Effect of Partial Substitution of NaCl with KCl on Halloumi Cheese during Storage: Chemical Composition,Lactic Bacterial Count,and Organic Acids Production

Abstract: The effect of partial substitution of NaCl with KCl on chemical composition, lactic bacterial count, and organic acids profile of Halloumi cheese was investigated. Halloumi cheeses were made and kept in 4 different brine solutions at 18% including NaCl only (HA), 3NaCl : 1KCl (HB), 1NaCl : 1KCl (HC), and 1NaCl : 3KCl (HD) and then stored at 4 °C for 56 d. No significant effect was observed between control and experimental cheeses in terms of moisture, fat, protein, lactic bacterial count, and pH values at the same storage period. There was a significant difference in ash, sodium, and potassium contents among experimental cheeses at the same storage period. Ash, sodium, and potassium contents increased significantly during storage at same salt treatment. There was no significant difference in lactic and citric acid contents among experimental cheeses and that of the control. In contrary, there was a significant difference in acetic acid among experimental cheeses. A strong positive correlation was observed between ash, Na, and K contents. An inverse correlation between organic acids and both Na and K contents was also observed.     

The effect of sodium chloride substitution with potassium chloride on texture profile and microstructure of Halloumi cheese

The effect of partial substitution of NaCl with KCl on texture profile and microstructure of Halloumi cheese was investigated. Four batches of Halloumi cheese were made and kept in 4 different brine solutions (18%, wt/wt), including A) NaCl only, B) 3NaCl:1KCl, C) 1NaCl:1KCl, and D) 1NaCl:3KCl and then stored at 4°C for 56 d. The texture profile was analyzed using an Instron universal machine, whereas an environmental scanning electron microscope was used to investigate the effect of NaCl substitution on the microstructure of cheeses. No significant difference was found in hardness, cohesiveness, adhesiveness, and gumminess among experimental cheeses at the same storage day. Hardness, cohesiveness, and gumminess decreased significantly during storage period with the same salt treatment, whereas adhesiveness significantly increased. Environmental scanning electron microscope micrographs showed a compact and closed texture for cheeses at the same storage period. The microstructure of all cheeses became more closed and compact with storage period. Calcium content negatively correlated with hardness and Na and K contents during storage with the same salt treatment.     

A comparison of the chemical,microbiological and sensory characteristics of bovine and ovine Halloumi cheese

Commercial samples of fresh and mature Halloumi cheeses made from ovine or bovine milk were studied in order to establish their chemical, microbiological and sensory characteristics. Significant differences were observed between the two types of Halloumi cheese both when fresh and mature. The free volatile fatty acid (FVFA) content of the cheeses increased with maturation from 483 to 1356 mg kg⁻¹ for the ovine product, but lower values (380–1248 mg kg⁻¹) were found in the bovine cheese. During maturation for 40 days, Enterococcus faecium, which dominated the microflora of fresh ovine cheese, was replaced by lactobacilli, including a new species, Lactobacillus cypricasei, which was not found in the bovine samples. Fewer than 100 cfu g⁻¹ lactic acid bacteria (LAB) were present in the fresh bovine cheeses, but a microflora dominated by lactobacilli developed with time. Yeast counts in the mature ovine and bovine cheeses reached 2.3–2.8×10⁵ cfu g⁻¹ and, as some of the yeasts were proteolytic and/or lipolytic, it was assumed that they were having a positive impact of the flavour of the cheeses. The sensory panel distinguished significant differences in texture and flavour between the fresh and mature samples of both ovine and bovine cheeses and, overall, there was a significant preference for the ovine brand.     

Characterization of Fiore Sardo cheese manufactured with the addition of autochthonous cultures

This work evaluated the effect of adjunct autochthonous cultures on the chemical, microbiological and sensory characteristics of Fiore Sardo cheese during ripening. A total of twelve batches of cheeses were manufactured according to the technical Disciplinary of Fiore Sardo cheese, with and without different combinations of autochthonous strains isolated from the native microflora of artisanal Fiore Sardo. There were no significant differences in the cheese compositional parameters between experimental and control cheeses, but the addition of cultures led to a statistically significant decrease in pH values in experimental cheeses. The evolution of total mesophilic bacteria, total coliforms and lactic acid bacteria were significantly influenced by the addition of autochthonous cultures in most of the experimental cheeses. As for sensory characteristics, all the experimental cheeses reported significantly higher scores especially for shape, texture, interior openings, taste and aftertaste. This study demonstrated the beneficial effect of the addition of selected autochthonous cultures in accelerating the disappearance of undesirable flora and improving the typical sensory characteristics of the cheese, and confirmed the importance of ewes' milk as a source of technologically interesting strains that could be used to ensure a higher quality of artisanal cheese productions.     

