Wathelet, Jean-Paul[Université de Liège - ULg > Chimie et bio-industries > Chimie générale et organique >]
du Jardin, Patrick[Université de Liège - ULg > Sciences agronomiques > Biologie végétale >]
Thonart, Philippe[Université de Liège - ULg > Département des sciences de la vie > Biochimie et microbiologie industrielles - Bio-industries >]
Regulatory Oxylipins : an international symposium
4-6 June 2009
[en] green leaf volatiles ; hydroperoxide lyase ; oxilipin
[en] Natural green note aromas (GLVs) are highly attractive flavors commonly used in the food industry. These are produced in extremely low levels upon physiological stress in plant organs of any sort. This weak sporadic presence entails a very expensive extraction step to obtain pure GLVs. Therefore catalytic biotransformations of fatty acid sources, the initial substrate for GLVs, have been developed. Enzymatic defense pathways and particularly the LOX pathway produce the major part of GLVs. Unlike GLV molecules that are emitted in the atmosphere, the enzymes are extractible from the plant material. Thus, a combination of plant enzyme extracts and substrate preparations provides all the ingredients for GLV production. Besides, sugar beet leaves present high levels of hydroperoxide lyase among plant sources and are available in large amounts during three months. In this enzymatic pathway, fatty acids are successively transformed by lipase, lipoxygenase and hydroperoxide lyase into aldehydes and alcohols, final compounds of GLVs pathway. Limiting and problematic steps occur with the action of hydroperoxide lyase, when enzymatic catalysis is followed by an enzyme destabilization. Alternative substrates bind irreversibly to the heme group of the enzyme and end the reaction. This poster briefly describes the development of a complete bioprocess for natural GLV production, from hydrolysis to purification. A high level of biotransformation could be achieved using optimum experimental conditions and a cheap source of plant materials.
Fonds de la Recherche Scientifique (Communauté française de Belgique) - F.R.S.-FNRS