Coffee Silver Skin: Chemical Characterization with Special Consideration of Dietary Fiber and Heat-Induced Contaminants
Coffee silver skin is produced in large amounts as a by-product during the coffee roasting process. In this study, coffee silver skin of the species <i>Coffea arabica</i> L. and <i>Coffea canephora</i> Pierre ex A. Froehner as well as silver skin pellets produced in the coffe...
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doaj-52ea5ed6e7b84818a14d0bb0cb2ae27b2021-08-26T13:44:50ZengMDPI AGFoods2304-81582021-07-01101705170510.3390/foods10081705Coffee Silver Skin: Chemical Characterization with Special Consideration of Dietary Fiber and Heat-Induced ContaminantsVera Gottstein0Mara Bernhardt1Elena Dilger2Judith Keller3Carmen M. Breitling-Utzmann4Steffen Schwarz5Thomas Kuballa6Dirk W. Lachenmeier7Mirko Bunzel8Chemisches und Veterinäruntersuchungsamt (CVUA) Karlsruhe, Weissenburger Straße 3, 76187 Karlsruhe, GermanyDepartment of Food Chemistry and Phytochemistry, Karlsruhe Institute of Technology (KIT), Adenauerring 20A, 76131 Karlsruhe, GermanyChemisches und Veterinäruntersuchungsamt (CVUA) Karlsruhe, Weissenburger Straße 3, 76187 Karlsruhe, GermanyDepartment of Food Chemistry and Phytochemistry, Karlsruhe Institute of Technology (KIT), Adenauerring 20A, 76131 Karlsruhe, GermanyChemisches und Veterinäruntersuchungsamt Stuttgart, Schaflandstr. 3/2, 70736 Fellbach, GermanyCoffee Consulate, Hans-Thoma-Stasse 20, 68163 Mannheim, GermanyChemisches und Veterinäruntersuchungsamt (CVUA) Karlsruhe, Weissenburger Straße 3, 76187 Karlsruhe, GermanyChemisches und Veterinäruntersuchungsamt (CVUA) Karlsruhe, Weissenburger Straße 3, 76187 Karlsruhe, GermanyDepartment of Food Chemistry and Phytochemistry, Karlsruhe Institute of Technology (KIT), Adenauerring 20A, 76131 Karlsruhe, GermanyCoffee silver skin is produced in large amounts as a by-product during the coffee roasting process. In this study, coffee silver skin of the species <i>Coffea arabica</i> L. and <i>Coffea canephora</i> Pierre ex A. Froehner as well as silver skin pellets produced in the coffee industry were characterized with respect to both nutritional value and potential heat-induced contaminants. Enzymatic-gravimetric/chromatographic determination of the dietary fiber content showed values ranging from 59 to 67 g/100 g with a comparably high portion of soluble fiber, whereas low molecular weight soluble fiber was not detected. Compositional and methylation analysis indicated the presence of cellulose and xylans in the insoluble dietary fiber fraction, whereas pectic polysaccharides dominate the soluble dietary fiber fraction. The protein content as determined by the Kjeldahl method was in the range of 18 to 22 g/100 g, and all essential amino acids were present in coffee silver skin; whereas fat contents were low, high ash contents were determined. Elemental analysis by inductively coupled plasma mass spectrometry (ICP-MS) showed the presence of macroelements in large amounts, whereas toxic mineral elements were only detected in trace amounts or being absent. Acrylamide was quantified with levels of 24–161 µg/kg. Although 5-hydroxymethylfurfural was detected, its concentration was below the limit of determination. Furfuryl alcohol was not detected.https://www.mdpi.com/2304-8158/10/8/1705coffee silver skindietary fiberelementsheat-induced contaminants |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Vera Gottstein Mara Bernhardt Elena Dilger Judith Keller Carmen M. Breitling-Utzmann Steffen Schwarz Thomas Kuballa Dirk W. Lachenmeier Mirko Bunzel |
spellingShingle |
Vera Gottstein Mara Bernhardt Elena Dilger Judith Keller Carmen M. Breitling-Utzmann Steffen Schwarz Thomas Kuballa Dirk W. Lachenmeier Mirko Bunzel Coffee Silver Skin: Chemical Characterization with Special Consideration of Dietary Fiber and Heat-Induced Contaminants Foods coffee silver skin dietary fiber elements heat-induced contaminants |
author_facet |
Vera Gottstein Mara Bernhardt Elena Dilger Judith Keller Carmen M. Breitling-Utzmann Steffen Schwarz Thomas Kuballa Dirk W. Lachenmeier Mirko Bunzel |
author_sort |
Vera Gottstein |
title |
Coffee Silver Skin: Chemical Characterization with Special Consideration of Dietary Fiber and Heat-Induced Contaminants |
title_short |
Coffee Silver Skin: Chemical Characterization with Special Consideration of Dietary Fiber and Heat-Induced Contaminants |
title_full |
Coffee Silver Skin: Chemical Characterization with Special Consideration of Dietary Fiber and Heat-Induced Contaminants |
title_fullStr |
Coffee Silver Skin: Chemical Characterization with Special Consideration of Dietary Fiber and Heat-Induced Contaminants |
title_full_unstemmed |
Coffee Silver Skin: Chemical Characterization with Special Consideration of Dietary Fiber and Heat-Induced Contaminants |
title_sort |
coffee silver skin: chemical characterization with special consideration of dietary fiber and heat-induced contaminants |
publisher |
MDPI AG |
series |
Foods |
issn |
2304-8158 |
publishDate |
2021-07-01 |
description |
Coffee silver skin is produced in large amounts as a by-product during the coffee roasting process. In this study, coffee silver skin of the species <i>Coffea arabica</i> L. and <i>Coffea canephora</i> Pierre ex A. Froehner as well as silver skin pellets produced in the coffee industry were characterized with respect to both nutritional value and potential heat-induced contaminants. Enzymatic-gravimetric/chromatographic determination of the dietary fiber content showed values ranging from 59 to 67 g/100 g with a comparably high portion of soluble fiber, whereas low molecular weight soluble fiber was not detected. Compositional and methylation analysis indicated the presence of cellulose and xylans in the insoluble dietary fiber fraction, whereas pectic polysaccharides dominate the soluble dietary fiber fraction. The protein content as determined by the Kjeldahl method was in the range of 18 to 22 g/100 g, and all essential amino acids were present in coffee silver skin; whereas fat contents were low, high ash contents were determined. Elemental analysis by inductively coupled plasma mass spectrometry (ICP-MS) showed the presence of macroelements in large amounts, whereas toxic mineral elements were only detected in trace amounts or being absent. Acrylamide was quantified with levels of 24–161 µg/kg. Although 5-hydroxymethylfurfural was detected, its concentration was below the limit of determination. Furfuryl alcohol was not detected. |
topic |
coffee silver skin dietary fiber elements heat-induced contaminants |
url |
https://www.mdpi.com/2304-8158/10/8/1705 |
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