Effects of chitosan coating containing lysozyme or natamycin on shelf‐life,microbial quality,and sensory properties of Halloumi cheese brined in normal and reduced salt solutions

The effects of chitosan (C) coating with or without lysozyme (L) or natamycin (N) on shelf‐life, microbial quality, and sensory properties of Halloumi cheese held at 3 °C or 25 °C in 5%, 10% or 15% (w/v) NaCl were examined. Coatings increased cheese shelf‐life by ≥ 5 days than the control when brined in 5% and 10% NaCl at 3 °C but did not affect the shelf‐life of cheese in 15% NaCl. Nonetheless, coatings reduced psychrotrophs, anaerobes, lactic acid bacteria, and yeasts and molds by 1.8 to 2.2 log in 15% brined cheese. Reductions of microbial species contaminating Halloumi cheese at 10% and 15% brine were not significantly different with CL and CN coatings throughout storage at 3 °C. Coatings did not adversely affect sensory properties of cheese. Therefore, brine concentration could be reduced to 10% for CL and CN‐coated cheeses.

Practical applications

Results support the possibility of reducing the high salt concentration in brine solution of Halloumi cheese by using a chitosan coating containing lysozyme or natamyc in which provided similar shelf‐life and microbial stability. The coatings did not adversely affect the sensory properties of cheese and can be applied by a simple step during processing which facilitates their use in the food industry.     

Effect of liquid whey protein concentrate–based edible coating enriched with cinnamon carbon dioxide extract on the quality and shelf life of Eastern European curd cheese

Fresh unripened curd cheese has long been a well-known Eastern European artisanal dairy product; however, due to possible cross-contamination from manual production steps, high moisture content (50–60%), and metabolic activity of present lactic acid bacteria, the shelf life of curd cheese is short (10–20 d). Therefore, the aim of this study was to improve the shelf life of Eastern European acid-curd cheese by applying an antimicrobial protein-based (5%, wt/wt) edible coating. The bioactive edible coating was produced from liquid whey protein concentrate (a cheese production byproduct) and fortified with 0.3% (wt/wt, solution basis) Chinese cinnamon bark (Cinnamomum cassia) CO₂ extract. The effect of coating on the cheese was evaluated within package-free (group 1) and additionally vacuum packaged (group 2) conditions to represent types of cheeses sold by small and big scale manufacturers. The cheese samples were examined over 31 d of storage for changes of microbiological (total bacterial count, lactic acid bacteria, yeasts and molds, coliforms, enterobacteria, Staphylococcus spp.), physicochemical (pH, lactic acid, protein, fat, moisture, color change, rheological, and sensory properties). The controlled experiment revealed that in group 1, applied coating affected appearance and color by preserving moisture and decreasing growth of yeasts and molds during prolonged package-free cheese storage. In group 2, coating did not affect moisture, color, or texture, but had a strong antimicrobial effect, decreasing the counts of yeasts and molds by 0.79 to 1.55 log cfu/g during 31 d of storage. In both groups, coating had no effect on pH, lactic acid, protein, and fat contents. Evaluated sensory properties (appearance, odor, taste, texture, and overall acceptability) of all samples were similar, indicating no effect of the coating on the flavor of curd cheese. The edible coating based on liquid whey protein concentrate with the incorporation of cinnamon extract was demonstrated to efficiently extend the shelf life of perishable fresh curd cheese, enhance its functional value, and contribute to a more sustainable production process.     

