Effect of oxidoreduction potential on aroma biosynthesis by lactic acid bacteria in nonfat yogurt

 ; The aim of this study was to investigate the effect of oxidoreduction potential (Eh) on the biosynthesis of aroma compounds by lactic acid bacteria in non-fat yogurt. The study was done with yogurts fermented by Lactobacillus bulgaricus and Streptococcus thermophilus. The Eh was modified by the application of different gaseous conditions (air, nitrogen, and nitrogen/hydrogen). Acetaldehyde, dimethyl sulfide, diacetyl, and pentane-2,3-dione, as the major endogenous odorant compounds of yogurt, were chosen as tracers for the biosynthesis of aroma compounds by lactic acid bacteria. Oxidative conditions favored the production of acetaldehyde, dimethyl sulfide, and diketones (diacetyl and pen…

A new approach to studying sponge cake aroma after storage in treated paper and plastic packaging by direct gas chromatography–olfactometry (D-GC–O)

The objective of this study was to use D-GC–O to compare the global odour of a sponge cake flavoured with either a ‘viennoiserie’ aromatic note or a simplified mixture of aroma compounds (used for physicochemical studies), then stored in a glass packaging (inert and impermeable) or in pouches made with treated papers or with plastic packaging, in accelerated ageing conditions (high temperature and relative humidity gradient). After 1 week of storage, the flavoured sponge cake headspace was SPME-extracted directly into the packaging and analysed by D-GC–O. The sponge cake global odour was better retained if plastic film rather than treated-papers was used, for both flavourings. Changes in th…

Impact flavor compounds in cooked rice cultivars from the Camargue area (France)

International audience; Rice from two scented (Aychade, Fidji) and one nonscented (Ruille) cultivars from Camargue area (France) together with one Asian scented rice (Thai) were cooked and volatile compounds were extracted by dichloromethane/pentane (1;2, v/v) solvent mixture. 40 odorous compounds were noticed during GC-O analysis of the organic extracts, amongst which oct-1-en-3-one and 2-acetyl-1-pyrroline were altmost constantly perceived. Hierarchical cluster analysis (HCA) of perceived odours enabled to distinguish the groups of rice cultivars. 60 compounds were identified and quantified by GC-MS. New odour-active components of cooked rice were detected for the first time including oct…

Impact flavor compounds in cooked rice cultivars from Camargue area (France)

International audience; Efforts have been undertaken for the last decades to promote the production of scented rice cultivars in Camargue, a traditional rice cultivation area in the south of France. Volatile compounds of cooked rice from two scented Camargue rice cultivars (Aychade and Fidji) were analysed and compared to that of a marketed Asian scented rice one (Thai)(1). Additionally volatile analysis from a cooked rice of a non-scented cultivar (Ruille) grown in Camargue was performed. (...)

The salivary reactor: an innovating tool for the categorization of food products through their aroma and taste compounds release profiles

ISBN-10: 3-938896-38-9 ISBN-13: 978-3-938896-38-9

Change in the aroma quality of a sponge cake during storage in flexible packaging films evalued by D-GC-O

Physico-chemical characterisation of a non-conventional food protein source from earthworms and sensory impact in arepas

International audience; This study aimed to characterise a non-conventional protein source: a powder made from earthworms, and to evaluate its potential use as human food. The way it was prepared led to low solubility and wide particle size distribution. Sensory analysis was used to assess the acceptability and the organoleptic properties of maize-based pan-cakes fortified with this novel protein powder. Satisfying products were obtained with a substitution level of 5.5% (w/w) earthworm powder in pan-cakes. GC-MS allowed the identification of more than seventy volatile compounds that may be responsible for the off-odour of the powder. The most abundant chemical groups found in the volatile …

Impact of oxydoreduction potential on biosynthesis of volatile compounds in acid skim milk gel: identification and quantification

International audience; Oxydoreduction potential (Eh) is an environmental parameter which defines balances between oxidant species (acceptors of electrons) and reduced species (donors of electrons) of a medium. It may modify the growth capacity of microorganisms, the metabolic fluxes, participate to the quality of fermented products (2, 6, 7) and affect the production and/or stability of volatile compounds (3,5). (...)