Shift of Volatile Organic Compounds (VOCs) in Gluten-Free Hemp-Enriched Sourdough Bread: A Metabolomic Approach

Abstract

Hemp seed flour represents a potential ingredient for protein enrichment of gluten-free bakery products, the nutritional value of which could be further increased by fermentation with sourdough or with beneficial lactic acid bacteria strains. In this study, a metabolomic approach was used to evaluate the effect of hemp seed flour addition and sourdough fermentation on the production of flavoring and health-related volatile organic compounds (VOCs) in a gluten-free bread. Multivariate analysis of VOCs provided an in-depth description of the effects of hemp seed flour addition and sourdough fermentation on flavoring and bioactive compounds. In particular, an increased concentration of antimicrobial compounds, a larger spectrum of bioactive VOCs and a typical flavoring profile was evidenced in comparison to standard products. Furthermore, an increase of fermentation metabolites was observed in comparison to a standard dough, relating to abundances of 2-butanone-3-hydroxy, acetic acid, ethanol, and 1,4-butanediol. This study provides new insights on the evolution of flavoring and bioactive hemp seed flour constituents during sourdough fermentation, evidencing their retention in baked goods, and describes a new approach that could guide the formulation of innovative, fermented food with enhanced nutritional value.

Yeast-Free Doughs by Zymomonas mobilis: Evaluation of Technological and Fermentation Performances by Using a Metabolomic Approach

“…Evaluation of volatile organic compounds (VOCs) was carried out on an Agilent 7890A Gas Chromatograph (Agilent Technologies, Santa Clara, CA, USA) coupled to an Agilent Technologies 5975 mass spectrometer operating in the electron impact mode (ionization voltage of 70 eV), equipped with a Chrompack CP-Wax 52 CB capillary column (50 m length, 0.32 mm ID) (Chrompack, Middelburg, The Netherlands). The SPME-GC-MS (solid phase micro-extraction gas chromatography–mass spectrometry) protocol and the identification of volatile compounds were done according to previous reports, with minor modifications [ 9 , 10 ]. Briefly, before each head space sampling, the fiber was exposed to the GC inlet for 10 min for thermal desorption at 250 °C in a blank sample.…”

“…Organic acids in bread making are principally produced during fermentation and give a large contribute both sensorially and nutritionally. An equilibrium in the content of organic acids is important because some, like short chain organic acids, are considered prebiotics and host health-related compounds, but confers a stinky rancid and putrid taste [10,13]. From ANOVA that included leavened samples (n = 36), nine molecules belonging to the class of organic acids (C2-C11) resulted statistically significant (P < 0.05).…”

“…Applying K-means clustering on PCA loadings, three clusters were drawn ( Figure 2C). related compounds, but confers a stinky rancid and putrid taste [10,13]. From ANOVA that included leavened samples (n = 36), nine molecules belonging to the class of organic acids (C2-C11) resulted statistically significant (P < 0.05).…”

“…FG_A and FG_B = FH_A and FH_B added with glucose; FGN A and FGN B = FG A and FG B added with NaCl; 3580G_A and 3580G_B = Z. mobilis 3580 leavened doughs added with glucose; 3580GN_A and 3580GN_B = 3580G_A and 3580G_B added with NaCl; 424G_A and 424G_B = Z. mobilis 424 leavened doughs added with glucose; 424GN_A and 424GN_B = 424GN_A and 424GN_B added with NaCl; 473G_A and 473G_B = Z. mobilis G473 leavened doughs added with glucose; 473GN_A and 473GN_B = 473G_A and 473G_B added with NaCl. 1 Propanoic acid ethyl ester; 2 Acetic acid trichloro nonyl ester; 3 Valeric acid but-2-enyl ester; 4 Hexanoic acid ethyl ester; 5 Heptanoic acid dec-2-enyl ester; 6 Octanoic acid ethyl ester; 7 L(+)-tartaric acid diethyl ester; 8 Pentadecanoic acid ethyl ester; 9 Hexadecanoic acid ethyl ester; 10 Octadec-2-enoic ethyl ester; 11 Linoleic acid ethyl ester; 12 Thiopheneacetic undec-2-enyl ester; 13 Butanoic acid ethyl ester; 14 Bromoacetic undec-2-enyl ester; 15 2-chloropropionic acid octadecyl ester. CBT reduction = reduction in AMC (Aerobic Mesophilic Counts); Y&M reduction = reduction in Yeast and Molds; Zm reduction = reduction in Z. mobilis.…”

“…The ability of Z. mobilis to develop volatile compounds in a dough has not been studied yet. Metabolomic profiling has been proposed as a promising tool to assess the traceability and quality of fermented food such as bread [ 8 , 9 , 10 ], dairy products [ 11 ], beverages [ 12 , 13 ], and other traditional fermented foods [ 14 ].…”