Skip to main content
SLU publication database (SLUpub)

Conference paper2019Peer reviewed

The underutilised side streams of broccoli and kale–valorisation via proteins and phenols

Berndtsson, Emilia; Nynäs, Anna-Lovisa; Newson, William Roy; Langton, Maud; Andersson, Roger; Johansson, Eva; Olsson, Marie


As the world's population is growing, simultaneously as availability of water, arable land and fertilisers are decreasing, an increase in the utilisation of biomass is essential in order to reach sustainable food production. In agricultural primary production an extensive part of the total biomass produced ends up in side streams, which today are of low value. Studies including the whole food supply chain, as well as studies on a global level are generally lacking. This knowledge gap is hindering the work towards sustainable food production. Broccoli (Brassica oleracea Italica group) and kale (Brassica oleracea Sabellica group) are examples of crops where at most 10% and 50% of the total plant is harvested, respectively, for further processing into consumable products. The side streams are mainly composed of stems and leaves, which are potential sources of contents beneficial to health, such as dietary fibres and bioactive phenolic compounds, as well as proteins of high nutritional value and functionality. These substances all have potential as high value side products, which could be used as food supplements or ingredients. One proposed approach to reach a more sustainable primary production system is to use side stream products in a biorefinery concept, where proteins, dietary fibres and phenolic compounds are the main targets. This paper aims to be a first step in evaluating the feasibility of broccoli and kale side streams in such a biorefinery process. This requires knowledge of what compounds are present, and in which quantities, in the leaves and stems of the two different crops. It can be concluded, based on pilot studies and previously reported data, that kale and broccoli side streams are candidates in further studies on usage in a biorefinery process. Ethical perspectives of these uses of broccoli and kale have not been investigated thoroughly.


biorefinery; primary production; food; climate impact

Published in

Title: Sustainable governance and management of food systems : ethical perspectives : EurSafe 2019 Tampere, Finland 18 – 21 September 2019
ISBN: 978-90-8686-341-9, eISBN: 978-90-8686-892-6
Publisher: Wageningen Academic Publishers


15th Congress of the European-Society-for-Agricultural-and-Food-Ethics (EurSafe), SEP 18-21, 2019, Tampere, FINLAND