Nutritional Evaluation of Cheese Spread Powder

A study on the nutritional evaluation of processed cheddar cheese and cheese spread powder made from it, was undertaken. Levels of all constituents, except phosphorus and moisture contents, were significantly higher in cheese spray-dried powder as compared to processed cheese. Biological evaluation of the products showed that a Modified Protein Efficiency Ratio (PER_D), Net Protein Utilization (NPU), and Digestibility Coefficient (DC) and also regeneration of certain organs, in protein depleted albino rats fed diets based on processed cheese and spray-dired powder made from it, were identical.     

Development of a Rat Model to Test the Nutritional Equivalency of Traditional vs Fabricated Foods: Cheddar Cheese vs Fabricated Cheddar Cheese

Based on the Food & Drug Administration's proposed 1978 standards for “nutritional equivalency,” we have developed a biological assay designed to test the “nutritional equivalency” of traditional vs fabricated foods using cheddar cheese and fabricated cheddar cheese as examples. Diets were formulated that lacked the FDA proposed vitamin and mineral requirements (riboflavin, vitamins B-12 and A, calcium, phosphorus, zinc) for cheese substitutes. By adding traditional or fabricated cheddar cheese to such diets, we were able to compare the overall presence and bioavailability of the vitamins/minerals required for nutritional equivalency. Throughout the 28 day test, the fabricated cheddar cheese did not support the growth of male Sprague-Dawley rats as well as cheddar cheese did.     

Emulsifying Salts Influence on Characteristics of Cheese Analogs from Calcium Caseinate

Cheese analogs were prepared from calcium caseinate, butter oil and emulsifying sodium salts (ES). Increasing ES levels gave cheese analogs with higher pH, degree of casein dissociation and degree of fat emulsification than the control without ES. Firmness of cheese analogs first increased, then decreased when the ES level was increased from 1 to 3%. Effects depended on the degree of polymerization of phosphate salts. Sodium citrate (>1%) or Na₂HPO₄ (>2%) made cheese analogs more able to melt upon reheating. Melting ability correlated with high pH, soft texture, high degree of casein dissociation and low degree of fat emulsification.     

Microstructure and Texture of Process Cheese,Milk Curds,and Caseinate Curds Containing Native or Boiled Soy Proteins

Scanning electron microscopy was used to examine the internal microstructure of process cheese, process cheese containing native soy protein, process cheese containing boiled soy protein, rennet coagulated milk curd, milk curd containing native soy protein, milk curd containing boiled soy protein, rennet coagulated caseinate curd, caseinate curd containing native soy protein, and caseinate curd containing boiled soy protein. Textural characteristics were determined with an Instron Food Testing System. Soy proteins caused the fine network microstructure of processed cheese to change to coarse porous structure. Hardness of cheese was lowered, but cohesiveness was increased by adding soy protein to process cheese. In milk curd, particles of soy protein were clustered in groups in micrographs. Cohesiveness of milk curd was lowered by native soy protein and even more by boiled soy protein. Hardness and springiness were lowered by boiled soy protein. Boiled soy protein was more extensively aggregated than was native soy protein. Soy proteins were not clearly distinguishable from casein in the micrograph of caseinate curds. Soy proteins reduced hardness and cohesiveness of caseinate curd but not as drastically as in milk curd.     

The compositional and functional properties of commercial mozzarella, cheddar and analogue pizza cheeses

The compositional and functional properties of commercial retail and/or wholesale samples (n = 8) of low-moisture mozzarella, cheddar and analogue (pizza) cheeses were compared. Inter-and intravariety differences were evident with intravariety differences in composition being relatively large for the analogue cheese. Cheddar had the lowest mean pH and level of expressible serum and the highest mean levels of proteolysis, expressible fat, and serum calcium and nitrogen (p < 0.05). Compared to mozzarella, the analogue cheeses had significantly lower (p < 0.05) mean levels of total protein and serum calcium, higher levels of total calcium and higher cheese pH. The mean stretchability of the melted mozzarella cheese was significantly higher than that of the melted cheddar or analogue cheeses. The melted cheddar had the highest mean flowability and lowest mean apparent viscosity (p < 0.05). The mean flowability and apparent viscosity of the analogue cheese were numerically lower and higher, respectively, than those of mozzarella.     

