Microwave superheated water extraction of polysaccharides from spent coffee grounds

Carbohydr Polym. 2013 Apr 15;94(1):626-33. doi: 10.1016/j.carbpol.2013.01.088. Epub 2013 Feb 4.

Abstract

The spent coffee grounds (SCG) are a food industry by-product that can be used as a rich source of polysaccharides. In the present work, the feasibility of microwave superheated water extraction of polysaccharides from SCG was studied. Different ratios of mass of SCG to water, from 1:30 to 1:5 (g:mL) were used for a total volume of 80 mL. Although the amount of material extracted/batch (MAE1) increased with the increase of the concentration of the sample, the amount of polysaccharides achieved a maximum of 0.57 g/batch for 1:10. Glycosidic-linkage composition showed that all extraction conditions allowed to obtain mainly arabinogalactans. When the unextracted insoluble material was re-extracted under the same conditions (MAE2), a further extraction of polysaccharides was observed (0.34 g/batch for 1:10), mainly galactomannans. Also, a high amount of oligosaccharides, mainly derived from galactomannans, can be obtained in MAE2 (0.96 g/batch for 1:10). This technology allows to obtain galactomannans and arabinogalactans in proportions that are dependent on the operating conditions.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Carbohydrate Conformation
  • Coffee / chemistry*
  • Ethanol / chemistry
  • Fractional Precipitation
  • Galactans / chemistry
  • Galactans / isolation & purification
  • Galactose / analogs & derivatives
  • Hot Temperature
  • Mannans / chemistry
  • Mannans / isolation & purification
  • Microwaves*
  • Polysaccharides / chemistry
  • Polysaccharides / isolation & purification*
  • Solid Phase Extraction / methods
  • Solvents / chemistry*
  • Waste Products
  • Water / chemistry*

Substances

  • Coffee
  • Galactans
  • Mannans
  • Polysaccharides
  • Solvents
  • Waste Products
  • Water
  • galactomannan
  • Ethanol
  • arabinogalactan
  • Galactose