Previously, Dr. Hahn demonstrated that the around 150 worldwide kale varieties can be divided into several genetically distinct groups. In the existing research study, Hahns team investigated the effect of cold temperature levels on the glucosinolate structure in kale leaves. Glucosinolate levels are particularly high in feral-type kale and tend to be significantly lower in Lacinato varieties.
For their research study the scientists chose the three varieties “Frostara,” “Palmizio,” and “Helgoländer,” which can be appointed to the curly kale, Lacinato kale, and feral-type kale groups, respectively. The biologist currently showed in a study published in 2020 that levels of sugar substances in kale leaves also increase at low temperature levels– nevertheless not just at sub-zero temperature levels, as is often assumed, but currently at temperatures in the above-zero single-digit variety.
Irregularity in Glucosinolate Concentrations
The research groups findings reveal that glucosinolate concentration in particular kale varieties increases under cold temperatures, while in others it decreases. “To acquire plants with an enhanced nutritional value, thinking about both temperature and the choice of cultivar is vital,” Hahn stresses.
Formerly, Dr. Hahn showed that the roughly 150 worldwide kale ranges can be divided into a number of genetically distinct groups. A 3rd group is made up of varieties with broad, smooth leaves which are typically grown in the United States and are more similar to the wild type or “feral-type” cabbage.
Chemical Protection From Caterpillars and Snails
In the present study, Hahns team investigated the effect of cold temperatures on the glucosinolate structure in kale leaves. Glucosinolate levels are particularly high in feral-type kale and tend to be considerably lower in Lacinato ranges.
For their research study the researchers chose the three varieties “Frostara,” “Palmizio,” and “Helgoländer,” which can be appointed to the curly kale, Lacinato kale, and feral-type kale groups, respectively. They grew 45 specimens of each variety in an environment chamber at the University and exposed the adult plants to temperature levels of 2 degrees Celsius for one week. Leaf samples for analyses of glucosinolate levels and structure were taken at warm temperature levels, after twelve hours of cold direct exposure, and after seven days of cold exposure. Concentrations of seven different glucosinolates were evaluated at all three time-points using a mass spectrometer.
Unexpected Findings and Implications for Taste
The result: the scientists discovered that total glucosinolate levels increased at low temperatures in both the curly kale and Lacinato samples, but reduced in the feral type. This came as a surprise for the team: “Based on our previous experiments we would not have actually anticipated the Lacinato kale to respond in precisely the exact same way as the curly variety, since it is adapted to different weather conditions,” Hahn commented.
How these outcomes impact the taste of kale was not investigated in the research study. “For the taste not simply the glucosinolates but likewise the sugar material is definitive,” Hahn explained. The biologist currently showed in a research study released in 2020 that levels of sugar compounds in kale leaves likewise increase at low temperatures– nevertheless not just at sub-zero temperatures, as is typically presumed, but currently at temperatures in the above-zero single-digit range.
Referral: “A Cold Case– Glucosinolate Levels in Kale Cultivars Are Differently Influenced by Cold Temperatures” by Christoph Hahn, Anja Müller, Nikolai Kuhnert and Dirk C. Albach, 22 August 2023, Horticulturae.DOI: 10.3390/ horticulturae9090953.
Kale varieties with curly leaves produce more mustard oil glycosides at low temperature levels. Credit: University of Oldenburg/ Ute Kehse
Researchers from Oldenburg and Bremen examined the effect of ecological aspects on genetically various ranges of kale.
Kale is extensively recognized as a particularly healthy vegetable, largely due to its high content of secondary plant compounds. These include glucosinolates, which contribute to the veggies particular cabbage taste.
A group of German researchers, led by Dr. Christoph Hahn and Professor Dr. Dirk Albach from the University of Oldenburg, has actually recently published a study in the science journal Horticulturae. This study reveals that the structure of these compounds, likewise referred to as mustard oil glycosides, is influenced by both environmental elements– in specific temperature– as well as genetic aspects.