益生菌对契达干酪成熟过程中抗氧化性变化的影响

为确定益生菌对契达干酪抗氧化性变化的影响,在菌株具备良好耐酸、耐盐性,适用于干酪生产前提下,以水解性和抗氧化性为指标,分别筛选出水解能力和抗氧化能力较强的菌株,并将其添加到契达干酪中,不添加益生菌的干酪为空白组,对干酪成熟过程中活菌数和抗氧化性进行分析。结果表明,9?株益生菌中,瑞士乳杆菌（Lactobacillus helveticus）1.0612和鼠李糖乳杆菌（Lactobacillus rhamnosus）1.0911分别具有较强的水解能力和抗氧化能力。在成熟过程中,添加L. helveticus 1.0612和L. rhamnosus 1.0911的两组干酪活菌数无显著差异,但均显著高于空白组。3?组干酪抗氧化能力均先升高再降低、最后趋于平缓,1,1-二苯基-2-三硝基苯肼（1,1-diphenyl-2-picrylhydrazyl,DPPH）自由基和羟自由基清除能力均在第4个月达到最大,还原能力在第5个月达到最大,且添加水解能力强的L. helveticus 1.0612干酪各项抗氧化能力的最大值（DPPH自由基、羟自由基清除能力和还原能力分别为51.05%、49.97%、0.66）均显著高于添加L. rhamnosus 1.0911的干酪（47.30%、46.19%、0.56）（P＜0.05）。因此,在契达干酪中添加水解能力较强的菌株,相比于添加本身具有良好抗氧化活性的菌株,可能会加剧干酪的蛋白水解,生成具有抗氧化能力的短肽和氨基酸,从而提高干酪的抗氧化活性。     

地衣芽孢杆菌凝乳酶对切达干酪成熟过程中蛋白水解的影响

利用地衣芽孢杆菌凝乳酶制作切达干酪和切达干酪类似物,分析干酪成熟过程中各蛋白水解指标的变化规律,以揭示地衣芽孢杆菌凝乳酶对切达干酪成熟过程中蛋白水解的影响。结果表明,CDF组（添加地衣芽孢杆菌D3.11凝乳酶所制切达干酪）、CD3组（添加地衣芽孢杆菌D3.11凝乳酶但未添加发酵剂制成的干酪类似物）和CCF组（添加商品凝乳酶所制切达干酪）干酪蛋白含量、pH 4.6-可溶性氮、12%三氯乙酸-可溶性氮、5%磷钨酸-可溶性氮、总游离氨基酸含量均随着成熟时间延长呈显著增加趋势,并且成熟期间CDF组干酪均显著高于CCF组干酪（P＜0.05）;十二烷基硫酸钠-聚丙烯酰氨凝胶电泳分析表明,CDF组干酪α-酪蛋白水解程度较大;pH 4.6-可溶性肽段分析表明,随着干酪的成熟,总肽含量呈先增加后下降趋势,但疏水性肽与亲水性肽的比值呈持续下降趋势,在成熟第6个月时,CDF组、CD3组和CCF组干酪疏水性肽与亲水性肽比值分别为2.668、2.822、3.788。主成分分析表明,3 组干酪的蛋白水解程度与成熟度呈正相关,与疏水性肽和亲水性肽的比值呈负相关。以上结果表明,利用地衣芽孢杆菌凝乳酶制作的干酪蛋白水解度更高,但其疏水性肽比例较小,研究结果可为地衣芽孢杆菌凝乳酶在干酪生产中的应用提供理论依据。     

酪蛋白降解对牦牛乳硬质干酪苦味的影响

针对牦牛乳硬质干酪的苦味缺陷,分别以小牛皱胃酶、微生物凝乳酶和木瓜蛋白酶制作的牦牛乳硬质干酪为研究对象,利用尿素聚丙烯酰胺凝胶电泳,研究牦牛乳硬质干酪pH 4.6水不溶性酪蛋白的降解程度,且对成熟过程中的牦牛乳硬质干酪苦味进行感官评价,探究牦牛乳硬质干酪pH 4.6水不溶性酪蛋白降解对其苦味的影响。结果表明：牦牛乳硬质干酪在成熟期间酪蛋白发生了明显的降解,且αs-酪蛋白均比β-酪蛋白降解速率快。经尿素聚丙烯酰胺凝胶电泳分离后,发现木瓜蛋白酶制作的牦牛乳硬质干酪pH 4.6水不溶性酪蛋白在Pre-αs-酪蛋白区域有较强的蛋白带。木瓜蛋白酶制作的牦牛乳硬质干酪pH 4.6水不溶性酪蛋白中αs-酪蛋白和β-酪蛋白降解程度均显著或极显著高于微生物凝乳酶和小牛皱胃酶制作的牦牛乳硬质干酪（P＜0.05或P＜0.01）,木瓜蛋白酶制作的牦牛乳硬质干酪的苦味值极显著高于微生物凝乳酶和小牛皱胃酶制作的牦牛乳硬质干酪的苦味值（P＜0.01）,通过主成分分析得出3 种凝乳酶制作牦牛乳硬质干酪的苦味值和未降解β-酪蛋白和αs-酪蛋白含量成极显著负相关。这为控制牦牛乳硬质干酪品质提供了理论参考。     

