原辅料对再制马苏里拉干酪品质特性的影响

以天然马苏里拉干酪为目标,以干酪融化后特性(融化性、油脂析出率、拉伸性和褐变性)、感官、微观结构为指标,研究原辅料对再制马苏里拉干酪融化后品质特性的影响。结果表明:选择比例为1∶1(m/m,下同)的成熟度为3个月切达干酪和马苏里拉干酪,配合比例为1∶4色拉油和奶油进行再制马苏里拉干酪的制作,既保证了再制干酪所需的质构,同时也赋予产品特有的风味;添加量为1.3%的乳化盐和2.0%的柠檬酸能提供再制干酪所需的乳化性和合理的p H值,产品的加工特性最佳。     

超高压处理对再制奶油干酪质构、流变学特性及微观结构的影响

以低饱和脂肪酸的再制奶油干酪为研究对象,探究不同条件超高压处理（压力：150、300、450 MPa;保压时间：10 min;保压温度：25 ℃）对再制奶油干酪质构、流变学特性及微观结构的影响。通过SPSS软件分析压力变化与干酪水分质量分数、水分活度、pH值及质构特性的相关性,通过质构分析仪测定干酪质构特性（涂抹性、硬度、黏合性及黏聚力）的变化,并使用流变仪分析干酪流变学特性变化;同时采用扫描电子显微镜观察干酪微观结构的变化。结果表明,随着压力的增加,干酪的水分质量分数变化不明显,150 MPa处理组干酪的水分活度显著高于其他组干酪（P＜0.05）;压力越大,干酪pH值越高;压力与水分质量分数正相关,相关系数为0.646,与水分活度负相关,相关系数为－0.346,压力与pH值、涂抹性、硬度、黏合性、黏聚力呈显著正相关,相关系数分别为0.963、0.959、0.951、0.956、0.956;超高压处理可以降低干酪黏度对温度的依赖性,增加了干酪网络结构的稳定性; 150 MPa和450 MPa条件下的干酪弹性模量与黏性模量高于对照组,黏弹性较好;超高压处理影响干酪微观结构变化,压力越大,图像中孔洞数量越少,蛋白质基质更加光滑和均匀,结构更加紧密。综上,超高压处理与再制奶油干酪质构、流变性和微观结构关系密切,研究结果可为超高压干酪的工艺研发提供数据参考。     

天然Mozzarella干酪和再制Mozzarella干酪理化特性和功能特性的比较

对天然Mozzarella干酪和再制Mozzarella干酪的理化特性（蛋白质、脂肪和水分质量分数及pH值）和功能 特性（质构特性、拉伸性、熔化性、油脂析出性和流变特性）进行分析。结果表明：天然Mozzarella干酪的蛋白质 量分数显著高于再制Mozzarella干酪,水分质量分数和pH值显著低于再制Mozzarella干酪,脂肪质量分数随干酪品 牌的不同存在差异;天然Mozzarella干酪的硬度、拉伸性、熔化性和油脂析出性都显著高于再制Mozzarella干酪;动 态温度扫描显示天然Mozzarella干酪和再制Mozzarella干酪的损耗角正切都随着温度的升高呈现先增加后降低的趋 势,天然Mozzarella干酪的损耗角正切在50～60 ℃时达到1,再制Mozzarella干酪的损耗角正切始终低于1。研究发 现天然Mozzarella干酪更适宜作为制作比萨、焗饭等需要焙烤食品的原料,再制Mozzarella干酪可以应用于三明治等 不需要焙烤的食品中。     

乳化温度对融化干酪品质的影响

研究了乳化温度对融化干酪的品质的影响。通过对融化干酪质构分析、微观结构和感官评价测定,比较了60、65、70、75、80℃五个水平温度对融化干酪品质的影响。试验结果表明,乳化温度70℃时,融化干酪具有较高的恢复性、黏聚性、黏着性和弹性,最低的硬度、咀嚼性、胶着性;融化干酪中的酪蛋白和脂肪球相对较小,分布比较均匀,新的蛋白质网络结构形成,整个体系处于一个较好的乳化状态;融化干酪的硬度适中、组织状态光滑无颗粒、口感风味良好、切片性较好。     

