Influence of Freezing Steps on Color Attributes, Phytochemical Contents and Antioxidant Capacity of Green Beans

Chlorophyll and phytochemical contents, antioxidant capacity and color attributes of green beans (Phaseolusvulgaris L.) after washing, blanching and freezing processes were evaluated. The hue angle values showed that thefrozen beans had a bright yellow-greenish color. Chlorophyll a and b, total carotenoids, total phenolic and totalflavonoid contents significantly decreased during processing steps (washing, blanching and freezing). The antioxidantcapacity measured by ABTS method significantly decreased during freezing process steps ranged from 494.20 μmoltrolox 100 g-1 of fresh green beans to 437.54 and 342.13 μmol trolox 100 g-1 (on dry weight basis) of blanched andfrozen green beans, respectively. A plot of antioxidant capacity of green beans measured by DPPH or ABTS assayversus phytochemical compounds studied showed a strong positive correlation with total phenolics (R2 = 0.9847 and0.9609, respectively) and total flavonoids (R2 = 0.9963 and 0.9636, respectively).