For each kilogram
of food protein wasted, between 15 and 750 kg
of CO2 end up in the atmosphere. With this alarming carbon
footprint, food protein waste not only contributes to climate change
but also significantly impacts other environmental boundaries, such
as nitrogen and phosphorus cycles, global freshwater use, change in
land composition, chemical pollution, and biodiversity loss. This
contrasts sharply with both the high nutritional value of proteins,
as well as their unique chemical and physical versatility, which enable
their use in new materials and innovative technologies. In this review,
we discuss how food protein waste can be efficiently valorized not
only by reintroduction into the food chain supply but also as a template
for the development of sustainable technologies by allowing it to
exit the food-value chain, thus alleviating some of the most urgent
global challenges. We showcase three technologies of immediate significance
and environmental impact: biodegradable plastics, water purification,
and renewable energy. We discuss, by carefully reviewing the current
state of the art, how proteins extracted from food waste can be valorized
into key players to facilitate these technologies. We furthermore
support analysis of the extant literature by original life cycle assessment
(LCA) examples run ad hoc on both plant and animal waste proteins
in the context of the technologies considered, and against realistic
benchmarks, to quantitatively demonstrate their efficacy and potential.
We finally conclude the review with an outlook on how such a comprehensive
management of food protein waste is anticipated to transform its carbon
footprint from positive to negative and, more generally, have a favorable
impact on several other important planetary boundaries.
