Effect of pectinolytic and cellulytic enzymes on the physical, chemical, and antioxidant properties of blueberry (Vaccinium corymbosum L.) juice

Blueberry (Vaccinium corymbosum L.) fruit, rich in anthocyanins, polyphenolics and antioxidant activity, has not been exploited fully for processing into juice. The objective of this study was to investigate the effect of commercial juice extraction enzymes (Cellubrix, Pectinex Ultra SPL, and Crystalzyme) on juice yield, total soluble solids (TSS), juice clarity, HPLC sugars profile, total anthocyanins (ACY), total phenolics (TPH), and antioxidant activity (assayed as FRAP). Enzyme treatments resulted in significantly (p ≤ 0.05) higher juice yield (86.91-87.29 mL/100 g with Pectinex and Crystalzyme as compared to 79.45 mL/100 g from control), higher juice clarity, and titratable acidity, and lower extraction loss. However, enzymes treatment had no effect on total soluble solids (°Brix), fructose, glucose, and total sugars. Generally, juice Hunter color values (L, a, and b), Hue angle (h°) and Chroma (C*) were affected positively by the enzymes treatment. As compared to the control (9.69 mg/100 mL), total ACY were significantly higher (11.49-12.90 mg/100 mL) in juice from enzyme-treated macerates; whereas there was no effect on TPH, determined as gallic acid equivalent (96-89‒101.30 mg GAE/100 mL) and FRAP antioxidant activity (3.87-3.97 μmol TE/100 mL). Total ACY, TPH, and FRAP were several-fold higher in the pomace than the juice.