Heat-Stable Flavours for Bakery: Surviving the Oven Without Losing Top Notes

A flavour that is exactly right on the bench can arrive weak, flat or unbalanced in a baked product, and the reason is the oven. Baking is the harshest routine step most flavours meet, a hot, dry, moving environment that carries the lightest aroma compounds out with the escaping steam and breaks others down before the product is even cool. For a bakery brief, heat stability is not a single property that a flavour either has or lacks. It is a question answered compound by compound and format by format, and it is the question EssenceLock, VKA's encapsulation technology, exists to answer. This guide sets out what the oven actually does to a flavour, why some notes survive it and others do not, and the levers that decide the outcome.

What the Oven Actually Does

Start with the temperature, because it is not one temperature. A 2022 study in Food Control that instrumented bread all the way through the bake describes three regions existing at once: “a peripheral region (crust), which quickly reaches temperatures above 100 °C; a mobile evaporation front, which is always kept near 100 °C; and an internal region (crumb) that tends, asymptotically, to 100 °C.” For the bread tested, the authors report that “the core temperature reaches a plateau at 100 °C, which occurs due to the phenomenon of evaporation-condensation of water, which does not allow the temperature to be higher than the water boiling point.” The study took browning to begin near 110 degrees. Across the process the loaf lost 11, 15 and 17 per cent of its moisture at oven settings of 180, 200 and 220 degrees, respectively, and the volatile compounds that carry aroma leave with that water.

Two Aroma Systems, One Product

That crust heat does two opposite things at once, and a bakery flavour has to account for both. Around 110 degrees, the point the Food Control study takes as the onset of browning, reactions generate the toasted, caramelised, biscuity notes that a person reads as baked. Those notes are created by the oven. The flavour you dose in, the vanilla, the butter, the fruit or the spice, has to survive the very same heat that is making them. A good bakery flavour is therefore designed to arrive intact through a process that is simultaneously destroying volatile compounds and building new ones, and to sit correctly alongside the baked notes rather than competing with them.

Loss Is Compound by Compound

Within the added flavour, the loss is selective, and a 2024 study in the Flavour and Fragrance Journal shows how selective. Its authors baked cookies at 130 and 160 degrees with three marker flavourings and tracked each one through baking and storage. The proportion of benzaldehyde in the flavour mix fell from 18.33 per cent in the dough to 4.31 per cent after baking at 160 degrees and two weeks of storage, while the proportion of vanillin rose from 47.24 per cent to 61.38 per cent over the same period. Benzaldehyde is a small, volatile aldehyde, the kind of bright top note that evaporates and degrades first; vanillin is heavier and far less volatile, so it holds, and its share of what remains actually grows as the lighter compounds leave. The lesson for a formulator is that heat stability is a property of individual molecules, not of a flavour as a whole, and the fresh, lifted top notes that make a bench sample smell alive are usually the first to be lost.

Where the Flavour Sits Matters

The same flavour is not equally exposed in every bakery product, because geometry decides where it sits on that temperature gradient. A thin biscuit or cookie is almost all surface and bakes down to a low moisture, so its flavour spends the bake in the hottest, driest part of the product, which is why the cookie result above is close to a worst case. A cake or a bread crumb keeps most of its flavour in a moist interior, which commonly sits close to 100 degrees Celsius under ordinary baking conditions. This is not an absolute ceiling: the Abedi cookie study notes that dissolved solids can raise the boiling point, so measure the actual product temperature profile. Enrobed fillings, laminated doughs and thick batters each place the flavour somewhere different again. Two products at the same oven setting can need very different flavour designs, and a flavour proven in a sponge is not automatically proven in a shortbread.

The Lever Most Briefs Miss: the Solvent

Before encapsulation, there is a cheaper lever that a bakery brief often overlooks, which is the solvent the flavour is carried in. A liquid flavour is mostly its carrier, and carriers differ in how tightly they hold volatiles through heat. A 2013 study in Food Chemistry compared two of the common ones in shortcake biscuits, propylene glycol and triacetin. Propylene glycol boils at 188 degrees; triacetin boils at roughly 260 degrees and is markedly less volatile. The study found that “Significantly more HMF was formed during baking of biscuits prepared with TA; these biscuits were also more stable to oxidative degradation and loss of vanillin during ageing than biscuits prepared with PG.” A 2025 study in Food Chemistry on spray-dried raspberry flavour pointed the same way, reporting that a triacetin blend improved the retention of low-boiling volatiles. The carrier is not a neutral diluent in a bake, it is part of the heat-stability decision, and the market limits that apply to each carrier are set out in our guide to flavour formats.

Encapsulation, and What It Is Really Buying

The stronger lever is to change the format. Encapsulation wraps the volatile compounds in a food-grade wall so the aroma is shielded from the heat, oxygen and moisture of the bake. A 2019 study in the Journal of Food Science and Technology tested this in biscuits, comparing cinnamon oil encapsulated in maltodextrin against the same oil simply dissolved in propylene glycol, and found the retention of cinnamaldehyde, eugenol and β-caryophyllene significantly higher in the encapsulated form, both through baking and across the shelf-life test. How much survives in the first place depends on the wall material. A 2009 study in the Journal of Agricultural and Food Chemistry measured retention through spray drying at 94 per cent for gum acacia, 88 per cent for modified starch and 87 per cent for whey protein isolate, and found that even the best wall held only 37 to 58 per cent of its aldehydes after 28 days at 40 degrees. Encapsulation is a real gain, but it is an engineered one, matched to the compound and the process, which is the whole basis of flavour encapsulation and EssenceLock.

An Efficiency Number Is Not a Through-Bake Number

For an assay measuring total and surface oil, encapsulation efficiency is the encapsulated fraction of total oil, calculated as (total oil minus surface oil) divided by total oil. Loading and process retention are separate measurements, and efficiency alone cannot predict survival in an oven; see our encapsulation guide.

The Bake Is Only the First Clock

A bakery flavour has to clear two hurdles, not one. It has to survive the oven, and then it has to hold through a shelf life that runs from a same-day loaf to a biscuit with a year on the ambient shelf. The compounds most at risk in the bake, the light aldehydes and esters, are often the same ones that oxidise later in the pack, so a flavour that only just survives baking can keep fading afterwards. The carrier and encapsulation choices that protect a flavour through the oven are the same ones that govern how it ages, which is why the two questions are specified together rather than in sequence. How a flavour degrades across its life, and what a specification actually promises, is covered in how long flavours last.

What a Bakery Brief Should Carry

A brief that lets a flavour house answer the heat-stability question quickly names a few things. The oven temperature and the bake time, and whether the product is thin and dry like a biscuit or moist-crumbed like a cake, because that decides where on the thermal gradient the flavour sits. The target character, and which of its notes are the volatile top notes most at risk. The format and carrier already assumed, if any, since those are exactly what can be changed. The post-bake shelf life and the storage conditions. And the label and market constraints on carriers and wall materials. With those in hand, the work becomes measurement rather than guesswork.

How VKA Builds a Bake-Stable Flavour

At VKA we develop bakery flavours for the Singapore and wider ASEAN market. Through EssenceLock, we can select the protective wall material for the vulnerable compounds and measure retention through a representative bake. Where a flavour is halal-certified, check its certification scope against your requirements. To see the profiles we build from, browse our Essences Portfolio and Culinary Portfolio, read how we choose a flavour format, or talk to a flavourist directly about your product, your oven and the notes you cannot afford to lose.