The changes of flavour and aroma active compounds content during production of Edam cheese

VITOVA, E., MOKAŇOVA, R., BABAK, L., ZEMANOVA, J., SKLENAŘOVA, K.: The changes of fl avour and aroma active compounds content during production of Edam cheese. Acta univ. agric. et silvic. Mendel. Brun., 2011, LIX, No. 1, pp. 255–262 This work deals with the problem of fl avour of Edam cheeses, i.e. natural hard cheese with low heat curd. The cheese samples were produced in dairy MILTRA B, Ltd., Městecko Trnavka. A number of volatile substances contribute to fl avour of cheese including alcohols, aldehydes, ketones, fatty acids, esters, lactones, terpenes etc. The development of these components during production was monitored in chosen Edam cheese (fat 30% w/w) using headspace-SPME-GC method. The samples were taken from cheesemilk up to technologically ripe cheese. In total 37 various organic compounds belonging to fi ve chemical groups were identifi ed in milk and cheese samples. Their total content increased during production. The fi rst increase was observed a er pressing and then especially in last part of ripening. Ethanol (185.8 ± 15.85 mg.kg−1), acetoin (97.7 ± 3.78 mg.kg−1), 2-methylpropanol (71.2 ± 5.23 mg.kg−1), acetic acid (54.4 ± 1.70 mg.kg−1) and acetaldehyde (36.4 ± 10.17 mg.kg−1) were the most abundant in ripened cheeses. The fl avour and other organoleptic properties (appearance, texture) of Edam cheese samples were also sensorially evaluated during ripening. The fi ve point ordinal scale and profi le tests were used for evaluation. The sensory quality was improved during ripening, until the fi nal marked fl avour characteristic for these cheese types. Edam cheese, fl avour, aroma active compounds, GC, SPME, sensory analysis Edam cheeses belong to the group of natural semihard cheeses with low heat curd. The consumer’s acceptance of cheese mainly depends on its sensory qualities and, in this context, the fl avour is determinant. Edam cheeses have mild, not very salty taste and very mild (almost imperceptible) aroma compared to other cheese types. The colour of Edam is yellowish; paleness is the indicator of insuffi cient rapidity (Roginski et al., 2003). These cheese types are the most popular with consumers in the Czech Republic. They are produced with 45, 40, 30 or 20% (w/w) of fat. Edam cheeses with low fat content are considered as Czech speciality. Characteristic organoleptic properties of cheese, i.e. appearance, colour, taste and aroma (fl avour) and texture, are the result of properly running biochemical pathways primarily during ripening of cheeses. Cheese fl avour is considered to be the result of a right balance between various volatile components, which individually do not refl ect the overall odour (Rehman et al., 2000). So called aroma active compounds (AAC), originated from proteolysis, lipolysis and lactose decomposition during cheese ripening, are the substantial part of aroma and partly of cheese taste (McSweeney, 2004; Pachlova et al., 2009). These AAC comprise alcohols, aldehydes, ketones, fatty acids, esters, lactones and other. Many parameters determine fl avour formation in cheese, e.g. starter cultures, nonstarter LAB, cheese making technology, salt and fat content, type of milk, ripening period. The starter bacteria for these cheese types have always been mesophilic lactic acid bacteria (LAB) (Van Leuven et al., 2008). The large and medium-sized peptides, perhaps even smaller peptides 256 E. Vitova, R. Mokaňova, L. Babak, J. Zemanova, K. Sklenařova are created during proteolysis. These are further degraded by exopeptidases, tripeptidases and dipeptidases to amino acids, which are the source of nutrition for LAB (Fox et al., 2000). The small peptides and amino acids contribute to fl avour by conversion into other compounds such as alcohols, amines, fatty acids, esters, carbonyl and sulphur compounds. Amino acid degradation is a major process for aroma formation in cheese (Smit et al., 2005; McSweeney et al., 2006; Nhuch et al., 2008). Edam cheese types lack the fatand fatty acids degrading enzyme systems that occur in mould ripened cheeses, consequently the fat degradation is diff erent and less pronounced. The formation of secondary fat-derived AAC during the ripening of these cheeses is not fully known (Alewijn et al., 2005). Several sensory defects can occur during ripening, e.g. bitterness in cheeses, which is most often due to bitter peptides. If they accumulate to an extensive concentration, bitterness occurs. However, they are further degraded to small peptides or amino acids which are non-bitter (McSweeney et al., 2000; McSweeney, 2004). The intensity of proteolysis depends on many factors, mainly time of ripening (Sousa et al., 2001). Edam cheese types are ripened 4–12 weeks (Roginski et al., 2003). The aim of this work was to follow the development of Edam cheese fl avour during the whole production process. AAC as a substantial part of fl avour were identifi ed and quantifi ed using gas chromatography-mass spectrometry (GC-MS) with SPME (solid-phase microextraction) extraction. The fl avour was evaluated sensorially using ordinal scale and profi le tests. MATERIALS AND METHODS