The influence of ripening temperature and sampling site on the lipolysis in Reggianito Argentino cheese

The effect of ripening temperature elevation and sampling site on lipolysis in Reggianito Argentino cheese was evaluated. Cheeses ripened at 12 or 18 °C and 85% relative humidity were assayed at 2, 4 and 6 months at two sampling zones (central and external). Samples were analysed to determine physicochemical parameters and the concentration of nine free fatty acids (FFAs) (C_6:0–C_18:2). Myristic, palmitic, stearic and oleic acids were found in higher concentration. While ripening time and temperature significantly affected the concentrations of the nine FFAs analysed, sampling zone significantly affected only two FFAs. Ripening temperature increased the lipolytic process, but it seems to have no effect on the pathways of lipolysis in Reggianito Argentino cheese.     

The influence of ripening temperature and sampling site on the proteolysis in Reggianito Argentino cheese

The effects of elevated ripening temperature and sampling site on proteolysis in Reggianito Argentino cheese were evaluated. Cheeses ripened at 12 or 18 °C and 85% relative humidity were analysed at 2, 4 and 6 months in 2 sampling zones (central and external). Samples were analysed to determine the physicochemical and proteolysis parameters through the urea-PAGE of the urea-soluble fraction, RP-HPLC analysis of the water-soluble fraction at pH 4.6, and the free amino acid analysis. Proteolysis was significantly affected by ripening temperature and sampling site. Urea-PAGE analysis showed that elevated temperature increased the degradation of α_s1- and β-casein. The degradation of α_s1-casein was larger in the central zone than in the external one, while β-casein degradation was similar in both zones. The majority peaks detected by RP-HPLC of the water-soluble fraction at pH 4.6 and free amino acids were significantly affected by ripening temperature and sampling site. Glu, His, Val, Leu, and Lys had the higher concentrations. Principal component analysis showed useful groupings when results from chromatograms were studied. In conclusion, the results obtained not only are useful to characterise the ripening of an Argentinean hard cheese, but also to evaluate the effect of an increase of ripening temperature on Reggianito Argentino cheese proteolysis.     

Accelerated ripening of Cheddar cheese at elevated temperatures

Blocks (20 kg) of Cheddar cheese from a single vat were obtained from a local factory. Half the cheeses were cooled rapidly (15 h) to ripening temperature (8, 12 or 16 °C) and half were cooled slowly over 8 days to the same ripening temperatures. Cheeses were ripened for 9 months at 7 different time/temperature combinations. Ripening temperature had little influence on the number of non-starter lactic acid bacteria in the cheeses after 9 months, although rapid cooling to and ripening at 8 °C drastically reduced the growth rate of these adventitious bacteria. Proteolysis (as determined by urea-polyacrylamide gel electrophoresis; increases in water-soluble N; increases in phosphotungstic acid-soluble N; Cd ninhydrin-reactive amino groups; and reverse-phase HPLC) and lipolysis were accelerated by increasing the ripening temperature and by slow cooling of the cheeses. The rate of ripening was increased or decreased by changing the temperature. Cheeses ripened at 16 °C generally received the highest flavour scores, particularly early during ripening. However, the texture of these cheeses deteriorated after prolonged ripening at 16 °C. Maturation at 12 °C was considered to be optimal for the commercial acceleration of Cheddar cheese ripening.     

Evolution of lipolysis during the ripening of traditional Feta cheese

Lipolysis was studied during ripening of traditional Feta cheese produced in two small dairies, A and B. The cheeses were made from a thermized mixture of ewes’/goats’ milk by using yoghurt as starter and artisanal rennet from lambs’ and kids’ abomasa (cheese A) or mixed artisanal rennet with calf rennet (cheese B).The acid degree value and the free fatty acids (FFA) contents in both cheeses increased sharply up to 18 d (pre-ripening period at 15 °C) and continued to increase throughout ripening. In both mature cheeses, acetic acid was found at high levels (13–18% of the total FFAs). However, except for this, all FFA contents differed significantly (P < 0.05) between the two cheeses throughout ripening. The levels of individual and total C2:0–C8:0, C10:0–C14:0 and C16:0–C18:2 fatty acids were significantly higher (P < 0.05) in cheese A than in cheese B. Presumably the difference, especially in the C2:0–C8:0 content, was due mainly to the type of the rennet used. Butyric acid was the dominant FFA in cheese A (20% of the total FFAs at 120 d), while the most abundant FFAs in cheese B were capric (18%) and lauric acid (18%). In general, the lipolysis degree of the two cheeses was higher than those reported for the industrially-made Feta cheese.In organoleptic evaluation, cheese A had a piquant taste that was attributed to its high content of butyric acid and showed a significantly (P < 0.05) higher total score than cheese B.     

