Monitoring of the fatty acid content in Swiss type cheese

abstrakt

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Cheese is generally defined as “a milk product made by precipitation of milk protein from milk by the use of rennet or other suitable coagulating agents, by the acidification and separation of the whey content” and matured cheese as “cheese which has been subjected to further biochemical and physical processes” (Directive 397/2016 Coll. (2016)). Swiss type cheese is a generic name for several related varieties of cheese, which resemble Emmental cheese, a yellow, medium-hard cheese that originated in the area around Emmental, Switzerland [2]. Most types of Swiss cheese have a distinctive appearance, as the blocks of the cheese are riddled with holes (0,5-1,5 cm) known as “eyes”. Swiss cheese without eyes is known as “blind” [1]. “Moravský blok/bochník” is a Swiss type cheese with a few or no eyes of Czech origin. Fatty acids represent important part of sensory active compounds that contribute to the flavour of cheese. They are carboxylic acids with long aliphatic chain, either saturated or unsaturated. Fatty acids in cheese are mostly part of triacylglycerols and/or phospholipids, if not bound they are called free fatty acids [3]. Current trends show that gas chromatography comes as very convenient method to assess both bound and free fatty acids. Combined with other isolation/separation techniques such as solid-phase extraction, microextraction and thin-layer chromatography comes a great tool to identify and quantify fatty acids in various matrices [4]. The aim of this study was to identify and quantify free and bound fatty acids in model samples of the Swiss type cheese (Moravský bochník). Model samples were produced at laboratory (pilot plant) conditions at Tomas Bata University in Zlín using a standard technological procedure. Commercial samples (Emmental cheese and Moravský bochník) were purchased at the local market. The ČSN EN ISO 1735:2005 method was chosen for the lipid extraction from cheese samples. Solid-phase extraction and thin-layer chromatography were compared for fractionation of lipids and to obtain especially fraction of free fatty acids. Present free and bound fatty acids were then converted to methylesters using methanolic solution of bortrifluoride (ČSN EN ISO 12966-2:2011) and assessed by gas chromatography with flame ionization detection. In total, 32 bound and 20 free fatty acids were identified in cheese samples, with the highest amount of caproic, caprylic, capric, lauric, myristic, palmitic, stearic and oleic acids. In the commercial samples concentrations of both bound and free fatty acids were similar. Comparing commercial vs. model samples, model samples had significantly higher concentrations of both free/bound fatty acids than purchased ones, which leads to higher amount of sensory active compounds and consequently probably to better sensory characteristics. Both commercially produced Swiss type cheeses had bland taste, probably owing to their often-practical use as a matrix for processed cheese productionproduction. References [1] R.E. Liggett, M.A. Drake, J.F. Delwiche, Journal of Dairy Science 91 (2008) 466. [2] A. Prandini, S. Sigolo, G. Piva, Journal of Food Composition and Analysis 24 (2011) 55. [3] S. Kaminarides, P. Stamou, T. Massouras, Food Chemistry 100 (2007) 219. [4] M. E. Johnson, Journal of Dairy Science 100 (2017) 9952 Acknowledgement This work was supported by a Standard project of specific research No. FCH-S-18-5334.

cheese, fatty acids, SPE, GC-FID

SÝKORA, M.; VÍTOVÁ, E.

15. 9. 2018

Vysoké učení technické v Brně, Fakulta chemická, Purkyňova 464/118, 612 00 Brno

978-80-214-5488-0

7th Meeting on Chemistry and Life 2018. Book of abstracts

první

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