Probiotic cheese production using Lactobacillus casei cells immobilized on fruit pieces

Lactobacillus casei cells were immobilized on fruit (apple and pear) pieces and the immobilized biocatalysts were used separately as adjuncts in probiotic cheese making. In parallel, cheese with free L. casei cells and cheese only from renneted milk were prepared. The produced cheeses were ripened at 4 to 6°C and the effect of salting and ripening time on lactose, lactic acid, ethanol concentration, pH, and lactic acid bacteria viable counts were investigated. Fat, protein, and moisture contents were in the range of usual levels of commercial cheeses. Reactivation in whey of L. casei cells immobilized on fruit pieces after 7 mo of ripening showed a higher rate of pH decrease and lower final pH value compared with reactivation of samples withdrawn from the remaining mass of the cheese without fruit pieces, from cheese with free L. casei, and rennet cheese. Preliminary sensory evaluation revealed the fruity taste of the cheeses containing immobilized L. casei cells on fruit pieces. Commercial Feta cheese was characterized by a more sour taste, whereas no significant differences concerning cheese flavor were reported by the panel between cheese containing free L. casei and rennet cheese. Salted cheeses scored similar values to commercial Feta cheese, whereas unsalted cheese scores were significantly lower, but still acceptable to the sensory panelists.     

Monitoring the ripening process of Cheddar cheese based on hydrophilic component profiling using gas chromatography-mass spectrometry

We proposed an application methodology that combines metabolic profiling with multiple appropriate multivariate analyses and verified it on the industrial scale of the ripening process of Cheddar cheese to make practical use of hydrophilic low-molecular-weight compound profiling using gas chromatography-mass spectrometry to design optimal conditions and quality monitoring of the cheese ripening process. Principal components analysis provided an overview of the effect of sodium chloride content and kind of lactic acid bacteria starter on the metabolic profile in the ripening process of Cheddar cheese and orthogonal partial least squares-discriminant analysis unveiled the difference in characteristic metabolites. When the sodium chloride contents were different (1.6 and 0.2%) but the same lactic acid bacteria starter was used, the 2 cheeses were classified by orthogonal partial least squares-discriminant analysis from their metabolic profiles, but were not given perfect discrimination. Not much difference existed in the metabolic profile between the 2 cheeses. Compounds including lactose, galactose, lactic acid, 4-aminobutyric acid, and phosphate were identified as contents that differed between the 2 cheeses. On the other hand, in the case of the same salt content of 1.6%, but different kinds of lactic acid bacteria starter, an excellent distinctive discrimination model was obtained, which showed that the difference of lactic acid bacteria starter caused an obvious difference in metabolic profiles. Compounds including lactic acid, lactose, urea, 4-aminobutyric acid, galactose, phosphate, proline, isoleucine, glycine, alanine, lysine, leucine, valine, and pyroglutamic acid were identified as contents that differed between the 2 cheeses. Then, a good sensory prediction model for “rich flavor,” which was defined as “thick and rich, including umami taste and soy sauce-like flavor,” was constructed based on the metabolic profile during ripening using partial least squares regression analysis. The amino acids proline, leucine, valine, isoleucine, pyroglutamic acid, alanine, glutamic acid, glycine, lysine, tyrosine, serine, phenylalanine, methionine, aspartic acid, and ornithine were extracted as ripening process markers. The present study is not limited to Cheddar cheese and can be applied to various maturation-type natural cheeses. This study provides the technical platform for designing optimal conditions and quality monitoring of the cheese ripening process.     

The effect of NaCl substitution with KCl on Akawi cheese: Chemical composition, proteolysis, angiotensin-converting enzyme-inhibitory activity, probiotic survival, texture profile, and sensory properties

The effect of partial substitution of NaCl with KCl on Akawi cheese with probiotic bacteria was investigated during 30 d of storage at 4°C. Chemical composition, the survival of probiotic and lactic acid bacteria, proteolytic activity, and texture profile analysis were analyzed and sensory analysis was carried out to determine the effects of substitution. No significant differences were observed in moisture, protein, fat, and ash contents among the experimental Akawi cheeses at the same storage period. Significant differences were observed in water-soluble nitrogen and phosphotungstic-soluble nitrogen between experimental cheeses at the same of storage period. No significant difference was observed in the growth of Lactobacillus delbrueckii ssp. bulgaricus between experimental cheeses at the same storage period. However, the growth of Streptococcus thermophilus, Lactobacillus casei, and Lactobacillus acidophilus was significantly affected among experimental cheeses. A significant difference was observed in soluble Ca among experimental cheeses at the same storage period. In general, no significant differences existed in hardness and adhesiveness among experimental cheeses at the same storage period. No significant differences existed in sensory attributes, including creaminess, bitterness, saltiness, sour-acid, and vinegar taste among experimental Akawi cheeses at the same storage period.     

