益生菌干酪的研究现状

干酪是保存益生菌的优良基质。它本身具有较高的pH和脂肪含量,能有效地保护益生菌免受胃肠道中不利条件的迫害。主要介绍了干酪中主要的益生菌类型及干酪贮藏过程中蛋白质、脂肪和质构的变化情况,为益生菌干酪的开发提供参考。     

一种硬质蒙古干酪的感官评价研究

对蒙古干酪的颜色、质构、微观结构和感官品评进行了研究。蒙古干酪外部亮度稍暗,偏微红色,内部干酪颜色趋向于纯色。在质构上,其硬度、弹性、黏着性和回复性分别为23.18 N、47.25、7.40和5.60,在硬度上和Cheddar干酪类似,但是其他3个方面要差一些。蒙古干酪具有致密的酪蛋白胶束组成微观结构,脂肪脱去形成的孔洞很少。蒙古干酪的综合感官分为69.23分,由于质地和口感的原因使得得分较低,但仍在可接受范围内。     

Textural Characterization of Cheeses Using Vane Rheometry and Torsion Analysis

ABSTRACT Vane rheometry was applied to textural characterization of cheeses and compared with torsion analysis. A Haake VT 550 viscotester was used for both vane and torsion tests at strain rates of 0.003 to 0.524 s^-1. Angular deformation and shear stress in the vane test increased with increasing low strain rate and was rate independent at higher rates. This shear rate dependency of stress and deformation varied with cheese types. Shear stresses from the vane method were lower than torsion shear stresses. Similar texture maps of cheeses were generated by plotting stress and strain or angular deformation values from the 2 testing methods. The findings indicate the vane technique can be used for rapid textural characterization of cheeses.     

Chemical, physical, and sensorial characteristics of "Terrincho" ewe cheese: changes during ripening and intravarietal comparison

The objectives of this study were to monitor the changes in chemical [moisture, acidity, pH, and water activity (a(w))] and physical (color and texture) parameters of "Terrincho" ewe cheese during 60 d of ripening, and to determine the correlations between the changes in instrumental texture and color parameters and the ripening time of the product. Intravarietal comparison of Terrincho ewe cheese from 5 different dairy plants was performed by evaluation of mechanical parameters from texture profile analysis (TPA) and color parameters in terms of CIELAB color space (L*, a*, and b*). In addition to mechanical and color tests, composition analyses and sensory tests were performed. The results were evaluated with statistical methods (single valued and multivariate analysis). During the first 20 d of ripening, an increase in hardness, fracturability, gumminess, chewiness, and yellowness occurred. Simultaneously, adhesiveness, resilience, L* (inside cheese, "i" and external "e"), and cohesiveness decreased. After 20 d of ripening hardness, fracturability, gumminess, and chewiness decreased and cohesiveness increased. The ripening time of Terrincho cheeses can be estimated with 6 variables: L* (external, e), L* (i), b* (inside cheese, i), hardness, a* (i), chewiness, and a constant. The estimation error was 4.2 d. Evaluation of composition, pH, texture profile analyses, color, and related sensory characteristics of Terrincho cheeses from 5 different dairy plants (with 30 d of ripening) revealed correlations between these parameters.     

超高压处理对干酪质构的影响

研究超高压(Ultra High Hydrostatic Pressure,HHP;200,600 MPa/10min)处理对5种市售干酪的硬度、黏着性、弹性、内聚性、咀嚼性和回复性6个功能特性的影响。结果显示,5种干酪在200 MPa处理时,其黏着性、弹性、内聚性、回复性差异不显著(P0.05),即较低压力处理对干酪的质构影响不大;超高压处理后,干酪的硬度和耐咀性分别降低31%,39%,且压力越大降低越显著(P0.05);高压处理后蓝纹、稀奶油干酪的内聚性分别增加了21%,15%;帕马森、切达干酪经超高压处理其各个性质基本无显著变化,而马索里拉、蓝纹、稀奶油干酪的各个功能性均有显著差异,说明超高压处理对干酪质构的影响与水分含量有关,即水分含量越高的干酪其质构受超高压处理变化越显著。     

