Seven surprising aroma insights from "The Science of Taste" at Greenwich
21 July 2025
Exploring the science of flavour at Greenwich
On 26 June 2025, Markes International and SepSolve Analytical held a focused technical workshop – The Science of Taste – at the University of Greenwich. Bringing together a small group of specialists from academia and industry, the event offered an in-depth look at how advanced analytical techniques are being used to decode the volatile organic compounds (VOCs) responsible for aroma and flavour.
With presentations from experts at the University of Reading, RISE, Teagasc and others, the day covered topics ranging from kale and cheddar to whisky, wine and plant-based proteins – all highlighting the growing role of techniques such as TD–GC–MS, HiSorb and GC–olfactometry in flavour analysis.
Here are seven surprising insights we took away from the event:
1. Young and old kale have distinct aroma profiles
A plant’s aroma can change significantly as it matures. Young kale leaves emit mustardy and peppery notes, while mature leaves lean towards grassy and sulphurous aromas. This shift is driven by the breakdown of glucosinolates, the compounds that give kale its characteristic bite, breakdown differently over time. As growers increasingly move away from peat-based growing media for environmental reasons, understanding how soil VOCs affect kale’s growth and flavour becomes even more important.
Dr Luke Bell (University of Reading) showed how techniques like headspace sampling and TD–GC–MS are being used to track how aroma profiles shift across the growing cycle. These insights can help growers optimise harvest timing for flavour or nutritional value.
2. Pea protein’s earthy off-notes share chemistry with coffee
Those beany, earthy off-notes in pea protein? They’re caused by alkyl methoxypyrazines – the same family of aroma compounds found in bell peppers, roasted coffee and wine. They’re extraordinarily potent, with odour thresholds as low as 0.0039 ppb (parts per billion) – just one drop diluted into 20 Olympic-sized swimming pools could still be detected by the human nose!
Diana Owsienko (RISE) used HiSorb high-capacity sorptive extraction and olfactometry to track these trace compounds in pea protein concentrates. She was able to reduce her sample size from 50 g to just 1 g when using HiSorb instead of purge-and-trap, while still detecting critical volatiles. She also showed how heat and ethanol treatments can suppress off-notes while generating nutty, desirable aromas (also linked to pyrazines). This work is key to improving the sensory appeal of plant-based products to consumers.
Download Diana’s slides on aroma profiling of plant-based alternatives
3. Cheddar and whisky share complex aroma chemistry
Mature cheddar cheese contains hundreds of aroma compounds, including acids, ketones, esters and sulfur compounds. These evolve over time and dramatically affect the sensory profile. Similarly, Irish whisky contains volatile congeners formed during fermentation and distillation that contribute to aroma. Understanding the science behind aroma is key to enhancing the tasting experience of cheese–whisky pairings, which is why flavour experts are keen to explore the chemistry that connects them.
David Mannion (Teagasc) compared HiSorb high-capacity sorptive extraction and solid-phase microextraction (SPME) for extracting aroma compounds from a range of cheddar cheeses. The two methods revealed different volatile profiles. By combining both with GC–olfactometry, David’s team identified 21 key odour-active regions, from citrus and bread crust to cooked potato and mushroom. He also coupled his headspace and SPME technique with multi-dimensional GC (GCxGC) to whisky, reducing co-elution and doubling the number of detectable aroma-active compounds.
4. Cork taint costs the wine industry over $10 billion a year
A musty smell in wine is often caused by 2,4,6-trichloroanisole (TCA), which has an odour threshold as low as 1.5 ng/L – detectable by the human nose even at parts-per-trillion levels. Even tiny traces can ruin a bottle.
Xi Ze (University of Greenwich) presented methodologies using thermal desorption and GC–MS to detect TCA and other trace-level off-notes early in wine-cork production. She also showed the aromatic contributions of different plant-based proteins: soya produced nutty, earthy aromas via pyrazines, while potato showed fresh aldehyde notes.
5. Packaging can influence flavour perception
That faint cardboard flavour in some foods? It might be VOCs migrating from the packaging.
Steve Smith (SepSolve Analytical) demonstrated how headspace sorptive extraction and GCxGC–TOF MS can identify both desirable aroma compounds and off-notes in oat-based foods. Using SmartSubtract® software (SepSolve Analytical), analysts can quickly compare clean and tainted samples to pinpoint contamination and prevent future quality issues.
This approach is especially important in plant-based foods, where subtle aroma changes can impact consumer acceptance.
6. Adulteration of spices remains a global issue
Food crime in the UK is estimated to cost between £409 million and £1.96 billion each year, according to a 2021 report by the National Food Crime Unit. A significant proportion of this relates to adulterated products, which can cause anything from mild quality issues to serious health risks. One example is the adulteration of powdered spices such as paprika, where cheaper or inferior substances are added to increase volume or improve colour.
Adulteration and quality control are key concerns in food product development and evaluation. Many foodstuffs are difficult to analyse due to matrix effects, where trace-level aroma or flavour compounds are masked by more abundant, non-desirable components.
Lucy Hearn demonstrated a range of automated techniques used to detect subtle differences in potentially adulterated samples, including headspace analysis on the Centri platform. She showed how chemometric tools can differentiate between authentic and adulterated samples, such as in the case of paprika. She also illustrated how multi-step enrichment (MSE) can build on traditional techniques like solid-phase microextraction (SPME), enhancing the detection of trace volatiles in complex, pungent samples such as garlic.
7. GC–O bridges chemistry and sensory perception
While GC–MS can identify hundreds of compounds, only a few truly shape what we smell. GC–olfactometry (GC–O) bridges this gap by enabling trained panellists to assess odours as compounds elute from the GC column.
Several speakers highlighted how GC–O can uncover the most sensory-relevant compounds in complex profiles. It combines human sensory expertise with analytical precision to deliver deeper insight into flavour.
From insight to innovation
The Science of Taste workshop highlighted how advanced analytical techniques are helping researchers and product developers tackle complex aroma challenges – from off-notes in plant-based foods to quality assurance in traditional products such as whisky and wine.
Whether your focus is routine QA, authenticity testing or sensory innovation, having the right tools to characterise aroma compounds is key to making informed decisions.
Markes International and SepSolve Analytical provide a range of platforms to support this work, from high-sensitivity VOC screening to expert-led GC–olfactometry.
