Asparagus waste streams to aroma-rich vegetable flavourings (The effect of partial replacement of maltodextrin with vegetable fibres in spray-dried white asparagus on its aroma properties)

White asparagus (A. officinalis) is a popular vegetable consumed worldwide and its cooked spears are appreciated for their distinct flavour profile. During asparagus harvesting, around one-third of the total material is usually discarded. This significant waste stream partially consists of the stem bases which are cut off to produce spears with the same desired length for delivery to the supermarket. This waste stream could become a valuable resource of food ingredients. Asparagus waste was used to generate an asparagus concentrate, and this was spray-dried in different carrier formulations in which maltodextrin was partially replaced by cellulose-based carriers, i.e. asparagus fibre, citrus fibre or microcrystalline cellulose. Powders obtained from feed solutions with an initial solids content of 40 % w/w showed better physical properties and aroma retention than 30 % w/w. Partial replacement of maltodextrin by cellulose-based carriers resulted in powders with similar physical properties to the control and did not detrimentally influence the aroma profiles as analysed by headspace solid-phase microextraction and gas chromatography-mass spectrometry. Aroma analysis was focused on asparagus key volatiles based on previous studies. This research showed that fibre obtained from asparagus waste streams could potentially be used as a carrier to produce spray-dried asparagus powder with retained key asparagus odorants such as 2-methoxy-3-isopropyl pyrazine. Valorisation of these materials could reduce the amount of agricultural waste while generating aroma-rich natural food products.