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SummaryIn this work, autochthonous lactic acid bacteria (LAB) were isolated from chia (Salvia hispanica L.) dough and selected on the basis of the kinetics of acidifi cation and proteolytic activity. Strain no. C8, identifi ed as Lactobacillus plantarum C8, was selected and used as start er to obtain chia sourdough. Lactic acid fermentation increased the organic acid mass fractions (lactic, acetic and phenyl lactic acids to 12.3 g, 1.0 g and 23.8 μg per kg of dough respectively), and antioxidant activities, which increased by approx. 33-40 % compared to unfermented chia fl our dough. In addition, total phenolic content increased 25 % and its composition was strongly modifi ed aft er 24 h of fermentation by L. plantarum C8. Chlorogenic acid was only found in the fermented dough (2.5 mg/g), while ferulic acid was detected from the beginning of fermentation, being 32 % higher in chia sourdough (5.6 mg/g). The use of fermented chia sourdough improved the overall characteristics of white bread, including physical (e.g. reduced hardness and chewiness of the crumb) and antioxidant properties (25 % on average), compared to the white bread. These results indicate that the use of chia sourdough could be a promising alternative to improve the technological and antioxidant properties of wheat bread. In addition, this work has shown, for the fi rst time, that lactic acid bacterium is able to ferment chia dough, improving its overall characteristics.

BACKGROUND: Propolis is a complex mixture that honey bees produce from the exudates of various plants and presents many medicinal properties. Its chemical composition varies according to the phytogeography characteristics of each region, among others. The aim of this study was to identify and characterize the volatile organic compounds (VOCs) present in Venezuelan propolis and compare with reference samples such as Brazilian and Argentinian propolis. RESULTS:A total of 90 VOCs were identified in a series of propolis samples using both solid-phase microextraction and dynamic headspace (DHS), both coupled to a gas chromatograph-electron ionization mass spectrometer. In the case of Venezuelan propolis, sesquiterpenes, esters, aromatic compounds, and aliphatic hydrocarbons were identified. Limonene was found only in Venezuelan samples, this being the first time it has been identified in samples from this country. In the case of green propolis, -caryophyllene and nerolidol were the major compounds. As for the Argentinian samples, prenyl acetate, benzyl acetate, and 2-phenylethyl acetate were detected only in these samples.CONCLUSIONS: Possible chemical markers of natural sources such as limonene were detected using DHS extraction. Several compounds have also been identified for the first time in Venezuelan propolis. Cluster analysis allowed the relating of the propolis VOCs profile to their provenance.

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