Invited Review: Perspectives on the Basis of the Rheology and Texture Properties of Cheese

Modulation of cream cheese physicochemical and functional properties with ultrafiltration and calcium reduction

The production of cream cheese from ultrafiltered (UF) milk can reduce acid whey generation but the effect of altered protein and calcium concentration on the physicochemical properties of cream cheese is not well understood. In this study, the effect of skim milk concentration by UF (2.5 and 5 fold) was assessed both with and without calcium reduction using 2% (w/v) cation resin treatment. UF concentration increased the concentration of peptides and free amino acids and led to a more heterogeneous and porous microstructure, resulting in a softer, less viscous and less thermally stable cream cheese. Calcium reduction decreased peptide generation, increased the size of corpuscular structures, decreased porosity and increased thermal stability but did not significantly decrease cheese hardness or viscosity. The study illustrates how protein or calcium concentration, can be used to alter functional properties.

Description of Ewiss cheese, a new ewe milk cheese processed by Swiss cheese manufacturing techniques: Microbiological, physicochemical, and sensory aspects

Typically, Swiss-type cheese is made from cow milk. However, in the present work an attempt to expand the sheep supply chain and product offering in this field was made by developing a new type of cheese using Swiss-type cheese technology. The cheese was manufactured under industrial conditions, and fermentations were carried out using freeze-dried commercial starters that are traditionally used in the production of Swiss cheese. Two experimental "Ewiss cheese" (EC) products were produced using raw milk (RM) and pasteurized milk (PM), respectively. Fourteen microbial groups were investigated by plate counts from curd until ripened cheeses. According to microbiological analyses, no statistically significant differences were found between the 2 productions with respect to the group of lactic acid bacteria (LAB). The curds were mainly characterized by mesophilic LAB cocci (7.45 log10 cfu/g in RM-EC and 7.33 log10 cfu/g in PM-EC). However, at the end of the ripening period (9 mo), the cheeses exhibited a higher presence of mesophilic LAB rods. Undesired microbiological groups were found only in the curd of raw milk cheese in the range of 104 to 105 cfu/g, but they were reaching undetectable levels by plate count in the cheese at the end of ripening. The RM-EC and PM-EC were characterized by 76% and 68% of DM, respectively. These cheeses contained 29.30% and 34.36% of protein, and 51.31% and 50.38% of fat, respectively. Textural analysis showed differences in terms of hardness, chewiness, and gumminess between the experimental cheeses and Swiss cheese sold on the market. These differences could be attributed to the higher protein content of ewe milk. The main fatty acids in the cheeses were palmitic acid, myristic acid, oleic acid, and capric acid. Among the organic acids, RM-EC had higher concentrations of lactic acid, whereas PM-EC was higher in propionic acid. The ewe cheeses emitted 46 volatile compounds, including acids, aldehydes, ketones, esters, alcohols, and other compounds. The PM-EC was characterized by the main compounds of Swiss-type cheese: acetic acid, butyric acid, ethyl butyrate, ethyl caproate, propanoic acid, and tetramethylpyrazine. Sensory evaluation showed that the new dairy products were generally appreciated, and PM-EC was the most preferred by the judges. This research has enabled the development of new ewe milk products, which could stimulate the valorization of a sector that has been long neglected and still has a large margin of improvement.

Use of high-pressure processing and low-temperature storage to extend the performance shelf life of 2 types of string cheese

The manufacturing method of string cheese is similar to mozzarella, but the hot curd is extruded through narrow tubes or pipes, which align the protein fibers that provide the characteristic ability for consumers to pull strings from this cheese. Firmness is another important performance attribute for consumers who just bite into the string cheese without peeling off strings. There have only been a few studies on string cheese, but it is known that stringiness and firmness decrease during prolonged storage, which is a particular challenge for exporting string cheese. We explored 2 treatments to try to retain the stringiness and firmness of string cheese for longer storage periods. The techniques used were high-pressure processing (HPP; 600 MPa for 3 min) and reduced storage temperature (0°C). In other cheese varieties, these techniques have helped extend the performance shelf life. We tested these techniques using the 2 main types of commercial string cheese: direct acid string cheese (DASC) and cultured string cheese (CSC), which were obtained from 2 different manufacturing facilities. The DASC had higher fat (∼2.2%) and higher pH values (∼0.2 units) compared with the CSC. The CSC had higher protein content (∼3.4%), higher insoluble calcium content (∼8 mg insoluble Ca/g protein) and higher texture profile analysis (TPA) hardness values (∼4 N) compared with the DASC. Due to the compositional differences, the 2 varieties were statistically analyzed separately for all other attributes. In both cheese types, HPP caused an immediate reduction in stringiness, some solubilization of insoluble calcium, and a slight increase in the cheese pH values. High-pressure processing also caused a slight increase in TPA hardness of the CSC samples until 14 d (possibly due to a slight increase in cheese pH). The use of the 0°C storage temperature reduced proteolysis and helped retain firmness during storage. Low-temperature storage could help extend the performance shelf life of string cheese by a couple of months, but HPP was not suitable, as the process caused an immediate reduction in stringiness due to the disruption of the matrix induced by the HPP treatment.

Assessment of protein and phospholipid bioaccessibility in ultrafiltered buttermilk cheese using TIM-1 in vitro gastrointestinal methods

To meet the high consumer demand, butter production has increased over the last few years. As a result, the buttermilk (BM) co-produced volumes require new ways of adding value, such as in cheese manufacturing. However, BM use in cheese milk negatively influences the cheesemaking process (e.g., altered coagulation properties) and the product's final quality (e.g., high moisture content). The concentration of BM by ultrafiltration (UF) could potentially facilitate its use in cheese manufacturing through an increased protein content while maintaining the milk salt balance. Simultaneously, little is known about the digestion of UF BM cheese. Therefore, this study aimed to characterize the impact of UF BM on cheese manufacture, its structure, and its behavior during in vitro digestion. A 2-fold UF concentrated BM was used for cheese manufacture (skim milk [SM] - control). Compositional, textural, and microstructural analyses of cheeses were first conducted. In a second step, the cheeses were fed into an in vitro TNO gastrointestinal digestion model (TIM-1) of the stomach and small intestine and protein and phospholipid (PL) bioaccessibility was studied. The results showed that UF BM cheese significantly differed from SM cheese regarding its composition, hardness (p < 0.05) and microstructure. However, in TIM-1, UF BM and SM cheeses showed similar digestion behavior as a percentage of protein and PL intake. Despite relatively more non-digested and non-absorbed PL in the ileum efflux of UF BM cheese, the initially higher PL concentration contributes to an enhanced nutritional value compared to SM cheese. To our knowledge, this study is the first to compare the bioaccessibility of proteins and PL from UF BM and SM cheeses.