不同植物油脂在再制奶油干酪中的应用

为研究不同种类的植物油脂替代黄油在再制奶油干酪中的应用以及对品质的影响,测定了不同种类植物油脂制作的再制奶油干酪的质构特性、乳清析出率、油脂析出率以及感官评定,并进行比较分析。结果表明,添加玉米油和葵花籽油的奶油干酪硬度与对照组干酪相接近,分别减小了13.29%和增加了3.13%,但总体差异不显著(P0.05)。添加葵花籽油的奶油干酪涂抹性与对照组相比,增加了1.27%,数值上最为接近。在黏聚力和黏着性方面,添加稻米油和椰子油的奶油干酪与对照组相比,差异较为明显(P0.05)。添加玉米油的奶油干酪乳清析出率要优于对照组干酪,而添加其他植物油脂的奶油干酪乳清析出较为严重(P0.05)。添加葵花籽油的干酪的油脂析出率最大,为6.19%,显著高于对照组干酪(1.82%);添加玉米油的奶油干酪的油脂析出率稍大于对照组,但差异不显著(P0.05)。感官分析上,添加植物油脂制作的奶油干酪总得分都低于对照组干酪,由玉米油植物清香风味和黄油的乳香味结合带来的干酪的风味接受度要高于其他植物油脂制作的干酪。综合各项指标,玉米油是替代黄油作为再制奶油干酪原料油脂较好的植物油脂选择。     

热变性乳清蛋白-黄油乳液凝胶对减钠再制干酪品质的影响

再制干酪中较高的钠含量被越来越多的消费者所关注。再制干酪中钠主要来自于原制干酪及乳化盐。乳化盐主要作用是促进脂肪在体系中均匀分布,使蛋白质、脂肪等形成均匀的网络体系。本研究利用热变性乳清蛋白对黄油进行预乳化处理,形成乳清蛋白-黄油乳液凝胶(WPI-EG)后,将其用于干酪加工,检测减钠再制干酪的油析性、融化性、质构及微观结构等,评价热变性乳清蛋白预乳化工艺对减钠再制干酪品质的影响。结果表明:预乳化工艺中WPI-EG的形成能够有效促进再制干酪中脂肪均匀分布,形成均匀的结构和质地。预乳化工艺提高了再制干酪的硬度、胶着度和咀嚼度,降低了干酪的油析性。降低30%含钠乳化盐的预乳化再制干酪(30%EC)与未预乳化的干酪(NEC)相比,钠含量降低52.9 mg/100 g,硬度增加27.1%,油析性降低0.53 cm。微观结构显示:30%EC样品脂肪分布及蛋白网络结构更加均匀、致密。本研究结果说明预乳化工艺能够有效降低再制干酪中含钠乳化盐添加量,改善干酪品质。     

非成熟Mozzarella干酪的品质研究

通过改进传统Mozzarella干酪的工艺,制备了非成熟Mozzarella干酪,使用质构测定仪、改良的Schreiber实验法、电子显微等方法分别测定了样品的TPA质构、融化性、油脂析出性、拉丝性和微观结构.结果表明,非成熟Mozzarella干酪的功能特性与传统Mozzarella干酪相比有所提高;微观结构显示成熟...     