不同工艺参数对Mozzarella干酪质构和功能特性的影响

采用三因素二次通用旋转组合设计,研究热缩温度、堆酿pH、拉伸温度等关键工艺参数对全脂Mozzarella干酪的质构特性(硬度、凝聚性、弹性)和功能特性(融化性和油脂析出性)的影响规律,结果表明提高热缩温度可增加干酪硬度及干酪的油脂析出性;提高拉伸温度也可增加干酪的油脂析出性;堆酿pH对干酪的弹性有较大影响,随着堆酿pH的降低,干酪的弹性增大,并与热烫拉伸温度之间有交互作用,即低的堆酿pH和高的拉伸温度时干酪的弹性大。     

Quality Attributes of Cheddar Cheese Containing Added Lactobacilli

Various strains of homo- and heterofermentative lactobacilli isolated from cheddar cheese were added to milk with a commercial streptococci culture to produce cheddar cheese. The heterofermatative lactobacilli L. brevis and L. fermentum almost always led to the development of fruity flavors, openness and late-gassing within 10 months of aging. Cheddar cheese produced using combined cultures of heterofermentative lactobacilli and L. casei-casei or L. casei-pseudoplantarum did not exhibit gas formation and openness. The overall grading scores of cheese containing added lactobacilli were not higher than those for the control cheese (without lactobacilli). A definite correlation was found between the lactobacilli used and the flavors of the cheese. The controlled acidity development during cheese making, the fat and the salt in moisture content of the cheeses were not affected.     

酶凝干酪素溶胶性及发酵对模拟干酪品质的影响

为改善模拟干酪的品质,首先研究了乳化盐种类、温度及pH值对酶凝干酪素溶胶性的影响,然后结合扫描电子显微镜观察确定乳酸发酵前酶凝干酪素的最低乳化盐添加量,最后进行发酵模拟干酪感官品质和微观结构的对比分析。结果表明：5 种乳化盐对酶凝干酪素的溶胶能力依次为五聚磷酸钠＞六偏磷酸钠＞JOHA PZ 7复合乳化盐＞柠檬酸钠＞焦磷酸四钠;从25～42 ℃变化范围内,酶凝干酪素的溶解度随温度的升高而增加且增加速率较大,而从42～85 ℃变化范围内,增加速率较小;从pH 5.5～11.5变化范围内,溶解度随pH值的升高而明显增加;发酵时最低乳化盐添加比例为：m（酶凝干酪素）∶m（五聚磷酸钠）∶V（水）=1 g∶25 mg∶2.5 mL;发酵模拟干酪的风味评定分数与感官评定总分均明显高于普通模拟干酪。因此,发酵模拟干酪不仅具备了模拟干酪应具有的外观与质构特征,且克服了普通模拟干酪固有的风味缺陷。     

Changes in functional properties of shark (Isurus oxyrinchus) cartilage gelatin produced by different drying methods

Fish gelatins extracted from shark ( Isurus oxyrinchus ) cartilage were dried by three different methods: freeze drying, hot-air drying and spray drying; and their functional properties were investigated. Freeze-dried gelatin was found to have the strongest gel strength, while gelatins made at high temperatures formed weaker gels. The 135-kPa gel strength of freeze-dried gelatin was relatively high. While foam formation ability of the freeze-dried gelatin was the highest, its foam stability was the lowest. In addition, spray-dried gelatin had the best emulsion capacities. Dynamic viscoelastic properties of shark cartilage gelatins prepared by these drying methods were closely correlated with their gel strength. Elasticity modulus ( G '; Pa) and loss modulus ( G "; Pa) of the freeze-dried gelatin had higher values than those prepared by hot-air drying and spray drying; viscoelastic properties of the freeze-dried gelatin were maintained longer than those of other drying methods.     