Soluble Salts in Processed Cheese Prepared with Citrate- and Phosphate-Based Calcium Sequestering Salts

In this study, the protein and salts distribution (Ca, P, Na and Mg) in processed cheese (PC) samples prepared with 180 or 360 mEq/kg of the calcium sequestering salts (CSS) disodium phosphate (DSP), disodium pyrophosphate (DSPP), sodium hexametaphosphate (SHMP) and trisodium citrate (TSC) was studied. For this purpose, a water-soluble extract (WSE) of PC samples was prepared. All PC samples contained 45-46% moisture, 26-27% fat and 20-21% protein and had a pH of 5.2 or 5.7. Ultracentrifugation slightly reduced the protein content of the WSE of PC, indicating that most protein in the WSE was non-sedimentable. At equal concentration of CSS, the protein content of the WSE was higher for PC at pH 5.7 compared to PC at pH 5.2. Approximately 55-85% of the Ca and P in the WSE of samples was 10 kDa-permeable for PC prepared with DSPP and SHMP. This suggests that the formation of non-permeable Ca-polyphosphate-casein complexes. For PC prepared with TSC, >90% of Ca in the WSE was 10 kDa-permeable, indicating that micellar disruption arises from sequestration of micellar Ca. These results indicate that the WSE method is an appropriate method to understand how salts present in PC are distributed. However, the WSE and ultracentrifugal supernatant of the WSE can include both soluble and protein-associated salts. Therefore, determining levels of salts in 10 kDa permeate of ultracentrifugal supernatant of the WSE is most appropriate.

Application of Ligilactobacillus salivarius SP36, a Strain Isolated from an Old Cheese Seal, as an Adjunct Culture in Cheesemaking

Adjunct cultures originating from artisanal cheese environments may play an important role in recreating and developing traditional cheese flavours, thanks to their enzymatic activities, involved in different metabolic pathways that occur during cheese ripening. In this work, Ligilactobacillus salivarius SP36, a strain isolated from an old cheese seal, was added as an adjunct culture to the cheese's raw milk, and its effect on the microbiological, physical-chemical and sensory characteristics of the cheese was studied. The use of L. salivarius SP36 in cheese manufacturing had no significant (p > 0.05) effect on the cheese microbiota, gross composition (fat percentage, protein, total solids, moisture and NaCl concentration), colour or texture of the cheese. However, L. salivarius SP36 increased (p < 0.01) the formation of 25 volatile compounds, including 10 esters, 1 aldehyde, 8 alcohols and 6 carboxylic acids. In addition, cheeses made with L. salivarius SP36 received higher scores (p < 0.01) for aroma intensity and quality than control cheeses. L. salivarius SP36 proved to be a good candidate as an adjunct culture for cheesemaking, since it improved the cheese flavour by making it more intense and recovering typical sensorial notes of traditional cheeses.

Lactose-6-phosphate as an alternative to disodium phosphate in the production of processed cheese food

Processed cheese food (PCF) is a dairy product prepared by blending dairy ingredients with nondairy ingredients and heating the blend with agitation to produce a homogeneous product with an extended shelf life. Emulsifying salts (ES), such as disodium phosphate (DSP) and trisodium citrate, have a critical effect on the emulsification characteristics of casein by sequestering the calcium from the calcium-paracaseinate phosphate complex in natural cheese. Lactose-6-phosphate (LP) is an organic compound produced from lactose that has the potential to function as ES. Lactose-6-phosphate is not approved for use as a substitute for ES in the large-scale production of PC. The objective of this study was to produce PCF with LP instead of DSP. Lactose-6-phosphate was prepared by mixing 1 mol of α-lactose with 0.5 mol of sodium cyclo-triphosphate. The pH of recombined solutions was adjusted using sodium hydroxide to get a pH of 12 to obtain 60.74% LP. The solution was stirred for 3 d at room temperature and then concentrated to 52% total solids (TS). The ingredients in the PCF formulations were Cheddar cheese, butter, water, milk permeate powder, and LP (at a ratio of 2.0, 2.4, 2.8, 3.2, 4.0, 5.0, and 6.0%) were formulated to contain 17.0% protein, 25.0% fat, 44.0% moisture, and 2.0% salt. Processed cheese food made with 2.0% DSP was also produced as a control. The PCF was prepared by mixing all ingredients in a Kitchen Aid stand mixer to make a homogeneous paste. A 25-g sample of the mixture was cooked in the rapid visco analyzer (Perten RVA 4500, Macquarie Park, Australia) for 3 min at 95°C at 1,000 rpm for the first 2 min and 160 rpm for the last minute. The PCF was then transferred into molds and refrigerated till further analyses. The PCF was analyzed for moisture, pH, end apparent cooked viscosity, hardness, melted diameter, and melting temperature. The experiment was repeated 3 times using different batches of LP. The moisture of PCF ranged from 42.3% to 44.0% with a pH of 5.6 to 5.8. The end apparent cooked viscosity increased from 818.0 to 2,060.0 cP as the level of LP raised from 0.63% to 1.90%, whereas it was 660.0 cP in control. The hardness of PCF made with LP elevated from 61.9 to 110.1g as the level of LP increased; however, it was 85.6 g in control. The melted diameter decreased from 43 mm in control to 29 mm in 1.90% LP, while the melting temperature of PCF increased from 37.7°C in control to 59.0°C in 1.90% LP. We conclude that LP can be used as a substitute for DSP in PCF manufacture and has more capacity than DSP.

