Biotransformation of carotenoids into aroma compounds: screening using solid phase microextraction

Biotransformation of carotenoids into aroma compounds: screening using solid phase microextraction

New Biotechnology · Volume 25S · September 2009 ABSTRACTS ciently to P. simplicissimum lipase production and consists of an alternative to subsequen...

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New Biotechnology · Volume 25S · September 2009

ABSTRACTS

ciently to P. simplicissimum lipase production and consists of an alternative to subsequently process scale-up. And this bioreactor also allows obtaining lipases with high industrial applicability at low-cost.

2.6.122

doi:10.1016/j.nbt.2009.06.223

A.P. Dionísio ∗ , D. Souza De Carvalho, G.M. Pastore

Biotransformation of carotenoids into aroma compounds: screening using solid phase microextraction

UNICAMP, University of Campinas, Campinas, Brazil

2.6.121 Study of tetramethylpyrazine formation in fermentation system from glucose by Bacillus subtilis XZ1124 B. Zhu ∗ , Y. Xu, W. Fan Jiangnan University, Wuxi, China

2,3,5,6-Tetramethylpyrazine (TTMP), as a heterocyclic nitrogencontaining compound, was widely used as flavor additives and was proved pharmacological activity in clinical medicine for its bioactive alkaloid properties. High yield of TTMP was obtained by fermentative conversion of endogenous precursor 3-hydroxy2-butanone (HB) from glucose by a newly isolated B. subtilis XZ1124 in this work. The fact of chemical synthesis of diammonia phosphate and HB from glucose were demonstrated in fermentation environment, increase of single diammonia phosphate or HB concentration in culture medium under fermentative conditions without inoculation resulted in improved TTMP production, while more TTMP was formed in culture medium inoculated with B. subtilis XZ1124. Diammonia phosphate was found to be critical for TTMP formation in fermentation system, compared with other ammonia salt such as ammonia acetate, ammonia sulphate and ammonia citrate. The effect of ammonia ion and phosphate ion on TTMP formation was investigated. The addition of single ammonia ion or phosphate ion in Bacillus spp. culture could evidently stimulate TTMP formation (10 times of production compared with control samples), while significantly enhancement of TTMP production (nearly 100 times of production compared with control samples) was only found with both ammonia ion and phosphate ion co-supplemented in culture medium. Considered the interest of TTMP formation in fermentation system, the contribution of chemical synthesis to total TTMP accumulation was also investigated. Experimental data showed that TTMP generated by chemical synthesis only accounted for 38% of total TTMP production with B. subtilis XZ1124 inoculated in culture medium, which indicated enzyme-catalyzed reactions might be involved in metabolic pathway of HB and ammonia phosphate in fermentation system by Bacillus spp. strain. doi:10.1016/j.nbt.2009.06.224

Carotenoids are widely distributed in nature and they are important precursors of a variety of compounds, like as C13carotenoid-derived compounds (norterpenoids/norisoprenoids). These compounds, such as ionones and damascones, constitute an essential aroma note in tea, grapes, roses, tobacco, and wine. Extraction of carotenoid-derived aroma compounds from plant sources is not economically realistic or considerably expensive and, the biotransformation seems to be a reasonable alternative to produce aroma compounds since they are considered as ‘natural’ and offers the production of enantiomerically pure molecules. The target of this investigation was to find microorganisms capable of cleaving ␤-carotene into aroma compounds using SPME (solid phase microextraction) analysis. SPME is a simple and effective adsorption and desorption technique that eliminates the need for solvents or complicated apparatuses. For this, more than 60 microorganisms isolated from Brazilian fruits are used. Three full loops of a 24h-old-culture on a Petri dish were transferred to a 50 mL conical flask, which contained yeast malt medium (glucose 10 g L−1 , peptone 5 g L−1 , malt extract 3 g L−1 , yeast extract 3 g L−1 ), and were incubated at 30 ◦ C/150 rpm for 24 h. After centrifuging the culture for 15 min (10.000 rpm), the supernatant was eliminated and the biomass was re-suspended in SPME vials containing 20 mL of mineral medium (0.5 g L−1 MgSO4, 3.0 g L−1 NaNO3 , 1 g L−1 K2 HPO4 , 0.5 g L−1 KCl, 0.01 g L−1 Fe2 SO4 ), and a solution containing 4 mg of ␤-carotene, 40 mg of Tween-40 (polyoxyethylenesorbitan monopalmitate), 0.4 mL of alcohol (99.9%) and 0.6 mL of distillated water. The flasks were incubated at 30 ◦ C/150 rpm, and the SPME fibers were exposed to the headspace after 0, 24, 48, 72 and 96 h. The exposure temperature/time was: 30 ◦ C and 30 min. A Gas Chromatograph (GC/FID Agilent 7890A) was used to analyze the volatiles compounds formed during the biotransformation. The working conditions were: injector 220 ◦ C, detector-FID 250 ◦ C (make-up gas He 1 mL min−1 ) and a HP 5 column (30m X 0.320 mm X 0.25 ␮m). The oven temperature was programmed from 40 ◦ C (1 min) to 110 ◦ C (5 min), and from 110 ◦ C to 220 ◦ C at 10 ◦ C/min, with a final holding time of 5 min. The results of this work demonstrated that the microorganisms could be biotransform the ␤-carotene in aroma compounds, like as ␤ionone and ␤-damascone. But, just three strains had shown more efficiency to biotransform than others, and studies with these microorganisms are being realized to quantify and to optimize the production of these compounds that have a very low olfactory perception thresholds and so have a high sensorial impact. doi:10.1016/j.nbt.2009.06.225

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