Microencapsulated Lactobacillus rhamnosus GG powders: relationship of powder physical properties to probiotic survival during storage

Freeze-dried commercial Lactobacillus rhamnosus GG (LGG) were encapsulated in an emulsion-based formulation stabilized by whey protein and resistant starch and either spray-dried or freeze-dried to produce probiotic microcapsules. There was no difference in loss of probiotics viability after spray drying or freeze drying. Particle size, morphology, moisture sorption, and water mobility of the powder microcapsules were examined. Particle size analysis and scanning electron microscopy showed that spray-dried LGG microcapsules (SDMC) were small spherical particles, whereas freeze-dried LGG microcapsules (FDMC) were larger nonspherical particles. Moisture sorption isotherms obtained using dynamic vapor sorption showed a slightly higher water uptake in spray-dried microcapsules. The effect of water mobility, as measured by nuclear magnetic resonance (NMR) spectroscopy, at various water activities (a(w) 0.32, 0.57, and 0.70) and probiotic viability during storage at 25 °C was also examined. Increasing the relative humidity of the environment at which the samples were stored caused an increase in water mobility and the rate of loss in viability. The viability data during storage indicated that SDMC had better storage stability compared to FDMC. Although more water was adsorbed for spray-dried than freeze-dried microcapsules, water mobility was similar for corresponding storage conditions because there was a stronger water-binding energy for spray-dried microcapsule. This possibly accounted for the improved survival of probiotics in spray-dried microcapsules.     

Manufactore of Ras cheese from ultrafiltered milk supplemented with caseinates

Whole cow's milk was ultrafiltered (conc. Factor 5), sodium and calcium caseinate were added to the milk retentate at the rate of 0.5 and 0.75% (w/w) of the milk. Ras cheese was made from milk retentate supplemented with different levels of caseinate salts, as well as unsupplemented retentates, and compared with Ras cheese made by the traditional method. Retentate supplemented with 0.5% Na and Ca caseinate was suitable for Ras cheese-making with limited whey drainage, supplementation of retentate with 0.75% Ca caseinate gave defective cheese at the end of ripening, while Na caseinate increased soluble N and free fatty acids in the cheese. Organoleptic scoring showed that supplementation with Na caseinate enhanced cheese ripening.     

Nutritional Evaluation of Cereal–Cheese Whey Mixtures

The chemical composition, amino acid content, PER, and digestibility of dehydrated sweet cheese whey, wheat flour, wheat bran, and lime-treated corn flour (nixtamal, used for making tortillas), as well as of 21 cereal-cheese whey mixtures were determined. The cheese whey was composed of 12% protein and 74% lactose. Diets containing a total of 8% protein were formulated with the cereal-cheese whey mixtures. The 50:50 (% protein) cereal-whey mixtures had the highest adjusted modified PERs, representing an increase over the cereals alone of 324% for the corn flour, 215% for wheat flour, and 177% for wheat flour, and 177% for wheat bran. The 50:50 (% protein) wheat bran mixture had the largest adjusted modified PER at 2.33 ± 0.13 (mean ± SEM) and the 50:50 wheat flour mixture, the smallest at 1.48 ± 0.21. Although the apparent digestibility was reduced from 10–14% for the latter two 50:50 cereal-whey mixtures compared to the cereals alone, this was not reflected in the PER. It was concluded that the nutritive value of all the cereals tested significantly increased with the addition of 155 25% or more (by weight) of dehydrated cheese whey.     

Effect of Ultra-high Temperature Treatment on the Enzymatic Cross-linking of Micellar Casein and Sodium Caseinate by Transglutaminase

ABSTRACT: It was found that ultra-high temperature (UHT) treatment of sodium caseinate and native whey protein-depleted micellar casein drastically increases the protein polymerization effect of an enzymatic treatment by microbial transglutaminase (TG). As a result the concentration of the isopeptide ε-(γ-glutamyl)lysine was increased significantly in UHT-treated micellar casein solutions after TG incubation compared with the unheated casein solution. Sodium caseinate was more susceptible to the cross-linking reaction as compared with the native casein micelles. The results demonstrate that the protein structure significantly affects the TG cross-linking reaction. The effect of an UHT treatment was considered to be related to a better TG accessibility due to a more open casein micelle structure and to the inactivation of a TG inhibitor substance. The results demonstrate that an unidentified component in the natural milk serum inhibits the TG reaction. The thermal inactivation of a TG inhibitor is the dominant effect explaining the improved cross-linking of UHT-treated casein micelles as well as sodium caseinate.     