Zinc Supplementation Improves Texture, Oxidative Stability of Caciotta Cheese and Reduces Biogenic Amines Production

Zinc is essential for animals, playing a vital role in enzyme systems and various biochemical reactions. It is crucial to ensure a sufficient intake of zinc through the diet to maintain efficient homeostasis. Only few studies on zinc effect in cow lactating diet evaluated the effects on milk and cheese quality, with conflicting findings. 24 cows of the Friesian breed were divided into two groups (CTR: control and TRT: treated group). Cows were selected for age, body weight, parity and phase of lactations (mid lactation, 140-160 days). CTR diet contained 38 mg/kg of Zn and TRT diet was supplied with 120 mg/kg of complete feed for 60 days. The objective of current investigation was to evaluate the impact of a dietary Zinc Oxide (ZnO) integration of lactating Friesian cows on chemical composition, zinc content, fatty acid and proteic profile, ammine content, pH, aw, texture, and sensory profile of cheese and to improve the chemical-nutritional quality of milk and cheese. The results showed that ZnO supplementation reduced mesophilic aerobic bacteria and Presumptive Pseudomonas spp. growth, proteolysis, biogenic amines content, lipid oxidation, odour intensity and sour and increased hardness, gumminess, chewiness, elasticity of cheese. Biogenic amines are considered an important aspect of food safety. ZnO integration in cow diet could represent a promising strategy for improving the quality, the safety and shelf-life of caciotta cheese.

Insights into the impact of complex phosphates on acid-induced milk fan gel properties: Texture, rheological, microstructure, and molecular forces

Milk fan cheese, a type of stretched -cheese, presents challenges in its stretch-forming. This study investigated the impacts of complex phosphates (sodium tripolyphosphate and sodium dihydrogen phosphate, STPP-DSP) on the gelling properties of acid-induced milk fan gel and the mechanisms contributing to its stretch-forming. The treatment of milk fan gel with STPP-DSP resulted in improved functional and textural properties compared with the control group. In particular, drawing length increased significantly from 69.67 nm to 80.33 nm, and adhesiveness increased from 1737.89 g/mm to 1969.79 g/mm. The addition of STPP-DSP also led to increased viscosity, elastic modulus (G'), and viscous modulus (G"). Microstructural analysis revealed the formation of a fibrous structure within the gel after STPP-DSP treatment, facilitating uniform embedding of fat globules and emulsification. Structural analysis showed that the addition of STPP-DSP increased β-fold and decreased random coiling of the gel, facilitating the unfolding of protein structures. Additionally, UV absorption spectroscopy and excitation-emission matrix spectroscopy results indicated the formation of a chelate between STPP-DSP and milk fan gel, increasing protein-protein molecular interactions. Evidence from differential scanning calorimetry and x-ray diffraction demonstrated the formation of sodium caseinate chelate. Fourier transform infrared spectroscopy and zeta potential analysis revealed that the sodium caseinate chelate formed through hydrophobicity, hydrogen bonding, and electrostatic forces. These findings provided theoretical insights into how phosphates can improve the stretch-forming of milk fan gel, facilitating the application of phosphate additives in stretched -cheese processing.

Properties of low-fat Cheddar cheese prepared from bovine-camel milk blends: Chemical composition, microstructure, rheology, and volatile compounds

Making cheese from camel milk (CM) presents various challenges due to its different physicochemical properties compared with bovine milk (BM). In this study, we investigated the chemical composition, proteolysis, meltability, oiling off, texture profile, color, microstructure, and rheological properties of low-fat Cheddar cheese (LFCC) prepared from BM-CM blends. LFCC was produced from BM or BM supplemented with 15% CM (CM15) and 30% CM (CM30), and analyzed after 14, 60, 120, and 180 d of ripening at 8°C. Except for salt content, no significant differences were observed among LFCC from BM, CM15, and CM30. The addition of CM increased the meltability and oiling off in the resulting cheese throughout storage. With respect to color properties, after melting, LFCC CM30 showed lower L* values than LFCC made from BM and CM15, and a* and b* values were higher than those of BM and CM15 samples. LFCC from CM30 also exhibited lower hardness compared with the other cheeses. Moreover, LFCC made from BM showed a rough granular surface, but cheese samples made from BM-CM blends exhibited a smooth surface. The rheological parameters, including storage modulus, loss modulus, and loss tangent, varied among cheese treatments. The determined acetoin and short-chain volatile acids (C2-C6) in LFCC were affected by the use of CM, because CM15 showed significantly higher amounts than BM and CM30, respectively. The detailed interactions between BM and CM in the cheese matrix should be further investigated.

Raw material-dependent changes in bacterial and compositional profiles are involved in insufficient pH decrease in natural lactic fermentation of Brassica rapa leaves

Sunki is an unsalted lactic fermented pickle made from red turnip leaves in the Kiso district, Japan. Accidental insufficient decrease in pH during sunki fermentation seriously reduces the product quality. To obtain insights into how the insufficient decrease occurs, we comprehensively analyzed differences in the microbiological and chemical properties of sunki made from three different turnip harvests and found a significant difference in their final pH. Microbiota and metabolome analyses revealed that the insufficient pH decrease showed strong relationships with the chemical composition (low lactic acid and high ammonia levels) and bacterial community structure (low Lactobacillus and high Limosilactobacillus). In vitro sunki fermentation experiments demonstrated that accumulated ammonia was associated with a decrease in glutamine and an increase in glutamic acid. Limosilactobacillus reuteri, a species of lactic acid bacteria possessing heterolactic metabolism, was suggested to be mainly responsible for insufficient decrease in pH related to accumulated ammonia during sunki fermentation.

Dairy Matrix Effects: Physicochemical Properties Underlying a Multifaceted Paradigm

When food products are often considered only as a source of individual nutrients or a collection of nutrients, this overlooks the importance of interactions between nutrients, but also interactions between nutrients and other constituents of food, i.e., the product matrix. This product matrix, which can be defined as 'The components of the product, their interactions, their structural organization within the product and the resultant physicochemical properties of the product', plays a critical role in determining important product properties, such as product stability, sensory properties and nutritional and health outcomes. Such matrix effects can be defined as 'the functional outcome of specific component(s) as part of a specific product matrix'. In this article, dairy matrix effects are reviewed, with particular emphasis on the nutrition and health impact of dairy products. Such matrix effects are critical in explaining many effects of milk and dairy products on human nutrition and health that cannot be explained solely based on nutrient composition. Examples hereof include the low glycemic responses of milk and dairy products, the positive impact on dental health, the controlled amino acid absorption and the absence of CVD risk despite the presence of saturated fatty acids. Particularly, the changes occurring in the stomach, including, e.g., coagulation of casein micelles and creaming of aggregated fat globules, play a critical role in determining the kinetics of nutrient release and absorption.

