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

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

Influence of the temperature of salt brine on salt uptake by Ragusano cheese

The influence of temperature (12, 15, 18, 21, and 24 degrees C) of saturated brine on salt uptake by 3.8-kg experimental blocks of Ragusano cheese during 24 d of brining was determined. Twenty-six 3.8-kg blocks were made on each of three different days. All blocks were labeled and weighed prior to brining. One block was sampled and analyzed prior to brine salting. Five blocks were placed into each of five different brine tanks at different temperatures. One block was removed from each brine tank after 1, 4, 8, 16, and 24 d of brining, weighed, sampled, and analyzed for salt and moisture content. The weight loss by blocks of cheese after 24 d of brining was higher, with increasing brine temperature, and represented the net effect of moisture loss and salt uptake. The total salt uptake and moisture loss increased with increasing brine temperature. Salt penetrates into cheese through the moisture phase within the pore structure of the cheese. Porosity of the cheese structure and viscosity of the water phase within the pores influenced the rate and extent of salt penetration during 24 d of brining. In a previous study, it was determined that salt uptake at 18 degrees C was faster in 18% brine than in saturated brine due to higher moisture and porosity of the exterior portion of the cheese. In the present study, moisture loss occurred from all cheeses at all temperatures and most of the loss was from the exterior portion of the block during the first 4 d of brining. This loss in moisture would be expected to decrease porosity of the exterior portion and act as a barrier to salt penetration. The moisture loss increased with increasing brine temperature. If this decrease in porosity was the only factor influencing salt uptake, then it would be expected that the cheeses at higher brine temperature would have had lower salt content. However, the opposite was true. Brine temperature must have also impacted the viscosity of the aqueous phase of the cheese. Cheese in lower temperature brine would be expected to have higher viscosity of the aqueous phase and slower salt uptake, even though the cheese at lower brine temperature should have had a more porous structure (favoring faster uptake) than cheese at higher brine temperature. Therefore, changing brine concentration has a greater impact on cheese porosity, while changing brine temperature has a larger impact on viscosity of the aqueous phase of the cheese within the pores in the cheese.     

Reducing salt in imitation cheese: Effects on manufacture and functional properties

Imitation cheeses (48% moisture, 0-1.5% NaCl) were manufactured using a Farinograph or Blentech cooker. The effects of NaCl reduction on cheese manufacture, functionality (assessed by texture profile analysis, flowability, dynamic rheology and microscopy), microbiological stability and sensory attributes were investigated. Reducing NaCl concentration decreased processing times and mixing energy required during manufacture and, post-manufacture, decreased cheese hardness, G′ values at 25 °C and crossover temperature and increased fat globule size. Cheeses from both cookers showed the same trend in functionality. Microbial stability was reduced at 0% NaCl, and the sensory panellists preferred the 50% reduced NaCl cheese to the standard.     

温度对市售片状奶酪质构的影响

研究不同温度(4、25℃)对8种片状奶酪的硬度、粘着性、弹性、凝聚性、胶粘性、咀嚼性和回复性等7个功能特性的影响。结果显示,温度从4℃上升到25℃时,硬度、胶粘性、咀嚼性和回复性的平均值分别下降了42%、42%、45%和17%,差异显著(p<0.05);弹性平均下降7%,差异不显著(p>0.05);粘着性和凝聚性的变化方向不一,差异不显著(p>0.05)。和其他品种相比,降低奶酪脂肪含量,奶酪的硬度和咀嚼性分别提高70%和60%以上;温度从4℃上升到25℃时,降脂奶酪的粘着性下降了20%以上,高钙奶酪可以有效维持弹性不变。     

Survival of Lactobacillus casei,Lactobacillus plantarum and Bifidobacterium bifidum in free and microencapsulated forms on Iranian white cheese produced by ultrafiltration

Survival of probiotic strains Lactobacillus casei ( ATCC 39392 ), Lactobacillus plantarum ( ATCC 8014 ) and Bifidobacterium bifidum ( ATCC 29521 ) was investigated either in microencapsulated or in free form in the Iranian white cheese produced by ultrafiltration technique. The results indicated that the survival of encapsulated probiotic bacteria was higher than free cells. Both free and microencapsulated forms were successful in keeping counts of L. casei, L. plantarum and B. bifidum in the cheese high enough for the therapeutic minimum (10⁶–10⁷ cfu/g) after 60 days. Addition of probiotic adjunct also did not alter the chemical composition, but pH was lower in probiotic cheeses.     

