ABSTRACT
BACKGROUND: A first approach was made to acquire knowledge of the global composition, proteolysis, lipolysis and volatile profile of Argentinean blue cheeses. A total of 20 samples belonging to six leading commercial brands were analysed. A comparison of the results with bibliographical data on other blue cheeses was performed and the variability among and within dairy plants was also evaluated. RESULTS: Values of global composition were intermediate in relation to those reported for mould-ripened cheeses. Levels of proteolysis and lipolysis were lower than those of other blue cheeses. Volatile compound profiles were characterised mainly by short-chain fatty acids, methyl ketones and secondary alcohols, as reported previously for blue cheeses. Wide-ranging values of physicochemical parameters, lipolysis and proteolysis levels as well as volatile compound areas of cheeses produced by each dairy plant were observed. Owing to this high variability in the chemistry and volatile profile of cheeses, principal component analysis of the data did not show groupings by commercial brands. CONCLUSION: On the whole, Argentinean blue cheeses were characterised both by gross intermediate composition values and by proteolysis and lipolysis levels lower than those of blue cheeses of different origins. A typical volatile compound profile of blue cheeses was observed. The high variability found within each commercial brand could reflect the lack of standardisation of the technological processes used in blue cheese manufacturing in Argentina.
Subject(s)
Cheese/analysis , Dietary Fats/analysis , Dietary Proteins/analysis , Food Microbiology , Volatile Organic Compounds/analysis , Alcohols/analysis , Argentina , Cheese/classification , Cheese/microbiology , Dairying , Fatty Acids, Volatile/analysis , Hydrolysis , Ketones/analysis , Principal Component AnalysisABSTRACT
BACKGROUND: In this work the proteolysis profiles of Argentinean sheep cheeses made by two different production methods were studied in order to develop products with typical and defined features. Cheeses with a starter of Streptococcus thermophilus, curd cut to corn grain size, washed and heated to 43 degrees C (S cheeses) and cheeses with a mixed starter of Streptococcus thermophilus, Lactobacillus helveticus and Lactobacillus bulgaricus, curd cut to rice grain size, unwashed and heated to 47 degrees C (L cheeses) were manufactured. The cheeses were ripened at 12 degrees C and 80% relative humidity for 180 days and samples were taken throughout this period. RESULTS: Gross composition and primary proteolysis were similar for both types of cheeses. Streptococci counts diminished from 10(9) to 10(7) colony-forming units g(-1) during ripening in both S and L cheeses. Lactobacilli counts in L cheeses decreased during ripening and disappeared at 180 days. L cheeses had significantly lower pH values and showed higher peptidolysis than S cheeses. Triangle sensory evaluation indicated important differences between the two types of cheeses. CONCLUSION: S cheeses had a low proteolysis level and a soft flavour, making them appropriate for consumption after a short ripening time. L cheeses had a higher proteolysis level and more intense sensory characteristics, making them appropriate for consumption after a longer ripening time.
Subject(s)
Cheese/microbiology , Food Handling/methods , Food Microbiology , Lactobacillus , Milk Proteins/metabolism , Streptococcus thermophilus , Taste , Animals , Argentina , Colony Count, Microbial , Fermentation , Humans , Hydrogen-Ion Concentration , Hydrolysis , Particle Size , Peptides/metabolism , Sensation , Sheep , Stem CellsABSTRACT
Samples (29) of natural whey starters used in the Santa Fe (Argentina) area for hard cheese production were examined. The microbial composition (including lactic microflora identification) and technological characteristics (acidifying and proteolytic activities) were determined. The cultures consisted mainly of thermophilic lactic acid bacteria belonging to the genus Lactobacillus . L. helveticus (66% the total strains) and L. delbrueckii subsp. lactis (33%) were the dominant species. In every sample, yeasts appeared as the only natural contaminants, at variable contents. The samples showed high acidity levels (1.2 to 1.4% lactic acid) with a mean pH value of 3.3. The acidifying and proteolytic activities were high at temperatures ranging from 37 to 50°C and negligible at 55°C.
