Effects Of Polyphenol And Ph On Cocoa Flavour Precursors And Flavour Compounds Using Lipidic Model System

Polyphenol is a naturally occurring compound in cocoa beans reported to reduce the concentration of flavour compounds, mainly pyrazines after cocoa roasting. This study was carried out to determine the effect of polyphenol concentrations and pH on cocoa flavour precursors (i.e. reducing sugars an...

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Main Author:	Sofian Seng, Noor Soffalina
Format:	Thesis
Language:	English English
Published:	2009
Subjects:	Polyphenols Cocoa - Analysis
Online Access:	http://psasir.upm.edu.my/id/eprint/12009/1/FSTM_2009_32_A.pdf
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spelling	my-upm-ir.120092013-05-27T07:50:46Z Effects Of Polyphenol And Ph On Cocoa Flavour Precursors And Flavour Compounds Using Lipidic Model System 2009-10 Sofian Seng, Noor Soffalina Polyphenol is a naturally occurring compound in cocoa beans reported to reduce the concentration of flavour compounds, mainly pyrazines after cocoa roasting. This study was carried out to determine the effect of polyphenol concentrations and pH on cocoa flavour precursors (i.e. reducing sugars and amino acids) and flavour compounds (i.e. alkylpyrazines) during roasting. The study was conducted using a lipidic model system at roasting temperature 1200C for 45 min. The concentration of amino acids and reducing sugars incorporated in the model systems was based on the results of the concentration found in fermented Malaysian cocoa beans. To determine the effect of polyphenol concentration, crude polyphenol extracted from cocoa bean was added into the lipidic model system at 0, 58, 116 and 174 g kg-1. Results showed that the higher concentrations of polyphenols (174 g kg-1) significantly (p<0.05) decreased the concentration of reducing sugars and amino acids during roasting. As the concentration of polyphenol increased from 58, 116 to 174 g kg-1, fructose was degraded at 33, 35, and 41% and glucose at 29, 30 and 33% respectively. Seventeen individual amino acids were detected, among all; alanine, tyrosine, valine and isoleucine were significantly (p<0.05) degraded higher than the others. These amino acids which are in the hydrophobic group were degraded at 41, 44, 45 and 43 % respectively at polyphenol concentration 174 g kg-1. Changes in procyanidins monomeric and polymeric constituents were correlated with the reduction of the precursors. High polyphenol concentration (174 g kg-1) significantly decreased the formation of alkylpyrazines in the model system. The Response Surface Methodology (RSM) plots revealed that lower concentration of amino acids and reducing sugars was obtained at higher polyphenol concentration (120 g kg-1) and lower pH value (4.5). Based on the constraints set on the obtained surface plots, the optimum region for polyphenol concentration of 43 – 58 g kg-1 and pH of 7.0 -7.5 was obtained for the optimum production of flavour precursors; while the optimum region polyphenol concentration of < 75g kg-1 and pH of > 6.0 was obtained for the production of alkylpyrazines. The optimum point was determined using response optimizer and it was found that the optimum polyphenol concentration of 49.5 g kg-1 and pH of 7.2 for flavor precursors and polyphenol concentration of 52.3 g kg-1 and pH of 7.0 for generated alkypyrazines.Thus, it is recommended that the acidity of the beans should be controlled during processing and extracting the excessive amount of polyphenol higher than 52.3 g kg-1 from the cocoa beans should be considered to lower its negative effect on reducing sugars and amino acids. Polyphenols Cocoa - Analysis 2009-10 Thesis http://psasir.upm.edu.my/id/eprint/12009/ http://psasir.upm.edu.my/id/eprint/12009/1/FSTM_2009_32_A.pdf application/pdf en public masters Universiti Putra Malaysia Polyphenols Cocoa - Analysis Faculty of Food Science and technology English
institution	Universiti Putra Malaysia
collection	PSAS Institutional Repository
language	English English
topic	Polyphenols Cocoa - Analysis