模拟Mozzarella干酪工艺参数优化的研究

模拟Mozzarella干酪是一种类似天然干酪的产品。为使其品质更接近于天然Mozzarella干酪,研究了以干酪的质构、融化性、拉伸性和油脂析出性为指标,对生产工艺中的几个关键工艺参数进行优化。结果表明,融化温度、搅拌时间和搅拌速度对模拟Mozzarella干酪未融化时的物理特性和融化时的主要功能特性都有极显著性影响(P<0.01);融化温度为85℃,搅拌时间(加柠檬酸前)为5min,搅拌速度为250r/min时加工的模拟干酪的品质最接近于天然Mozzarella干酪。因此,在模拟Mozzarella干酪的加工工艺中选择融化温度85℃,搅拌时间5min,搅拌速度250r/min。     

凝乳粒的pH值对融化干酪品质的影响

研究了凝乳粒的p H值对融化干酪的品质的影响。通过对融化干酪主要成分、感官评价、质构分析和微观结构的测定,比较了凝乳粒p H值为6.0、5.8、5.6、5.4、5.2对融化干酪品质的影响。结果表明:随着p H值的降低,融化干酪的脂肪含量和蛋白质含量逐渐减少,含水率增加;凝乳粒p H值为5.6时,切面光滑平整、组织状态均一、口感细腻;具有最高的恢复性,硬度适中,较低的咀嚼度、胶着性、黏聚性和弹性;融化干酪的网络结构更加密实,质地均匀,融化干酪整个体系有最佳的乳化效果。     

玉米油在再制奶油干酪中的应用及其对品质的影响

研究不同比例玉米油取代黄油在再制奶油干酪中的应用及对品质的影响。测定不同油脂比例再制奶油干酪的硬度、涂抹性、黏聚力、黏着性、乳清析出率、油脂析出率及感官评定,并进行比较分析。结果表明,黄油与玉米油提供的油脂比例为4︰1和3︰1时制得的试验组干酪与全黄油制得的对照组干酪相比,在质构特性上均无显著性差异(p0.05)。感官分析表明,干酪中油脂提供比例为3︰1,即玉米油提供油脂比例为25%时,试验组与对照组干酪表现最为接近(p0.05)。但油脂提供比例为2︰1时,试验组与对照组干酪在质构及感官评价方面差异均较为明显(p0.05)。结果表明,玉米油能以25%的比例取代黄油应用于再制奶油干酪的生产。     

水分添加量对常温保存再制奶酪品质的影响

以实验室自制Mozzarella奶酪为主要原料研究了的常温保存再制奶酪,经过切割、加热融化、UHT超高温瞬时灭菌等工艺,利用质构仪、扫描电镜等仪器分析水分添加量对常温保存再制奶酪品质的影响。结果表明:水分添加量对再制奶酪的融化性和溶胶系数均有显著增大的趋势(P<0.05);而对再制奶酪物性中的硬度、黏着性、咀嚼性有相似的减小的趋势;水分对酪蛋白的乳化作用的影响体现在溶胶系数和pH值的增大,以及脂肪球的分散和数量减少,在一定范围内水分增加对酪蛋白乳化作用越好。     

Mechanisms of structure formation underlying the creaming reaction in a processed cheese model system as revealed by light and transmission electron microscopy

The “creaming reaction,” a general thickening of the molten cheese mass during the manufacture of processed cheese, which is often seen to occur in a stepwise fashion, affects the viscosity and texture of the finished product. Thus, this phenomenon is of critical importance for the processed cheese industry, yet mechanisms underlying the structure formation in this surprisingly complex and dynamic food system are only poorly understood. Using a model system consisting of micellar casein concentrate, vegetable oil, water, and a mixture of melting salts, we followed the characteristic viscosity profile with its primary and secondary increase over time. A rheometer equipped with a custom-made cup geometry was used, which served as a mini-reaction vessel to simulate the conditions during the manufacture of processed cheese. The mixture was subjected to constant heat (90°C) and stirring (7.93 rpm), comparable to processed cheese cooking, for up to 410 min. At specific time points, samples were taken, and the micro- and ultrastructure was investigated with light and transmission electron microscopy. Results from our extensive study uncovered the following key steps: (1) a decrease in fat globule size with concomitant increase in the number of fat globules, which were also more evenly distributed; (2) a progressive separation of the casein matrix into fibrillogenic and nonfibrillogenic fractions; (3) formation of fibrils and their higher-order structuring followed by their partial degradation; and (4) increasing interactions of the fibrils with the fat globule surface leading to a higher degree of emulsification. Of these different observations, results indicate that after the caseins dissociated under the influence of the melting salts, protein–protein interactions were the primary driver of the structure formation and thus contributed to the initial viscosity increase. Fat globules were involved in the structure formation at later time points. Therefore, fat–protein interactions in addition to continued protein–protein interactions were assumed to contribute to the secondary viscosity increase. An updated processed cheese creaming model is presented. The use of the term “texturization” instead of “creaming” is proposed.     