Decarboxylase activity of the non-starter lactic acid bacterium Loigolactobacillus rennini gives crack defects in Gouda cheese through the production of γ-aminobutyric acid

Ten Gouda cheese wheels with an age of 31 weeks from six different batch productions were affected by a crack defect and displayed an unpleasant off-flavor. To unravel the causes of these defects, the concentrations of free amino acids, other organic acids, volatile organic compounds, and biogenic amines were quantified in zones around the cracks and in zones without cracks, and compared with those of similar Gouda cheeses without crack defect. The Gouda cheeses with cracks had a significantly different metabolome. The production of the non-proteinogenic amino acid γ-aminobutyric acid (GABA) could be unraveled as the key mechanism leading to crack formation, although the production of the biogenic amines cadaverine and putrescine contributed as well. High-throughput amplicon sequencing of the full-length 16S rRNA gene based on whole-community DNA revealed the presence of Loigolactobacillus rennini and Tetragenococcus halophilus as most abundant non-starter lactic acid bacteria in the zones with cracks. Shotgun metagenomic sequencing allowed to obtain a metagenome-assembled genome of both Loil. rennini and T. halophilus. However, only Loil. rennini contained genes necessary for the production of GABA, cadaverine, and putrescine. Metagenetics further revealed the brine and the rennet used during cheese manufacturing as the most plausible inoculation sources of both Loil. rennini and T. halophilus.IMPORTANCECrack defects in Gouda cheeses are still poorly understood, although they can lead to major economic losses in cheese companies. In this study, the bacterial cause of a crack defect in Gouda cheeses was identified, and the pathways involved in the crack formation were unraveled. Moreover, possible contamination sources were identified. The brine bath might be a major source of bacteria with the potential to deteriorate cheese quality, which suggests that cheese producers should regularly investigate the quality and microbial composition of their brines. This study illustrated how a multiphasic approach can understand and mitigate problems in a cheese company.

Changes of physicochemical and functional properties of processed cheese made with natural cheddar and mozzarella cheeses during refrigerated storage

The present study aimed to investigate changes of physicochemical and functional properties of the processed cheeses (PCs) made with Cheddar (PC1), Mozzarella (PC2) and both of them at a ratio of 1:1 (PC3) during storage at 4 °C for 4 months. The results showed that the type of natural cheese used affected the composition of PCs with lower fat content in PC2 due to the lower fat content of Mozzarella cheese used. PC2 with lower fat content showed decreased meltability and oil leakage compared with PC1 and PC3. The stretchability of all the samples significantly (P < 0.05) decreased during storage, and PC1 showed lower stretchability. This was confirmed by increased protein hydrolysis of all the samples during the storage with a higher level of proteolysis in PC1, leading to decreased stretchability of PCs. Further low-field nuclear magnetic resonance analysis indicated more entrapped water in cheese due to moisture migration into the cheese matrix that might squeeze the fat globules to aggregate, causing more fat leakage during later stages of storage. This was evidenced by microstructural analysis showing different extents of increase in fat particle sizes and decrease in free serum in all the PC samples over the storage time. Therefore, the present study provides further understanding of the mechanism of quality change of PC during refrigerated storage as affected by proteolytic properties and composition of natural cheese used.

Functionality of process cheese made from Cheddar cheese with various rennet levels and high-pressure processing treatments

Due to its versatility and shelf stability, process cheese is gaining interest in many developing countries. The main structural component (base) of most processed cheese formulations is young Cheddar cheese that has high levels of intact casein. Exporting natural Cheddar cheese base from the United States to distant overseas markets would require the aging process to be slowed or reduced. As Cheddar cheese ripens, the original structure is broken down by proteolysis and solubilization of insoluble calcium phosphate. We explored the effect of varying rennet levels (we also used a less proteolytic rennet) and application of high-pressure processing (HPP) to Cheddar cheese, as we hoped these treatments might limit proteolysis and concomitant loss of intact casein. To try to retain high levels of insoluble Ca, all experimental cheeses were made with a high-draining pH and from concentrated milk. To compare our intact casein results with current practices, we manufactured a Cheddar cheese that was prepared according to typical industry methods (i.e., use of unconcentrated milk, calf chymosin [higher levels], and low draining pH value [∼6.2]). All experimental cheeses were made from ultrafiltered milk with protein and casein contents of ∼5.15% and 4.30%, respectively. Three (low) rennet levels were used: control (38 international milk clotting units/mL of rennet per 250 kg of milk), and 25% and 50% reduced from this level. All experimental cheeses had similar moisture contents (∼37%) and total Ca levels. Four days after cheese was made, half of the experimental samples from each vat underwent HPP at 600 MPa for 3 min. Cheddar cheese functionality was monitored during aging for 240 d at 4°C. Cheddar cheese base was used to prepare process cheese after aging for 14, 60, 120, 180, and 240 d. Loss tangent (LT) values of cheese during heating were measured by small strain oscillatory rheology. Intact casein levels were measured using the Kjeldahl method. Acid or base titrations were used to determine the buffering capacity and insoluble Ca levels as a percentage of total Ca. The LTmax values (an index of meltability) in process cheese increased with aging for all the cheese bases; the HPP treatment significantly decreased LTmax values of both base (natural) and process cheeses. All experimental cheeses had much higher levels of intact casein compared with typical industry-make samples. Process cheese made from the experimental treatments had visually higher stretching properties than process cheese made from Cheddar with the typical industry-make procedure. Residual rennet activity was not affected by rennet level, but the rate of proteolysis was slightly slower with lower rennet levels. The HPP treatment of Cheddar cheese reduced residual rennet activity and decreased the reduction of intact casein levels. The HPP treatment of Cheddar cheese resulted in process cheeses that had slightly higher hardness values, lower LTmax values, and retained higher storage modulus values at 70°C. We also observed that the other make procedures we used in all experimental treatments (i.e., using a less proteolytic chymosin, using a concentrated cheese milk, and maintaining a high draining pH value) had a major effect on retaining high levels of intact casein.