Manufacture of magnesium-fortified Chihuahua cheese

The aim of this study was to manufacture magnesium-fortified Chihuahua cheese and to evaluate the effect of magnesium fortification on quality parameters. Addition of magnesium chloride to milk during pasteurization (5.44, 10.80, 16.40, 22.00, and 25.20 g of MgCl₂·6H₂O/L of milk) resulted in cheese with increased magnesium content, proportional to the amount of magnesium added (up to 2,957.13 mg of Mg/kg of cheese). As magnesium content increased, coagulation time and moisture content also increased, whereas calcium content decreased. Higher levels of magnesium fortification (16.40 g of MgCl₂·6H₂O/L of milk or more) induced the development of bitter-acid flavors and softer texture. Addition of 10.80 g of MgCl₂·6H₂O/L to milk resulted in Chihuahua cheese that meets regulatory standards and possesses physicochemical and sensory characteristics similar to those of nonfortified Chihuahua cheese. Under this milk fortification level, the manufactured cheese is able to provide 148.4 mg of magnesium per day (35% of the recommended daily intake of magnesium for adult males and 46% for adult females) assuming 3 portions (28 g each) are consumed.     

Influence of emulsifying salts on the textural properties of nonfat process cheese made from direct acid cheese bases

The objective of this study was to investigate the influence of several types of emulsifying salts (ES) on the texture of nonfat process cheese (NFPC). Improperly produced nonfat cheese tends to exhibit several problems upon baking including stickiness, insufficient or excessive melt, pale color upon cooling, formation of a dry skin (skinning) often leading to dark blistering, and chewy texture. These attributes are due to the strength and number of interactions between and among casein molecules. We propose to disrupt these interactions by using suitable emulsifying salts (ES). These ES chelate Ca and disperse caseins. Stirred curd cheese bases were made from skim milk using direct acidification with lactic acid to pH values 5.0, 5.2, and 5.4, and ripened for 1 d. Various levels of trisodium citrate (TSC; 0.5, 1, 1.5, 2, 2.5, 3, and 5%), disodium phosphate (DSP; 1, 2, 3, and 4%), or trisodium phosphate (TSP; 1, 2, 3, and 4%) were blended with the nonfat cheese base. Cheese, ES, and water were weighed into a steel container, which was placed in a waterbath at 98°C and then stirred using an overhead stirrer for 9 min. Molten cheese was poured into plastic containers, sealed, and stored at 4°C for 7 d before analysis. Texture and melting properties were determined using texture profile analysis and the UW-Melt-profiler. The pH 5.2 and 5.4 cheese bases were sticky during manufacture and had a pale straw-like color, whereas the pH 5.0 curd was white. Total calcium contents were approximately 400, 185, and 139 mg/100 g for pH 5.4, 5.2, and 5.0 cheeses, respectively. Addition of DSP resulted in NFPC with the lowest extent of flow, and crystal formation was apparent at DSP levels above 2%. The NFPC manufactured from the pH 5.0 base and using TSP had reduced melt and increased stickiness, whereas melt was significantly increased and stickiness was reduced in NFPC made with pH 5.4 base and TSP. However, for NFPC made from the pH 5.4 cheese and with 1% TSP, the pH value was >6.20 and crystals were observed within a few days. Use of TSC increased extent of flow up to a maximum with the addition of 2% ES for all 3 types of cheese bases. Addition of high levels of TSC to the pH 5.2 and 5.4 cheese bases resulted in increased stickiness. Similar pH trends for attributes such as extent of flow, hardness, and adhesiveness were observed for both phosphate ES but no consistent pH trends were observed for the NFPC made with TSC. These initial trials suggest that the pH 5.0 cheese base was promising for further research and scale-up to pilot-scale process cheese making, because cheeses had a creamy color, reasonable melt, and did not have high adhesiveness when TSC was used as the ES. However, the acid whey produced from the pH 5.0 curd could be a concern.     

The effect of substituting NaCl with KCl on Nabulsi cheese: chemical composition, total viable count, and texture profile

The effect of substituting NaCl with KCl on Nabulsi cheese characteristics was investigated. Nabulsi cheese was made and stored in 4 different brine solutions at 18%, including NaCl only (A; control); 3NaCl:1KCl (wt/wt; B); 1NaCl:1KCl (wt/wt; C); and 1NaCl:3KCl (wt/wt; D). Chemical composition, proteolysis, total viable count, and texture profile analysis were assessed at monthly intervals for 5 mo. No significant effect was found among experimental cheeses in terms of chemical composition or texture profile. Proteolytic activities were higher in cheeses kept in brine solutions that contained higher KCl (B, C, and D) compared with the control. At the end of the storage period, water-soluble nitrogen in Nabulsi cheeses stored in B, C, and D was higher than that in the control cheese (A). In addition, total viable count increased significantly after 1 mo of storage for all salt treatments. Hardness and gumminess generally decreased significantly during storage within the same salt treatment.     