Effect of natural cheese characteristics on process cheese properties

Natural cheese is the major ingredient utilized to manufacture process cheese. The objective of the present study was to evaluate the effect of natural cheese characteristics on the chemical and functional properties of process cheese. Three replicates of 8 natural (Cheddar) cheeses with 2 levels of calcium and phosphorus, residual lactose, and salt-to-moisture ratio (S/M) were manufactured. After 2 mo of ripening, each of the 8 natural cheeses was converted to 8 process cheese foods that were balanced for their composition, including moisture, fat, salt, and total protein. In addition to the standard compositional analysis (moisture, fat, salt, and total protein), the chemical properties (pH, total Ca, total P, and intact casein) and the functional properties [texture profile analysis (TPA), modified Schreiber melt test, dynamic stress rheometry, and rapid visco analysis] of the process cheese foods were determined. Natural cheese Ca and P, as well as S/M, significantly increased total Ca and P, pH, and intact casein in the process cheese food. Natural cheese Ca and P and S/M also significantly affected the final functional properties of the process cheese food. With the increase in natural cheese Ca and P and S/M, there was a significant increase in the TPA-hardness and the viscous properties of process cheese food, whereas the meltability of the process cheese food significantly decreased. Consequently, natural cheese characteristics such as Ca and P and S/M have a significant influence on the chemical and the final functional properties of process cheese.     

Interaction of brine concentration, brine temperature, and presalting on salt penetration in Ragusano cheese

Thirty-one 3.6-kg blocks of Ragusano cheese were made on each of 6 different days (in different weeks) starting with a different batch of milk on each day. On d 1, 3, and 5, the cheeses were not presalted and on d 2, 4, and 6, all cheeses were presalted (PS). One of the 31 blocks of cheese was selected at random for analysis before brine salting (i.e., on d 0). The remaining 30 blocks were randomly divided into 2 groups of 15 blocks each; one group was placed in 18% brine (18%B) and the other group was placed in saturated brine (SB). For the 15 blocks within each of the 2 brine concentrations (BC), 5 blocks were placed in a brine tank at 12° C, 5 at 15° C, and 5 at 18° C, and submerged for 24 d. The research objective was to determine the combined impacts (i.e., interactions) of PS the curd before stretching, BC (SB vs. 18%B), and brine temperature (BT; 12, 15, and 18° C) on salt uptake, moisture content, and yield of Ragusano cheese. Although BC, BT, and PS each had their own separate impacts on salt uptake, there was little interaction of these effects on salt uptake when they were used in combination. The PS most quickly delivered salt to the interior of the cheese and was the most effective approach to salting for controlling early gas formation. There were strong separate impacts of BC, BT, and PS on cheese moisture content, moisture loss, and net weight loss, with BC having the largest separate impact on these parameters. Reducing BT reduced salt content and increased moisture, but the effects were small. The more important effect of reduced BT was to reduce growth of gas forming bacteria. The 18%B produced higher moisture, and less moisture and weight loss than SB. The effect of interactions of BC, BT, and PS on moisture loss and net weight loss were small. To achieve the maximum benefit from the various approaches to salting for controlling early gas formation in Ragusano cheese, PS combined with slightly lower BT (i.e., 15° C instead of 18° C) should be used. Although using 18%B instead of SB did increase salt uptake, the point at which improved salt uptake occurred due to use of 18%B did not provide benefit in prevention of early gas formation, as reported separately. However, use of 18%B instead of SB provided a 9.98% increase in cheese yield due to reduced moisture loss during brining; this would be very attractive to cheese makers. The increase in yield needs to be balanced against the risk of growth of undesirable bacteria in the 18%B and the creation of another cheese quality defect.     

