Detail publikace

Aroma Compounds of White Surface Mould Cheeses

VÍTOVÁ, E. LOUPANCOVÁ, B. HRADILOVÁ, J. BEZDĚKOVÁ, Š. ZEMANOVÁ, J.

Originální název

Aroma Compounds of White Surface Mould Cheeses

Anglický název

Aroma Compounds of White Surface Mould Cheeses

Jazyk

en

Originální abstrakt

White surface mould cheeses are characterized by felt-like coating of white mycelia from the growth of mould Penicillium camemberti or Penicillium caseicolum. The presence of moulds gives these cheeses appearance, a taste and an aroma which clearly differentiate them from other types of cheese. A typical example of surface mould ripened cheeses is Camembert, originated from France. The other principal cheeses with a surface mould are Brie, Coulommier and Carré de Est, a mild fermented cheese. The manufacture of these cheeses is widespread in France, followed by other European countries. Traditional Camembert is made from raw milk; the other surface mould cheeses are manufactured from raw or pasteurized milk. Some types, called for example Hermelín, Kamadet, Premium or Plesnivec, are made in Czech Republic. They are made from pasteurized milk using starter culture consist of thermophilic streptococci or a mixture of streptococci and lactococci. In order to obtain a more aromatic product, selected strains of yeasts, corynebacteria, yeast-like mould Geotrichum candidum and Penicillium spp. spores can be added to milk. Moulds are endowed with a markedly greater enzymatic potential than bacteria, consequently, the major processes of maturation, consisting of glycolysis, lipolysis and proteolysis, are more marked in mould-ripened cheeses than in other types. The presence of mould confers on cheese a typical aroma which plays a major role in their uniqueness. There are very many constituents in the volatile fraction of these cheeses and they belong to very different families of compounds (hydrocarbons, aldehydes, ketones, alcohols, fatty acids, esters, lactones, sulphur and nitrogen compounds). Not all produce an odour, but the role of certain compounds has been clearly identified [1]. The aim of this work was to compare aroma profile of several types of white surface mould cheeses produced in Czech Republic and to follow changes during ripening. Many of the aroma compounds are present only at very low concentrations; consequently, it is necessary to extract these compounds from their matrix. There are several methods for extraction, concentration and isolation of volatile compounds from a solid matrix: steam distillation, extraction with organic solvents and supercritical fluids, headspace techniques and solid-phase extraction. In our case volatile aroma compounds of cheeses were isolated using Solid-phase microextraction (SPME). SPME has been introduced by Arthur and Pawliszyn [2] for the extraction of organic compounds from environmental samples. This relatively new extraction technique is an alternative to traditional extraction procedures; it is based on the partition of the analyte between the extraction phase and the matrix. The method uses a small fused-silica fibre, coated on the outside with a suitable polymeric phase, mounted in a syringe-like protective holder. During extraction the fibre is exposed to the sample and analytes are directly extracted and concentrated to the fibre coating. Sorption of the analytes on the fibre takes place in either the sample by direct-immersion or the head-space of the sample. Analytes are thermally desorbed directly in the injector of gas chromatograph. This method shows a number of advantages compared with traditional techniques: simplicity, rapidity, low cost, compatibility with analytical systems, automation, solvent-free extraction, reduces analyte loss during extraction and requires only small volumes of samples. The aroma components of cheeses analysed were extracted using a Carboxen/PDMS 85 ?m fibre and analysed by gas chromatography. A total of 28 compounds were identified in single cheese types.

Anglický abstrakt

White surface mould cheeses are characterized by felt-like coating of white mycelia from the growth of mould Penicillium camemberti or Penicillium caseicolum. The presence of moulds gives these cheeses appearance, a taste and an aroma which clearly differentiate them from other types of cheese. A typical example of surface mould ripened cheeses is Camembert, originated from France. The other principal cheeses with a surface mould are Brie, Coulommier and Carré de Est, a mild fermented cheese. The manufacture of these cheeses is widespread in France, followed by other European countries. Traditional Camembert is made from raw milk; the other surface mould cheeses are manufactured from raw or pasteurized milk. Some types, called for example Hermelín, Kamadet, Premium or Plesnivec, are made in Czech Republic. They are made from pasteurized milk using starter culture consist of thermophilic streptococci or a mixture of streptococci and lactococci. In order to obtain a more aromatic product, selected strains of yeasts, corynebacteria, yeast-like mould Geotrichum candidum and Penicillium spp. spores can be added to milk. Moulds are endowed with a markedly greater enzymatic potential than bacteria, consequently, the major processes of maturation, consisting of glycolysis, lipolysis and proteolysis, are more marked in mould-ripened cheeses than in other types. The presence of mould confers on cheese a typical aroma which plays a major role in their uniqueness. There are very many constituents in the volatile fraction of these cheeses and they belong to very different families of compounds (hydrocarbons, aldehydes, ketones, alcohols, fatty acids, esters, lactones, sulphur and nitrogen compounds). Not all produce an odour, but the role of certain compounds has been clearly identified [1]. The aim of this work was to compare aroma profile of several types of white surface mould cheeses produced in Czech Republic and to follow changes during ripening. Many of the aroma compounds are present only at very low concentrations; consequently, it is necessary to extract these compounds from their matrix. There are several methods for extraction, concentration and isolation of volatile compounds from a solid matrix: steam distillation, extraction with organic solvents and supercritical fluids, headspace techniques and solid-phase extraction. In our case volatile aroma compounds of cheeses were isolated using Solid-phase microextraction (SPME). SPME has been introduced by Arthur and Pawliszyn [2] for the extraction of organic compounds from environmental samples. This relatively new extraction technique is an alternative to traditional extraction procedures; it is based on the partition of the analyte between the extraction phase and the matrix. The method uses a small fused-silica fibre, coated on the outside with a suitable polymeric phase, mounted in a syringe-like protective holder. During extraction the fibre is exposed to the sample and analytes are directly extracted and concentrated to the fibre coating. Sorption of the analytes on the fibre takes place in either the sample by direct-immersion or the head-space of the sample. Analytes are thermally desorbed directly in the injector of gas chromatograph. This method shows a number of advantages compared with traditional techniques: simplicity, rapidity, low cost, compatibility with analytical systems, automation, solvent-free extraction, reduces analyte loss during extraction and requires only small volumes of samples. The aroma components of cheeses analysed were extracted using a Carboxen/PDMS 85 ?m fibre and analysed by gas chromatography. A total of 28 compounds were identified in single cheese types.

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