Improving Study On Fruity Flavor Of Camembert-type Cheese

Camembert cheese is a kind of typical mold mature soft cheese characterized with mushroom sensationa and lacking of fruity flavor. In the past study, ethyl esters were detected at traces levels in Camembert cheese, and an increase in the concentration of esters in Camembert cheese might be beneficial and could potentially enhance the fruity sensation in Camembert cheese. This study mainly focused on the improving the ethyl ester contents in the Camembert cheese by the different methods. The research investigated the influence of the substrate ethanol and adjunt cultures with high esterase and alcohol acyltransferase for the synthesis of the ethyl ester and the fruity flavour of cheese.This study investigated how the formation of ethyl esters was influenced by the addition of different concentrations of ethanol(0-1200 μg/g) in Camembert cheese, and the influence of ethanol addition on the composition, texture and flavor profile of Camembert cheese. No dramatic differences were found in the composition, microbes, and textures of the experimental cheeses and control except the moisture prior to storage and cohesiveness and chewiness of 4th week. However, when compared with the control cheese, more ethyl esters(E1-25.99 ng/g,E2-116.82 ng/g、E3-79.93 ng/g) and a significant enhancement in fruity flavor sensations were reported in the experimental cheeses.Then the potential adjunct culture was screened with a multi-step method by considering the growth of strains in cheese ripening environment, acidifying abilities, autolysis degrees, ester synthesis of esterase and alcohol acyltransferase activity as indexes. Among the 12 strains, three strains with different characteristics, CCFM12, CCFM177 and CCFM410, were explored further for application as adjunct culture. CCFM12 showed potential as an adjunct culture with high esterase and alcohol acyltransferase activities and low decomposition ability of esterase. For CCFM12 the ability to produce acid was 1.32±0.02, autolyzed degrees was 18.10±0.28, the esterase synthetic ability of ethyl acetate, ethyl butanoate and ethyl decanoate were 0.87±0.10 mg/g, 3.93±0.94 mg/g, 17.42±0.47 mg/g respectively. The alcohol acyltransferase activity of ethyl acetate, ethyl butanoate and ethyl decanoate of CCFM12 were 9.94±0.61 mg/g, 0.67±0.23 mg/g and 27.49±0.36 respectively. The decomposition ability of esterase of CCFM12 was 0.53±0.00 μmol p NP·min-1·g-1.To investigate the influence of different enzyme activity on the ethyl ester synthesis rate in cheese, CCFM177 and CCFM410 were also chosen with a moderate and low esterase and alcohol acyltransferase activities. Three lactobacillus plant strains, CCFM12, CCFM177 and CCFM410, were added as adjunct cultures to the Camembert cheese. At the same time in order to conpare the influence between the substrate ethanol and enzyme activity for the ethyl ester synthesis, 400 and 800 ppm ethanol was added to the cheese trial of CCFM12. Six groups of cheese were kept at 14℃ and 90% RH for one month to observe the influence on basic physical and chemical index and quality of cheese. Results showed that comparing with the control cheese, in the sample made with CCFM12(without addition of ethanol), ethyl ester was detected. However, compared with CCFM12 trial cheese with addition of 400 or 800 μg/g ethanol, the ester contents had a dramatic enhancement(p<0.05). Though there was no significant difference in the basic physical and chemical indexs of cheese, the p H and microbial counts had the significant difference because of the addition of the different adjunt cultures and ethonal. In addition, comparing with the control cheese, no significant difference was reported among the samples in the texture except the coherence and resilience. The contents of free amino acids in the experimental group and the rate of protein degradation increased significantly(p<0.05). The fruity flavor in experimental group improved significantly except the CCFM410 cheese and control cheese.The above research results showed that ethanol and screening of the adjunt cultures for high esterase and alcohol acyltransferaseactivities could improve the levels of ethyl ester of Camembert-type cheese and provide the fruity flavor, which proved that the ethanol, esterase and alcohol acyltransferase are the key limiting factors to influence the synthesis of ethyl ester and the formation of the fruity flavor in the Camembert-type chessee.