Antioxidative properties and proximate analysis of spent coffee ground (SCG) extracted using ultrasonic-methanol assisted technique as a potential functional food ingredient

M.K Zainol,Fisal Ahmad,Zamri Amir Izzwan,I Mohd Subri,H Mamat,Zamzahaila Mohd Zin

doi:10.26656/fr.2017.4(3).358

Abstract

Spent coffee ground (SCG) produced in tons by restaurants and cafeterias and domestic consumers is a potentially good source of natural antioxidants because it contains substantial amounts of bioactive compounds. The purpose of this study was to identify the physicochemical and antioxidant properties of three different types of spent coffee ground (SCG), namely Robusta, Arabica and Liberica extracted using ultra-sonicmethanol assisted technique. DPPH, FTC, TBA, total phenolic content (TPC) and total flavonoid content (TFC) were used to measure the antioxidant properties. Robusta SCG exhibited the highest DPPH inhibition 41.63±0.04%), FTC (60.42±0.03%) and TBA analysis (73.09±0.08%). The total phenolic compounds in the samples varied widely ranging from 18.94±0.06 to 26.23±0.86 mg GAE/g sample, with Robusta SCG showing the highest value among the three, while Arabica SCG depicted the highest amount total flavonoid content (47.62±0.05 to 56.20±0.08). A strong correlation between antioxidant activity and total phenolic content were observed in this study. Compared to Arabica and Liberica SCGs expended, Robusta SCG demonstrated a stronger beneficial effect against lipid peroxidation. This study reveals that SCGs can be regarded as a new useful source of natural antioxidant with a view to increasing the use of antioxidant synthetics by using the ingredient of agro-industrial residues in food production especially ingredients for functional food.

Highlights

One of the major residues of the coffee industry is the solid by-product known as spent coffee grounds (SCG)
The resulting SCG may be considered as a source of potentially valuable bioactive compounds during the brewing process (Panusa et al, 2013)
For fat content, Liberica SCG depicted the highest fat compared to Arabica and Robusta SCGs

Summary

Introduction

Coffee is one of the most popular beverages in the world, grown mainly in tropical and subtropical regions of Central and South America, Africa and South-East Asia, in temperature between 600 and 2500 m above sea level (Schenker et al, 2002). Coffee beans contain several classes of chemicals related to health, such as phenolic compounds, melanoidins, diterpenes, xanthines and vitamin precursors, especially antioxidants (AlDhabi et al, 2017). Coffee phenolics have attracted a lot of interest in recent years thanks to their powerful antioxidant and metal-chelating properties. The coffee industry produces large quantities of residues and by-products, both liquid and solid (Nabais et al, 2008). One of the major residues of the coffee industry is the solid by-product known as spent coffee grounds (SCG). SCG is the residue obtained during the treatment of raw coffee powder with hot water or steam for instant coffee preparation with fine particle size, high humidity (ranging from 80 to 85%), organic load and acidity. Despite the large quantities that have been produced, few studies focus on their use in different and productive applications. The antioxidant properties are one of the beneficial factors that could be attributed by SCG

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