Free fatty acid content of Manchego-type cheese salted by brine vacuum impregnation

A new salting method based on the brine vacuum impregnation of porous products was tested in Manchego-type cheese in order to assess its effect on cheese lipolysis during ripening. This new salting method would allow a faster salt diffusion and a more homogeneous initial salt distribution, and would reduce the disposal of brine. Salt-in-moisture content was evaluated in three different cheese zones during a 90-day ripening period in order to monitor salt penetration in the cheese. Lipolysis was evaluated by means of gas chromatography of individual free fatty acids in the medium and internal zones of both cheeses salted by the conventional and the new salting procedures. Free fatty acid concentration regularly increased during ripening. Short-chain free fatty acid content was higher in the internal zone of conventionally salted cheeses than in the internal and medium zones of vacuum impregnated cheeses from the first month after manufacturing, probably due to the low initial salt concentration achieved in the inner zone of conventionally salted cheeses, which can enhance both bacterial and indigenous lipase activity. Panelists considered that conventionally salted cheeses presented a more intense aroma than vacuum impregnated cheeses, though no differences in global flavor intensity were observed.     

Effect of some technological parameters on microbiological, chemical and sensory qualities of Civil cheese during ripening

The objective of this research was to determine the effects of different ripening methods [brine salting, dry salting, incorporating with Lor cheese (LR) and vacuum packaging] of Civil cheeses on its microbiological, chemical and sensory properties. Civil cheeses were analysed on the 2nd, 30th, 60th and 90th day of ripening. Chemical compositions of the cheeses were significantly different. While the highest dry matter and titratable acidity values were determined on dry salted cheeses, the highest fat and fat in dry matter contents were found in Civil cheese ripened together with LR. The water-soluble nitrogen and ripening index values were lower in cheese ripened incorporating with LR. Excessive proteolysis was not seen in any of cheese samples. The ripening in different methods affected microbiological and sensory properties of Civil cheese. Panellists preferred vacuum packaging and dry-salting cheeses compared to the other samples on the 90th day of ripening.     

Effect of natamycin-containing coating on the evolution of biochemical and microbiological parameters during the ripening and storage of ovine hard-Gruyère-type cheese

The effect of a coating containing natamycin on the ripening course of the hard-Gruyère-type cheese Graviera Kritis was assessed. A single treatment at an early stage of ripening was carried out; samples from natamycin-treated (NT) and control cheeses (CTR) were then taken throughout a 12 month ripening and storage period. Coating gave a statistically significant reduction in the yeasts and moulds counts in the cheese rind. It did not influence the counts and the evolution of the thermophilic bacteria related to starter or of the propionic acid bacteria, nor did it affect the associated aminopeptidase activities. Gross composition of NT cheeses did not differ significantly from that of the control cheeses; the same was also true for proteolysis. Natamycin in the cheese rind after the removal of coating was lower than 0.1 mg dm⁻² at all stages of ripening and no migration to the cheese interior was observed.     

Proteolysis in reduced sodium Feta cheese made by partial substitution of NaCl by KCl

Feta cheeses (five trials) of different sodium content were made, using ewes’ milk, from split lots of curd by varying the salting procedure, i.e. dry salting with NaCl (control) or mixtures of NaCl/KCl (3:1 or 1:1, w/w basis) and filling the cans with brine made with NaCl or the above NaCl/KCl mixtures, respectively, in order to study the influence of the partial substitution of NaCl by KCl on the proteolysis during cheese ripening. The extent and characteristics of proteolysis in the cheeses were monitored during aging by using Kjeldahl determination of soluble nitrogen fractions (water-soluble nitrogen, trichloroacetic acid-soluble nitrogen, phosphotungstic acid-soluble nitrogen), the cadmium–ninhydrin method for the determination of total free amino acids (FAA), urea–polyacrylamide gel electrophoresis of cheese proteins followed by densitometric analysis of the α_s1- and β-casein fractions, reverse-phase HPLC analysis of the water-soluble extracts of cheeses, and ion-exchange HPLC analysis of FAA. The results showed that proteolysis was similar in control and experimental cheeses at all sampling ages, indicating that the partial substitution of NaCl by KCl in the manufacture of Feta cheese had no significant effect on the extent and characteristics of proteolysis during cheese aging.     

