Previous studies on bioactive components of asparagus have revealed that the by-products are rich in many of the phytochemicals located in the edible part of the spears. The main components responsible of asparagus bioactivity are phenols (flavonoids and hydroxycinnamic acids) and saponins.

At the Instituto de la Grasa, Consejo Superior de Investigaciones Científicas (Spain), a process for obtaining added-value compounds from asparagus by-products by the hydrothermal treatment of the samples has been developed.

Two fractions are separated after the hydrothermal treatment, consisting on an aqueous functional extract containing most soluble bioactive compounds from asparagus by-product, and a fibrous residue that, after being dried, constitutes the asparagus bioactive fibre. The process includes a column purification step, using an adsorbent polymeric resin, which allows aqueous extracts, partially purified to be obtained and enriched in specific compounds (phenolics and/or saponins). All these presentations have been investigated for their biological activity.

The preliminary results showed that the distinct products obtained from asparagus by-products are of interest for their biological activity and are suitable for being used as functional ingredients. Based on their antioxidant capacity, it could be proposed that their regular use could help the prevention of several diseases related to the oxidative damage.