Effects of starter culture combinations using isolates from traditional cheese on the quality of Turkish white cheese

Four types of Turkish white cheese with good curd and acid formation properties were produced, one by using commercial starter culture and the other three by using different combinations of isolates from traditional cheese with no starters added. The effects of using these combinations on quality were determined. Starter culture combinations did not influence the chemical properties of cheese significantly. However, one cheese type produced from combinations of isolates of rural cheese was found to be comparable to the samples produced from commercial starter cultures in terms of sensory and microbial quality. This combination could have promise for white cheese production.     

Probiotic white cheese with Lactobacillus acidophilus

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

乳化盐对干酪粉物理化学特性的影响

研究了焦磷酸钠、磷酸氢二钠、柠檬酸钠、三聚磷酸钠及它们的复合盐（磷酸氢二钠＋柠檬酸钠、三聚磷酸钠＋柠檬酸钠）对喷雾前干酪浆的表观黏度、pH值、可溶性氮含量；干酪粉的容重、溶解度、水分含量、游离脂肪酸含量、感官评价等物理化学特性的影响。结果表明，添加不同的乳化盐对干酪粉的水分含量、游离脂肪酸含量有显著影响（p〈0．05），添加量（2％-4％之间）对干酪粉的水分含量影响显著（P〈0．05）。当三聚磷酸钠与柠檬酸钠比为1：1，添加量为原料干酪的3．0％左右时，干酪粉有较好的物理化学特性，而且感官评分最高。     

Petit suisse manufactured with cheese whey retentate and application of betalains and anthocyanins

Petit suisse cheese was elaborated with substitution of 30% milk volume for cheese whey retentate (volumetric reduction ratio=5.0) obtained by ultrafiltration (cheese 1) and 100% milk (cheese 2). These were evaluated regarding physicochemical composition: moisture, ash, total solids, lipids, total proteins, acidity in lactic acid and pH. Natural pigments were added to the cheeses: Cabernet Sauvignon (Vitis vinifera L.) grape anthocyanins or (Beta vulgaris L.) beetroot betalains. The cheese samples were maintained at 6±1 °C for 40 days in light-impermeable packaging and evaluated regarding pigment stability by determining half-life time and percentage color retention. The results of the physicochemical analyses demonstrated that significant differences occurred between cheeses 1 and 2 regarding total solid content, moisture, protein, lipids and carbohydrates. The half-life time and percentage color retention values obtained for the anthocyanin and betalain extracts added to the cheeses were adequate for the shelf life of this product.     

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

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

成熟温度对Mozzarella干酪蛋白水解和质构的影响

研究了温度为4,7,10℃时对干酪成熟过程中蛋白水解和质地的影响。结果表明,随着干酪成熟温度的升高,成熟期间干酪中可溶性氮与总氮的比值增加较快,干酪的硬度下降速度也较快。说明在较高的成熟温度下,干酪在较短的时间内能够达到成熟的状态。     

Salting and the role of salt in cheese

Salt levels in cheese range from ∼0.7% (w/w) in Swiss-type to ∼6% (w/w) in Domiati. Salt has three major functions in cheese: it acts as a preservative, contributes directly to flavour, and is a source of dietary sodium. Together with the desired pH, water activity and redox potential, salt assists in cheese preservation by minimizing spoilage and preventing the growth of pathogens. The dietary intake of sodium in the modern western diet is generally excessive, being two to three times the level recommended for desirable physiological function (2.4 g Na, or ∼6 g NaCl per day). However, cheese generally makes a relatively small contribution to dietary sodium intake except if high quantities of high-salt cheeses such as Domiati and feta are consumed. In addition to these functions, salt level has a major effect on cheese composition, microbial growth, enzymatic activities and biochemical changes, such as glycolysis, proteolysis, lipolysis and para -casein hydration, that occur during ripening. Consequently, the salt level markedly influences cheese flavour and aroma, rheology and texture properties, cooking performance and, hence, overall quality. Many factors affect salt uptake and distribution in cheese and precise control of these factors is a vital part of the cheesemaking process to ensure consistent, optimum quality.     