Ice crystallization and structural changes in cheese during freezing and frozen storage: implications for functional properties

Temperature-mediated preservation techniques offer a simple, scalable, effective, and fairly efficient method of long-term storage of food products. In order to ensure the uninterrupted availability of cheese across the globe, a critical understanding of its techno-functional properties as affected by freezing and frozen storage is essential. Detailed studies of temperature-mediated molecular dynamics are available for relatively simpler and homogeneous systems like pure water, proteins, and carbohydrates. However, for heterogeneous systems like cheese, inter-component interactions at sub-zero temperatures have not been extensively covered. Ice crystallization during freezing causes dehydration of caseins and the formation of concentration gradients within the cheese matrix, causing undesirable changes in texture-functional attributes, but findings vary due to experimental conditions. A suitable combination of sample size, freezing rate, aging, and tempering can extend the shelf life of high- and low-moisture Mozzarella cheese. However, limited studies on other cheeses suggest that effects and suitability differ by cheese type, in most cases adversely affecting texture and functional attributes. This review presents an overview of the understanding of the effects of refrigeration, freezing techniques, and frozen storage on structural components of cheese, most prominently Mozzarella cheese, and the corresponding impact on microstructure and functionality. Also included are the mechanism of ice formation and relevant mathematical models for estimation of the thermophysical properties of cheese to assist in designing optimized schemes for their frozen storage. The review also highlights the lack of unanimity in critical understanding concerning the effect of freezing on the long-term storage of Mozzarella cheese with respect to its functionality.

Sensory characterization of functional guava symbiotic petit cheese product

The consumption of functional dairy products continues to rise due to consumer needs. This study aimed to develop a dairy guava functional symbiotic petit cheese product that included probiotics (Bifidobacterium animalis subsp. lactis BB-12, Chr. Hansen, Denmark) and prebiotics (inulin), which had adequate organoleptic characteristics. Moreover, adequate physicochemical, microbiological, and sensory characteristics during its shelf life were expected. A pasteurized skim milk curd flavored with a guava pulp was stabilized with gelatin to formulate this product. As sweeteners, iso maltol, erythritol, and Luo Han Guo extract from monk fruit (Siraitia Grosvenorii) were added. The prebiotic used was inulin, and the probiotic (Bifidobacterium animalis subsp. lactis BB-12, Chr. Hansen, Denmark). The product was kept refrigerated (4 °C) during the shelf life of 28 days. For the organoleptic analysis (100 consumers), the evaluations performed were: (1) overall liking (OL), (2) CATA (Check all that apply) testing 19 attributes, and (3) purchase intention was evaluated. Results were analyzed with FIZZ Software Biosystèmes. During shelf life, (1) physicochemical, microbiological, and sensory tests were performed. The product was evaluated as "liked much'' (7.16 out of 9); it was described as a creamy (71 %) natural product (73 %) with a fruity odor (57 %). It could be suitable for marketing because 82 % of the consumers would buy it. The product's probiotic character (over 1 × 106) was established through a microbiological count. On day one, the CFU was found to be 4.15 × 108, and after 28 days, 1.98 × 108 CFU of viable Bifidobacterium animalis subsp. lactis BB-12, leading us to establish its probiotic characteristics. The shelf life was estimated at 21 days.

Engineering artificial casein micelles for future food: Is casein phosphorylation necessary?

Industrial-scale production of recombinant proteins for food products may become economically feasible but correct post-translational modification of proteins by microbial expression systems remains a challenge. For efficient production of hybrid products from bovine casein and recombinant casein, it is therefore of interest to evaluate the necessity of casein post-translational phosphorylation for the preparation of hybrid casein micelles and study their rennet-induced coagulation. Our results show that dephosphorylated casein was hardly incorporated into artificial casein micelles but was capable of stabilising calcium phosphate nanoclusters with an increased size through adsorption on their surface. Thereby, dephosphorylated casein formed larger colloidal particles with a decreased hydration. Furthermore, the presence of increasing amounts of dephosphorylated casein resulted in increasingly poor rennet coagulation behaviour, where dephosphorylated casein disrupted the formation of a coherent gel network by native casein. These results emphasise that post-translational phosphorylation of casein is crucial for their assembly into micelles and thereby for the production of dairy products for which the casein micelle structure is a prerequisite, such as many cheese varieties and yoghurt. Therefore, phosphorylation of future recombinant casein is essential to allow its use in the production of animal-free dairy products.

Methodology and development of a high-protein plant-based cheese alternative

Animal-based food products, such as meat and dairy, contribute the most to greenhouse gas emissions in the food sector. This, coupled with the demonstrably worsening climate crisis, means that there needs to be a shift to more sustainable alternatives in the form of plant-based foods. In particular, the plant-based cheese alternative industry is relevant, as the products lack critical functionalities and nutrition compared to their dairy-based counterparts. Waxy starch, plant-protein isolate, and coconut oil were combined to create a novel high-protein (18% w/w) plant-based cheese alternative. We determined that when using native waxy starch, we can enhance its existing viscoelastic properties by modulating gelatinization through adding plant protein and fat. Texture profile analysis indicated that the cheese analogues could reach hardness levels of 15-90N, which allowed samples to be tailored to a broader range of dairy products. We determined that plant proteins and fat can behave as particulate fillers, enhance network strength, and create strategic junction points during starch retrogradation. The degree of melt and stretch of the high-protein plant-based analogues were 2-3 times greater than those observed for commercial plant-based cheese alternatives and significantly more similar to dairy cheese. The rheological melting kinetics saw that the high-protein plant-based cheese alternative displayed more viscous properties with increasing temperature. Tan δ (G"/G') at 80 °C was used as an indicator for sample meltability where, values ≥ 1 indicate better melt and more viscous systems. The high-protein plant-based cheese alternative reached Tan δ values upwards to 0.7, whereas commercial plant-based cheese alternatives only reached tan δ values around 0.1. Ultimately, the novel high-protein plant-based cheese alternative demonstrates the use of simple ingredients to form complex food systems.

