Making a plant-based patty look red before cooking is not the same task as making it turn an appropriate brown afterward. In a study by Sakai and colleagues, control patties containing beet red and methylcellulose remained visibly red after grilling; formulations combining laccase with sugar beet pectin showed a pronounced red-to-brown change.[30]
If a patty looks convincing raw but stays red when cooked, a more heat-resistant red ingredient is not necessarily the answer. The useful question is whether the formulation needs to preserve its color or change it during cooking. Two routes deserve separate consideration: adjusting the underlying shade and creating a reaction within the food matrix.
Adjusting the shade is not the same as creating a color transition
A 2023 study by Lee and colleagues combined beet powder with caramel color, optimizing six responses together: L*, a*, and b* before and after cooking. L* describes lightness, while a* and b* are the red–green and yellow–blue axes.[23][30]
There is an important qualification. Despite “meat analogs” in the title, this experiment did not use a soy- or pea-based patty. The researchers repeatedly washed beef to remove myoglobin, then added the colors to that model.[23] For the color measurements, the patties were vacuum-packed and heated at 80 °C until the core reached 75 °C; the paper separately shows an oven-cooked appearance comparison.[23] This model helps explore how the two colors work together, but does not establish inclusion rates for a plant-protein patty.
The combination with the highest overall desirability contained 1.32% beet powder and 1.08% caramel color, with a desirability score of 0.65. The third optimized combination contained 1.30% and 1.51%, respectively, with a score of 0.60.[23] Desirability is a multi-objective optimization score, not “65% similarity to beef.” The percentages are the study’s formulation levels, not pigment purity.
Nor did the study achieve an exact match in both states. For the first combination, Table 3 reports a* falling from 20.84 to 11.04 on cooking, compared with 21.76 to 6.69 for beef. Its b* rose from 19.39 to 25.18, whereas the beef value fell from 18.33 to 14.62.[23] Redness moved in the same direction; yellowness did not. The discussion favors the third combination when considering cooked appearance and lightness, while the conclusion recommends the first combination on overall desirability.[23] Those recommendations use different priorities.
The practical lesson is to avoid choosing a formula on raw redness alone. Decide whether caramel color fits the product brief, then consider raw appearance, cooked appearance, and the cut surface together.
Sugar beet pectin has a role beyond thickening
Sakai and colleagues’ 2022 work used a genuine plant-based system: pea-based textured vegetable protein, pea protein isolate, olive oil, and beet red. The named sugar beet pectin was GENU pectin type BETA BI-J; the laccase was Amano Enzyme’s LC-Y120.[30] The findings apply to those tested materials; equal-dose substitution needs its own evaluation.
Adding laccase to patties containing beet red and methylcellulose did not produce the pronounced browning seen when laccase and sugar beet pectin were used together.[30] The a* values in Table 1 make that distinction clear:
| Study formulation | a* before grilling | a* after grilling |
|---|---|---|
| Beet red + methylcellulose, without laccase | a* before grilling48.5 ± 0.9 | a* after grilling47.9 ± 1.0 |
| Beet red + methylcellulose + laccase | a* before grilling48.4 ± 0.6 | a* after grilling47.0 ± 2.8 |
| Beet red + sugar beet pectin + laccase | a* before grilling47.9 ± 2.4 | a* after grilling9.3 ± 1.1 |
| Beet red + methylcellulose + sugar beet pectin + laccase | a* before grilling48.3 ± 3.2 | a* after grilling9.4 ± 1.6 |
Source: Table 1 of the 2022 study. The a* coordinate is dimensionless; ± values are reproduced as reported.[30] In this formulation, adding the enzyme and adding the enzyme together with sugar beet pectin were plainly different treatments.
In the authors’ proposed mechanism, laccase and oxygen oxidize ferulate groups in sugar beet pectin to form radicals. These act as mediators, helping oxidize the beet pigment; reactions involving ferulate groups and protein tyrosine residues could also produce pectin–protein crosslinks.[30] This explains why the pectin is being studied as a reaction partner, not just a thickener. The pathway remains a proposal, and the work does not validate ordinary citrus or apple pectin as substitutes.