Instron texture profile of buffalo milk cheddar cheese as influenced by composition and ripening changes

Buffalo milk Cheddar cheese samples of different ages were analysed for compositional attributes (CA), ripening indices (RI) and Instron Textural Profile (ITP). All samples were compositionally alike, except for pH and salt-in-moisture (SM) contents. RI showed significant variations. CA and RI showed highly significant correlations within themselves and with each other, except for moisture with pH, SM with moisture, MNFS, Fat and FDM and Fat with MNFS. The ITPs of cheeses showed significant variations and had highly significant intercorrelations indicating their interdependence. CA (except moisture and MNFS) and RI showed a highly significant correlationship with ITPs. Moisture content showed a highly significant correlationship with all ITPs, except cohesiveness and springiness, where it was significant. MNFS content showed significant correlations only with hardness and brittleness. Stepwise regression analysis revealed that MI was the most predominant factor influencing cheese texture, followed by pH, SM, FDM and TVFA. Knowing Ca and RI, the textural properties of cheeses can be forecast through mathematical equations. Similarly the age of cheese can also be predicted if RI and/or textural properties are known.     

钢丝的扭转性能分析

对国产和进口钢丝的试样分别进行扭转性能的测试并对结果进行分析,从钢丝的试样尺寸、表面缺陷、内部质量均匀性、钢丝织构化程度等方面讨论影响扭转性能的主要因素,指出在其他条件相同的情况下,织构化程度高的钢丝具有较低的扭转次数。     

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

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

The effect of natural cheddar cheese ripening on the functional and textural properties of the processed cheese manufactured therefrom

ABSTRACT:  Cheddar cheese ripened at 8 °C was sampled at 7, 14, 28, 56, 112, and 168 d and subsequently used for the manufacture of processed cheese. The cheddar cheese samples were analyzed throughout ripening for proteolysis while the textural and rheological properties of the processed cheeses (PCs) were studied. The rate of proteolysis was the greatest in the first 28 d of cheddar cheese ripening but began to slow down as ripening progressed from 28 to 168 d. A similar trend was observed in changes to the texture of the PC samples, with the greatest decrease in hardness and increase in flowability being in the first 28 d of ripening. Confocal scanning laser microscopy showed that the degree of emulsification in the PC samples increased as the maturity of the cheddar cheese ingredient increased from 7 to 168 d. This increased emulsification resulted in a reduction in the rate of softening in the PC in samples manufactured from cheddar cheese bases at later ripening times. Multivariate data analysis was performed to summarize the relationships between proteolysis in the cheddar cheese bases and textural properties of the PC made therefrom. The proportion of α _{s 1}-casein (CN) in the cheddar cheese base was strongly correlated with hardness, adhesiveness, fracturability, springiness, and storage modulus values for the corresponding PC. Degradation of α _{s 1}-CN was the proteolytic event with the strongest correlation to the softening of PC samples, particularly those manufactured from cheddar cheese in the first 28 d of ripening.     

大豆分离蛋白对涂抹型再制干酪质构的影响

添加大豆蛋白可降低涂抹型再制干酪的成本，但也会对再制干酪的质构产生一定的影响。设计4因素3水平正交实验．应用TA—XT2i型物性分析仪考察添加了大豆蛋白后的再制干酪产品的质构变化，使用Statistix 8.0统计分析软件对实验结果进行统计分析并作出比较和对正交试验作极差分析。结果表明，4个因素在水平不同的9组正交实验的结果的差异性显著（p〈0.05），在极差分析中，4个因素对硬度的影响排序为D〉C〉A〉B；4个因素对剪切功的影响排序为D〉A〉B〉C；4个因素对粘着性的影响排序为A〉B〉D〉C；4个因素对感官评价的影响排序为A〉D〉C〉B。最后重做不同的最优组并再次测定各项指标，得到最好的组合为大豆蛋白添加量6％．黄油添加量10％，乳化盐添加量1、5％，加水量50％（均为质量分数，下同）。     