Kinetics of Proteolysis of β-Casein During Ripening of Fynbo Cheese Salted with NaCl or NaCl/KCl and Ripened at Different Temperatures

ABSTRACT: The proteolysis of β-casein during ripening of low-fat Fynbo cheese was studied using 1st-order kinetics to improve the knowledge of the p-casein hydrolysis in Fynbo cheeses salted with NaCl or NaCl/KCl and ripened at different temperatures. Effects of ripening temperature, partial replacement of NaCl by KCl during cheese salting, and total salt concentration were evaluated. Central and external zones from cheeses at 1, 5, 10, 20, 30, 60, and 90 ripening days were analyzed by polyacrylamide gel electrophoresis. No significant differences in the kinetic parameters were observed between cheeses salted with NaCl and those salted with a NaCl/KCl brine. Kinetic constants were significantly affected by region within cheese and ripening temperature. Kinetic constant values were in the range of 0.004/d to 0.018/d, and the activation energy of the reaction was approximately 19 kcal/gmol.     

Kinetics of Casein Degradation during Ripening of Fynbo Cheese Salted with NaCl/KCl Brine

First-order kinetics with respect to the α_s1-casein concentration was used to study casein degradation during low-fat Fynbo cheese ripening. Effects of partial NaCl replacement by KCI during cheese salting were studied by statistical treatment of the casein degradation results. Four zones from cheeses at 1, 5, 10, 20, and 30 ripening days were analyzed by a polyacrylamide gel electrophoresis method. Similar kinetic parameters were obtained for a cheese salted with a NaCl/KCl brine and for a control cheese during ripening. Results were more affected by salt concentration than by salt substitution. KCl did not strongly influence kinetics of Fynbo cheese proteolysis.     

Chemometric analysis of proteolysis during ripening of Ragusano cheese

Chemometric modeling of peptide and free amino acid data was used to study proteolysis in Protected Denomination of Origin Ragusano cheese. Twelve cheeses ripened 3 to 7 mo were selected from local farmers and were analyzed in 4 layers: rind, external, middle, and internal. Proteolysis was significantly affected by cheese layer and age. Significant increases in nitrogen soluble in pH 4.6 acetate buffer and 12% trichloroacetic acid were found from rind to core and throughout ripening. Patterns of proteolysis by urea-PAGE showed that rind-to-core and age-related gradients of moisture and salt contents influenced coagulant and plasmin activities, as reflected in varying rates of hydrolysis of the caseins. Analysis of significant intercorrelations among chemical parameters revealed that moisture, more than salt content, had the largest single influence on rates of proteolysis. Lower levels of 70% ethanol-insoluble peptides coupled to higher levels of 70% ethanol-soluble peptides were found by reversed phase-HPLC in the innermost cheese layers and as the cheeses aged. Non-significant increases of individual free amino acids were found with cheese age and layer. Total free amino acids ranged from 14.3 mg/g (6.2% of total protein) at 3 mo to 22.0 mg/g (8.4% of total protein) after 7 mo. Glutamic acid had the largest concentration in all samples at each time and, jointly with lysine and leucine, accounted for 48% of total free amino acids. Principal components analysis and hierarchical cluster analysis of the data from reversed phase-HPLC chromatograms and free amino acids analysis showed that the peptide profiles were more useful in differentiating Ragusano cheese by age and farm origin than the amino acid data. Combining free amino acid and peptide data resulted in the best partial least squares regression model (R(2) = 0.976; Q(2) = 0.952) predicting cheese age, even though the peptide data alone led to a similarly precise prediction (R(2) = 0.961; Q(2) = 0.923). The most important predictors of age were soluble and insoluble peptides with medium hydrophobicity. The combined peptide data set also resulted in a 100% correct classification by partial least squares discriminant analysis of cheeses according to age and farm origin. Hydrophobic peptides were again discriminatory for distinguishing among sample classes in both cases.     