Both laccase papers came from researchers affiliated with Amano Enzyme. They provide original experimental evidence, not independent replication by an outside team.[28][30]
Color was not the only property affected. The research also examined changes in hardness, chewiness, and cooking loss.[30] A promising color result still needs to meet the product’s texture brief; an instrumental texture result is not evidence of consumer preference.
The useful reaction window is during heating
A 2024 follow-up examined reaction products in patties containing soy-based textured vegetable protein, pea protein isolate, sugar beet pectin, and beet red.[28] That is a different base from the 2022 pea-based formulation, rather than a repeat of an identical recipe.
In the follow-up, patties were cooked in an oven at 150 °C for 15 minutes. Their internal temperature approached an approximately 85 °C plateau around 10 minutes. The authors report that extracted residual laccase activity was undetectable at 10 minutes, although the corresponding point in Figure 1 appears slightly above the baseline.[28] The study supports a limited reaction window during heating, not a precisely established universal inactivation time. Oven temperature, internal product temperature, and enzyme activity are distinct quantities. Figure 1 describes a reaction window under the study’s conditions, not a universal instruction to heat every product for 10 minutes.
The researchers extracted pigments from the patties and combined chromatographic retention-time comparisons with standards and solution reaction experiments. They proposed a pathway in which betanidin is cleaved to betalamic acid and cyclodopa, followed by formation of unknown brown polymers.[28] “Unknown” matters: the final brown material was not fully structurally identified and was not confirmed to be melanin.[28]
The authors also state that losses of brown compounds during molecular-weight cut-off treatment could not be quantified.[28] The chromatograms therefore do not establish an exact whole-system conversion yield.
Choosing a useful next formulation trial
Use the formulation problem to choose the next comparison:
If the main problem is a patty that is too pale or pink, while its cooking transition is already acceptable, start with shade adjustment. The beet-powder/caramel study illustrates joint optimization of several color targets, but its myoglobin-removed beef matrix remains a major limitation.[23] Use the actual plant protein, oil phase, and cooking process rather than copying its optimum percentages.
If the main problem is a red cooked interior, consider beet red, sugar beet pectin, and laccase as a research candidate—not a ready-to-use formula.[30][28] Keep the existing formula as a control and distinguish pectin-only, enzyme-only, and combined treatments. Judge the outside and cut surface separately, so surface browning does not conceal an unchanged interior.
If texture must stay within a narrow range, screen color and structure together. The laccase–sugar beet pectin route concerns more than removing redness; the original work also discusses crosslinking, hardness, and water-holding-related behavior.[30] Define the acceptable texture range before deciding whether the color improvement is useful.
Keep the material identities and dose bases intact. Beet powder, a commercial beet-red preparation, and purified pigment are not interchangeable descriptions. In particular, supplementary Table S1 of the 2022 study reports laccase as 50 U/g TVP—not 50 U/g finished patty.[31] Before production use, confirm the specific enzyme preparation and its activity specification, permitted uses in the target market, labeling requirements, and the product safety process.
The most useful outcome is not a universal percentage. It is a sharper formulation question: does the product need a better background shade, or a controlled color transition during cooking? Keeping those tasks separate prevents ingredient heat stability, finished appearance, and cooking safety from becoming the same decision. A brown appearance should not replace the product’s own time–temperature safety validation.
Sources
[23] https://www.ebi.ac.uk/europepmc/webservices/rest/PMC10493565/fullTextXML — Lee et al. 2023 — original full-text XML
[28] https://www.jstage.jst.go.jp/article/fstr/30/2/30_FSTR-D-23-00182/_html/-char/en — Sakai et al. 2024 — laccase and betanidin original full text
[30] https://www.ebi.ac.uk/europepmc/webservices/rest/PMC8782913/fullTextXML — Sakai et al. 2022 — laccase and pectin original full text
[31] https://www.ebi.ac.uk/europepmc/webservices/rest/PMC8782913/supplementaryFiles