工艺参数对再制干酪的质构和流变性质的影响

利用质构仪和流变仪对影响再制干酪品质的多个因素进行了研究。结果表明，水分影响再制干酪的质构和流变性质：乳化盐对再制干酪产品的质构没有显著的影响；不同的温度和不同的搅拌时间对样品的质构有着相似的变化；在所有加工条件下．再制干酪的G′始终大于G″，G′和G″没有交叉点，而且复合黏度η^＊随着频率的增加而急剧降低，体系表现出了弱凝胶的特性。     

Relationships between cheese-processing conditions and curd and cheese properties to improve the yield of Idiazabal cheese made in small artisan dairies: A multivariate approach

Very diverse cutting and cooking intensity processes are currently used in small artisan dairies to manufacture Idiazabal cheese. The combination of the technical settings used during cheese manufacturing is known to affect cheese composition and yield, as well as whey losses. However, the information regarding the effect on microstructure and texture of cheese is scarce, especially in commercial productions. Therefore, the effect of moderate- and high-intensity cutting and cooking processes on whey losses, curd-grain characteristics, microstructure and cheese properties, and yield were analyzed. Three trials were monitored in each of 2 different small dairies during the cheesemaking of Idiazabal cheese, which is a semihard cheese made from raw sheep milk. The role and know-how of the cheesemakers are crucial in these productions because they determine the cutting point and handle semi-automatic vats. The 2 dairies studied used the following settings: dairy A used moderate-intensity cutting and cooking conditions, and dairy B used high-intensity cutting and cooking settings. Multiple relationships between cheese-processing conditions and curd, whey, and cheese properties as well as yield were obtained from a partial least square regression analysis. An increased amount of fat and casein losses were generated due to a combination of an excessively firm gel at cutting point together with high-intensity cutting and cooking processes. The microstructural analysis revealed that the porosity of the protein matrix of curd grains after cooking and cheese after pressing was the main feature affected, developing a less porous structure with a more intense process. Moderate-intensity cutting and cooking processes were associated with a higher cheese yield, regardless of the longer pressing process applied. No significant differences were observed in cheese composition. After 1 mo of ripening, however, the cheese was more brittle and adhesive when the high-intensity cutting and cooking process was applied. This could be associated with the composition, characteristics, and size distribution of curd grains due to differences in the compaction degree during pressing. These results could help to modify specific conditions used in cheesemaking, especially improving the process in those small dairies where the role of the cheesemaker is crucial.     

Reduced fat process cheese made from young reduced fat Cheddar cheese manufactured with exopolysaccharide-producing cultures

In a previous study, exopolysaccharide (EPS)-producing cultures improved textural and functional properties of reduced fat Cheddar cheese. Because base cheese has an impact on the characteristics of process cheese, we hypothesized that the use of EPS-producing cultures in making base reduced fat Cheddar cheese (BRFCC) would allow utilization of more young cheeses in making reduced fat process cheese. The objective of this study was to evaluate characteristics of reduced fat process cheese made from young BRFCC containing EPS as compared with those in cheese made from a 50/50 blend of young and aged EPS-negative cheeses. Reduced fat process cheeses were manufactured using young (2 d) or 1-mo-old EPS-positive or negative BRFCC. Moisture and fat of reduced fat process cheese were standardized to 49 and 21%, respectively. Enzyme modified cheese was incorporated to provide flavor of aged cheese. Exopolysaccharide-positive reduced fat process cheese was softer, less chewy and gummy, and exhibited lower viscoelastic moduli than the EPS-negative cheeses. The hardness, chewiness, and viscoelastic moduli were lower in reduced fat process cheeses made from 1-mo-old BRFCC than in the corresponding cheeses made from 2-d-old BRFCC. This could be because of more extensive proteolysis and lower pH in the former cheeses. Sensory scores for texture of EPS-positive reduced fat process cheeses were higher than those of the EPS-negative cheeses. Panelists did not detect differences in flavor between cheeses made with enzyme modified cheese and aged cheese. No correlations were found between the physical and melting properties of base cheese and process cheese.     

干酪流变学性质及其对质地的影响

综述了关于流变学性质方面的构成因素、影响因素、作用机理、对质地的影响以及酪蛋白凝胶结构的形成机理和它对流变学特性的影响。同时讨论了分子问相互作用对流变学性质的作用机理和加工条件对它的影响情况。通过对流变学和质地性质的研究，将有助于干酪生产者更好的地预测和控制产品的质量。