Investigations of the connection between structure and ice recrystallization inhibition activity of carrageenans
Final Report Abstract
Carrageenans are polysaccharides which are extracted from red algae and used in isolated form as thickeners, gelling agents, or stabilizers. In addition, carrageenans exhibit recrystallization inhibition (IRI) activity. However, most previous studies only used selected carrageenans which were not structurally characterized. Furthermore, the cations already present in carrageenan preparations have not been considered. Therefore, little is known about how the structural composition of carrageenans affects their IRI activity. In this project, various carrageenans were characterized in detail and subsequently modified to draw conclusions about the relationship between carrageenan structure and the IRI activity. An analysis of the structural composition of 17 different commercial carrageenans with established analytical methods revealed that the manufacturer specifications do not always correspond to the actual structures present. Furthermore, the results indicated a considerable structural heterogeneity and differences regarding the associated cations. To gain more detailed insights into the structure, specific carrageenases were produced in recombinant form and used for the hydrolysis of selected carrageenans. The hydrolysates were analyzed by HPLC-MS or HPSEC- RI. This approach revealed differences in the occurrence of larger blocks of the individual structural units as well as the block size. The carrageenans characterized in detail were subsequently converted into various monocationic forms (potassium, calcium, and partially sodium). In addition, precursor structural elements were removed by alkaline treatment. The obtained samples were analyzed for their IRI activity. The results clearly showed that the functionality of carrageenans depends on both the molecular structure and the associated cations. Pure κ-carrageenan exhibited the highest IRI activity in the potassium form, while samples with high portions or long blocks of κ-structural elements also were very active. In contrast, ι-carrageenan and samples with a high proportion of ι-structural elements were less active. However, κ/ι hybrid carrageenans showed significantly improved functionality in the calcium form. Overall, a certain portion of κ-structural elements or a poorly sulfated DA unit is essential for a high IRI activity. The results of the project thus provide a deeper understanding of the relationship between carrageenan structure and IRI activity, which will enable future adjustments of carrageenan production and a more targeted application of the resulting carrageenans.
Publications
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Strukturelle Charakterisierung verschiedener kommerziell erhältlicher Carrageene, LChG „Tweet-your-poster-event 2020“
Hale, J. & Wefers, D.
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Ice recrystallization inhibition of commercial κ-, ι-, and λ-carrageenans. Journal of Food Engineering, 290, 110269.
Kiran-Yildirim, Bercem; Hale, Julia; Wefers, Daniel & Gaukel, Volker
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Analyse von Carrageenen mittels Hydrophilic interaction liquid chromatography und Massenspektrometrie (HILIC-MS), 50. Deutscher Lebensmittelchemikertag, Hamburg
Hale, J. & Wefers, D.
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Entwicklung einer HILIC-MS-Methode zur Charakterisierung kommerziell erhältlicher Carrageene, Arbeitstagung des Regionalverbands Südwest der LChG, Karlsruhe
Hale, J. & Wefers, D.
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Commercially available carrageenans show broad variation in their structure, composition, and functionality.
Hale, Julia; Gerhäuser, Julian; Gaukel, Volker & Wefers, Daniel
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Ice recrystallization inhibition activity of chemically defined carrageenans.
Hale, Julia; Furch, Alisa; Gerhäuser, Julian; Gaukel, Volker & Wefers, Daniel
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Strukturelle Zusammensetzung und funktionelle Eigenschaften verschiedener Carrageene, GDL-Symposium Hydrokolloide IX, Stuttgart
Hale, J., Gerhäuser, J., Gaukel, V. & Wefers, D.
