4 July 2023
Laura McGregor (Product Marketing Manager, SepSolve Analytical Ltd)
Plant-based is a term used to describe food products created
using plants, including plant-based meat, dairy, eggs, and seafood.1 The demand for plant-based
food substitutes is on the rise, putting pressure on food producers to create
products that mimic the appearance, texture, smell, and taste of real meat and
dairy.
The taste of plant-based foods is key to consumer acceptance,
with 73 % of consumers agreeing that plant-based meat should mimic the taste of
real-meat.2 Companies such as Beyond Meat, a global front runner in
plant-based food, are designing their products to have the same sensory
experience as animal-based products, and they are working with big corporations
such as McDonalds and Disneyland to achieve the popular real-meat taste.3
However, it is a real challenge to produce plant-based foods
with flavours that are as rich and nuanced as those found in traditional meat
and dairy products. Before we can try to mimic these flavours and aromas, we
first need to know what causes them.
Flavour challenges with plant-based foods
Characteristic flavours and aromas are the result of complex
combinations of hundreds (if not thousands) of volatile organic compounds
(VOCs). Understanding the nature and quantity of these VOCs is the key to
recreating the smell and flavour of real meat and dairy products.
Unfortunately,
this is a challenge in itself.
For example, real meat can release hundreds of different volatiles
throughout the cooking process, many of which are aroma-active and cover a wide
range of chemical classes. Odour thresholds of these compounds may also span
many orders of magnitude, meaning that even trace quantities of potent compounds
will have a huge impact on the overall aroma.
The raw ingredients of plant-based products (e.g., pea,
potato or soy protein) will also contribute characteristic aroma volatiles,
which may not always be desirable. For example, pea protein has been known to
impart a “beany” off-flavour that must be reduced, or masked, in the final
product.4
Gas chromatography–mass spectrometry (GC–MS) can be used to
separate and identify the volatile compounds that contribute to aromas, but
GC–MS alone is often not enough to provide the depth of information required
because of the complexity of these samples. The diverse range of chemical
classes, wide-spanning concentration ranges and odour thresholds, as well as high
water content, all amount to a considerable analytical challenge.
Advanced analytical techniques to reverse-engineer plant-based products
Advanced analytical techniques can help to address these
challenges by providing improved extraction, separation, identification, and
comparison of aroma profiles.
Complicated sample preparation can be overcome using high-capacity sorptive extraction. Enhanced separation is achieved through comprehensive two-dimensional gaschromatography (GCxGC), and confident identification of aroma volatiles obtained
using time-of-flight massspectrometry (TOF MS).
The workflow is such that aroma volatiles are firstly captured
using high-capacity
sorptive extraction probes, that can be suspended in the headspace of solid
food products or directly immersed in beverages. These probes offer greater sensitivity compared
to solid-phase
microextraction (SPME) because of the larger volume of sorptive phase they
have, which means that they can trap more VOCs.
When used in combination with Markes’
Centri® sample extraction and enrichment platform, this offers fully
automated sorptive extraction with trap-based focusing, for enhanced
chromatographic performance, improved water management and the bonus of a
labour-saving automated workflow.
As mentioned above, when the sample preparation step
(high-capacity sorptive extraction) is used in conjunction with standard GC–MS,
important compounds may be hidden or masked because standard GC–MS lacks the
separation capacity to resolve these complex samples. This is overcome using GCxGC,
which uses two columns to separate the sample based on two different chemical
properties – for example, by volatility and then by polarity – for enhanced
separation of the diverse chemical classes.
Combining GCxGC with TOF MS,
results in highly-sensitive detection and confident identification of the
individual components, producing a more comprehensive aroma profile.
The final piece of the workflow is then the data
analysis. ‘Smart software’ is used to automatically align and ‘spot the
difference’ between the aroma profiles of animal products and plant-based
alternatives, to help accelerate product development and improve consumer
acceptance.
Easy-to-use chemometrics software
highlights differences between samples to accelerate development of new flavour
formulations.
Comparing meat and plant-based substitutes
We recently undertook a study using the workflow discussed to
compare the volatile profiles of ground meat and plant-based burgers. 5
The findings showed that the burgers did in fact have many volatiles in common
(green, above) – for example, aldehydes (like hexanal) dominated the aroma
profiles for all samples.
However, the plant-based burgers had a more diverse
composition, with increased levels of pyrazines, terpenes and
sulphur-containing compounds (blue) likely contributed by the plant proteins and
added flavourings (such as garlic powder).
On the other hand, ground beef was found to have increased levels of
acetoin, which has previously been correlated with a desirable buttery,
fat-flavour in beef.6
The level of information captured by this combination of sorptive
extraction and GC×GC–TOF MS enables flavourists to optimise ingredient mixes
for plant-based burgers to more closely mimic the taste and smell of real meat.
The future of food
Tackling the flavour challenge is imperative to the future success
of the plant-based food industry.
Ultimately, to achieve the taste that
consumers desire, manufacturers need better tools for the job, and advanced
analytical techniques, such a GCxGC–TOF MS, bring them a step closer to true reverse-engineering
of plant-based products.
For more in-depth information on this fascinating and
rapidly developing area, watch our on-demand webinar, entitled “Great taste and plant-based: Can advanced analytical tools help tackle flavour challenges in plant-based foods?” and read our white paper, “Reverse engineering the aroma of plant-based meat substitutes”.
References
- The Science of Plant Based Meats. GFI (2023) The Good Food Institute. https://gfi.org/science/the-science-of-plant-based-meat/
- Consumer Insights, GFI (2023) The Good Food Institute. https://gfi.org/resource/consumer-insights/
- Beyond Meat (2023). https://www.beyondmeat.com/en-GB/
- Bendall, J.G. (2001) ‘Aroma compounds of fresh milk from New Zealand cows fed different diets’, Journal of Agricultural and Food Chemistry, 49(10), pp. 4825–4832. doi:10.1021/jf010334n.
- Reverse engineering the aroma of plant-based meat substitutes [White Paper 039]. SepSolve Analytical (2023). https://www.sepsolve.com/white-papers/food-and-drink/aroma-of-plant-based-meat-substitutes.aspx
- How can plant-based burgers be made to taste exactly like meat? Scientists try to crack the code. ABC News (2023). https://www.abc.net.au/news/2021-10-12/plant-based-meat-research-taste/100529982