Substitution of natural whey starter by mixed strains of Lactobacillus helveticus in the production of Reggianito Argentino cheese

Reggianito Argentino cheeses were manufactured with mixed strains of Lactobacillus helveticus cultured in free viable bacteria whey. As controls, cheeses with natural whey starter were made. Gross composition of cheeses did not differ significantly. The number of total termophilic lactic acid bacteria at the end of ripening was near 10⁷ CFU/g, but when the strain Lh 209 was present in the mixture, this number was 10⁶ CFU/g. Soluble nitrogen at pH 4.6 did not differ between control and experimental cheeses, but soluble nitrogen in tricloroacetic acid 12% and phosphotungstic acid 2.5% showed significant differences at the end of ripening, being higher the values when the strain Lh 209 was present in the mixture. Electrophoretic profiles for control and experimental cheeses were very similar at 0, 90 and 180 days of ripening. An increase in the acid degree value of fat during ripening was noticeable indicating a lipolytic activity in the cheese matrix that was similar for the different strains mixtures. Results from sensory analysis did not show differences among the cheeses of these tests. Despite some differences in the production tricloroacetic and phosphotungstic acid soluble nitrogen were observed for mixtures in which Lh 209 was present, all cheeses were good quality Reggianito Argentino cheeses. These results open and interesting prospective for the use of selected strains culture in whey in substitution of natural whey.     

Effects of different ripening procedures on the final characteristics of Picante cheese

 Picante da Beira Baixa (or Picante) cheese is a hard, piquant, salted traditional cheese manufactured in Portugal from raw sheep's and goat's milks. The purpose of this work was to quantitatively assess the influence of various ripening procedures on the final characteristics of Picante cheese. Two alternative ripening protocols were considered, the traditional one and another with controlled environmental conditions via use of maturation chambers set at different preselected temperatures. The experimental cheeses were characterised in terms of microbiological, physicochemical, biochemical, sensorial and textural properties. Ripening time and temperature were statistically significant parameters for all microflora. The two ripening methods led to statistically significant differences in all physicochemical and biochemical parameters, especially the moisture content and the soluble nitrogen fractions (i.e. water loss was slower and proteolysis was faster in cheeses ripened via the traditional method). Differences in microbiological, physicochemical and biochemical properties were probables implicated in differences in textural and sensorial properties, especially cheese hardness and flavour. It was concluded that the standard ripening method was closest to the traditional one in terms of final cheese characteristics when the ripening temperature was above 11.5  °C. Received: 3 February 1998     

β-Galactosidase in the acceleration of Ras cheese ripening

An attempt has been carried out to accelerate Ras cheese ripening by pre-treatment of cheese milk with β-galactosidase. Milk was treated with a β-galactosidase enzyme preparation, namely lactozym (1 ml/kg milk), at 33°C for 1 h or at 4°C for 18 h and used for Ras cheese making. Flavour intensity, formation of soluble nitrogen compounds, free amino acids and liberation of free fatty acids were enhanced in cheese made from β-galactosidase treated milk. In addition, the ripening period was reduced to 2 months compared with 4 months required for control cheese. Treatment of cheese milk with β-galactosidase at 4°C or 33°C showed a similar effect on the properties of cheese.     