Effects of salting method and storage time on composition and quality of feta cheese

Feta cheese was manufactured by using five different salting methods (dry salting for one day followed by addition of 6% NaCl brine, dry salting for 1,2 or 3 days followed by addition of 7% NaCl brine and dry salting for 3 days followed by addition of 8% NaCl brine). The effects of salting method and storage time on the composition, physicochemical, organoleptic and rheological properties of feta cheese were studied. It was found that moisture was not affected by salting method or storage time. The salting method but not the storage time had a significant effect on salt content. As the salt content of cheeses increased or the storage time was prolonged the moisture decreased. pH and cheese yield were not influenced by salting method but did decrease with storage time. Protein content was not affected by salting method or storage time, whereas fat content was affected by both factors. Proteolysis, lipolysis, organoleptic and rheological properties of cheeses were not influenced by the salting methods applied. On the other hand, storage time had a significant effect on proteolysis, lipolysis, cheese appearance, fracturability and percentage compression at the yield point. Dry salting of cheese for one day and preservation in 7% NaCl brine was considered as the most appropriate salting method for practical application.     

Effect of chymosin and salt reduction on the quality of ultrafiltrated white-salted cheese

This study demonstrated that both chymosin and salt-in-moisture (SM) were important factors for proteolysis in the manufacture of ultrafiltrated white-salted cheese, with significant effects on water-soluble nitrogen and nitrogen soluble in trichloroacetic acid. In contrast, the levels of free amino acids were not significantly affected by chymosin and salt treatments. The cheeses made, using high levels of chymosin with low SM had lower levels of residual alpha(S1)- and beta-casein at the end of ripening. On texture profile analysis, the hardness and fracturability of the cheeses significantly increased with SM and decreased during ripening. Increases in chymosin significantly contributed to the overall weakening of the structure throughout ripening. Bitter flavour was detected after 12 weeks in the cheese made with the higher chymosin level and lower SM, which could be the result of accumulation of gamma-casein fractions. The sensory data indicated that the hedonic responses for low chymosin with low SM cheeses were good and acceptable in flavour, which may be due to the moderate levels of proteolysis products.     

Probiotic white cheese with Lactobacillus acidophilus

The objective of the present study was to determine the effects of Lactobacillus acidophilus on the sensory attributes, ripening time, and composition of Turkish white cheese and to investigate the survival of L. acidophilus during ripening of the cheese stored in vacuum or in brine. Two types of white cheeses, traditional cheese (control, made with Lactococcus lactis ssp. lactis and Lactococcus lactis ssp. cremoris) and probiotic cheese (made with Lactococcus lactis ssp. lactis, Lactococcus lactis ssp. cremoris and L. acidophilus 593 N), were produced and ripened in vacuum pack or in brine at 4°C for 90 days. Cheese samples were assessed for microbiological and compositional properties, proteolysis, and sensory evaluation at different ripening stages. On ripening in vacuum pack, L. acidophilus survived to numbers >10⁷ cfu g⁻¹, which is necessary for positive effects on health. Protein, dry matter, salt content, and percentage of lactic acid in the vacuum-packed and brine-salted probiotic cheeses were significantly different. Also, the lactic acid content of probiotic cheeses was slightly higher than that of the controls for both vacuum- and brine-packed cheeses. Vacuum-packed probiotic cheese had the highest levels of proteolysis and the highest sensory scores of all cheeses. Consequently, L. acidophilus could be used for the manufacturing of probiotic white cheese to shorten ripening time and vacuum packaging is the preferred storage format.     

Physicochemical differences between Croatian cheese matured in a lamb skin sack (Sir iz misine) and cheese matured in a rind throughout ripening

The aim of this study was to research differences in physicochemical parameters between Croatian cheese in a lamb skin sack (Sir iz misine) and cheese in a rind throughout ripening. Cheese in a sack had significantly (P < 0.05) lower content of total solids, fat, proteins and salt which showed the ‘protective’ effect of skin sack and higher permeability of natural rind. The water‐soluble nitrogen in the total nitrogen (%TN) and 12% trichloroacetic acid‐soluble nitrogen (%TN) at the end of ripening was significantly (P < 0.05) higher in cheese in a sack than in cheese in a rind which indicates intensive proteolysis in cheese in a sack.     

