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.

Manufacture of a novel cultured micellar casein concentrate ingredient for emulsifying salt free process cheese products applications

Micellar casein concentrate (MCC) is a high protein ingredient that is typically produced using 3 stages of microfiltration with a 3× concentration factor and diafiltration. Acid curd is an acid protein concentrate, which can be obtained by precipitating the casein at pH 4.6 (isoelectric point) using starter cultures or direct acids without the use of rennet. Process cheese product (PCP) is a dairy food prepared by blending dairy ingredients with nondairy ingredients and then heating the mixture to get a product with an extended shelf-life. Emulsifying salts are critical for the desired functional characteristics of PCP because of their role in calcium sequestration and pH adjustment. The objectives of this study were to develop a process to produce a novel cultured micellar casein concentrate ingredient (cMCC; culture-based acid curd) and to produce PCP without emulsifying salts using different combinations of protein from cMCC and MCC in the formulations (2.0:1.0, 1.9:1.1, and 1.8:1.2). Skim milk was pasteurized at 76°C for 16 s and then microfiltered in 3 microfiltration stages using graded permeability ceramic membranes to produce liquid MCC (11.15% total protein; TPr and 14.06% total solids; TS). Part of the liquid MCC was spray dried to produce MCC powder (75.77% TPr and 97.84% TS). The rest of the MCC was used to produce cMCC (86.9% TPr and 96.4% TS). Three PCP treatments were formulated with different ratios of cMCC:MCC, including 2.0:1.0, 1.9:1.1, and 1.8:1.2 on the protein basis. The composition of PCP was targeted to 19.0% protein, 45.0% moisture, 30.0% fat, and 2.4% salt. This trial was repeated 3 times using different batches of cMCC and MCC powders. All PCP were evaluated for their final functional properties. No significant differences were detected in the composition of PCP made with different ratios of cMCC and MCC except for the pH. The pH was expected to increase slightly with elevating the MCC amount in the PCP formulations. The end apparent viscosity was significantly higher in 2.0:1.0 formulation (4,305 cP) compared with 1.9:1.1 (2,408 cP) and 1.8:1.2 (2,499 cP). The hardness ranged from 407 to 512 g with no significant differences within the formulations. However, the melting temperature showed significant differences with 2.0:1.0 having the highest melting temperature (54.0°C), whereas 1.9:1.1 and 1.8:1.2 showed 43.0 and 42.0°C melting temperature, respectively. The melting diameter (38.8 to 43.9 mm) and melt area (1,183.9 to 1,538.6 mm²) did not show any differences in different PCP formulations. The PCP made with a 2.0:1.0 ratio of protein from cMCC and MCC showed better functional properties compared with other formulations.

Expression and characterization of a novel lipase from Bacillus licheniformis NCU CS-5 for application in enhancing fatty acids flavor release for low-fat cheeses

A novel lipase from Bacillus licheniformis NCU CS-5 was expressed in different Escherichia coli cells. The recombinant enzyme achieved a high activity (161.74 U/mL) with protein concentration of 0.27 mg/mL under optimal conditions at the large-scale expression of 12 h. The recombinant lipase showed optimal activity at 40 ℃ and pH 10.0, and maintained more than 80% relative activity after 96 h of incubation at pH 9.0-10.0. This typical alkaline lipase was activated under medium temperature conditions (30 and 45 ℃ for 96 h). The lipase exhibited a degree of adaptability in various organic solvents and metal ions, and showed high specificity towards triglycerides with short and medium chain fatty acids. Among different substrates, the lipase showed the strongest binding affinity towards pNPP (Km = 0.674 mM, Vmax = 950.196 μM/min). In the experiments of its application in enhancing fatty acids flavor release for low-fat cheeses, the lipase was found to hydrolyze cheeses and mainly increase the contents of butyric acid, hexanoic acid, caprylic acid and decanoic acid. The results from NMR and GC provided the possibility of enhancing fatty acids flavor released from low-fat cheeses by the lipolysis method.

