Chromatography Tracks Glycoalkaloids in Fried Potatoes

Glycoalkaloids (GAs) are naturally occurring compounds found in plants like potatoes and are considered unwanted substances in food. Despite this, not much is known about how they behave when potatoes are cooked at high temperatures, such as during frying. In response to this knowledge gap, researchers set out to examine how these compounds change and what new substances they might form when exposed to the intense heat of cooking.

Building on the idea that this naturally occurring potato compound may interact with fats within the potato's own cells, the researchers set out to study these interactions more closely. They combined the pure compound with five different types of common fatty acids and heated them to typical deep-frying temperatures (180 °C). The resulting products were then identified and analyzed using multi-stage high-resolution mass spectrometry (HRMS) and liquid chromatography-coupled tandem mass spectrometry (LC-MS/MS). A paper based on their efforts was published in Current Research in Food Science.¹

What is Already Known About Glycoalkaloids in Potatoes, and Where Are the Gaps in Current Knowledge?

When potatoes start to sprout, they produce higher levels of GAs, especially in the sprouts themselves. The health risks associated with these compounds in potatoes are already understood; they become a concern mainly when people eat green or sprouting potatoes, or large amounts of potato skin.^2-4

It is already known that peeling and boiling potatoes can reduce the levels of these compounds; peeling removes them physically, while boiling causes them to leach out into the water.^5,6 Choosing the right potato variety and storing potatoes properly can also help keep levels low.⁷ However, much less is known about what happens to these compounds when potatoes are cooked at higher temperatures, such as when making hash browns, French fries, or potato chips. In these processes, potatoes are typically cooked at around 170 to 180°C for three to five minutes, and how the compounds behave under these conditions is not yet well understood.⁸

What Did the Study Find, and What Further Research is Still Needed?

The study uncovered two previously unknown ways that a naturally occurring compound in potatoes chemically transforms during cooking : it can bond with fats as well as undergo a structural change in another part of its molecule. Importantly, these changes were also observed in cooked potato products without any added frying oil, suggesting that the fats naturally present in the potato itself are responsible. These findings help build a clearer picture of what happens to this compound when potatoes are heated. That said, further research is still needed to measure exactly how much of these new compounds are formed, and whether they pose any health risks to people who eat them.¹

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References

1. Mittau, K.; Meyers, C.; Rawel, H. M. et al. Stability of Potato Glycoalkaloids Under Heating Conditions - Reactions with Fatty Acids. Curr Res Food Sci. 2026, 12, 101438. DOI: 10.1016/j.crfs.2026.101438
2. Friedman, M. Potato Glycoalkaloids and Metabolites: Roles in the Plant and in the Diet. J Agric Food Chem. 2006, 54 (23), 8655-8681. DOI: 10.1021/jf061471t
3. Milner, S. E.; Brunton, N. P.; Jones, P. W. et al. Bioactivities of Glycoalkaloids and their Aglycones from Solanum Species. J Agric Food Chem. 2011, 59 (8), 3454-84. DOI: 10.1021/jf200439q
4. EFSA Panel on Contaminants in the Food Chain (CONTAM); Schrenk, D.; Bignami, M.; Bodin, L. et al. Risk Assessment of Glycoalkaloids in Feed and Food, in Particular in Potatoes and Potato-Derived Products. EFSA J. 2020, 18 (8), e06222. DOI: 10.2903/j.efsa.2020.6222
5. Mäder, J.; Fischer, W.; Schnick, T. et al. Changes in Glycoalkaloid Composition During Potato Processing: Simple and Reliable Quality Control by HPTLC. J. Plan. Chromatogr. 2009, 22 (1), 43-47. DOI: 10.1556/JPC.22.2009.1.8
6. Mäder, J.; Rawel, H.; Kroh, L. W. Composition of Phenolic Compounds and Glycoalkaloids α-solanine and α-chaconine During Commercial Potato Processing. J. Agric. Food Chem.2009, 57 (14), 6292-6297. DOI: 10.1021/jf901066k
7. Petersson, E. V.; Arif, U.; Schulzova, V. et al. Glycoalkaloid and Calystegine Levels in Table Potato Cultivars Subjected to Wounding, Light, and Heat Treatments. J Agric Food Chem.2013, 61 (24), 5893-5902. DOI: 10.1021/jf400318p
8. Arslan, M.; Xiaobo, Z.; Shi, J. et al. Oil Uptake by Potato Chips or French Fries: A Review. Eur. J. Lipid Sci. Technol.2018, 120 (10), 1800058. DOI: 10.1002/ejlt.201800058