Spray drying of asparagus waste into flavour-rich ingredients

Summary

Significant food waste is common in the production chain of many agricultural products. This PhD project focused on converting vegetable waste streams into flavour-rich ingredients that can be used for instant soups for example. The vegetable powders currently available in the market often suffer from a poor flavour profile since aromas get lost during the conventional hot-air drying process. White asparagus was chosen as model crop knowing that during its production about 15 % of the stem is wasted. A split-stream process was proposed to process wasted asparagus stems, thereby separating the juice from the fibre fraction. The asparagus juice was mildly concentrated and spray-dried into powder by using maltodextrin as carrier agent. The asparagus fibres were processed via different methods to reintroduce the fibre in the final asparagus product. This study demonstrates that more aroma compounds are retained by spray drying asparagus juice than by hot-air drying.