Optimisation of processing methods for roasting coffee beans and classification of roasted coffee beans using multivariate analysis / Ku Madihah Ku Yaacob

The aroma and flavour of coffee are developed in the roasting process. Major volatile flavour compounds identified in roasted coffee beans are pyrazines. Since the roasting process significantly affects these volatile compounds, the roasting conditions need to be optimised in ensuring the quality of...

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Main Author:	Ku Yaacob, Ku Madihah
Format:	Thesis
Language:	English
Published:	2015
Subjects:	Dietary studies, food values, experiments, tests, etc.
Online Access:	http://ir.uitm.edu.my/id/eprint/16119/ http://ir.uitm.edu.my/id/eprint/16119/1/TP_KU%20MADIHAH%20KU%20YAACOB%20AS%2015_5.pdf

id	uitm-16119
recordtype	eprints
spelling	uitm-161192017-02-16T04:30:19Z http://ir.uitm.edu.my/id/eprint/16119/ Optimisation of processing methods for roasting coffee beans and classification of roasted coffee beans using multivariate analysis / Ku Madihah Ku Yaacob Ku Yaacob, Ku Madihah Dietary studies, food values, experiments, tests, etc. The aroma and flavour of coffee are developed in the roasting process. Major volatile flavour compounds identified in roasted coffee beans are pyrazines. Since the roasting process significantly affects these volatile compounds, the roasting conditions need to be optimised in ensuring the quality of roasted coffee beans. In this study, the roasting temperature and roasting time for Indonesian Arabica and Robusta coffee beans were optimised based on the concentration of selected pyrazines (2-methylpyrazine, 2,3dimethylpyrazine, 2~5-dimethylpyrazine, 2~3,5-trimethylpyrazine and 2,3,5,6tetramethylpyrazine) using response surface methodology (RSM), supported by overall sensory evaluation by an expert panelist and trained panelists. Since undesirable acrylamide is known to be produced during roasting process, minimising the amount of acrylamide was also considered in the optimisation of roasting process. Pyrazines were extracted using solid phase microextraction (SPME) and gas chromatgraphy with flame ionisation detector (GC-FID) while acrylamide was analysed using solid-phase extraction (SPE) and GC-FID. Optimised conditions for roasting coffee beans were obtained at roasting temperature of 167°C for 22 minutes for Arabica coffee beans and roasting temperature of 167°C for 27 minutes for Robusta coffee beans. The optimised conditions were applied in roasting coffee beans samples from different varieties (Arabica and Robusta) and origins (Asia, Africa and America) and the dataset on the amount of pyrazines was subjected to multivariate analysis. Principal component analysis (PCA) was able to discriminate between Arabica and Robusta coffee beans with total variance of 91.94%, supported by hierarchical cluster analysis (HCA) showing two distinct clusters and discriminant analysis (DA) with 1000/0 correct classification. PCA revealed two groups whereby coffee beans from Asia were distinctly separated from those of America and Africa with total variance of 92.74%. In accordance, HCA showed 2 clusters, cluster 1 for Asia and cluster 2 for America and Africa. The analysis of pyrazines was applied to commercial coffee samples. Application of PCA and HCA resulted in 5 groups; 2 groups consisting of pure coffee samples and three groups of instant coffee samples. A method to reduce the amount of aery lamide produced during roasting without affecting the amount of pyrazines was studied by the addition of asparaginase. Reduction of acrylamide up to 96.53% was obtained by soaking the coffee beans with 3000U/g of prior incubating at 50°C for 30 min. This study highlighted the significant contribution of pyrazines in the production of quality coffee beans and can be a promising parameter in classifying the types and origins of coffee beans. 2015 Thesis NonPeerReviewed text en http://ir.uitm.edu.my/id/eprint/16119/1/TP_KU%20MADIHAH%20KU%20YAACOB%20AS%2015_5.pdf Ku Yaacob, Ku Madihah (2015) Optimisation of processing methods for roasting coffee beans and classification of roasted coffee beans using multivariate analysis / Ku Madihah Ku Yaacob. PhD thesis, Universiti Teknologi MARA.
repository_type	Digital Repository
institution_category	Local University
institution	Universiti Teknologi MARA
building	UiTM Institutional Repository
collection	Online Access
language	English
topic	Dietary studies, food values, experiments, tests, etc.
