Pilot scale biotransformation of vegetal oil into natural green note flavor using sugar beet leaves as sources of hydroperoxide lyase

Poster (2009, June 02)

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 ... [more ▼]

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. [less ▲]

Identification of a new tomato lipoxygenase gene belonging to the aldehyde-producing lipoxygenase group: TomLoxF

Poster (2009, April)

Ylang-ylang (Cananga odorata (Lam.) Hook. & Thoms. var. genuina) essential oils from Comoros Islands: characterization and variability

Poster (2009)

The Union of the Comoros is the world’s biggest producer of ylang-ylang essential oils. Comorian ylang-ylang also provides the most valuable essential oil that can be found on international market. This ... [more ▼]

The Union of the Comoros is the world’s biggest producer of ylang-ylang essential oils. Comorian ylang-ylang also provides the most valuable essential oil that can be found on international market. This product represents a high percentage of Comoros’ annual currency. Ylang-ylang essential oil is obtained by fractionned hydrodistillation or steam distillation of Cananga odorata fresh flowers. This oil is commercialized in five different quality grades (extra S; extra; I; II; III) which possess their own physicochemical properties. [less ▲]

Mise au point d’un test de sélection précoce de l’orge de printemps pour ses qualités brassicoles

Report (2009)

Potato (Solanum Tuberosum L.) Tuber Ageing Induces Changes In The Proteome And Antioxidants Associated With The Sprouting Pattern

in Journal of Experimental Botany (2009), 60(4), 1273-1288

Attacks by a piercing-sucking insect (Myzus persicae Sultzer) or a chewing insect (Leptinotarsa decemlineata Say) on potato plants (Solanum tuberosum L.) induce differential changes in volatile compound release and oxylipin synthesis

in Journal of Experimental Botany (2009), 60(4), 1231-1240

Plant defensive strategies bring into play blends of compounds dependent on the type of attacker and coming from different synthesis pathways. Interest in the field is mainly focused on volatile organic ... [more ▼]

Plant defensive strategies bring into play blends of compounds dependent on the type of attacker and coming from different synthesis pathways. Interest in the field is mainly focused on volatile organic compounds (VOCs) and jasmonic acid (JA). By contrast, little is known about the oxidized polyunsaturated fatty acids (PUFAs), such as PUFA-hydroperoxides, PUFA-hydroxides, or PUFA-ketones. PUFA-hydroperoxides and their derivatives might be involved in stress response and show antimicrobial activities. Hydroperoxides are also precursors of JA and some volatile compounds. In this paper, the differential biochemical response of a plant against insects with distinct feeding behaviours is characterized not only in terms of VOC signature and JA profile but also in terms of their precursors synthesized through the lipoxygenase (LOX)-pathway at the early stage of the plant response. For this purpose, two leading pests of potato with distinct feeding behaviours were used: the Colorado Potato Beetle (Leptinotarsa decemlineata Say), a chewing herbivore, and the Green Peach Aphid (Myzus persicae Sulzer), a piercing-sucking insect. The volatile signatures identified clearly differ in function with the feeding behaviour of the attacker and the aphid, which causes the smaller damages, triggers the emission of a higher number of volatiles. In addition, 9-LOX products, which are usually associated with defence against pathogens, were exclusively activated by aphid attack. Furthermore, a correlation between volatiles and JA accumulation and the evolution of their precursors was determined. Finally, the role of the insect itself on the plant response after insect infestation was highlighted. [less ▲]

Impact of polyunsaturated fatty acid degradation on survival and acidification activity of freeze-dried Weissella paramesenteroides LC11 during storage

in Applied Microbiology & Biotechnology (2008), 79(6), 1045-1052

Abstract The impact of polyunsaturated fatty acid (PUFA) degradation on the survival and acidification activity of freeze-dried Weissella paramesenteroides LC11 was investigated over 90-days storage at 4 ... [more ▼]

Abstract The impact of polyunsaturated fatty acid (PUFA) degradation on the survival and acidification activity of freeze-dried Weissella paramesenteroides LC11 was investigated over 90-days storage at 4 °C or 20 °C in vacuumsealed aluminium foil or glass tubes with two water activities (aw=0.11 or 0.23). Colony counts, acidification activity (% lactic acid/g), linoleic/palmitic (18:2/16:0) or linolenic/palmitic (18:3/16:0) ratio by gas chromatography and 18:2 or 18:3 oxylipins by reversed phase-high performance liquid chromatography were determined. The viable cells, acidification activity and 18:2/16:0 or 18:3/ 16:0 ratio decreased as the storage time increased. The survival, acidification activity and 18:2/16:0 or 18:3/16:0 ratio were greatest for the freeze-dried strain held in vacuum-sealed aluminium foil at 4 °C. The 18:2/16:0 or 18:3/16:0 ratio decrease was correlated with the accumulation of 18:2 or 18:3 oxylipins during storage in glass tubes. Hydroperoxy PUFAs, hydroxy PUFAs, divinyl ether PUFAs and oxo PUFAs were the main oxylipins identified. A large decrease in the 18:2/16:0 or 18:3/16:0 ratio and a rapid accumulation of oxylipins during storage might be enough to cause high cell death and loss of metabolic activity. These results provide further experimental support for the hypothesis that lipid oxidation and survival or activity of freeze-dried bacteria might be related. [less ▲]

Valorisation des produits issus des feuilles de betteraves : extraction de molécules à note verte

Report (2008)

Volatile blends and oxylipins profiles in potato leaves (Solanum tuberosum L.) exposed to insects infestations and mechanical wounding.

Conference (2008)

Chemical characterization of essential oils extracted from two ylang-ylang floral morphotypes (Cananga odorata (Lam.) HooK. & Thoms. var. genuina) from Comoros Islands.

Conference (2008)