Chemical Composition, Antioxidant and Enzyme Inhibitory Properties of Different Extracts Obtained from Spent Coffee Ground and Coffee Silverskin.

Gokhan Zengin,Ahmed M Mustafa,Mohamad Fawzi Mahomoodally,Kouadio Ibrahime Sinan,Filippo Maggi,Giovanni Caprioli,Sauro Vittori,Simone Angeloni

doi:10.3390/foods9060713

Abstract

In a world where an eco-friendlier approach is becoming more and more necessary, it is essential to reduce waste production and to reuse residues of the company’s supply chain. Coffee silverskin (CS) and spent coffee ground (SCG), two by-products of coffee production, are important sources of bioactive compounds and, for this, some authors have proposed their reuse in the nutraceutical, food, and cosmetic sector. However, their potential enzyme inhibitory properties have been poorly investigated. Hence, the objective of the current work was to study the enzymatic inhibitory activities against acetylcholinesterase, butyrylcholinesterase, α-amylase, α-glucosidase, and tyrosinase of different extracts of CS and SCG. Before these in vitro bioassays, the phytochemical composition of each extract was investigated via colorimetric assays and HPLC-MS/MS analysis. In addition, the antioxidant activities were evaluated by different chemical approaches. SCG extracts contained a higher content of bioactive compounds, notably the SCG EtOH:H2O extract was the richest in caffeine and possessed the highest antioxidant activities. The hydroalcoholic and methanolic extracts were shown to be the most active against all tested enzymes, while the water extracts displayed lower activity. Our results showed a weak correlation between bioactive compounds and enzyme inhibitory effects, proving inhibitory activities likely due to non-phenolic molecules such as alkaloids and terpenoids. Obtained findings could be a starting point to develop novel nutraceuticals from CS and SCG.

Highlights

Coffee is one of the most consumed beverages in the world and, in addition, coffee beans are considered an important agricultural product of the international trade [1]
Coffee silverskin (CS) and spent coffee ground (SCG) are two important by-products of coffee processing; the first one, a thin tegument which covers the coffee seeds, is released during roasting, while the second one is the residue obtained in large part from the soluble coffee company and brewing process [9]
Our findings suggest the possibility of reutilization of coffee by-products, in particular SCG, as natural antioxidant sources for application in pharmaceutical, nutraceutical and cosmeceutical products

Summary

Introduction

Coffee is one of the most consumed beverages in the world and, in addition, coffee beans are considered an important agricultural product of the international trade [1]. Some authors have proposed the use of both by-products for different uses which affect various fields; for instance, some researchers have suggested to employ them as adsorbent material for removing potential toxic metals [4], while some studies have dealt with the possibility to recover bioactive compounds from these two co-products and employing them in the food, pharmaceutical and cosmetic industry [3,10,11]. In this context, interesting works took advantages of their high content of dietary fibers, phenolic compounds, chlorogenic acids and caffeine for the formulation of fortified foods [12,13]. SCG and CS contain a variegated phytochemical profile characterized by diverse biological activities, e.g., antioxidant and antimicrobial [7,14,15,16]

Objectives

Methods

Conclusion