posted on 2016-10-07, 12:26authored byJoanne Gould, Guillermo Garcia-Garcia, Bettina Wolf
In this paper, we demonstrate the functionality and functionalisation of waste particles as an emulsifier for oil-in-water (o/w) and water-in-oil (w/o) emulsions. Ground coffee waste was chosen as a candidate waste material due to its naturally high content of lignin, a chemical component imparting emulsifying ability. The waste coffee particles readily stabilised o/w emulsions and following hydrothermal treatment adapted from the bioenergy field they also stabilised w/o emulsions. The hydrothermal treatment relocated the lignin component of the cell walls within the coffee particles onto the particle surface thereby increasing the surface hydrophobicity of the particles as demonstrated by an emulsion assay. Emulsion droplet sizes were comparable to those found in processed foods in the case of hydrophilic waste coffee particles stabilizing o/w emulsions. These emulsions were stable against coalescence for at least 12 weeks, flocculated but stable against coalescence in shear and stable to pasteurisation conditions (10 min at 80 °C). Emulsion droplet size was also insensitive to pH of the aqueous phase during preparation (pH 3–pH 9). Stable against coalescence, the water droplets in w/o emulsions prepared with hydrothermally treated waste coffee particles were considerably larger and microscopic examination showed evidence of arrested coalescence indicative of particle jamming at the surface of the emulsion droplets. Refinement of the hydrothermal treatment and broadening out to other lignin-rich plant or plant based food waste material are promising routes to bring closer the development of commercially relevant lignin based food Pickering particles applicable to emulsion based processed foods ranging from fat continuous spreads and fillings to salad dressings.
Funding
This research was funded through the EPSRC Centre for Innovative Manufacturing in Food
grant (EP/K030957/1).
History
School
Mechanical, Electrical and Manufacturing Engineering
Published in
Materials
Volume
9
Citation
GOULD, J., GARCIA-GARCIA, G. and WOLF, B., 2016. Pickering particles prepared from food waste. Materials, 9 (9), 791.
Publisher
MDPI
Version
VoR (Version of Record)
Publisher statement
This work is made available according to the conditions of the Creative Commons Attribution 4.0 International (CC BY 4.0) licence. Full details of this licence are available at: http://creativecommons.org/licenses/ by/4.0/
Acceptance date
2016-09-14
Publication date
2016-09-21
Copyright date
2016
Notes
This is an Open Access Article distributed under the Creative Commons Attribution License (CC BY 4.0). Full details of this licence are available at: http://creativecommons.org/licenses/by/4.0/