title: Component analysis by sensomics concept on flavour enhancement of smoked ingredients
Creators: name: Panchan, Kanokkan
Publisher: name: University of Reading
Year: 2024

description: Smoked ingredients are used to improve the organoleptic qualities of culinary products 
in the food industry. This can be due to the pleasant fragrant aroma derived from the smoke, 
but we hypothesise that it may also be due to taste enhancement, either directly through the 
activity of tastant molecules or possibly from odour-induced taste enhancement (OITE). It 
might be possible to use smoked ingredients to reduce salt or monosodium glutamate (MSG)
levels in food products. However, the smoking process, which is required for flavour 
development, also produces a series of polyaromatic hydrocarbons (PAHs), including the 
known human carcinogen benzo[a]pyrene. The concentrations of PAHs can now be reduced 
using Puresmoke technologyTM (PST). This technology has been shown to remove aroma 
compounds from the smoke, but also results in a more balanced aroma. The aim of the thesis 
is to investigate the contribution smoked water makes to the flavour of a soup matrix, 
comparing both PST and traditionally smoked water (TR).
In the first instance, it is important to understand what the important aroma compounds 
in smoke are and the impact of PST on the flavour profile. Smoked water was selected for an 
in-depth analysis of the aroma compounds using a low (P25) and a high (P50) number of filter 
plates of PST. The effect of P25 and P50 on 77 volatile compounds using 3 wood types (apple, 
beech, and oak) was investigated using a sensomics approach. Solid phase microextraction 
(SPME) and solid phase extraction (SPE) which used diethyl ether as the eluent, were the two 
most effective extraction techniques for smoked water based on the number of compounds 
extracted. Seventy-seven aroma-active compounds were detected in P50 and TR apple-wood 
smoked water. The most abundant compounds were phenol and phenol derivatives, followed 
by aldehydes, ketones, diketones and guaiacol and guaiacol derivatives, in that order. In 
general, the main constituents were found in higher concentrations in TR than in PST smoked 
water. 
Aroma extract dilution analysis (AEDA) was employed in both SPME and SPE extracts 
to determine the most odour-active compounds. A total of 67 aroma-active compounds were 
detected by gas chromatography-olfactometry (GC-O), the majority of which were phenols and 
guaiacols. At least 22 compounds with odour activity values (OAVs) more than 1 were 
identified as potent aroma compounds. To confirm the identity of the odour-active compounds, 
the identified 22 potent aromas were combined to generate full and partial recombinates at 
concentrations corresponding to those in P50 smoked water. The sensory profiling scores (5-
point scale) of four descriptors, smoky, woody, ashy, and phenolic, of the recombinates did not 
closely correspond to the original P50 smoked water, indicating that more refinement of the 
recombinate was required. The effect of PST on the aroma profile (77 compounds) was 
analysed in smoked water prepared from three different types of hardwood, each compared to 
TR smoked water. When the PST was used, the majority of compounds were reduced. The 
difference between P25 and P50 was significantly less than the difference between TR and P25. 
The principal component analysis (PCA) plot determined that apple smoked waters were 
associated with higher concentrations of phenols group, traditionally beech smoked water had 
high levels of syringols and guaiacols. All three samples of oak-smoked water were similar and 
had high levels of furans. 
Three mechanisms of smoked water on flavour enhancement were investigated using 
trained sensory panellists. In the absence of MSG, the panel with the aroma excluded through 
wearing of nose clips, detected an umami taste in the presence of apple-wood smoked water. 
In the complex mixture of model soup, the smoked water made little difference to the umami 
taste and when smoked water was added to the mixture of MSG and 5'-ribonucleotides, there 
was no umami enhancement. However, an umami enhancement was observed in the model 
soup containing MSG and 5'-ribonucleotides at subthreshold umami levels (below 344 mg/L 
or 0.038%). Intriguingly, umami was the primary taste that was enhanced when smoked water 
was combined with 5'-ribonucleotides in salt-reduced soups without using nose clips. This 
result suggests that odour-induced taste enhancement was the primary mechanism by which 
smoked water enhanced flavour. In contrast, partial recombinate (17 compounds) did not 
significantly enhance the tastes of salt-reduced soup compared to salt-reduced soup without 
recombinate.