Olive leaves have been underutilized primarily due to limited awareness of their health benefits, overshadowed by the popularity of olives and olive oil in culinary traditions. There are many challenges in processing techniques, regulatory constraints, and limited research development and consumer awareness which also contribute to their infrautilization. In this article, we would like to dive deeper on the many reasons why revalorisation of olive leaves is crucial.
Have you ever wondered what happens to olive leaves after olive recollection and pruning? They remain in the field and olive mills!Accounting for a staggering volume of biomass currently underutilised. Olive trees that are grown to produce table olives need to be pruned every year, whilst olive trees grown for olive oil need to be pruned every second year. It is estimated that a whopping 1.25 million tons of olive leaf biomass is produced annually in Spain alone
, representing approximately 50% of the world’s total production. Most of the biomass generated from the pruning has traditionally been incorporated back to land, fed to livestock, or burned in field, contributing to greenhouse gas emissions and meaning that a valuable resource is largely underutilised. As such, these discarded olive leaves are starting to be recognised as a precious source of biomass.
Indeed, olive leaf biomass is rich in valuable bioactive compounds such as polyphenols
, essential oils
, and lignocellulose
, making it a potential asset in various industries including food, feed, chemical, nutraceutical, cosmetic, and pharmaceutical sectors. Collecting and finding the best valorisation route for a given batch of leaves is very challenging and something that has been rarely tried before.OLEAF4VALUE
is a 3-year collaborative EU-funded project (funded under the BBI-JU, now known as CBE-JU
) which began in June 2021 and ends in July 2024. It brings together a consortium of 16 experienced partners
dedicated to fully exploiting the potential of this underutilised biomass. The project uses enzymatic biotransformation and nanoencapsulation technologies to create tailored products for the specific end-user markets. The consortium includes entities from the entire value chain, encompassing the collection and supply of raw material, biorefining processes, post-extraction technologies, and bio analysis, market validation, and impact assessment, including sustainability.
The project’s primary goal is to provide a sustainable solution for the comprehensive valorisation of olive leaves, that is, finding the best final product for the given condition of the leaves. Factors like tree location, horticultural practices, tree type, and leaf origin within the tree (i.e. whether the leaves grew on older, low-hanging branches, or new growth near the tree crown) can impact on what compounds can be extracted and in which quantities from the leaves. The project aims to establish six new value chains that will introduce 24 bio-based and cost-effective products to the market.
These products aim to create value across the entire chain, with a particular emphasis on the primary sector.
Olive leaf samples by INGECOR, OLEAF4VALUE partners.Notable compounds such as oleuropein, luteolin,
and oleanolic acid
found in olive leaf extracts are currently being investigated in the valorisation process. Examples of subsequent products include natural preservatives; treatments for certain health conditions such as diabetes; antioxidants for the food market; new feed additives to enhance animal health and reduce the use of antibiotics; and lastly, new building blocks and natural antioxidants for the chemical sector. Additionally, several bio-based compounds generated by the project show promising results as potential cosmetic ingredients, for example, offering protection against oxidative stress.
Biomass AssessmentTo date, OLEAF4VALUE has successfully developed cutting-edge uses for sensors, for example, NIR spectroscopy
, a technique that shows promising results in evaluating key components like oleuropein and other bioactive compounds in olive leaves. The project has also explored the impact of different treatments on the leaves prior to valorisation, like drying or fermentation, on the final chemical composition.
Smart Biorefinery DesignFurthermore, the OLEAF4VALUE project is currently putting the finishing touches to an innovative smart biorefinery design which will be capable of producing over 40 different bioproducts from olive leaves.
Biochemical InnovationsUsing enzymes and microbial strains, the OLEAF4VALUE project has been able to obtain over 20 molecules from oleanolic acid and oleuropein, some of which are entirely new.
Product TestingThe OLEAF4VALUE project’s extracts are proving to be effective antioxidants
and antimicrobial agents. This could have benefits for gut health and the immune system, though these effects are still undergoing testing. Oleanolic Acid has pharmacological activity, participating in processes such as hepatoprotection, anti-inflammation, antioxidation, anti-diabetic, anti-tumoral, and anti-microbial activities. However, their therapeutic applications are limited by its poor water solubility, bioavailability, and permeability. Within the OLEAF4VALUE project, research partners have found that different formulations, like microemulsions
and solid dispersions,
have improved the solubility of the compounds making them easier to administer and to absorb in an effective manner.
Market LaunchIn addition to research and development and product testing, OLEAF4VALUE partners are also involved in the exploitation of promising results arising from the technical areas of the project. In order to promote the commercialisation of key exploitable results following the end of the project, partners are developing novel business models, business plans and exploitation plans. The aim is to drive the exploitation of new value chains and products and to quantify the value and benefits of OLEAF4VALUE outputs to the wider European bioeconomy.
is a H2020 BBI JU funded project that works to set up the basis of six smart value chains based on a newly developed 4.0 concept: Smart Dynamic Multi-Valorisation-Route Biorefinery (SAMBIO)
for the cascade valorisation of the olive leaf biomass according to its initial composition (Biomass Suitability Index – BSI).