Possibility of Using Different Calcium Compounds for the Manufacture of Fresh Acid Rennet Cheese from Goat's Milk

Calcium can be added to cheese milk to influence the coagulation process and to increase cheese yield. Calcium compounds used in the dairy industry show substantial differences in their practical application. Therefore, this study aimed to evaluate the potential use of 0, 5, 10, 15, and 20 mg Ca 100 g-1 of milk in the form of calcium gluconate, lactate, and carbonate as alternatives to calcium chloride in manufacturing fresh acid rennet cheese from high-pasteurized (90 °C, 15 s) goat's milk. The pH value of the cheese was reduced most strongly by the addition of increasing doses of calcium lactate (r = -0.9521). Each cheese sample showed increased fat content with the addition of calcium. Only calcium chloride did not reduce protein retention from goat's milk to cheese. The addition of 20 mg Ca 100 g-1 of milk in the form of gluconate increased cheese yield by 4.04%, and lactate reduced cheese yield by 2.3%. Adding each calcium compound to goat's milk significantly increased Ca and P levels in the cheese (p ≤ 0.05). The highest Ca levels were found in cheese with the addition of 20 mg Ca 100 g-1 of milk in the form of lactate. In all groups, similar contents of Mn, Mo, and Se were found. Calcium addition significantly affected cheese hardness, while higher calcium concentrations increased hardness. Carbonate caused the greatest increase in the cohesiveness of cheese. The addition of calcium compounds increased the adhesiveness and springiness of cheese compared to controls. The cheese with calcium chloride had the highest overall acceptability compared to the other cheese samples. The addition of calcium carbonate resulted in a lower score for appearance and consistency, and influenced a slightly perceptible graininess, sandiness, and stickiness in its consistency, as well as provided a slightly perceptible chalky taste.

Graduate Student Literature Review: History, technologies of production, and characteristics of ricotta cheese

This review focused on the historical, technological, and analytical characteristics of ricotta cheese available in the literature. Ricotta cheese is a typical dairy product that originated from Italy, used in the preparation of several traditional dishes, both sweet and salted. The available studies pertaining to ricotta cheese revealed a considerable biodiversity in the production with a large number of varieties produced, whose production varies according to the local uses and customs. The review shows the main chemical and microbial characteristics of the product and also the several parameters that affect the mechanism of the production process and the final characteristics of the product, including the raw materials, the processing methods, the season, the animals' diet, the animals' species, and breeds. Ricotta production can be artisanal or industrial, with differences in the making process. New trends in ricotta cheese production have been developed, with particular attention to the functional effect on human health and the novel technologies applied to extend the shelf-life of the products. Currently, it is not easy to find these new developments in the market, probably related to the cost of production, which is not always bearable by the farms. However, despite the large classification reported and the great interest by the cheese industry, just a few numbers of studies were found for artisanal ricotta productions, which still need to be characterized and studied.

Plant-Based Alternatives to Cheese Formulated Using Blends of Zein and Chickpea Protein Ingredients

In this study, zein protein isolate (ZPI) and chickpea protein concentrate (CPC) ingredients were used to formulate five plant-based cheese alternatives. Ingredient ratios based on protein contributions of 0:100, 25:75, 50:50, 75:25 and 100:0 from ZPI and CPC, respectively, were used. Formulations were developed at pH ~4.5, with a moisture target of 59%. Shea butter was used to target 15% fat, while tapioca starch was added to target the same carbohydrate content for all samples. Microstructural analysis showed differences among samples, with samples containing ZPI displaying a protein-rich layer surrounding the fat globules. Schreiber meltability and dynamic low amplitude oscillatory shear rheological analyses showed that increasing the proportion of ZPI was associated with increasing meltability and greater ability to flow at high temperatures. In addition, the sample containing only CPC showed the highest adhesiveness, springiness and cohesiveness values from the texture profile analysis, while the sample containing only ZPI exhibited the highest hardness. Furthermore, stretchability increased with increasing ZPI proportions. This work will help understanding of the role and potential of promising plant-protein-ingredient blends in formulating plant-based alternatives to cheese with desirable functional properties.

Effects of Process Parameters on the Fibrous Structure and Textural Properties of Calcium Caseinate Extrudates

Textured calcium caseinate extrudates are considered promising candidates in producing fish substitutes. This study aimed to evaluate how the moisture content, extrusion temperature, screw speed, and cooling die unit temperature of the high-moisture extrusion process affect the structural and textural properties of calcium caseinate extrudates. With an increase in moisture content from 60% to 70%, there was a decrease in the cutting strength, hardness, and chewiness of the extrudate. Meanwhile, the fibrous degree increased considerably from 1.02 to 1.64. The hardness, springiness, and chewiness showed a downward trend with the rise in extrusion temperature from 50 °C to 90 °C, which contributed to the reduction in air bubbles in the extrudate. Screw speed showed a minor effect on fibrous structure and textural properties. A low temperature (30 °C) in all cooling die units led to damaged structure without mechanical anisotropy, which resulted from fast solidification. These results show that the fibrous structure and textural properties of calcium caseinate extrudates can be effectively manipulated by adjusting the moisture content, extrusion temperature, and cooling die unit temperature.

Effect of plasmin on casein hydrolysis and textural properties of rennet-induced model cheeses

Plasmin plays an important role in casein hydrolysis during cheese ripening, which may influence the properties of the casein network and the texture of the final product. In view of this, the relation between plasmin-induced casein hydrolysis and textural changes of cheese during ripening was investigated in this study. Four batches of model cheese with different concentrations of added plasmin (0, 0.4, 0.6 and 1.0 μL/g milk) were prepared, and were stored for 12 weeks at 16 °C. During this period, plasmin activity, casein hydrolysis, textural properties and other compositional characteristics (pH, dry matter) were determined. Our results show that the addition of plasmin had significant effect on both the degree and the pattern of proteolysis. As a result, cheeses with different plasmin content showed different textural properties. With increased plasmin concentration, Young's modulus, hardness, resilience and cohesion decreased, while brittleness increased. All textural properties showed linear relations with the degree of casein hydrolysis, and logarithmic relations with the percentage of intact casein fractions. At the beginning of ripening, only slight changes in textural properties were found, although a substantial part (40-60 %) of the casein fractions was already been broken down. When ripening progressed, ongoing proteolysis significantly weakened the protein network and consequently led to noticeable textural changes. Model cheeses became softer, more brittle and less elastic. The knowledge gained from this study provide new insights in the changes of different textural parameters of model cheese. This will help to optimize the existing products and create new ones.

