Technical Yearbook 2024

galactopyranoses. Due to its gelling properties, carrageenan is widely used in the food industry and pharmaceutical applications as a thickener and stabiliser. The chemical composition of carrageenan varies based on the number of sulphated groups present in the disaccharide repeating unit, with the most used forms being kappa-carrageenan, iota carrageenan and lambda-carrageenan, which have one, two and three sulphated groups, respectively. Carrageenan can bind different types of ions, particularly K + , Ca 2+ and Mg 2+ . Specifically, kappa-carrageenan and lambda-carrageenan exhibit strong affinity for K + and Ca 2+ , and their association is primarily driven by ionic bonding between the ions and the sulphated groups. The presence of a 3,6-anhydrogalactose group can cause Ca 2+ to exist in an electrostatic state that stabilises the helicoidal structure of the hydrocolloid. Based on this premise, a research study aimed to prevent the formation of CaT crystals and subsequent precipitation by adding a commercial mixture of kappa-carrageenan and lambda-carrageenan to wines before protein stabilisation with sodium-bentonite. Experimental layout • Four white and two rosé wines, which exhibited varying CaT and KHT stability levels, were analysed. • Carrageenan was prepared by dissolving and homogenising it in distilled water using a magnetic stirrer until it was completely soluble. • Next, carrageenan was added to the wine samples at concentrations of 25 g/hL and 75 g/hL, and the mixture was continuously stirred for three days at room temperature. • After three days, 50 g/hL of sodium bentonite, soaked in water for 24 hours, was added to the treated wines and kept in contact with the wines for four days at room temperature. • All samples were examined on the third day after adding carrageenan and on the fourth day after adding sodium bentonite. • The wine samples that did not receive the carrageenan treatment were controls. All treatments were conducted in triplicate. Results • All wines were CaT stable after adding carrageenans and sodium bentonite. • Most wines were also protein stable, except for one that was still slightly unstable. • Additionally, KHT stability was improved. • The mini-contact test with micronised CaT seeds, DLS analysis and FTIR spectra confirmed that CaT stability

Conclusion Currently, carrageenan is permitted as a processing aid in winemaking only in Australia (Standard 4.5.1 Wine Production Requirements). It has not been approved for winemaking by the OIV or the European Union. However, as an environmentally friendly alternative to bentonite and a possible solution to manage climate change-induced calcium instability in wines, it may soon be approved for use in winemaking in the rest of the world.  of kappa-carrageenan on protein stability and wine macromolecular composition. Their results showed that kappa-carrageenan reduced the content of pathogenesis related proteins (thaumatin-like proteins and chitinases) and, consequently, protein instability in Albariño wines. Additionally, kappa-carrageenan was more effective than sodium and calcium bentonites in achieving this result. was due to colloidal stabilisation rather than Ca 2+ ions removal. The stabilisation mechanism may involve complexes involving carrageenan, calcium ions and proteins. • Furthermore, the synergistic effect of bentonite may be attributed to the competitive adsorption of proteins, which results in the adsorption of larger amounts of Ca 2+ ions by carrageenan. Carrageenan and white wine protein stabilisation Previous research in Australia has demonstrated that specific carrageenans can heat-stabilise wine at lower dosages than typically used for bentonite. However, the study’s authors also discovered that excessive amounts of certain carrageenan types, if not removed by filtration, could cause a haze in the wine. A follow-up study, therefore, aimed to identify the most effective carrageenans for heat-stabilising white wine without causing negative side effects, such as poor filtration or inadequate heat stabilisation. The study screened a broad range of commercially available carrageenans and found that certain types, such as kappa-carrageenans in sodium or potassium salt form or a blend of kappa- and iota carrageenans (containing up to 10% iota-carrageenans), were effective for this purpose. On the other hand, lambda carrageenan or ‘pure’ iota-carrageenan did not heat-stabilise wines. Portuguese researchers aimed to investigate the impact

References https://www.wineland.co.za/the-use-of-carrageenan-in-calcium-tartrate-and-protein-stabilisation-of-wines/

For more information, contact Karien O’Kennedy at karien@sawine.co.za.

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TECHNICAL YEARBOOK 2024