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

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

Use of low concentration factor ultrafiltration retentates in reduced-fat Minas Frescal cheese manufacture: effect on yield and sensory properties

The yield and sensory properties of reduced-fat Minas Frescal cheese made from low concentration factor (CF) retentates were studied. Three different CFs were tested (1.2, 1.5 and 1.8). The chemical compositions of the milk, retentate, whey and cheese were determined, as well as the cheese yield. The cheese moisture content decreased with increasing CF. The cheese yield was significantly dependent on the CF in the same direction as the moisture content. Despite compositional differences among the samples, only the cheese made with a CF of 1.8 presented low sensorial acceptance. CF 1.2 was found to be the optimum value for reduced-fat Minas Frescal cheese manufacture in the CF range studied.     

Variation in organic acids content during ripening of pickled white cheese

Nine organic acids (formic, pyruvic, lactic, acetic, orotic, citric, uric, propionic, and butyric) were analyzed during ripening of pickled White cheese for 12 mo by high-performance liquid chromatography with a reverse phase C18 (120x 5-mm) column and UV detector. The level oftotal organic acids showed an increase along the ripening period, but its composition varied during the process. Initially, lactic acid accounted for 95% of the total, after 9 and 12 mo of ripening, butyric acid constituted 20 and 27% of the total, respectively. Each organic acid presented a characteristic pattern of change during ripening. Discriminant analysis classified cheeses according to their age. Stepwise regression analysis allowed estimation of the ripening time of samples according to their organic acid levels.     

不同亲水胶体对再制奶油奶酪品质的影响

通过研究刺槐豆胶、卡拉胶、海藻酸钠、瓜尔豆胶和黄原胶5种不同亲水胶体对以切达奶酪为原料,直接酸化法得到的再制奶油奶酪品质的影响,来选择较佳的亲水胶体方案。实验结果表明,亲水胶体对样品各方面的性质影响显著,对持水性和持油性的影响尤为明显。本体系适用不凝胶的亲水胶体。黄原胶和刺槐豆胶是最佳的选择,并建议2种胶体单独使用。     

Influence of presalting and brine concentration on salt uptake by Ragusano cheese

The impact of presalting and nonsaturated brine on salt uptake by Ragusano cheese was determined. The study included four treatments: 1) the traditional method using no presalting and saturated brine, 2) presalting and saturated brine, 3) no presalting and 18% brine for 8 d followed by 16 d in saturated brine, and 4) presalting and 18% brine for 8 d followed by 16 d in saturated brine. Cheese blocks were weighed and sampled before brine salting (time 0) and after 1, 4, 8, 16, and 24 d of brining for each treatment. Presalting delivered 60% of the normal level of salt in the center of the block prior to brine salting without decreasing the rate of uptake of salt from either saturated or 18% brine. Use of 18% salt brine for the first 8 d of 24 d of brine salting increased the rate of salt uptake, compared with 24 d in saturated brine. The increased rate of salt uptake with 18% brine compared with saturated brine was related to the impact of salt brine on the moisture content and porosity of the cheese near the surface of the block. Brine with higher salt content causes a rapid loss of moisture from cheese near the surface of the block. Moisture loss causes shrinkage of the cheese structure and decreases porosity, which impedes moisture movement out and salt movement into the block. The use of 18% salt brine for the first 8 d delayed the moisture loss and cheese shrinkage at the exterior of the block and allowed more salt penetration.     

Relationships between proteolytic and lipolytic activity and sensory properties (taste–odour) of traditional Turkish white cheese

Protein and lipid changes and their effects on the sensory properties (taste–odour) of Turkish white cheese were studied. Mean values for the chemical properties of white cheese were: total solids (TS) 44.39 g/100 g; titratable acidity 2.15% (as lactic acid); pH value 4.50; fat-in-dry matter 47.80 g/100 g; salt-in-dry matter 8.65 g/100 g; total nitrogen (TN) 2.50 g/100 g; water-soluble nitrogen (WSN) 0.48 g/100 g; ripening index (RI) 18.98%; tyrosine 65.00 mg/100 g; acid degree value (ADV) 385.96 mg KOH/100 g fat; volatile fatty acids (VFA) 15.54 mL 0.1 N NaOH/100 g and total free fatty acids (TFFA) 1325.96 mg/100 g cheese. Sensory scores for taste and odour were 23.67 (out of 35) and 8.28 (out of 10), respectively. The chemical qualities of the cheeses, including acidity, dry matter, fat-in-dry matter and VFA had an effect on flavour ( P  < 0.05).