Bitterness and pungency are important parameters for olive oil quality. Therefore, two instrumental methods for evaluation of these taste attributes were developed. The first one is based on the photometric measurement of total phenolic compounds content, whereas the second one is based on the semiquantitative evaluation of hydrophilic compounds by highperformance liquid chromatography−mass spectrometry (HPLC-MS). Evaluation of total phenolic compounds content was performed by a modified method for the determination of the K 225 value using a more specific detection based on the pH value dependency of absorbance coefficients of phenols at λ = 274 nm. The latter method was not suitable for correct prediction, because no significant correlation between bitterness/pungency and total phenolic compounds content could be found. For the second method, areas of 25 peaks detected in 54 olive oil samples by a HPLC-MS profiling method were correlated with the bitterness and pungency by partial least-squares regression. Six compounds (oleuropein aglycon, ligstroside aglycon, decarboxymethyl oleuropein aglycon, decarboxymethyl ligstroside aglycon, elenolic acid, and elenolic acid methyl ester) show high correlations to bitterness and pungency. The computed model using these six compounds was able to predict bitterness and pungency of olive oil in the error margin of the sensory evaluation (±0.5) for most of the samples.
The class of fatty alcohol alkoxylates describes surfactants that are synthesised by reaction of fatty alcohols with alkoxides such as ethylene oxide or propylene oxide or a combination of both as copolymers. Such alkoxylates are used, for example, as nonionic surfactants in home and industrial cleaning and washing agents. Chemical characteristics of such alkoxylate copolymers, for example the degree of alkoxylation, the arrangement of building blocks (random or block polymerisation), the type of the starter, and endcapping, play an important role in application behaviour. The analysis of these characteristics is challenging because in many cases such copolymers have high polydispersity and a large number of constitutional isomers depending on the degree of alkoxylation. Furthermore, the alkoxylates often occur in a complex multicomponent matrix. Here we present a method for characterization of silylated fatty alcohol alkoxylates in the low-molecular-weight range by means of comprehensive two-dimensional gas chromatography-mass spectrometry with electron impact and chemical ionisation. This method also enables detailed analysis of the alkoxylates in a complex matrix such as modern detergents.
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