Effect of Traditional Fermentation Time on Total Phenolic Content and In vitro Antioxidant Activity of Kocho: Ethiopian Fermented Food from Enset (Ensete ventricusum welw. Chessman)

Engeda Dessalegn

doi:10.7176/fsqm/91-05

Abstract

Ensete ventricusum, locally known as Enset, is the main crop of a sustainable food source that ensures food security in Central ,South and South West Ethiopia. It has been used as a food and local medicine for thousands of years. Kocho is a product of matured Enset prepared traditionally by fermenting (for few weeks to some months) a mixture of pulverized pseudostem and corm in pit. The objective of this study was to evaluate the effect of traditional fermentation period on the total phenolic content and antioxidant activity of Kocho . The sample was fermented in the pit for 15, 30, 45, 60, 75, 90, 105 and 120 days. Oven dried Kocho powder was extracted with methanol followed by water. Total phenolic content of the extract was determined by the Folinciocalteu method. Antioxidant activities of the extracts were evaluated with 2, 2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity and total antioxidant activity using phosphomolybdenum assay. The results revealed that Kocho showed greater total phenolic content and antioxidant activities than unfermented product. Methanol extract of Kocho fermented for 45 days showed the highest amount of total phenolic content (9.27 ± 0.44 milligram of gallic acid equivalent per gram of dried extract). In comparison of DPPH scavenging and total antioxidant, methanol extracts were also superior to aqueous extracts. Methanol extract of Kocho fermented for 60 days exhibited the strongest DPPH scavenging activity (IC 50 = 0.15 ± 0.02 mg/mL) and total antioxidant activity (0.43 ± 0.04 milligram of ascorbic acid equivalent per gram of dried extract). Thus fermentation offers a tool to further increase the bioactive compounds and antioxidant potential of Kocho. Keywords: antioxidant activity, Ensete ventricusun , , fermentation, Kocho, total phenolic DOI : 10.7176/FSQM/91-05 Publication date :October 31 st 2019

Highlights

Enset is one of the potential indigenous crops for food, and the Enset cultivation system is economically viable, and is one of the few successful indigenous and sustainable agricultural systems (Yemataw et al, 2018)
Chemicals Gallic acid, butylated hydroxyl toluene (BHT), Folin–Ciocalteau reagent, 2,2-diphenyl-1-picrylhydrazyl (DPPH), sodium phosphate, ammonium molybdate, and ascorbic acid were purchased from sigma-aldrich
The results showed good linear correlation in the cases of DPPH scavenging activity (R2 = 0.53, p > 0.05) and total antioxidant activity (R2 = 0.52, p > 0.05) with total phenolic content of methanol extracts of Kocho fermented up to 120 days

Summary

Introduction

Enset is one of the potential indigenous crops for food, and the Enset cultivation system is economically viable, and is one of the few successful indigenous and sustainable agricultural systems (Yemataw et al, 2018) It is sustainable because it has been providing food for humans for generations from the same plot, and maintains the quality of life of the people (Negash and Anke 2004). It grows in a wide range of environmental conditions. Kocho is the bulk of the fermented food obtained from the mixture of the decorticated (scraped) leaf sheaths and grated corm (Tiruha et al, 2014) (underground stem base). The recent study (Zenebe et al, 2018) on fibers, obtained from the scraping of the pseudo stem, as well as the inflorescence stalk remaining after leaves sheath removal, showed the presence of lignin, polysaccharides and extractives

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