Freiberg University of Technology Team Analyzes Biomarkers for Strawberry Quality Index
Scientists Crack the Code to Perfect Strawberries—Flavor and Nutrition Mapped
Sweet flavors and healthy nutrients make strawberries one of the world's most beloved berries. The complex biochemical compounds that determine a strawberry's taste and nutritional value—known as biomarkers—can only be precisely identified by experts using advanced analytical techniques. Now, a team from Freiberg University of Technology (TU Bergakademie Freiberg), working with Serbian researchers, has for the first time examined various strawberry cultivars using ultra-high-resolution mass spectrometry to determine how these biomarkers are distributed within the fruit.
The chemists found that most biomarkers are concentrated in the strawberry's red skin. Their findings were recently published in the academic journals Analytical Science and Plants.
Visualization of a strawberry cross-section showing total ion abundance detected during analysis. Areas with high biomarker concentrations exhibit strong signal intensity in the mass spectrum and are illustrated in red.(c) TU Bergakademie Freiberg
In the strawberry skin, the research team led by Dr. Jan Zuber from TU Bergakademie Freiberg identified biomarkers such as pelargonidin-3-O-malonyglucoside. "This molecule has antioxidant properties," explains Zuber, a research associate at the Institute of Analytical Chemistry. "In the human body, these chemical compounds can neutralize free radicals, providing anti-inflammatory and vascular protective effects." The studied strawberry varieties also contain other biomarker molecules, including organic acids like citric acid and sugars such as glucose. The taste and nutritional quality of each strawberry cultivar depend on the concentration and ratio of these biomarkers—most of which are also found primarily in the skin.
Ultra-thin strawberry slices for detailed analysis
The team's ability to pinpoint biomarker concentrations so precisely is due to the high-tech analytical instrument they used: an ultra-high-resolution mass spectrometer. This device first converts biomarkers into charged particles, or ions, using a laser, then separates them based on mass and charge. "Our analysis allowed us, for the first time, to distinguish between biomarkers whose masses differ only in the sixth decimal place," says Zuber. The biomarkers are visualized in a color-coded map of the measured signals from the ultra-thin strawberry slices. "This clearly shows that the biomarkers crucial for the fruit's taste and quality are found in particularly high concentrations in the strawberry's skin."
Targeted strawberry cultivation
Together with researchers from the University of Belgrade in Serbia, Zuber's team analyzed 25 novel strawberry cultivars using this method. "Since these biomarkers are key to both flavor and quality, it is valuable for breeders to know exactly where they are located and in what concentrations," Zuber explains. "These insights can help select the most productive and nutrient-rich varieties for commercial cultivation. Additionally, the findings assist in predicting how new cultivars will be received by consumers."
Background: Analyzing samples with mass spectrometry
The sample used for analysis is just a few micrometers thick. To prepare it for measurement in the mass spectrometer, researchers employ a specialized cutting device known as a cryo-microtome. The ultra-thin slice is then coated with a UV-active matrix, which is essential for converting the various biomarkers into their corresponding ions. Next, the team overlays a measurement grid onto the prepared sample. Each point on this grid is excited using the mass spectrometer's laser, and the resulting ions are detected. Thanks to the ultra-high-resolution mass spectrometer, even the smallest differences in mass between biomarker ions can be resolved and used for differentiation. The collected data is then analyzed and visualized through distribution maps, revealing which biomarkers are detectable in specific regions of the thin section.
The ultra-high-resolution measurements were conducted by the German-Serbian research team as part of a project funded by the German Academic Exchange Service (DAAD, reference number: 57602001).
Scientific contact: Dr. Jan Zuber Institute of Analytical Chemistry Phone: +49 3731 39-4193 Email:
Original publication:https://doi.org/10.3390/plants12122238https://analyticalscience.wiley.com/content/article-do/characterization-biomarkers-strawberries-ms-imaginghttps://tu-freiberg.de/news/strawberries-under-the-high-tech-microscope