Comparison of full-fat and low-fat cheese analogues with or without pectin gel through microstructure, texture, rheology, thermal and sensory analysis

The effects of pectin gel and protein base on processed semi-solid cheese analogues were studied through microstructure, texture, rheology, thermal analysis and sensory evaluation. Scanning electron microscopy revealed differences in the microstructure of processed cheese analogues. Samples made with full-fat contained higher concentrations of fat globules and were denser compared with low-fat cheese analogues with or without pectin gel. The pectin gel in the products acted as a linkage with other ingredients and made the products more compact and had less cavity compared with the products without pectin gel added. On rheological analysis, the full-fat products manifested a more solid-like form. The storage modulus of pectin gel sample was higher than that without pectin gel. All the samples' rheological parameters were depending on the oscillatory frequency and temperature. In low-fat samples, pectin gel added or not affected the hardness, gumminess, chewiness and adhesiveness significantly. The pectin gel addition show positive effect to the texture profile of the low-fat cheese analogues. Through thermal analysis, the meltability and glass transition temperature of the processed cheese analogues were measured. The low-fat cheese analogue with pectin gel addition got the higher texture and mouthfeel scores through sensory evaluation.     

pH值对再制干酪功能特性的影响

利用质构仪、流变仪、扫描电镜分析pH值对再制干酪产品功能特性的影响,揭示了pH在再制干酪生产过程中的重要作用。结果表明,pH值影响再制干酪的融化性,但是这种影响没有呈现一定的规律性;随着pH值的升高,再制干酪产品的表观黏度也随之升高;在各质构参数中,硬度和咀嚼性随着pH值的升高而降低,pH值对弹性的影响显著(P<0.05);pH值影响水和乳化的过程,pH值越高,越利于水和乳化。     

乳化盐及加工条件对再制干酪质地及理化特性的影响

研究乳化盐及加工条件对再制干酪质地及理化特性的影响。结果表明,增加乳化盐的用量、融化温度和延长搅拌时间明显降低了再制干酪的融化性(p<0.01),不同种类乳化盐在相同添加水平下,制得样品的融化性:焦磷酸钠>磷酸氢二钠>柠檬酸钠;增加乳化盐的用量和延长搅拌时间制得的样品硬度显著增加、黏着性显著减小(p<0.01),提高融化温度制得的样品硬度增加,但其黏着性差异不显著(p>0.01)。在添加量相同的情况下,柠檬酸钠制得样品的硬度和黏着性最大,焦磷酸钠使样品的硬度和黏着性最小。     

Effect of trisodium citrate concentration and cooking time on the physicochemical properties of pasteurized process cheese

The effects of the concentration of trisodium citrate (TSC) emulsifying salt (0.25 to 2.75%) and holding time (0 to 20 min) on the textural, rheological, and microstructural properties of pasteurized process Cheddar cheese were studied using a central composite rotatable design. The loss tangent parameter (from small amplitude oscillatory rheology), extent of flow (derived from the University of Wisconsin Meltprofiler), and melt area (from the Schreiber test) all indicated that the meltability of process cheese decreased with increased concentration of TSC and that holding time led to a slight reduction in meltability. Hardness increased as the concentration of TSC increased. Fluorescence micrographs indicated that the size of fat droplets decreased with an increase in the concentration of TSC and with longer holding times. Acid-base titration curves indicated that the buffering peak at pH 4.8, which is due to residual colloidal calcium phosphate, decreased as the concentration of TSC increased. The soluble phosphate content increased as concentration of TSC increased. However, the insoluble Ca decreased with increasing concentration of TSC. The results of this study suggest that TSC chelated Ca from colloidal calcium phosphate and dispersed casein; the citrate-Ca complex remained trapped within the process cheese matrix. Increasing the concentration of TSC helped to improve fat emulsification and casein dispersion during cooking, both of which probably helped to reinforce the structure of process cheese.     

