Emmanuel M. Anifantakis

Evolution of microbial populations during traditional Feta cheese manufacture and ripening.

In three different dairies (A, B and C) located in Peloponess region (Southern Greece), traditional Feta cheese trials took place February to March using mixtures of sheeps and goats milk. Only small variations in the evolution of microbial groups were observed during the whole ripening period. The main groups, such as thermophilic cocci, mesophilic lactococci, thermophilic lactobacilli, nonstarter lactic acid bacteria (NSLAB), presumptive Leuconostoc, enterococci and micrococci, reached their highest levels during the first 16 days, and then declined approximately 1-2 log units until the end of ripening. The remaining groups investigated, comprising yeasts, coliforms and Escherichia coli, were highest at day 4. The yeasts remained constant, while coliforms and E. coli decreased sharply and were not detectable after 120 days of ripening. A number of 146 isolates (dairy A) taken from all stages of the manufacturing and ripening process were purified and studied. Lactobacillus plantarum (58/146) and isolates of related species Lactobacillus pentosus and Lactobacillus paraplantarum (16/146) were the most common microorganisms found during cheese ripening. Streptococcus thermophilus (23/146) and Lactobacillus delbrueckii subsp. bulgaricus (20/146) were detected in high levels up to 20 days, and then gradually reduced. Enterococcus faecium (29/146) was found in all manufacturing and ripening stages.

Suitability of some microbial coagulants for Feta cheese manufacture

Etude comparative de succedanes de presure obtenus a partir de Mucar pusillus, M. miehei et Endothia parasitica avec la presure de veau

Effect of draining temperature on the biochemical characteristics of Feta cheese

Two different draining temperatures, 15 and 21°C were applied to five Feta cheese curds made with different starters, containing mesophilic or thermophilic strains or mixtures of them. After 20 h of draining, the pH of curds made with thermophilic starters ranged from 5.28 to 5.49. The draining temperature significantly affected (P<0.05) the pH and the total solids of the cheeses. The inclusion of whey proteins in the cheese curd due to the insufficient draining of cheeses at 15°C, resulted in higher water-soluble nitrogen (WSN), as % of total nitrogen content. Free amino acid contents were significantly affected (P<0.05) by the draining temperature and by the presence of thermophilic lactobacilli in the starter mixture. Draining temperature also significantly affected (P<0.05) residual αs- and β-casein and the RP-HPLC profiles of the WSN. The C2:0 to C8:0 free fatty acids, hardness (kg) and fracturability (kg), as well as the total organoleptic scores, were significantly (P<0.05) higher in feta drained at 21°C.

Nitrogenous fractions during the manufacture of whey protein concentrates from Feta cheese whey

Abstract Samples taken from different manufacturing stages of Feta cheese whey protein concentrates (WPCs), with 65 and 35% total protein content, were analyzed by chemical methods and by reversed-phase HPLC and by size-exclusion chromatography. Mean total protein content of Feta cheese whey was 1.37%. 22% of total nitrogen (TN) was non-protein N (NPN) and 12% was proteose–peptone N (PPN). The mean native N (NN), NPN and PPN percentages of WPC 65 and 35%, were 63 and 71%, 10 and 14%, 0.08 and 0.08%, respectively. According to reversed-phase HPLC data, the percentages of β -Lg and α -La and their ratio were high; 56.5 and 59% of native proteins of whey and of WPC powders, respectively, were β -Lg. The respective α -La percentages were 13.1 and 14.1% and the respective caseino-macropeptide (CMP) percentages were 12.9 and 15.3%. Apart from ultrafiltration, the most critical stage for nitrogenous fraction composition was the evaporation process before spray drying.

Detection of caprine casein in ovine Halloumi cheese

Abstract Halloumi cheeses were made from different mixtures of ovine and caprine milk, and in some cases from bovine milk also. The casein fractions of the cheese were analyzed for para-κ-casein using cation-exchange high performance liquid chromatography for para-κ-casein. The detection of caprine casein in cheese was based on the retention times and on the peak areas of caprine and ovine para-κ-caseins. Bovine para-κ-casein in Halloumi cheese could not be detected. The detection limit of caprine milk in the total of ovine and caprine cheese milk was 5%, w/w. The estimated percentages of caprine para-κ-casein detected in the cheese were lower than the corresponding percentages of caprine milk in the cheese milk. However, the levels of caprine para-κ-casein in the cheese were significantly correlated with the level of caprine milk in the ovine-caprine milk mixture used for cheese manufacture.

Preparation and properties of rennets from lamb's and kid's abomasa

Lamb and kid rennets were prepared by extraction of dried abomasa with 6% (w/v) NaCl-2% (w/v) H 3 BO 3 and activation of the proenzymes at pH 2·0. Each gave one zone of precipitation on casein-agar gel diffusion, enabling them to be differentiated from calf rennet and pig pepsin. After agarose gel electrophoresis, the proteinase activity of lamb rennet occurred in chymosin and pepsin bands only, whereas kid rennet contained an additional proteinase of intermediate mobility. Relative to their milk-clotting activities, lamb and kid rennets contained less pepsin and were less proteolytic on both haemoglobin at pH 1·8 and casein at pH 5·3 than calf rennet. The milk-clotting activities of lamb and kid rennets increased less with decrease in pH and were more stable to storage at both the pH value of maximum stability and lower pH values than that of calf rennet. Neither cathepsin activity nor lipolytic activity on milk fat was detected in any of the 3 rennets, but lamb rennet caused slight hydrolysis of tributyrin.

Ripening changes in Kopanisti cheese.

Changes in a Greek traditional soft cheese, Kopanisti, were followed during ripening. The a s -casein content was hydrolysed faster than the β-casein so that in mature cheese only 23% and 35% respectively of these proteins remained intact. Leucine, γ-aminobutyric acid, valine and alanine were the dominant free amino acids in the mature cheese. Lipolysis was intense. The characteristic rich flavour and peppery taste appeared after 16 d ripening and the best overall cheese quality was produced after 32 d maturation