Analysis of the Ability to Produce Pleasant Aromas on Sour Whey and Buttermilk By-Products by Mold Galactomyces geotrichum: Identification of Key Odorants

Abstract

Currently, there is a growing demand for flavorings, especially of natural origin. It is worth paying attention to the biotechnological processes of flavor production, characterized by simplicity, high efficiency and relatively low cost. In this study, we analyzed the ability of the Galac tomyces geotrichum mold to transform by-products of the dairy industry: sour whey and buttermilk to complex flavour mixtures with pleasant, honey-rose aroma. Furthermore, the aroma complexity of the fermentation product has been carefully identified applying a sensomic approach involving the use of gas chromatography-olfactometry (GC-O), gas chromatography-mass spectrometry (GC-MS) and stable isotope dilution assay (SIDA) to identify and quantify aroma compounds. Based on the calculation of odor activity value (OAV), 13 key aroma compounds were present in both tested variants. The highest OAVs were found for phenylacetaldehyde (honey-like) in the buttermilk variant (912) and 2-phenylethanol (rose-like) in the sour whey variant (524). High values of this indicator were also recorded for phenylacetaldehyde (319) and 3-methyl-1-butanol with a fruity aroma (149) in the sour whey culture. The other compounds identified are 3-methylbutanal (malty), 2,3-butanedione (cheesy), isovaleric acid (cheesy), 3-(methylthio)-propanal (boiled potato), butanoic acid (vinegar), (E)-2-nonenal (fatty), ethyl furaneol (burnt sugar), dimethyl trisulfide (cabbage), and acetic acid (vinegar).

Application of Sorbent-Based Extraction Techniques in Food Analysis

“…Many studies about key aroma compounds in selected food products involve SPME, but mostly as an addition to exhaustive extraction techniques like SAFE and SDE [120]. SPME usually is less efficient in the extraction of aroma compounds than exhaustive techniques.…”

Emerging Trends and Advancements in the Processing of Dairy Whey for Sustainable Biorefining

“…[170,171]. Galactomyces geotrichum has been reported to produce a flavor complex having a pleasant honey-rose aroma in dairy whey and buttermilk [172]. An attempt has been made to isolate several yeast strains and screen for 2phenyl ethanol (2-PE) production using whey, glucose, and their combination as carbon sources.…”

The Combined Effect of Lactic Acid Bacteria and Galactomyces geotrichum Fermentation on the Aroma Composition of Sour Whey

“…L-phenylalanine is a precursor of phenylacetaldehyde and 2-phenylethanol-compounds that were characterized by the highest OAVs in the aroma produced by G. geotrichum on substrates with by-products of the The analyzed medium and the fermentation product contained 11 free amino acids: alanine, glycine, valine, leucine, isoleucine, threonine, γ-aminobutyric acid (GABA), proline, aspartic acid, tyrosine, and L-phenylalanine. L-phenylalanine is a precursor of phenylacetaldehyde and 2-phenylethanol-compounds that were characterized by the highest OAVs in the aroma produced by G. geotrichum on substrates with by-products of the dairy industry [12,13,26]. It is an amino acid present in sour whey and is additionally supplemented with the substrate to ensure the possibility of its bioconversion to the highest possible concentration of honey and rose aroma compounds [30].…”

“…The G. geotrichum strain was protected by freeze-drying. The preparation of the G. geotrichum strain for this study followed the methodology described in our previous studies [12,13].…”