The effect of elevated temperature on ripening of Dutch type cheese

The aim of this study was to explore the effect of elevated temperature (16 °C) on ripening of Dutch-type cheese. Three slices of each cheese block were further divided into three layers. The processes in the control samples of cheese ripening at 10 °C were also monitored. The contents of free amino acids in accelerated cheese were two times higher than were those in control samples. The highest contents of free amino acids were observed in the cores of all slices of cheeses ripening at both temperatures. The contents of tyramine, in layers of the studied slices, reached almost 500 mg kg⁻¹ during 56 days of the experiment. The contents of biogenic amines in the edges grew even higher. Accelerated cheese showed faster equalisation of hardness than did control samples. The increase of temperature by 6 °C can reduce the ripening time in cellars by approximately one half.     

Microbiological,compositional, biochemical and textural characterisation of Caciocavallo Pugliese cheese during ripening

A microbiological, compositional, biochemical and textural characterisation of the pasta filata Caciocavallo Pugliese cheese during ripening is reported. Fully ripened cheese contained a total of ca. log 8.0 cfu g⁻¹ mesophilic bacteria and ca. log 6.0 cfu g⁻¹ presumptive staphylococci, while the number of thermophilic and mesophilic rod and coccus lactic acid bacteria varied during ripening. A two-step RAPD-PCR protocol was used to differentiate biotypes. The natural whey starter was composed mainly of Lactobacillus delbrueckii, Lb. fermentum, Lb. gasseri, Lb. helveticus and Streptococcus thermophilus strains. After day 1 of ripening, Lb. delbrueckii became dominant and some strains of Enterococcus durans and E. faecalis appeared. Non-starter lactic acid bacteria, such as Lb. parabuchneri and Lb. paracasei subsp. paracasei formed a large part of the lactic microflora at 42 and 60 d of ripening. The level of pH 4.6-soluble nitrogen increased from the outer to the inner of the cheese and also increased in each section as ripening progressed, attaining values of 18–15%. Urea-PAGE electrophoresis showed that degradation of α_s1-casein was more rapid than that of β-casein throughout ripening and the rates at which both caseins were degraded greatly increased from the outside to the inside of the cheese. Based on the primary proteolysis products, both chymosin and plasmin appeared to be active. RP-HPLC profiles of the 70% ethanol-soluble, pH 4.6-soluble nitrogen, showed a large number of peaks, indicating a heterogeneous mixture of proteolytic products. There were both age- and section-related changes in the area of the different peptide peaks. Butyric (C4:0), caproic (C6:0), palmitic (C16:0) and oleic (C18:1) acids were the free fatty acids found at the highest concentrations. The level of short chain fatty acids (e.g., butyric and caproic) decreased from the middle and inner to outer sections of the cheese. Peptidase activity in the curd was pronounced, increased during ripening and varied with the cheese section. The greatest increase of the peptidase activity coincided with a change in the lactic microflora and with the prevalence of non-starter lactic acid bacteria. Microbial esterases were supposed to be active together with rennet paste. Little change in the firmness and fractures stress during maturation were found by textural analyses of the raw cheese. The flowability was similar to that of typical low-moisture Mozzarella cheese, while stretchability was lower. The heat-induced changes in phase angle of Caciocavallo Pugliese cheese indicated a phase transition from largely elastic rheological characteristics in unheated cheese to a more viscous and fluid character in melted cheese.     

Effects of the freezing process on proteolysis during the ripening of Port Salut Argentino cheeses

The effect of freezing at −30 °C, frozen storage at −22 °C for 30 days and thawing at 5 °C on proteolysis during ripening of Port Salut Argentino cheese was studied. Cheeses were sampled at different ripening times (1, 6, 13, 27 and 56 days) and two sampling zones (central and external). Moisture content, salt concentration and RP-HPLC of the nitrogenous fractions (water-insoluble fraction, water-soluble fraction and free amino acids in the sulfosalicylic acid-soluble fraction) were analysed. The freezing process did not affect moisture and salt contents at the beginning of the ripening period nor moisture and salt redistribution during the ripening period studied. However, the freezing process affected proteolysis during ripening of Port Salut Argentino cheeses that had been frozen prior to ripening. There was increased breakdown of α_s1-casein and α_s1-I-casein, and increased breakdown of peptides of the water-soluble fraction (including α_s1-CN (f1-23)) along with an early development of free amino acids.     