Compositional and Functional Characteristics of Feta-Type Cheese Made from Micellar Casein Concentrate

Micellar casein concentrate (MCC) is a high protein ingredient (obtained by microfiltration of skim milk) with an elevated level of casein as a percentage of total protein (TP) compared to skim milk. It can be used as an ingredient in cheese making. Feta-type cheese is a brined soft cheese with a salty taste and acid flavor. We theorize that Feta-type cheese can be produced from MCC instead of milk, which can improve the efficiency of manufacture and allow for the removal of whey proteins before manufacturing Feta-type cheese. The objectives of this study were to develop a process of producing Feta-type cheese from MCC and to determine the optimum protein content in MCC to make Feta-type cheese. MCC solutions with 3% (MCC-3), 6% (MCC-6), and 9% (MCC-9) protein were prepared and standardized by mixing water, MCC powder, milk permeate, and cream to produce a solution with 14.7% total solids (TS) and 3.3% fat. Thermophilic cultures were added at a rate of 0.4% to MCC solutions and incubated at 35 °C for 3 h to get a pH of 6.1. Subsequently, calcium chloride and rennet were added to set the curd in 20 min at 35 °C. The curd was then cut into cubes, drained for 20 h followed by brining in 23% sodium chloride solutions for 24 h. Compositional analysis of MCC solutions and cheese was carried out. The yield, color, textural, and rheological measurements of Feta-type cheese were evaluated. Feta-type cheese was also made from whole milk as a control. This experiment was repeated three times. The yield and adjusted yield of Feta-type cheese increased from 19.0 to 54.8 and 21.4 to 56.5, respectively, with increasing the protein content in MCC from 3% to 9%. However, increasing the protein content in MCC did not show significant differences in the hardness (9.2-9.7 kg) of Feta-type cheese. The color of Feta-type cheese was less white with increasing the protein content in MCC. While the yellowish and greenish colors were high in Feta-type cheese made from MCC with 3% and 6% protein, no visible differences were found in the overall cheese color. The rheological characteristics were improved in Feta-type cheese made from MCC with 6% protein. We conclude that MCC with different levels of protein can be utilized in the manufacture of Feta-type cheese.

Optimization of Spiral-Wound Microfiltration Process Parameters for the Production of Micellar Casein Concentrate

A systematic selection of different transmembrane pressures (TMP) and levels of diafiltration (DF) was studied to optimize these critical process parameters during the manufacturing of micellar casein concentrate (MCC) using spiral-wound polymeric membrane filtration. Three TMPs (34.5, 62.1, and 103.4 kPa) and four DF levels (0, 70, 100, and 150%) were applied in the study. The effect of the TMP and DF level on flux rates, serum protein (SP) removal, the casein-to-total-protein ratio, the casein-to-true-protein ratio, and the rejection of casein and SP were evaluated. At all transmembrane pressures, the overall flux increased with increases in the DF level. The impact of DF on the overall flux was more pronounced at lower pressures than at higher pressures. With controlled DF, the instantaneous flux was maintained within 80% of the initial flux for the entire process run. The combination of 34.5 kPa and a DF level of 150% resulted in 81.45% SP removal, and a casein-to-true-protein ratio of 0.96. SP removal data from the lab-scale experiments were fitted into a mathematical model using DF levels and the square of TMPs as factors. The model developed in this study could predict SP removal within 90-95% of actual SP removal achieved from the pilot plant experiments.

Progress in micellar casein concentrate: Production and applications

Micellar casein concentrate (MCC) is a novel ingredient with high casein content. Over the past decade, MCC has emerged as one of the most promising dairy ingredients having applications in beverages, yogurt, cheese, and process cheese products. Industrially, MCC is manufactured by microfiltration (MF) of skim milk and is commercially available as a liquid, concentrated, or dried containing ≥9, ≥22, and ≥80% total protein, respectively. As an ingredient, MCC not only imparts a bland flavor but also offers unique functionalities such as foaming, emulsifying, wetting, dispersibility, heat stability, and water-binding ability. The high protein content of MCC represents a valuable source of fortification in a number of food formulations. For the last 20 years, MCC is utilized in many applications due to the unique physiochemical and functional characteristics. It also has promising applications to eliminate the cost of drying by producing concentrated MCC. This work aims at providing a succinct overview of the historical progress of the MCC, a review on the manufacturing methods, a discussion of MCC properties, varieties, and applications.