The effect of fat content on the microbiology and proteolysis in cheddar cheese during ripening dairy foods

We investigated the effect of incremental reduction in fat content, in the range 33 to 6% (wt/wt), on changes in the microbiology and proteolysis of Cheddar cheese, over a 225-d ripening period at 7 degrees C. A reduction of fat content resulted in significant increases in contents of moisture and protein and a decrease in the concentration of moisture in nonfat substance. Reduced fat had little effect on the age-related changes in the population of starter cells. The populations of nonstarter lactic acid bacteria decreased with fat content, and counts in the low fat cheese (6% wt/wt) were significantly lower than those in the full fat cheese (33% wt/wt) at ripening times >1 and <180 d. Proteolysis as measured by the percentage of total N soluble at pH 4.6 or in 70% ethanol decreased significantly as the fat content decreased. However, the content of pH 4.6 soluble N per 100 g of cheese was not significantly influenced by fat content. At ripening times >60 d, the content of 70% ethanol soluble N per 100 g of full fat (33% wt/wt) cheese was significantly lower than that in either the half fat (17% wt/wt) or low fat (6% wt/wt) cheeses. The concentration of AA N, as a percentage of total N, was not significantly affected by fat content. However, when expressed as a percentage of total cheese, amino acid N increased significantly with decreasing fat content. Analysis of pH 4.6 soluble N extracts by reverse phase- and gel permeation HPLC revealed that fat content affected the pattern of proteolysis, as reflected by the differences in peptide profiles.     

Proteolysis and microstructure of Piacentinu Ennese cheese made using different farm technologies

The aim of this study was to provide the biochemical and structural characterization of Piacentinu Ennese cheese and to evaluate the impact of different farm technologies on cheese proteolysis and microstructure. Fifteen cheeses were manufactured according to traditional technology, i.e., from raw milk and farmhouse rennet in the absence of starter culture. Pasteurized milk, commercial rennet, and starter were used for production of 20 nontraditional cheeses. Proteolysis in Piacentinu Ennese cheese was monitored during a 2- to 10-mo ripening time. Low rates of overall proteolysis were observed in cheese, as percentages of total N soluble at pH 4.6 and in 12% trichloroacetic acid were about 11.40 and 8.10%, respectively, after 10 mo of age. Patterns of primary proteolysis by urea-PAGE showed that alpha(s)-caseins were degraded to a larger extent than were beta-caseins, although a considerable amount of both caseins was still intact after 10 mo. Reversed phase-HPLC analysis of the cheese peptide fractions showed a slow decrease in the levels of hydrophobic peptides coupled to increasing levels of hydrophilic compounds as the cheese aged. The structural characteristics of Piacentinu Ennese cheese were evaluated by scanning electron microscopy after 2, 4, and 6 mo of age. The micrographs showed a sponge-like structural network with a well-distributed system of empty spaces, originally occupied by whey and fat. The microstructure changed during cheese ripening to become more compact with cavities of smaller size. Farm technology significantly affected cheese proteolysis and microstructure. Nontraditional cheeses had higher levels of pH 4.6-soluble N and showed a larger hydrolysis of alpha(s)-casein fractions by urea-PAGE analysis than did traditional cheeses. Large differences between cheese-types also concerned the patterns of secondary proteolysis. Nontraditional cheeses had higher levels of 12% trichloroacetic acid-soluble N and showed larger proportions of free amino acids and hydrophilic peptides in the HPLC profiles of the corresponding 70% ethanol-soluble N fraction than traditional cheeses. Nontraditional cheeses also had a more open structure with a coarser and less continuous appearance than did traditional cheeses. A large amount of variability in cheese proteolysis and structure within nontraditional treatment reflected farm-dependent changes in manufacturing conditions related to the use of various types of rennet and starter.     

Influence of process temperature and salting methods on starter and NSLAB growth and enzymatic activity during the ripening of cheeses produced with Streptococcus thermophilus and Lactobacillus helveticus

The effect of varying cook temperature (40 or 50 °C) and salting method (dry or brine salting) on bacterial viability, enzymatic activity and chemical composition in cheeses made using Streptococcus thermophilus and Lactobacillus helveticus were investigated. Dry salting resulted in decreased cell viability of L. helveticus, increased lactate dehydrogenase activity and increased free amino acid levels, compared with brine salted cheeses, irrespective of cook temperature. A cook temperature of 50 °C resulted in reduced primary proteolysis and increased pH in comparison with that in cheeses cooked to 40 °C. Salting method influenced moisture content with higher levels in brine salted cheeses; cook temperature was also influential with higher cook temperature resulting in lower moisture within each salting method. Variations in manufacture procedure can allow for the development of cheese varieties with novel flavour and texture profiles using existing Cheddar or Swiss-style manufacturing facilities.     