乳酸菌胞外多糖对低脂Mozzarella奶酪质构、微观结构等品质的影响

目的 研究乳酸菌胞外多糖对低脂Mozzarella奶酪质构等品质特性的影响。方法 在脱除50%乳脂肪的原料中加入0.5%乳酸菌胞外多糖制作低脂Mozzarella奶酪, 同时以全脂Mozzarella奶酪和低脂Mozzarella奶酪为对照, 对Mozzarella奶酪成熟过程中的硬度、弹性、胶黏性、咀嚼性、融化性、油脂析出性、微观结构及感官评分等指标进行分析。结果 0.5%乳酸菌胞外多糖提高了低脂Mozzarella奶酪的水分含量、出品率, 改善了低脂Mozzarella奶酪致密的结构, 形成了类似全脂Mozzarella奶酪疏松、光滑的组织结构, 降低了低脂Mozzarella奶酪的硬度、胶黏性和咀嚼性, 提高了弹性、融化化性和油脂析出, 成熟90 d加入多糖低脂Mozzarella奶酪的滋味和气味、组织状态、色泽接近全脂Mozzarella奶酪。结论 乳酸菌胞外多糖可以提高低脂Mozzarella奶酪的水分含量和出品率, 改善低脂Mozzarella奶酪的组织结构和质构特性。     

The effect of cheese maturity on selected properties of processed cheese without traditional emulsifying agents

The aim of this work was to compare selected properties (hardness, cohesiveness, adhesiveness, characteristics of fat globules, pH, meltability and sensory characteristics – homogeneity, rigidity and flavour) of processed cheeses (dry matter content 40 g/100 g; fat in dry matter content 50 g/100 g) made with traditional emulsifying salts (sodium salts of phosphates) and products in which the traditional emulsifying salts were replaced with 1 g/100 g κ-carrageenan. The development of the above-mentioned properties was studied in dependence on the maturity level of cheese (raw material; 1–16 weeks' maturity). The samples made without the use of traditional emulsifying salts were nearly five times as hard as the products with phosphates regardless of the maturity level of cheese. In both types of samples, hardness was decreasing and adhesiveness was rising with the increasing maturity level of cheese. Meltability of the samples without traditional emulsifying salts was very low and remained practically unchanged with the increasing maturity level of cheese. On the other hand, in the processed cheeses with phosphates, meltability was increasing with the rising maturity level of cheese.     

Effects of different dairy ingredients on the rheological behaviour and stability of hot cheese emulsions

The influence of sodium caseinate (SC), butter milk powder (BMP) and their combinations on particle size, rheological properties, emulsion stability and microstructure of hot cheese emulsions made from mixtures of Cheddar and soft white cheese was studied. All emulsions exhibited shear-thinning flow behaviour and increasing SC concentration (1–4%) led to an increase in particle size and a decrease in apparent viscosity. In contrast, increasing BMP concentration caused significant decrease in particle size and slightly reduced the apparent viscosity. Stability against creaming and precipitation increased with increasing concentration of SC, whereas BMP destabilised the emulsions resulting in extensive precipitation. Confocal laser scanning microscopy images showed that SC exerted markedly better emulsification ability than BMP. Emulsions containing equal amounts of SC and BMP presented better stability against creaming and precipitation and this could be developed into a novel strategy to replace emulsifying salts in production of cheese powder.