Changes in the composition and sensory properties of Croatian cheese in a lamb skin sack (Sir iz mišine) during ripening

Croatian traditional cheese, which ripens in a lamb skin sack, was studied to determine compositional, biochemical and sensory changes over 60 days of ripening. The ripening time had a significant effect on the chemical, biochemical and sensory parameters, particularly on the medium‐ and long‐chain free fatty acids (P < 0.05) and total FFAs (P < 0.001). At the end of ripening palmitic, oleic and stearic acids were the predominant FFAs. Cheese ripened for more than 45 days was less acceptable to consumers as a consequence of extensive proteolysis and lipolysis. Therefore, ripening for more than 45 days, which is commonly practised by cheesemakers, is not recommended.     

Free fatty acid profiles of Reggianito Argentino cheese produced with different starters

Reggianito Argentino cheeses were made at pilot plant scale using a natural whey starter (control) and different combinations of strains of selected Lactobacillus helveticus (experimental cheeses). Free fatty acids (FFAs) were extracted from cheese samples at different ripening times, and FFAs from C_6:0 to C_18:2 were analysed by gas chromatography. The characteristics of the chromatographic profiles were studied by principal components and linear discriminant analysis were performed. Levels of individual FFAs from caproic (C_6:0) to linoleic (C_18:2) acids increased significantly $(p<0.05)$ during ripening in control and experimental cheeses. Palmitic (C_16:0) and oleic (C_18:1) acids were the most abundant FFAs throughout ripening in all cheeses. No significant differences were found between FFA profiles of control and experimental cheeses. The possibility of using selected strains of Lactobacillus to replace traditional “natural whey starter” in the production of the cheese is discussed.     

Effects of different ripening procedures on the final characteristics of Picante cheese

 Picante da Beira Baixa (or Picante) cheese is a hard, piquant, salted traditional cheese manufactured in Portugal from raw sheep's and goat's milks. The purpose of this work was to quantitatively assess the influence of various ripening procedures on the final characteristics of Picante cheese. Two alternative ripening protocols were considered, the traditional one and another with controlled environmental conditions via use of maturation chambers set at different preselected temperatures. The experimental cheeses were characterised in terms of microbiological, physicochemical, biochemical, sensorial and textural properties. Ripening time and temperature were statistically significant parameters for all microflora. The two ripening methods led to statistically significant differences in all physicochemical and biochemical parameters, especially the moisture content and the soluble nitrogen fractions (i.e. water loss was slower and proteolysis was faster in cheeses ripened via the traditional method). Differences in microbiological, physicochemical and biochemical properties were probables implicated in differences in textural and sensorial properties, especially cheese hardness and flavour. It was concluded that the standard ripening method was closest to the traditional one in terms of final cheese characteristics when the ripening temperature was above 11.5  °C. Received: 3 February 1998     

Study of the chemical composition,proteolysis, lipolysis and volatile compounds profile of commercial Reggianito Argentino cheese: Characterization of Reggianito Argentino cheese

Reggianito is a typical variety of grana-type hard cheese produced in Argentina. It is the most exported and due to its organoleptic characteristics is very appreciated by the consumers. The objective of this study was to characterise the global composition, lipolysis, proteolysis and volatile compound profiles of commercial Reggianito cheeses from different dairy plants.Statistical differences (P ? 0.05) in some physicochemical parameters, nitrogen fractions and FFA levels among commercial brands were detected. The volatile profiles were studied by SPME–GC–MS/FID. A total of 53 compounds were identified, the majority belonging to the groups of ketones, alcohols, acids, esters and aldehydes. All these compounds have been reported in Italian grana-type cheeses. Visualization of the analytical results was performed by principal component analysis. This analysis clustered cheese samples according to dairy plants. This fact could be, among other factors, consequences of differences in technologies and ripening time of different manufacturers.     