Manufacture of fresh soft white cheese (Domiati-type) from ultrafiltered goats' milk

Manufacturing procedures and compositional characteristics were studied for fresh soft white cheese (Domiati-type) made from goats' milk, using ultrafiltration (UF) and conventional processes. Yields, recovery of protein, fat, total solids and sensory characteristics of this type of cheese were also evaluated. The cheeses made by UF process was higher in pH, moisture content and ash, whereas protein and fat contents were lower compared to those cheeses made by the conventional process. An increase of 21% in cheese yields, 21–26% in protein recovery, 15–19% in fat recovery and 17–22% in total solids recovery was achieved by the UF process. Moreover, the UF process showed 83–85, 83.3, 75, 82.5 and 75% reduction in the total process time, salt, starter culture, rennet and calcium chloride used, respectively. The mean score for texture of cheeses made by UF was significantly higher than that of cheeses made by the traditional process. However, a difference in flavour and overall acceptability between UF cheeses and traditional process cheeses was not verified. The most acceptable cheeses were these made with yogurt or lactic ferment starter culture.     

Evaluation of isolated starter lactic acid bacteria in Ras cheese ripening and flavour development

Eighteen cultures of starter lactic acid bacteria with or without added adjunct cultures, isolated from Egyptian dairy products, were evaluated in experimental Ras cheese for flavour development. Chemical composition of experimental cheeses was within the legal limit for Ras cheese in Egypt. All cultures used in this study had no effect on chemical composition of Ras cheese. Very significant variations in free amino acids, free fatty acids and sensory evaluation have been found among the cultures used in Ras cheesemaking. The levels of free amino acids and free fatty acids were correlated well with flavour development in Ras cheese. Seven of the tested cultures produced acceptable flavour and texture of Ras cheese. The highest overall score of flavour intensity, flavour and texture acceptability were in cheese made using YY47 lactic culture in addition to adjunct culture of Lactobacillus helveticus, Lactobacillus paracasei subsp. paracasei, Lactobacillus delbrueckii subsp. lactis and Enterococcus faecium. This culture can be recommended for Ras cheese manufacture using pasteurized milk.     

Effect of Added Lactobacilli on Composition and Texture of Cheddar Cheese During Accelerated Maturation

The evolution of cheese composition and texture was studied in maturing Cheddar cheese supplemented with live cells and cell homogenates of Lactobacillus casei-casei L2A in order to accelerate maturation. The pH was significantly modified by the lactic acid of the bacterial additives. The Theological properties showed the same general pattern of evolution in experimental as in control cheeses. The process we developed has led to a good-quality matured cheese with 40% increase in flavor intensity compared to control cheeses.     

Comparison of effect of vacuum-condensed and ultrafiltered milk on cheddar cheese

The objective of this study was to compare the effects of vacuum-condensed (CM) and ultrafiltered (UF) milk on some compositional and functional properties of Cheddar cheese. Five treatments were designed to have 2 levels of concentration (4.5 and 6.0% protein) from vacuum-condensed milk (CM1 and CM2) and ultrafiltered milk (UF1 and UF2) along with a 3.2% protein control. The samples were analyzed for fat, protein, ash, calcium, and salt contents at 1 wk. Moisture content, soluble protein, meltability, sodium dodecyl sulfate-PAGE, and counts of lactic acid bacteria and nonstarter lactic acid bacteria were performed on samples at 1, 18, and 30 wk. At 1 wk, the moisture content ranged from 39.2 (control) to 36.5% (UF2). Fat content ranged from 31.5 to 32.4% with no significant differences among treatments, and salt content ranged from 1.38 to 1.83% with significant differences. Calcium content was higher in UF cheeses than in CM cheeses followed by control, and it increased with protein content in cheese milk. Ultrafiltered milk produced cheese with higher protein content than CM milk. The soluble protein content of all cheeses increased during 30 wk of ripening. Condensed milk cheeses exhibited a higher level of proteolysis than UF cheeses. Sodium dodecyl sulfate-PAGE showed retarded proteolysis with increase in level of concentration. The breakdown of alphas1- casein and alphas1-I-casein fractions was highest in the control and decreased with increase in protein content of cheese milk, with UF2 being the lowest. There was no significant degradation of beta-casein. Overall increase in proteolytic products was the highest in control, and it decreased with increase in protein content of cheese milk. No significant differences in the counts of lactic starters or nonstarter lactic acid bacteria were observed. Extent as well as method of concentration influenced the melting characteristics of the cheeses. Melting was greatest in the control cheeses and least in cheese made from condensed milk and decreased with increasing level of milk protein concentration. Vacuum condensing and ultrafiltration resulted in Cheddar cheeses of distinctly different quality. Although both methods have their advantages and disadvantages, the selection of the right method would depend upon the objective of the manufacturer and intended use of the cheese.     

