Obtaining Aroma from By-products and Effluents of the Food Industry

Aroma molecules extracted from food by-products and effluents are usually of high value and have also the benefit of being natural. It could be of economic interest to develop effective techniques for their recovery. This chapter is reviewing the different methods used to recover and concentrate some of these compounds from a variety of solid, liquid or gaseous by-products and effluents from the food industry. Depending on the properties of the compounds to be extracted, quite different principles and methods are used. These can be physical (distillation, hydro-distillation, membrane mediated systems), chemical (partition between non-miscible solvents with water solutions) or biological (enzyme assisted extraction). Common problematics are the food safety of the extracted aroma compounds and the efficiency of the process. Different examples illustrate these methods and give order of magnitude of the important variables to characterize the extraction efficiency (concentrations, flux, yields, …).