Properties of cholesterol‐reduced Camembert cheese made by crosslinked β‐cyclodextrin

The present study was designed to examine the physicochemical and sensory properties in cholesterol‐reduced Camembert cheese made by crosslinked β‐cyclodextrin (β‐CD). The composition of cholesterol‐reduced Camembert cheese was similar to the control and the cholesterol reduction reached 90.6%. No difference was found in the total amount of short‐chain free fatty acids between the cholesterol‐reduced cheese and the control at every ripening period. The release of butyric and capric acid mostly contributed to the increase of total amount of short‐chain free fatty acids in both groups. The cholesterol‐reduced cheese produced similar amounts of individual free amino acids to the control in all periods. The scores of all rheological characteristics except for springiness were continuously increased up to 2 weeks’ ripening and decreased thereafter. Mouldy characteristics in both appearance and flavour were increased dramatically through the ripening period in both cholesterol‐reduced and the control cheeses. Based on these results, no significant difference was found in most physicochemical and sensory properties between cholesterol‐reduced Camembert cheese and the control. Therefore, we may find it possible to develop cholesterol‐reduced Camembert cheese using crosslinked β‐cyclodextrin.     

Evidence of a relationship between autolysis of starter bacteria and lipolysis in cheddar cheese during ripening

Cell viability, autolysis and lipolysis were studied in Cheddar cheese made using Lactococcus lactis subsp. cremoris AM2 or Lactococcus lactis subsp. cremoris HP. Cheddar cheese was made in triplicate over a 3 month period and ripened for 238 days at 8 degrees C. Cell viability in cheese was lower for AM2 (a non-bitter strain) than for strain HP (a bitter strain). Autolysis, monitored by the level of the intracellular marker enzyme, lactate dehydrogenase (EC 1.1.1.27) in cheese 'juice' extracted by hydraulic pressure, was much greater in the cheese made using AM2 than that made with HP. Lipolysis was determined by the increase during ripening of individual free fatty acids (FFA) from butyric (C4:0) to linolenic acid (C18:3) measured using a high performance liquid chromatographic technique. Levels of individual FFA from butyric (C4:0) to linolenic (C18:3) acids increased significantly (P<0.05) during ripening in cheeses made with either starter culture. Palmitic (C16:0) and oleic (C18:1) acids were the most abundant FFA throughout ripening in all cheeses. Levels of caprylic (C8:0), myristic (C14:0), palmitic (C16:0) and stearic (C18:0) acids were significantly higher (P<0.05) in cheeses manufactured with Lc. lactis subsp. cremoris AM2 than in cheeses manufactured with Lc. lactis subsp. cremoris HP. Differences in levels of lipolysis between strains was not due to differences in the specific lipolytic or esterolytic activities in cell free extracts of the strains as measured by activity on triolein (lipase) and p-nitrophenylbutyrate (esterase) substrates. Therefore, evidence is provided for a relationship between the extent of starter cell autolysis and the level of lipolysis during Cheddar cheese ripening.     

Microbiological,chemical, textural and sensory characteristics of Hispánico cheese manufactured using frozen ovine milk curds scalded at different temperatures

Hispánico cheese is a semi-hard variety, manufactured in Spain from a mixture of pasteurized bovine and ovine milk. To study one strategy for overcoming a seasonal shortage of ovine milk in summer and autumn, curds made from ovine milk, scalded at 32, 35 or 38 °C, were pressed for 30 min and frozen at ?24 °C for 4 months. After thawing, they were added to fresh bovine milk curd for the manufacture of experimental Hispánico cheeses. Control cheese was made from a mixture of pasteurized bovine and ovine milk in the same (80:20) proportion. No significant effect of the addition of frozen ovine milk curd or scalding temperature was found for lactic acid bacteria counts, dry matter content, hydrophilic and hydrophobic peptides, 45 out of 65 volatile compounds, texture, and sensory characteristics throughout a 60-day ripening period. Differences between cheeses, of low magnitude and little practical significance, were found for pH value, aminopeptidase activity, proteolysis, free amino acids, free fatty acids, and the remaining 20 volatile compounds. Thus, the addition of frozen ovine milk curd to fresh bovine milk curd does not alter the main physicochemical and sensory characteristics of Hispánico cheese.