The effect of two types of mould inoculants on the microbiological composition,physicochemical properties and protein hydrolysis in two Gorgonzola‐type cheese varieties during ripening

The aim of this paper was to investigate the role of two types of Penicillium roqueforti moulds (type esportazione and dolce) in the ripening of two Gorgonzola‐type cheese varieties. Cheeses were analysed after 4, 14, 30 and 60 days of ripening. Microbiological analysis showed high numbers of total bacterial count, yeasts and moulds in both 60‐day‐old cheese varieties. The concentration of water‐soluble N, nonprotein N and 5% phosphotungstic acid‐soluble N increased significantly during ripening. Patterns of proteolysis by urea‐polyacrylamide gel electrophoresis showed that rind‐to‐core gradients and age‐related changes in moisture and salt content influenced mould and other enzyme activities, which are reflected in various rates of protein degradation. The hydrolysis of αs₁‐ and β‐caseins was more extensive in the core than under the rind of both cheese varieties.     

The effect of ripening and cooking temperatures on proteolysis and lipolysis in Manchego cheese

The influence of ripening temperature on proteolysis and lipolysis was studied on four lots of raw ewe's milk Manchego cheese held for 60 days at 5, 10, 15 or 20°C. Mean levels of pH 4·6, trichloroacetic acid and phosphotungstic acid soluble N in 20°C cheeses were 52%, 78% and 95% higher than the respective levels in 5°C cheeses at the end of the ripening period. Free fatty acids content after 60 days was 90% higher in 20°C cheeses than in 5°C cheeses. Significant effects of the cooking temperature of the curd (30, 36, 38 or 40°C) on pH, moisture and NaCl content were recorded, but levels of nitrogenous fractions or free fatty acids in 60-day cheeses were not affected.     

Ectoine as a natural component of food: detection in red smear cheeses

Ectoine is a compatible solute accumulated in halophilic bacteria in response to high salt concentrations and offers protection from osmotic stress. The occurrence of compatible solutes is widespread among bacteria, yet ectoine has never been detected in foods. The use of an ectoine producing microorganism (Brevibacterium linens) in the surface ripening of red smear cheeses led to the question whether ectoine can be found in cheese. Therefore we examined samples from a variety of cheese manufacturers and different types of red smear cheeses for the presence of ectoine using HPLC and HPLC/MS analysis. Ectoine solely appears in the rind and was detected up to 178 mg/200 g red smear cheese, depending on several factors like ripening status and conditions throughout the cheese production process (e.g. salt concentrations of used brine baths).     

Utilization of interesterified fat in the production of Turkish white cheese

The chemical, physicochemical, proteolysis, sensory, and texture characteristics of white cheeses made from interesterified fat were examined throughout ripening for 90 days. The water-soluble nitrogen based ripening indexes of cheeses increased throughout the ripening period. However, there were not large quantitative differences between the peptide profiles of the all cheese samples. Cheeses produced by using fully interesterified fat had higher values for hardness, chewiness, and gumminess than that of control cheese (p<0.05). The polyunsaturated to saturated fatty acid ratios of cheeses were increased due to the presence of interesterified fat. The cholesterol values of cheeses decreased at the rate of between 58.83–89.04% depending on interesterified fat addition. In the sensory analysis, similar scores were obtained for both the control cheese and the other cheeses. The results showed that interesterified fat in cheese production could be used to fully or partially replace the milk fat in cheese.     

Effect of commercial adjunct lactobacilli on biochemical and sensory characteristics of Iranian white-brined cheese

Iranian white-brined cheese was made in open vats using commercial adjunct culture of Lactobacillus helveticus Lh.Bo2 in viable and freeze-shocked (FS) forms. Biochemical and sensory characteristics of the trial cheese were studied during 2 months of ripening. Assessment of primary proteolysis by SDS-PAGE and water soluble nitrogen for the trial cheese showed no or small differences throughout ripening. However, the experimental cheeses exhibited significantly greater rates of free amino group formation. Lipolysis as measured by total free fatty acid was consistently higher in cheese made with the FS adjunct culture. Expert panellists detected significant differences between the control and the experimental cheese.