A Review on the Effect of Calcium Sequestering Salts on Casein Micelles: From Model Milk Protein Systems to Processed Cheese

Phosphates and citrates are calcium sequestering salts (CSS) most commonly used in the manufacture of processed cheese, either singly or in mixtures. Caseins are the main structure forming elements in processed cheese. Calcium sequestering salts decrease the concentration of free calcium ions by sequestering calcium from the aqueous phase and dissociates the casein micelles into small clusters by altering the calcium equilibrium, thereby resulting in enhanced hydration and voluminosity of the micelles. Several researchers have studied milk protein systems such as rennet casein, milk protein concentrate, skim milk powder, and micellar casein concentrate to elucidate the influence of calcium sequestering salts on (para-)casein micelles. This review paper provides an overview of the effects of calcium sequestering salts on the properties of casein micelles and consequently the physico-chemical, textural, functional, and sensorial attributes of processed cheese. A lack of proper understanding of the mechanisms underlying the action of calcium sequestering salts on the processed cheese characteristics increases the risk of failed production, leading to the waste of resources and unacceptable sensorial, appearance, and textural attributes, which adversely affect the financial side of processors and customer expectations.

An assessment of the intact casein content in natural cheddar cheese to determine its suitability in processed cheeses with desired properties

As compared to age, intact casein in the natural cheddar cheese is a better index of selection for manufacturing processed cheese. In view of this, the present investigation was designed to establish relation between intact casein of the natural cheese with desirable properties of the processed cheese so that the most desirable intact casein in the natural cheddar cheese can be selected on the basis of required properties of the processed cheese. Processed cheese was prepared by using natural cheddar cheese of different intact casein content (ICC) and analysed for meltability, oiling off and hardness. Multiple linear regression was used for prediction of ICC using meltability, oiling off and hardness and it was observed that the all the independent variables significantly affected ICC. Adjusted R2 value of 0.952 and root mean square error of 1.04 suggested a good fit and validation of the developed equation.

Development of Novel Whey-Mango Based Mixed Beverage: Effect of Storage on Physicochemical, Microbiological, and Sensory Analysis

The present study was aimed at developing whey-mango-based mixed beverages and characterizing their physicochemical properties. Three different formulations were prepared by varying proportions of whey and mango (sample-1 = 60:20 mL, sample-2 = 65:15 mL, and sample-3 = 70:10 mL). Prepared beverage samples during 25 days of storage revealed a significant increase in acidity (0.27 ± 0.02−0.64 ± 0.03%), TSS (17.15 ± 0.01−18.20 ± 0.01 °Brix); reducing sugars (3.01 ± 0.01−3.67 ± 0.01%); moisture (74.50 ± 0.02−87.02 ± 0.03%); protein (5.67 ± 0.02−7.58 ± 0.01%); fat (0.97 ± 0.01−1.39 ± 0.04%); and carbohydrate (18.01 ± 0.02−3.45 ± 0.02%). The sedimentation rate was only 1%. The total plate count for the prepared samples ranged from 3.32 ± 0.08 to 3.49 ± 0.15 log CFU/mL while yeast and mold counts varied between 0.48 ± 0.01 to 1.85 ± 0.11 Log CFU/mL. The coliform count was below the detection limit (<1). The overall sensory score revealed that the whey beverage with more mango juice could attain acceptable quality upon processing. Based on the findings, it may be concluded that whey can be utilized with fruits and vegetables to develop whey-based beverages.

The Impact of Different Hydrocolloids on the Viscoelastic Properties and Microstructure of Processed Cheese Manufactured without Emulsifying Salts in Relation to Storage Time

The current study was conducted to evaluate the effect of the addition of selected hydrocolloids [agar (AG), κ-carrageenan (KC), or gelatin (PG); as a total replacement for emulsifying salts] on the viscoelastic properties and microstructure of processed cheese (PC) samples during a storage period of 60 days (at 6 ± 2 °C). In general, PC viscoelastic properties and microstructure were affected by the addition of hydrocolloids and the length of storage time. The evaluated PC reported a more elastic behavior (G′ > G″) over the viscous one. The highest values of viscoelastic moduli (G′; G″; G*) were recorded for PC samples manufactured with KC addition, followed by those prepared with AG and PG. The control sample presented values of viscoelastic moduli similar to those of the PG sample. All PC samples tested had fat globule size values lower than 1 μm. Moreover, PC with AG and KG addition presented similar microstructures and sizes of fat globules.

Low-moisture part-skim mozzarella cheese made from blends of camel and bovine milk: Gross composition, proteolysis, functionality, microstructure, and rheological properties

Camel (CM) milk is used in variety of ways; however, it has inferior gelling properties compared with bovine milk (BM). In this study, we aimed to investigate the physicochemical, functional, microstructural, and rheological properties of low-moisture part-skim (LMPS) mozzarella cheese, made from BM, or BM mixed with 15% CM (CM15%) or 30% CM (CM30%), at various time points (up to 60 d) of storage at 4°C after manufacture. Low-moisture part-skim mozzarella cheeses using CM15% and CM30% had high moisture and total Ca contents, but lower soluble Ca content. Compared with BM cheese, CM15% and CM30% LMPS mozzarella cheese exhibited higher proteolysis rates during storage. Adding CM affected the color properties of LMPS mozzarella cheese manufactured from mixed milk. Scanning electron microscopy images showed that the microstructure of CM15% and CM30% cheeses had smooth surfaces, whereas the BM cheese microstructures were rough with granulated surfaces. Low-moisture part-skim mozzarella cheeses using CM15% and CM30% showed significantly lower hardness and chewiness, but higher stringiness than BM cheese. Compared with BM cheese, CM15% and CM30% cheeses showed lower tan δ levels during temperature surges, suggesting that the addition of CM increased the meltability of LMPS mozzarella cheese during temperature increases. Camel milk addition affected the physicochemical, microstructural, and rheological properties of LMPS mozzarella cheese.

