Effect of oven and freeze drying on antioxidant activity, total phenolic and total flavonoid contents of fig (Ficus carica L.) leaves

I.M Elshaafi,N Abdullah Sani,K.H Musa

doi:10.26656/fr.2017.4(6).072

Abstract

Effect of drying processes on the antioxidant activities, total phenolic (TPC) and total flavonoid (TFC) contents of three fig (Ficus carica L.) leaves’ cultivars namely Brown Turkey Masuri 6 (BTM 6), Masui Dauphine Jumbo (MD-J) and Taiwan Golden Fish Jumbo (TGF-J) were studied. Oven drying which was conducted at 40oC, 50oC, 60oC and freeze drying at -80oC were run for 48 hrs. Antioxidant activities were evaluated using radical-scavenging capacity by 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azino-bis (3- ethylbenzothiazoline-6-sulphonic acid) (ABTS), ferric-reducing antioxidant power (FRAP) and cupric reducing antioxidant capacity (CUPRAC) assays. TPC and TFC were evaluated using Folin-Ciocaltue and aluminum chloride assays respectively. It was found that using oven drying at 40oC revealed significantly (p<0.05) the highest antioxidant activities of the three fig cultivars followed by oven drying at 50oC, freeze dried and oven drying at 60oC respectively. Fresh leaves revealed the significantly lowest antioxidant activities for all antioxidant assays and for all fig cultivars. Regardless of the drying process, fig cultivar BTM 6 revealed significantly (p<0.05) the highest antioxidant activities followed by TGF-J and MD-J. Positive correlations between antioxidant, TPC and TFC activities of fig leaves extracts were observed at oven drying at 40oC, oven drying at 60oC and freeze drying but not with oven drying at 50oC and fresh samples. High levels of antioxidant activities were obtained in F. carica L. leave samples (all cultivars), indicating that the leaves have potential as a source of natural antioxidants compounds.

Highlights

In the past few years, farmers in Malaysia successfully started importing and growing different fig (Ficus carica L.) cultivars, where the main products sold are fruits and leaves
The moisture content of fig leaves was determined after drying processes were completed
There were no differences among freeze drying and oven drying at (50oC and 60oC) results of the three fig cultivars, where the activities were ranging from 591 to 655 mg gallic acid equivalent (GAE)/100 g dry weight (DW)

Summary

Introduction

In the past few years, farmers in Malaysia successfully started importing and growing different fig (Ficus carica L.) cultivars, where the main products sold are fruits and leaves. Their leaves have been used as a tea and claimed to have medicinal properties. The secondary metabolites of plant work as antioxidants have been proved to fight cardiovascular diseases, cancer and diabetes (Chan et al, 2009; Shahinuzzaman et al, 2019). The protective properties fighting these illnesses remain possibly implemented by the occurrence of several functional secondary metabolites, like polyphenols, vitamins and minerals (Asami et al 2003; Chang et al, 2006; Roy et al, 2007; Sagrin and Chong, 2013). Polyphenols from various plant sources include an excessive diversity of bioactive compounds, such as flavonoids (anthocyanins, flavonols, flavanols, flavanones) and numerous classes of non-flavonoids such as (phenolic acids, stilbenes and other molecules) (Panche et al, 2016; Tan et al, 2018)

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