was found in cryoconcentrated juice. The use of cryoconcentration for prickly pear juices shows good results for physicochemical parameters, preservation of bioactive, and process parameters with the exception of solute yield.