GPR120 agonists enhance the fatty orosensation when added to fat-containing system, but do not evoke it by themselves in humans

Dietary fat, an important macronutrient, has been considered to be perceived by texture and olfaction. Recently, fatty acid transporter, CD36, and fatty acid receptor, GPR120 are considered to be involved in human gustatory fatty acids perception in humans. However, limited information is currently available to show that agonists of CD36 and GPR120 evoke fatty oral sensations regarding to dietary fat in humans. Therefore, the role of GPR120 agonists in dietary fat perception in humans was investigated herein. An emulsion prepared from vegetable oil had a stronger fatty orosensation, an orosensation similar to an oily mouth-coating sensed 5 - 10 s after tasting, than that prepared from mineral oil; however, the physical properties of both emulsions, such as viscosity, particle distribution, interfacial tension, contact angle, frictional load, and ζ-electric potential were similar. The potent GPR120 agonist, TUG-891 enhanced the fatty orosensation when added to the emulsion prepared from vegetable oil, but not to that from mineral oil. All GPR120 agonists tested enhanced the fatty orosensation when added to a low-fat food system whereas they did not evoke any fatty sensation in aqueous solution at the concentrations tested in food system, and sensory activity positively correlated with GPR120 activity. These results suggest that GPR120 agonists enhance the fatty orosensation in humans when added to vegetable oil or a low-fat food system, but do not evoke it by themselves.

Properties of Rennet Cheese Made from Whole and Skimmed Summer and Winter Milk on a Traditional Polish Dairy Farm

Simple Summary

Milk from traditional family farms is a valuable raw material for cheese making. The aim of the study was to compare the textural and physicochemical characteristics, as well as the organoleptic properties, of soft rennet cheese from the milk of Polish Holstein–Friesian cows. The tests were carried out on 24 cheeses made from the bulk milk in the two production seasons: summer (July–September) and winter (January–March). The results indicate that both the season and the fat content of the milk affected the physicochemical (acidity, color) and rheological parameters (firmness and stickiness) of the cheese. What is more, the fat content of the milk had a more significant effect on the organoleptic parameters of the cheese than the season. In addition, low-fat cheeses received satisfactory organoleptic assessments, which indicates that they can serve as substitutes for full-fat cheeses for people looking for low-fat products.

Abstract

The aim of this study was to compare the rheological and physicochemical parameters, as well as the organoleptic properties, of soft rennet cheese made from whole and skimmed milk in different seasons on a traditional family farm. We analyzed milk from twenty Polish Holstein–Friesian cows for basic composition, number of somatic cells, acidity, and color in terms of the Comission Internationale de l’Eclairage (CIE) lightness*redness*yellowness (L*a*b*) system, and 24 cheeses in terms of texture, acidity, color in terms of the CIE L*a*b* system, and organoleptic parameters in summer and winter. We determined the effects of the season and the fat content of milk on the pH, titratable acidity, color, firmness, and stickiness of the cheese. Cheeses from summer milk showed greater acidification than those from winter milk (p ≤ 0.05). Skimmed milk cheeses from both seasons showed increased firmness and stickiness, and worse organoleptic characteristics, particularly in taste and consistency, than whole milk cheeses (p ≤ 0.05). The highest level of yellow (b*) was found in whole milk summer cheeses; those produced in winter were 16% less yellow. Milk from traditional family farms is a valuable raw ingredient for the production of soft, unripe rennet cheese. However, the variability of organoleptic characteristics related to the season should be taken into account in cheese production. Skimmed cheese can serve as an alternative to full-fat cheese, especially for people looking for low-fat products, regardless of the time of year.

Ripening of Hard Cheese Produced from Milk Concentrated by Reverse Osmosis

The application of reverse osmosis (RO) for preconcentration of milk (RO-milk) on farms can decrease the overall transportation costs of milk, increase the capacity of cheese production, and may be highly attractive from the cheese manufacturer’s viewpoint. In this study, an attempt was made to produce a hard cheese from RO-milk with a concentration factor of 1.9 (RO-cheese). Proteolysis, volatile profiles, and sensory properties were evaluated throughout six months of RO-cheese ripening. Moderate primary proteolysis took place during RO-cheese ripening: about 70% of α_s1-casein and 45% of β-casein were hydrolyzed by the end of cheese maturation. The total content of free amino acids (FAA) increased from 4.3 to 149.9 mmol kg⁻¹, with Lys, Pro, Glu, Leu, and γ-aminobutyric acid dominating in ripened cheese. In total, 42 volatile compounds were identified at different stages of maturation of RO-cheese; these compounds have previously been found in traditional Gouda-type and hard-type cheeses of prolonged maturation. Fresh RO-cheese was characterized by a milky and buttery flavor, whereas sweetness, saltiness, and umami flavor increased during ripening. Current results prove the feasibility of RO-milk for the production of hard cheese with acceptable sensory characteristics and may encourage further research and implementation of RO technology in cheese manufacture.