Effect of Freeze-Drying of Prickly Pear (Opuntia Ficus-Indica) on Flavonoids and Antioxidants

Abstract

Prickly pear fruits (PPF) play a high-quality role in health due to its rich content of antioxidant and phenolic materials. This research is a cross sectional descriptive study, the efficacy of the drying method on the chemical attributes of PPF pulp on quality and safety during the storage period. The sample was divided into control and treatment by drying (oven-drying (OD) and freeze-drying (FD)). The flavonoid concentration in the pulp methanolic extracts was measured using spectrophotometry; the diphenylpicrylhydrazyl (DPPH) capacity was assessed using an adapted DPPH free radical-scavenging method, values of total phenolic content (TPC) and total flavonoid content (TFC) of fresh and dried PPF. The drying method had a significant effect on TFC; values were 39.88 and 18.05 μg/g CE fresh weight (FW) for the OD and FD, respectively. The FD exhibited about 77.56 ± 8.4 for TPC whereas the TFC estimated to 26.8 ± 11.4 mg GAE/100 gm FW. The DPPH for FD samples was significantly higher (249.8 ± 20.6) than that of the OD (75.2 ± 7.2). Mean values of Cupric Ion Antioxidant Reducing Capacity (CUPRAC) were 1005, 973 and 553 µM TE for fresh, FD and OD samples respectively. Meanwhile, the values were in significant differences in comparison between FD and OD of 973.5 ± 87.1 and 553.15 ± 16.6, respectively. The chemical composition, antioxidant capacity (DPPH, FARAP & CUPRAC) of PPF, and TFC of fruits were changed by drying. FD had the best results for the antioxidant capacity values as were the closest to the values of the fresh sample. Therefore, FD for PPF storage is proven to be recommended. Keywords: freeze-drying, prickly pear, Opuntia ficus-indica, antioxidants. https://doi.org/10.55463/issn.1674-2974.50.2.22