Characterization of Aroma-Active Compounds in Four Yeast Extracts Using Instrumental and Sensory Techniques

Abstract

Gas chromatography–olfactometry coupled with sensory analysis and partial least-squares regression (PLSR) analysis led to the identification of the odorants responsible for the different flavors of four yeast extracts. Sensory analysis showed that LA00L had an intense sulfurous attribute, and LA00 was characterized by fatty and green notes, FA31 exhibited the floral odor, while KA02 had strong phenolic, animal, fermented, roasted, and caramellic notes. A total of 37 key aroma compounds with odor activity values greater than 1 were determined. 2,4-Di-tert-butylphenol and methional were the most potent aroma compounds. In addition, the key aroma compounds in LA00L were nonanal, dimethyl disulfide, and γ-decalactone. Octanal, dimethyl disulfide, and benzeneacetaldehyde were the key aroma compounds in LA00. In FA31, styrene, benzeneacetaldehyde, and acetophenone were the key aroma compounds, while indole, 2-methoxyphenol, benzeneacetaldehyde, and p-cresol contributed significantly to the aroma of KA02. PLSR showed that p-cresol and indole were significantly responsible for the phenolic and animal notes inducing the off-flavor (yeasty odor) of yeasty extracts. More significantly, indole was first reported to have an important effect on yeasty odor.

Determination of the effect of wheat germ on the mineral and fatty acid composition and aroma compounds of tarhana: A traditional fermented cereal food

“…The most odor‐active compounds were acetic acid and 2‐acetylpyyrole in all samples; however, samples differed in their less odor‐active compound contents. 2‐acetylpyrrole might be formed by the addition of yeast to the tarhana; since it was identified in yeast extract samples as one of the main aroma‐active compounds (Wang et al., 2019). It was also detected in white bread prepared from sourdough, while it was in trace levels in commercially prepared bread samples (Maeda et al., 2009).…”

Absolute Quantitative Volatile Measurement from Fresh Tea Leaves and the Derived Teas Revealed Contributions of Postharvest Synthesis of Endogenous Volatiles for the Aroma Quality of Made Teas

“…Removing or reducing these endogenous unpleasant volatiles could be an important aspect for tea processing; another possibility could be that some volatiles showed totally different characteristics in a concentration-dependent manner. One well-characterized example was indole; at very low concentrations indole had a flowery smell [39], however, in high concentrations it smelled animal-like [40]. Under our experimental conditions, only about 14% of the indole from fresh tea leaves was retained in green tea or oolong tea (Table 1).…”

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

“…This resulted in the corresponding OAV’s; 39 and 32 for sour whey post-fermentation product and 13 and 13 for buttermilk one. These compounds can be formed by microbial metabolism—isovaleric acid is formed during the transformation of amino acids (isoleucine and leucine) and butanoic acid during the transformation of carbohydrates and triglycerides [ 5 , 41 ]. When considering the methods of whey management, Prazeres et al [ 10 ] presented the use of controlled whey fermentation processes to produce butanoic and acetic acid.…”