spellingShingle	Polyphenols Cocoa - Analysis Sofian Seng, Noor Soffalina Effects Of Polyphenol And Ph On Cocoa Flavour Precursors And Flavour Compounds Using Lipidic Model System
description	Polyphenol is a naturally occurring compound in cocoa beans reported to reduce the concentration of flavour compounds, mainly pyrazines after cocoa roasting. This study was carried out to determine the effect of polyphenol concentrations and pH on cocoa flavour precursors (i.e. reducing sugars and amino acids) and flavour compounds (i.e. alkylpyrazines) during roasting. The study was conducted using a lipidic model system at roasting temperature 1200C for 45 min. The concentration of amino acids and reducing sugars incorporated in the model systems was based on the results of the concentration found in fermented Malaysian cocoa beans. To determine the effect of polyphenol concentration, crude polyphenol extracted from cocoa bean was added into the lipidic model system at 0, 58, 116 and 174 g kg-1. Results showed that the higher concentrations of polyphenols (174 g kg-1) significantly (p<0.05) decreased the concentration of reducing sugars and amino acids during roasting. As the concentration of polyphenol increased from 58, 116 to 174 g kg-1, fructose was degraded at 33, 35, and 41% and glucose at 29, 30 and 33% respectively. Seventeen individual amino acids were detected, among all; alanine, tyrosine, valine and isoleucine were significantly (p<0.05) degraded higher than the others. These amino acids which are in the hydrophobic group were degraded at 41, 44, 45 and 43 % respectively at polyphenol concentration 174 g kg-1. Changes in procyanidins monomeric and polymeric constituents were correlated with the reduction of the precursors. High polyphenol concentration (174 g kg-1) significantly decreased the formation of alkylpyrazines in the model system. The Response Surface Methodology (RSM) plots revealed that lower concentration of amino acids and reducing sugars was obtained at higher polyphenol concentration (120 g kg-1) and lower pH value (4.5). Based on the constraints set on the obtained surface plots, the optimum region for polyphenol concentration of 43 – 58 g kg-1 and pH of 7.0 -7.5 was obtained for the optimum production of flavour precursors; while the optimum region polyphenol concentration of < 75g kg-1 and pH of > 6.0 was obtained for the production of alkylpyrazines. The optimum point was determined using response optimizer and it was found that the optimum polyphenol concentration of 49.5 g kg-1 and pH of 7.2 for flavor precursors and polyphenol concentration of 52.3 g kg-1 and pH of 7.0 for generated alkypyrazines.Thus, it is recommended that the acidity of the beans should be controlled during processing and extracting the excessive amount of polyphenol higher than 52.3 g kg-1 from the cocoa beans should be considered to lower its negative effect on reducing sugars and amino acids.
format	Thesis
qualification_level	Master's degree
author	Sofian Seng, Noor Soffalina
author_facet	Sofian Seng, Noor Soffalina
author_sort	Sofian Seng, Noor Soffalina
title	Effects Of Polyphenol And Ph On Cocoa Flavour Precursors And Flavour Compounds Using Lipidic Model System
title_short	Effects Of Polyphenol And Ph On Cocoa Flavour Precursors And Flavour Compounds Using Lipidic Model System
title_full	Effects Of Polyphenol And Ph On Cocoa Flavour Precursors And Flavour Compounds Using Lipidic Model System
title_fullStr	Effects Of Polyphenol And Ph On Cocoa Flavour Precursors And Flavour Compounds Using Lipidic Model System
title_full_unstemmed	Effects Of Polyphenol And Ph On Cocoa Flavour Precursors And Flavour Compounds Using Lipidic Model System
title_sort	effects of polyphenol and ph on cocoa flavour precursors and flavour compounds using lipidic model system
granting_institution	Universiti Putra Malaysia
granting_department	Faculty of Food Science and technology
publishDate	2009
url	http://psasir.upm.edu.my/id/eprint/12009/1/FSTM_2009_32_A.pdf
_version_	1747811292477915136

Effects Of Polyphenol And Ph On Cocoa Flavour Precursors And Flavour Compounds Using Lipidic Model System

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