spellingShingle	Dietary studies, food values, experiments, tests, etc. Ku Yaacob, Ku Madihah Optimisation of processing methods for roasting coffee beans and classification of roasted coffee beans using multivariate analysis / Ku Madihah Ku Yaacob
description	The aroma and flavour of coffee are developed in the roasting process. Major volatile flavour compounds identified in roasted coffee beans are pyrazines. Since the roasting process significantly affects these volatile compounds, the roasting conditions need to be optimised in ensuring the quality of roasted coffee beans. In this study, the roasting temperature and roasting time for Indonesian Arabica and Robusta coffee beans were optimised based on the concentration of selected pyrazines (2-methylpyrazine, 2,3dimethylpyrazine, 2~5-dimethylpyrazine, 2~3,5-trimethylpyrazine and 2,3,5,6tetramethylpyrazine) using response surface methodology (RSM), supported by overall sensory evaluation by an expert panelist and trained panelists. Since undesirable acrylamide is known to be produced during roasting process, minimising the amount of acrylamide was also considered in the optimisation of roasting process. Pyrazines were extracted using solid phase microextraction (SPME) and gas chromatgraphy with flame ionisation detector (GC-FID) while acrylamide was analysed using solid-phase extraction (SPE) and GC-FID. Optimised conditions for roasting coffee beans were obtained at roasting temperature of 167°C for 22 minutes for Arabica coffee beans and roasting temperature of 167°C for 27 minutes for Robusta coffee beans. The optimised conditions were applied in roasting coffee beans samples from different varieties (Arabica and Robusta) and origins (Asia, Africa and America) and the dataset on the amount of pyrazines was subjected to multivariate analysis. Principal component analysis (PCA) was able to discriminate between Arabica and Robusta coffee beans with total variance of 91.94%, supported by hierarchical cluster analysis (HCA) showing two distinct clusters and discriminant analysis (DA) with 1000/0 correct classification. PCA revealed two groups whereby coffee beans from Asia were distinctly separated from those of America and Africa with total variance of 92.74%. In accordance, HCA showed 2 clusters, cluster 1 for Asia and cluster 2 for America and Africa. The analysis of pyrazines was applied to commercial coffee samples. Application of PCA and HCA resulted in 5 groups; 2 groups consisting of pure coffee samples and three groups of instant coffee samples. A method to reduce the amount of aery lamide produced during roasting without affecting the amount of pyrazines was studied by the addition of asparaginase. Reduction of acrylamide up to 96.53% was obtained by soaking the coffee beans with 3000U/g of prior incubating at 50°C for 30 min. This study highlighted the significant contribution of pyrazines in the production of quality coffee beans and can be a promising parameter in classifying the types and origins of coffee beans.
format	Thesis
author	Ku Yaacob, Ku Madihah
author_facet	Ku Yaacob, Ku Madihah
author_sort	Ku Yaacob, Ku Madihah
title	Optimisation of processing methods for roasting coffee beans and classification of roasted coffee beans using multivariate analysis / Ku Madihah Ku Yaacob
title_short	Optimisation of processing methods for roasting coffee beans and classification of roasted coffee beans using multivariate analysis / Ku Madihah Ku Yaacob
title_full	Optimisation of processing methods for roasting coffee beans and classification of roasted coffee beans using multivariate analysis / Ku Madihah Ku Yaacob
title_fullStr	Optimisation of processing methods for roasting coffee beans and classification of roasted coffee beans using multivariate analysis / Ku Madihah Ku Yaacob
title_full_unstemmed	Optimisation of processing methods for roasting coffee beans and classification of roasted coffee beans using multivariate analysis / Ku Madihah Ku Yaacob
title_sort	optimisation of processing methods for roasting coffee beans and classification of roasted coffee beans using multivariate analysis / ku madihah ku yaacob
publishDate	2015
url	http://ir.uitm.edu.my/id/eprint/16119/ http://ir.uitm.edu.my/id/eprint/16119/1/TP_KU%20MADIHAH%20KU%20YAACOB%20AS%2015_5.pdf
first_indexed	2023-09-18T22:55:21Z
last_indexed	2023-09-18T22:55:21Z
_version_	1777417817359908864

Optimisation of processing methods for roasting coffee beans and classification of roasted coffee beans using multivariate analysis / Ku Madihah Ku Yaacob

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