Microwave-assisted extraction of polyphenol from coffee liberica L

Date of Publication

2010

Document Type

Bachelor's Thesis

Degree Name

Bachelor of Science in Chemical Engineering

College

Gokongwei College of Engineering

Department/Unit

Chemical Engineering

Thesis Adviser

Josephine Q. Borja
Marylou Mora Uy

Defense Panel Chair

Teddy G. Monroy

Defense Panel Member

Florinda Tiangco Bacani
Lawrence P. Belo

Abstract/Summary

Polyphenols are alcohols containing two or more benzene rings that have at least one hydroxyl group (OH) attached. Several thousand molecules having polyphenol structures have been identified in higher plants and several hundreds have been found in edible plants. They have been the subject of research by drugs and food manufacturers because of their antioxidant properties and their probable role in the prevention of various diseases.

Recently, some green technologies such as Microwave Assisted Extraction (MAE) and supercritical fluid extraction, to mention a few, were the focus of study on extraction of important polyphenol compounds from plants. Thus, this study investigated the combined effects of extraction parameters in extracting polyphenols from roasted coffee beans of Coffee liberica L. using MAE in the presence of ethanol as extracting solvent. The extraction parameters were extraction temperature of 50, 70 and 90C extraction time of 5, 7 and 10 minutes solvent-to-sample ratio of 10, 20, and 30ml/2g and solvent concentration of 0.6, 0.7 and 0.8 volume/volume ratio.

A preliminary run was conducted using a full factorial design (34) which comprised 81 experimental runs followed by the main experimental run using Taguchi method that consisted of 27 runs. For the main experimental set-up the range of the solvent-to-sample ratio was changed to 5, 10, and 15ml/2g and solvent concentration to 0.6, 0.7 and 0.8 (v/v) while extraction temperature and time remained the same.

Results showed that the solvent-to-sample ratio had the most significant effect on yield and recovery. Recovery and yield increased with decrease in solvent-to-sample ratio. The increase in solvent concentration also resulted in increase of yield and recovery but only up to a concentration of 0.7 (v/v). On the other hand, extraction temperature and time had minimal effect on yield and recovery. The highest yield was 304.97 mgGAE/L and this was obtained at extraction temperature of 70C, extraction time of 7 minutes, solvent-to sample ratio of 5ml/2g and solvent concentration of 0.7 (v/v).

Of the four major polyphenol tested in the extract only chlorogenic acid was identified having a concentration of 3,152.15 mg/L which represent 47.85% of the total polyphenols in the extract.

Abstract Format

html

Language

English

Format

Print

Accession Number

TU15944

Shelf Location

Archives, The Learning Commons, 12F, Henry Sy Sr. Hall

Physical Description

x, 123 leaves : ill. ; 28 cm.

Keywords

Microwaves--Industrial applications; Extraction (Chemistry); Polyphenols; Coffee

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