几个影响新鲜软质干酪品质的因素研究

对影响新鲜软质干酪加工的主要因素进行了研究,通过研究新鲜软质干酪加工过程中发酵剂菌种配比、凝乳酶添加量、加热终温度,确定干酪的工艺流程及工艺参数。结果表明,原料乳中添加发酵剂(乳脂链球菌:嗜热链球菌)比例为8∶1,凝乳酶添加量为0.01 mL/100L牛乳,加热终温度为55℃为宜,可得到产率较高,口感良好的新鲜软质干酪。     

软质干酪工艺研究

研究了软质干酪的加工工艺结果表明，含脂率为3.2％的鲜牛乳，经75℃，15min杀菌冷却后接种体体积分数为1％的乳酸菌(V(保加利亚德氏乳杆菌)：V(嗜热链球菌)=2：3)并于32℃发酵40min，调节酸度至pH值为6．0，再依次加入质量分数为0．02％的CaCl2和质量浓度为2g／L牛乳的凝乳酶(m(小牛皱胃酶)：m(毛霉凝乳酶)=3：1)，恒温(32℃)发酵约1h，最后经切割、升温、搅拌、排乳清、撒盐、成熟等工艺制备出一种软质、质地良好、奶香浓郁相对价格较低的软质干酪。     

新鲜软质干酪加工工艺的研究

以鲜牛乳为原料,研究了新鲜软质干酪的制作工艺,采用L9(34)正交试验的方法,研究了不同发酵剂菌种添加比例、发酵温度、切割pH值对成品干酪滋味口感、色泽和涂抹性的影响,最终确定了该产品生产的最佳配方和工艺条件:菌种比为1:1(质量比),发酵剂添加量为3%(质量分数),发酵温度为37℃,切割pH值为4.6。     

新鲜干酪工艺研究

本实验通过对酶法生产新鲜干酪的工艺参数进行研究,分析了酸度、CaCl2添加量、酶添加比例、凝乳温度等因素对凝乳效果、产率及品质等的影响。结果表明,酸度为28°T,CaCl2添加量为0.02%,酶添加比例为0.04%,凝乳温度为35℃时可得到较佳的效果。     

软质干酪凝乳特性的研究

研究探讨了软质干酪生产过程中原料乳的比重、CaCl2的添加量、凝乳酶质量浓度以及pH值对其凝乳特性的影响,结果表明:当原料乳比重为1.029g/mL、CaCl2的添加量为0.02%、凝乳酶质量浓度为2.5g/L牛乳、pH值为5.8时可以制作出风味柔和、组织状态细腻的软质干酪。     

Mozzarella干酪的研制

以新鲜牛乳为主要原料,通过干酪制造条件的优化研究,确定了制造Mozzarella干酪的工艺流程及主要参数,实验表明,新鲜牛乳经标准化使得酪蛋白与脂肪之比为0．84,然后加入发酵剂和凝乳酶,凝乳形成后,经切割,排乳清,并在热水中拉伸,盐渍即到成品,产品的平均脂肪和水分的含量分别为22．82％和50．74％,达到了Mozzarella干酪的质量要求。     

绿茶混合软质干酪质量控制研究

研究了绿茶粉豆乳混合干酪的制作工艺,试验结果表明,绿茶混合干酪的最佳工艺条件应为:绿茶粉加入量1%,豆乳添加量为20%,混合乳采用75℃杀菌15s,冷却后加入2%的发酵剂,其中保菌和嗜菌比例为2:3,发酵温度为35℃.当发酵乳pH值达到5.6时停止发酵,发酵后牛乳加入0.04?Clo<,2>和0.02%混合凝乳酶(动物凝乳酶和微生物凝乳酶比例为4:1),35℃条件下凝乳65 min后经排乳清,加盐后熟化得到干酪产品,产品风味较好.出品率为9.12%.     

硬质干酪加工工艺的研究

以鲜牛乳为原料,研究了硬质干酪的制造工艺,确定了发酵剂;凝乳酶;氯化钙的添加量和成熟条件等主要工艺参数,并探讨了影响凝乳酶活力的主要因素.     

工艺条件对豆奶干酪产率影响的研究

通过对豆奶干酪生产工艺的研究,发现豆乳添加量、混合乳杀菌温度、添加剂的加入、乳清的排出等过程对干酪的产率都有影响。实验结果表明,为了提高豆奶干酪的产率,同时保证产品的品质,豆奶的添加量为10%;杀菌条件为72℃、15s;调酸pH为6.0;凝乳酶添加量为4g/L;CaCl2添加量为0.3‰;热缩温度为40℃;堆酿pH为5.30。     

白牦牛乳软质干酪的加工及其质构特性的研究

以甘肃天祝牧区白牦牛乳为原料制作软质干酪。优化了加工白牦牛乳软质干酪的工艺参数,并测定其保藏期前后的理化指标和质构。结果表明,牦牛乳软质干酪在发酵剂添加量2g/100mL,凝乳温度35℃,凝乳pH5.9,CaCl2添加量0.01g/100mL时,品质最佳,出品率为22.5g/100g;保藏30d后的软质干酪与新鲜干酪相比,其非脂物质水分含量(P<0.01)、干物质脂肪含量(P<0.01)、胶着性(P<0.05)、硬度(P<0.01)和咀嚼性(P<0.01)均有显著变化。      