Inhibitory Effect of Sodium Alginate Nanoemulsion Coating Containing Myrtle Essential Oil (Myrtus communis L.) on Listeria monocytogenes in Kasar Cheese

The present study aimed to characterize the physical properties of nanoemulsion-based sodium alginate edible coatings containing myrtle (Myrtus communis L.) essential oil and to determine its inhibitory effects on Listeria monocytogenes in fresh Kasar cheese during the 24-day storage at 4 °C. The GC-MS analysis showed that the main components of myrtle essential oil were 1,8-cineol (38.64%), α-pinene (30.19%), d-limonene (7.51%), and α-ocimene (6.57%). Myrtle essential oil showed an inhibitory effect on all tested L. monocytogenes strains and this effect significantly increased after ultrasonication. Minimum inhibitory and minimum bactericidal concentrations of myrtle essential oil nanoemulsion were found to be 4.00-4.67 mg/mL and 5.00-7.33 mg/mL, respectively. The antibacterial activity of myrtle essential oil nanoemulsion against L. monocytogenes was confirmed by the membrane integrity and FESEM analyses. Nanoemulsion coatings containing myrtle essential oil showed antibacterial activity against L. monocytogenes with no adverse effects on the physicochemical properties of cheese samples. Nanoemulsion coatings containing 1.0% and 2.0% myrtle essential oil reduced the L. monocytogenes population in cheese during the storage by 0.42 and 0.88 log cfu/g, respectively. These results revealed that nanoemulsion-based alginate edible coatings containing myrtle essential oil have the potential to be used as a natural food preservative.

Milk-Gelling Properties of Proteases Extracted from the Fruits of Solanum Elaeagnifolium Cavanilles

There is little information on the milk coagulation process by plant proteases combined with chymosins. This work is aimed at studying the capability of protease enclosed in the ripe fruits of Solanum elaeagnifolium (commonly named trompillo) to form milk gels by itself and in combination with chymosin. For this purpose, proteases were partially purified from trompillo fruits. These proteases had a molecular weight of ~60 kDa, and results suggest cucumisin-like serine proteases, though further studies are needed to confirm this observation. Unlike chymosins, trompillo proteases had high proteolytic activity (PA = 50.23 U_Tyr mg protein⁻¹) and low milk-clotting activity (MCA = 3658.86 SU mL⁻¹). Consequently, the ratio of MCA/PA was lower in trompillo proteases (6.83) than in chymosins (187 to 223). Our result also showed that milk gels formed with trompillo proteases were softer (7.03 mPa s) and had a higher release of whey (31.08%) than the milk gels clotted with chymosin (~10 mPa s and ~4% of syneresis). However, the combination of trompillo proteases with chymosin sped up the gelling process (21 min), improved the firmness of milk gels (12 mPa s), and decreased the whey release from milk curds (3.41%). Therefore, trompillo proteases could be combined with chymosin to improve the cheese yield and change certain cheese features.

Cynara cardunculus as a potential source of milk coagulating protease: Effects on physical properties of cow's milk

In the present research study, Cynara cardunculus (wild cardoon) flowers were blended and extracted using different types of buffers (phosphate buffer; citrate buffer and distilled water) for different maceration times. The most reliable, quick and efficient buffer was found to be phosphate (pH = 6.5) with a 6‐h maceration time, which was used throughout this study. C. cardunculus extract (CE) was found to have high clotting and proteolytic activities. The extracted enzyme was found to be very stable against a wide range of pH values as well as of temperature. The formation of milk gels prepared in the presence of CE with different types of milk was evaluated using dynamic rheology and Turbiscan. The evolution of both elastic (G′) and viscous (G″) moduli was monitored with time. The values of the whole milk enriched with milk powder gels were higher. Coagulum stability was evaluated using Turbiscan. The textural properties and the curd‐firming rate of coagulum were also determined. In conclusion, the prepared CE could be an efficient milk‐clotting agent in the production of dairy products.

Modeling colloidal interactions that predict equilibrium and non-equilibrium states

Modulating the interaction potential between colloids suspended in a fluid can trigger equilibrium phase transitions as well as formation of non-equilibrium 'arrested states' such as gels and glasses. Faithful representation of such interactions are essential for using simulation to interrogate the microscopic details of non-equilibrium behavior, and for extrapolating observations to new regions of phase space that are difficult to explore in experiment. Although the extended law of corresponding states predicts equilibrium phases for systems with short-ranged interactions, it proves inadequate for equilibrium predictions of systems with longer-ranged interactions, and for predicting non-equilibrium phenomena in systems with either short-ranged or long-ranged interactions. These shortcomings highlight the need for new approaches to represent and disambiguate interaction potentials that replicate both equilibrium and non-equilibrium phase behavior. In this work, we use experiments and simulations to study a system with long-ranged thermoresponsive colloidal interactions and explore whether a resolution to this challenge can be found in regions of the phase diagram where temporal effects influence material state. We demonstrate that the conditions for non-equilibrium arrest by colloidal gelation are sensitive to both the shape of the interaction potential and the thermal quench rate. We exploit this sensitivity to propose a kinetics-based algorithm to extract distinct arrest conditions for candidate potentials that accurately selects between potentials that differ in shape but share the same predicted equilibrium structure. The method reveals that each potential has a quantitatively distinct arrest line, providing insight into how the shape of longer-ranged potentials influences the conditions for colloidal gelation.

Low-fat akawi cheese made from bovine-camel milk blends: Rheological properties and microstructural characteristics

Camel milk (CM) can be used as an ingredient to produce various dairy products but it forms weak rennet-induced and acid-induced gels compared with bovine milk (BM). Therefore, in this study, we aimed to investigate the effect of blending bovine milk with camel milk on the physicochemical, rheological (amplitude sweep and frequency sweep), and microstructural properties of low-fat akawi (LFA) cheese. The cheeses were made of BM only or BM blended with 15% (CM15%) or 30% (CM30%) camel milk and stored at 4°C for 28 d. The viscoelastic properties as a function of temperature were assessed. The LFA cheeses made from blended milks had higher moisture, total Ca, and soluble Ca contents, and had higher pH 4.6-water-soluble nitrogen compared with those made from BM. Analysis by scanning electron microscopy demonstrated that the microstructures formed in BM cheese were rough with granular surfaces, whereas those in blended milk cheeses had smooth surfaces. Hardness was lower for LFA cheeses made from blended milk than for those made from BM only. The LFA cheeses demonstrated viscoelastic behavior in a linear viscoelastic range from 0.1 to 1.0% strain. The storage modulus (G') was lower in LFA cheese made from BM over a range of frequencies. Adding CM reduced the resistance of LFA cheeses to flow as temperature increased. Blended cheeses exhibited lower complex viscosity values than BM cheeses during temperature increases. Thus, the addition of camel milk improved the rheological properties of LFA cheese.