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Pickering particles prepared from food waste

Gould, Joanne; Garcia-Garcia, Guillermo; Wolf, Bettina


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.


Gould, J., Garcia-Garcia, G., & Wolf, B. (2016). Pickering particles prepared from food waste. Materials, 9(791),

Journal Article Type Article
Acceptance Date Sep 14, 2016
Publication Date Sep 21, 2016
Deposit Date Sep 22, 2016
Publicly Available Date Sep 22, 2016
Journal Materials
Electronic ISSN 1996-1944
Publisher MDPI
Peer Reviewed Peer Reviewed
Volume 9
Issue 791
Keywords pickering emulsions; particles; lignin; food emulsions
Public URL
Publisher URL
Copyright Statement Copyright information regarding this work can be found at the following address:


materials-09-00791.pdf (5.8 Mb)

Copyright Statement
Copyright information regarding this work can be found at the following address:

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