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RESEARCH PRODUCT

Revelation of aroma potential of grape pomace and spent coffee ground by the use of microbial glycosidases.

subject

description

The food industry is evolving and tends to reduce its environmental impact, to control its waste and to valorise all of its production. Grapes and coffee are among the main agricultural products in the world and not all of the byproducts resulting from their processing are still valued today. New ways of valorisation are seeked in order to limit production losses. Yet, these byproducts are rich in glycosides, the amount of which may be from two to five times greater than that of the free volatile compounds. Grape pomace and spent coffee ground could be used to naturally produce volatile compounds from their glycosides. These volatile compounds could be useful in the production of cosmetics, for example. The glycosides of coffee and those of its co-products have been little studied. Glycosides of grape pomace have already been characterized and commercial enzyme preparations have been developed to release volatile compounds from glycosides. However, these preparations contain side enzymatic activities that can produce phenolic off-flavours and their use can be expensive at industrial scale. During this PhD preparation, we first studied the evolution of coffee glycosides during certain stages of the processing of coffee beans. Then we were interested in the development of a screening for bacteria producing specific glycosidases of some glycosides in grape pomace. This study could envisage a new way of spent coffee ground valorisation via its glycosidic fraction and could demonstrate the interest of the use of certain bacterial strains in the production of varietal volatile compounds from grape pomace glycosides