Impact of Freezing and Freeze-drying Processes on Color, Phytochemical Contents and Antioxidant Capacity of Pomegranate Seeds

S, Al-Sanabani; Youssef, K.; Shatta, A.; El-Samahy, S.

doi:10.21608/scuj.2016.6659

Impact of Freezing and Freeze-drying Processes on Color, Phytochemical Contents and Antioxidant Capacity of Pomegranate Seeds

Document Type : Original Article

Authors

¹ Food Technology Department, Faculty of Agriculture, Suez Canal University, Ismailia 41522, Egypt.

² Food Technology Department, Faculty of Agriculture, Suez Canal University, Ismailia 41522, Egypt

10.21608/scuj.2016.6659

Abstract

The effects of freezing and freeze-drying processes on the antioxidant capacity and some phytochemical
contents as well as the color of pomegranate seeds were evaluated. The fresh pomegranate seeds exhibited high
antioxidant activity (79.50% and 3894.73 μmol trolox/100 g dry weight, measured by DPPH and ABTS assays,
respectively). The pomegranate seeds had high contents of total anthocyanins (22.80 mg/100 g), total phenolics (633.55
mg GAE/100 g) and total flavonoids (593.23 mg quercetin equivalent/100 g). Processing did not significantly affect the
color attributes of the pomegranate seeds except the hue angle values. Freeze-drying process significantly decreased the
antioxidant activity and phytochemicals contents of pomegranate seeds whereas freezing process had less negative
effect. The total anthocyanins, total phenolic and total flavonoid contents of pomegranate seeds well correlated with
their antioxidant capacity. The best correlations were between the total anthocyanins content with DPPH radical
scavenging activity (R2= 0.9652) and ABTS•+ scavenging capacity (0.9752) values.

Keywords