Processing Methods

World Food Waste Network

FSCW extraction methods adhere to the principles of green chemistry. Being more efficient, use less solvent and using renewable feedstocks.

A team of 27 researchers, supported by the COST Action, compiled and published the most comprehensive ever review of extraction and processing techniques for FSCW (available here). Waste associated with food has features different to other biowastes and, therefore, has its own set of processing methods, some of these are highlighted below.

1. Pre-treatment

Physical Methods

In order to ensure the longevity, transportability and the density of the product they are typically broken into smaller pieces, dried and packed in pellets, bails or briquettes.

2. Extraction

Subcritical Water

Subcritical water (100-240°C water) can be used due to the change in its nature from ambient temperature water. At these temperatures the water becomes more solvent and is more likely to be in a dissociated state allowing it to be a key part of acid and base reactions.

Supercritical Carbon Dioxide

Supercritical CO2 (>31.1°C,>7.39MPa) is a renewable, non-toxic and easily recyclable super selective solvent. It can be used for the extraction of oils, waxes and other molecules.

Microwave Assisted Extraction

MAE is preferable over traditional heating methods as it has reduced energy and solvent consumption and a reduced extraction time.

3. Filtration

Simulated Moving Bed Chromatography

SMBC tackles column chromatography inefficiencies by amending the simulated speed, taking the slow moving particles in the direction of the bed and allowing the fast moving ones to move countercurrent– facilitating collection from different outlets.

4. Pre-consumer

High Hydrostatic Pressure

HHSP is a process in which finished items (already packed) are subjected to pressures in excess of 400MPa, which inactivates bacteria, viruses and moulds.