Effect of apple leaves addition on physicochemical properties of cloudy beverages

The effect of apple leaves addition on viscosity, turbidity, stability of turbidity, the composition of phenolics, antioxidant activity and color properties were studied to evaluate the potential application of leaves addition on cloudy apple beverages production. Beverages were obtained from ‘Šampion’ apples cultivar, after addition of 0.5%, 1% and 5%, respectively, of leaves.The viscosity of enriched beverages obtained after leaves addition ranged from 7.3% to 11.8%, and was significantly higher than the viscosity of the control sample, without the addition of leaves (6.6%). Higher turbidity and lower stability of turbidity was obtained upon leaves addition. The total content of phenolic compounds in apple beverages ranged between 1665 mg/L and 2541 mg/L and it was higher than in control juice (440 mg/L). Antioxidant capacity was positively correlated with content of polyphenolic compounds (correlation coefficient r = 0.63). According to HPLC–ABTS+ on-line analysis, the compounds of the flavan-3-ols group had the biggest impact on the antioxidant capacity value. Quercetin glycosides and dihydrochalcones, which are the main phenolics in leaves, influenced the antioxidant capacity to the minor and lesser extent, respectively.

► The viscosity and turibidty of cloudy apple beverages was higher after addition of apple tree leaf.
► After addition of apple leaves increase of total polyphenols was observed.
► Flavan-3-ols have the greatest influence on the value of the antioxidant capacity.
► Apple beverages, produced with the addition of apple leaves can be a valuable food product, because of their important biological and pharmacological properties.