Microbiological and biochemical changes in herby cheese during ripening

The aim of this study was to determine and compare the microbiological, biochemical and sensory characteristics of herby cheese made with two different methods. In the first method (M1), milk and herbs were pasteurized at 65°C for 30 min, and Lactococcus lactis subsp. lactis and L. lactis subsp. cremoris were added as starter culture at an inoculum ratio of 1.5%. In the second method (M2), the conventional cheesemaking was applied. Microbiological and biochemical changes were monitored throughout the ripening period of 90 days. Samples were taken from cheeses on days 1, 15, 30, 60, and 90. At the end of ripening, sensory characteristics of cheeses manufactured with both methods were evaluated. The obtained results suggested that most changes in pH, titratable acidity, and dry matter contents of cheese varieties were not found to differ statistically significant, but the difference in salt content was significant (P < 0.01). Total aerobic count, lactic acid bacteria, Staphylococcus aureus, coliforms, moulds, yeasts, proteolytic and lipolytic microorganism counts were lower in M1 cheese samples than those of M2 cheese samples (P < 0.01). The numbers of psychrotrophic microorganism in both cheese types were not found to differ significantly. Moreover, the results suggested that there were significant differences (P < 0.01) in the degrees of proteolysis and lipolysis of the cheese varieties. High proteolysis and lipolysis rates were monitored in the traditional cheese samples. However, there were no significant differences between the sensory characteristics of cheese samples.     

Influence of microfiltration and adjunct culture on quality of Domiati cheese

The effects of microfiltration and pasteurization processes on proteolysis, lipolysis, and flavor development in Domiati cheese during 2 mo of pickling were studied. Cultures of starter lactic acid bacteria isolated from Egyptian dairy products were evaluated in experimental Domiati cheese for flavor development capabilities. In the first trial, raw skim milk was microfiltered and then the protein:fat ratio was standardized using pasteurized cream. Pasteurized milk with same protein:fat ratio was also used in the second trial. The chemical composition of cheeses seemed to be affected by milk treatment—microfiltration or pasteurization—rather than by the culture types. The moisture content was higher and the pH was lower in pasteurized milk cheeses than in microfiltered milk cheeses at d 1 of manufacture. Chemical composition of experimental cheeses was within the legal limits for Domiati cheese in Egypt. Proteolysis and lipolysis during cheese pickling were lower in microfiltered milk cheeses compared with pasteurized milk cheeses. Highly significant variations in free amino acids, free fatty acids, and sensory evaluation were found among the cultures used in Domiati cheesemaking. The cheese made using adjunct culture containing Lactobacillus delbrueckii ssp. lactis, Lactobacillus paracasei ssp. paracasei, Lactobacillus casei, Lactobacillus plantarum, and Enterococcus faecium received high scores in flavor acceptability. Cheeses made from microfiltered milk received a higher score in body and texture compared with cheeses made from pasteurized milk.     

Cheddar Cheese Texture Related to Salt Release During Chewing, Measured by Conductivity—Preliminary Study

Salt is dispersed throughout the matrix of Cheddar cheese. We hypothesized that the manner in which salt is released into the mouth during chewing may be directly related to cheese breakdown, and hence texture. Conductivity (used as the best estimate of salt) in the mouth was continually monitored during consumption of a range of Cheddars. Characteristics of conductivity changes varied between cheeses. Relationships were observed between such changes and instrumental and sensory measures of texture. This preliminary study, based on responses of a single subject, suggests the potential of salt release data to help distinguish texture in cheese.