Optimization of the roasting conditions to lower acrylamide content and improve the nutrient composition and antioxidant properties of Coffea arabica.

Huluager Endeshaw,Abera Belay

doi:10.1371/journal.pone.0237265

Abstract

Roasting is the most common method of processing coffee. During roasting, aromatic compounds are generated due to various reactions, which are important for developing color, flavor and aroma. Acrylamide is an undesirable carcinogenic substance that is metabolically activated and formed during the coffee roasting process. Coffea arabica was first found in Ethiopia, and Ethiopia can produce a large volume of coffee. The major coffee-producing areas in Ethiopia are Hararghe, Sidama, Gimbi/Nekemte, Yergachefe and Limu. The primary purpose of this study was to quantify the acrylamide contents of brewed and roasted coffee collected from street coffee sellers and industrial processors found in Addis Ababa, Ethiopia, and optimize the roasting conditions for Sidama coffee. The acrylamide contents were determined by HPLC using a DAD at 210 nm, the antioxidant property were examined using a UV–spectrophotometer, and moisture and nutrient composition of coffee was determined using the method described by the AOAC (Association of Official Analytical Chemists). The roasting temperature and time were optimized based on the acrylamide content, nutritional composition and antioxidant property of the coffee using central composite design. The roasting temperature and time significantly affected (p<0.05) the acrylamide level, nutritional composition and antioxidant property of the coffee. The acrylamide contents of street and industrial processed powdered coffee were 346 ±19 to 701±38μg/kg and 442±14 to 906±7μg/kg, respectively. Brewed coffee from street vendors and industrial processing had acrylamide contents of 25±2 to 49±1μg/L and 63±2 to 89±4μg/L, respectively. The EC50 values for scavenging radicals for the optimized coffee ranged from 171±0 to 111±4 μg/L. The optimal roasting temperature and time were 190°C and 6 minutes, at this temperature and time the acrylamide content decreased, and the antioxidant and nutritional compositions of the coffee improved.

Highlights

Coffee is the most frequently consumed beverage around the world [1]
The acrylamide contents in powdered coffee from street vendors and industrially processed coffee ranged from 346±19 to 906±0 μg/kg (Table 1)
A significant difference (p

Summary

Introduction

Coffee is the most frequently consumed beverage around the world [1]. It has a good fragrance, taste, health benefits and caffeine content, which make it a highly acceptable beverage throughout the world. Aromatic compounds are generated due to different reactions, such as the Maillard reaction, Strecker degradation, the degradation of sugars and the breakdown of amino acids, which are important for developing color, flavor and aroma [1]. Acrylamide is a thermal processing contaminant that is produced in the Maillard reaction, a series of nonenzymatic reactions between reducing sugars and free amino acids [4,5]. Acrylamide is not found in raw and unprocessed food items. It is formed when food containing certain precursors are thermally processed at temperatures of 120 ̊C or above, such as by frying, baking, roasting, grilling and toasting [7,8]

Objectives

Methods

Results

Conclusion