Casein molecular assembly affects the properties of milk fat emulsions encapsulated in lactose or trehalose matrices

Properties of spray-dried anhydrous milk fat emulsions stabilized by micellar casein (milk protein isolate—MPI) or non-micellar casein (sodium caseinate—Na-caseinate) with trehalose or lactose as encapsulants were studied. A lower concentration of Na-caseinate (0.33%) compared with MPI (1.26%) was sufficient to stabilize a 10% fat emulsion. Reconstituted emulsions showed larger droplet size than fresh emulsions, especially for MPI systems (from<1 μm to around 14 μm), which was attributed to lower shear resistance during atomization. Creaming behavior reflected changes in particle size. Powder surface free fat was affected by protein type and concentration. Trehalose systems (regardless of protein type) released significantly lower amounts of encapsulated fat upon crystallization compared with those containing lactose. Individual and hence, more mobile and flexible casein molecules, as opposed to aggregated and less mobile casein micelles, appear to result in superior co-encapsulation properties of Na-caseinate compared with MPI.     

微胶囊化蛋白酶在干酪制备中的应用及干酪成熟过程中电泳分析

将采用冷冻干燥工艺得到的明胶-阿拉伯胶-凝乳酶微胶囊用于干酪制备过程中,在排乳清之后向干酪中添加5.00 g微胶囊化蛋白酶,以促进干酪的成熟。在干酪成熟过程中通过三羟甲基氨基甘氨酸-尿素-十二烷基磺酸钠聚丙烯酰胺凝胶电泳以及毛细管电泳分析监测干酪中pH 4.6不溶性氮部分的变化情况。结果表明：干酪在成熟初期,αs1-酪蛋白较β-酪蛋白先水解,生成αs1-酪蛋白（f 102～199）和αs1-I-酪蛋白;干酪成熟21 d时,β-酪蛋白开始水解,αs1-酪蛋白继续保持水解,生成的大的水解产物同时也发生二次水解;干酪成熟90 d时干酪中β-酪蛋白比αs1-酪蛋白具有更广泛的水解程度,酪蛋白降解的同时,生成大量新的小分子肽。     

Mechanically Separated Spleen: Its Composition and Protein Efficiency Ratio

Beef spleens were freed of undesirable capsular and internal connective tissue by passage through a Beehive Model AU 4171 deboner fitted with a desinewing head. The resulting product (called mechanically separated spleen or MSS) was recovered at a 79% yield and contained 17.0% protein, 2.9% fat and 762 ppm iron. The effect of mechanical separation on protein quality was determined by protein efficiency ratio (PER). Rats fed MSS and whole spleen diets exhibited significantly greater weight gains than those fed casein. PER values for whole spleen (2.4) and MSS (2.3) were not significantly different. The PER value for casein (2.5) was significantly higher than that of MSS but not whole spleen.     

甲醇芽孢杆菌凝乳酶对马苏里拉干酪加工特性的影响

为了探究甲醇芽孢杆菌（Bacillus methanolicus）凝乳酶在马苏里拉干酪加工中的应用,分别以使用甲醇芽孢杆菌凝乳酶、混合酶制剂（含质量分数10%甲醇芽孢杆菌凝乳酶和90%商品凝乳酶）制作的马苏里拉干酪作为实验组,以商品凝乳酶干酪作为对照组,测定不同组别干酪成熟期间的蛋白水解特性、质构、风味和微观结构变化,研究甲醇芽孢杆菌凝乳酶对马苏里拉干酪加工特性的影响。结果表明,实验组干酪在成熟过程中pH值（4.6～5.3）、微生物数量（8.80～9.68（lg（CFU/g）））与对照组无显著差异（P＞0.05）;实验组干酪水分质量分数（混合酶干酪为（43.21±1.17）%、甲醇芽孢杆菌凝乳酶干酪为（46.15±0.94）%）均显著高于对照组（（41.08±1.04）%）,得率（混合酶干酪为（9.27±0.17）%、甲醇芽孢杆菌凝乳酶干酪为（9.46±0.16）%）也显著高于对照组（（8.98±0.13）%）（P＜0.05）;且实验组干酪的蛋白水解特性（pH 4.6时可溶性蛋白、酪蛋白水解程度和游离氨基酸质量分数）以及风味物质种类和相对含量等指标也优于对照组干酪。但是实验组中甲醇芽孢杆菌凝乳酶干酪保形性相对欠佳,感官评定得分偏低,混合酶干酪与对照组质构及感官基本得分一致,因此甲醇芽孢杆菌凝乳酶可以作为商品酶的部分代替品应用于干酪的生产中。