Production of fresh Cheddar cheese curds with controlled postacidification and enhanced flavor

Cheddar cheese in curd form is very popular in eastern Canada. It is retailed immediately after cheese manufacturing and can be maintained at room temperature for 24 h to provide better texture and mouthfeel. Subsequently, the cheese curds must be stored at 4°C. The shelf life is generally 3 d. In this study, Cheddar cheese curds were produced by adding a high diacetyl flavor-producing strain (Lactococcus diacetylactis) to a thermophilic-based starter. The objective was to achieve both postacidification stability to increase the shelf life and enhanced flavor. The addition of L. diacetylactis increased processing time but did not affect cheese composition or the evolution of proteolysis and texture. During cheese manufacturing, streptococci became the dominant microflora in all cheeses, whereas populations of Lactococcus cremoris and L. diacetylactis decreased. During cheese storage, viable counts of L. diacetylactis and Streptococcus thermophilus increased but the counts of L. cremoris decreased. During cheese manufacturing and storage, the concentrations of lactic acid and diacetyl increased rapidly in cheeses produced with L. diacetylactis. Citric acid and galactose contents remained high in cheese made without L. diacetylactis. Sensory evaluation indicated that cheeses containing the L. diacetylactis strain were more flavorful and also had less sourness and could be stored at 4°C for up to 7 d.     

水分含量对新鲜干酪贮藏特性的影响

对水分含量不同的4组干酪进行贮藏期水分含量、水分活度、pH、酸价、TBA值测定和感官评定。结果表明:干酪水分含量与水分活度随贮藏期呈递减趋势,并且呈正相关关系;酸价随着贮藏期的延长先增加后减少;pH则相反,呈先下降后上升的趋势;TBA值呈逐渐上升趋势。表明水分含量低的干酪,其耐贮藏性较好。感官特征测定在贮藏的第18d开始,干酪逐渐开始出现腐败特征,水分含量较低的干酪感官评分高。     

转谷氨酰胺酶交联乳蛋白对新鲜干酪特性的影响

利用转谷氨酰胺酶(TG)交联酪蛋白,研究其对新鲜干酪凝乳的成分和质构特征的影响。结果表明,TG能够加速凝乳发酵过程,提高乳中蛋白质和脂肪的回收率,并显著降低了乳清中的蛋白含量,对凝乳的质构特征也具有明显修饰作用。但与凝乳酶同时作用时,TG酶对凝乳的修饰作用不显著。     

不同杂交代水牛奶对Mozzarella鲜奶酪品质的影响

本文分析了尼里-拉菲及其不同杂交代水牛奶的理化特性,并研究了以尼里-拉菲及其不同杂交代水牛奶制备的Mozzarella鲜奶酪的理化指标、感官、盐水贮存中的含水率及在2⁶℃冷柜内保存期间p H变化。结果表明,不同杂交代水牛奶的蛋白质、脂肪、总乳固体含量均高于尼里-拉菲,不同杂交代水牛奶制备的Mozzarella鲜奶酪蛋白质含量13%、脂肪含量23%、水分含量59%、出品率20%左右,采用尼杂二代、三代及以上的水牛奶制备的Mozzarella鲜奶酪质量较好,鲜奶酪在2⁶℃的冷柜内保存宜控制在10d内。      

Standardization of milk using cold ultrafiltration retentates for the manufacture of Swiss cheese: effect of altering coagulation conditions on yield and cheese quality

Fortification of cheesemilk with membrane retentates is often practiced by cheesemakers to increase yield. However, the higher casein (CN) content can alter coagulation characteristics, which may affect cheese yield and quality. The objective of this study was to evaluate the effect of using ultrafiltration (UF) retentates that were processed at low temperatures on the properties of Swiss cheese. Because of the faster clotting observed with fortified milks, we also investigated the effects of altering the coagulation conditions by reducing the renneting temperature (from 32.2 to 28.3°C) and allowing a longer renneting time before cutting (i.e., giving an extra 5 min). Milks with elevated total solids (TS; ∼13.4%) were made by blending whole milk retentates (26.5% TS, 7.7% CN, 11.5% fat) obtained by cold (<7°C) UF with part skim milk (11.4% TS, 2.5% CN, 2.6% fat) to obtain milk with CN:fat ratio of approximately 0.87. Control cheeses were made from part-skim milk (11.5% TS, 2.5% CN, 2.8% fat). Three types of UF fortified cheeses were manufactured by altering the renneting temperature and renneting time: high renneting temperature = 32.2°C (UFHT), low renneting temperature = 28.3°C (UFLT), and a low renneting temperature (28.3°C) plus longer cutting time (+5 min compared to UFLT; UFLTL). Cutting times, as selected by a Wisconsin licensed cheesemaker, were approximately 21, 31, 35, and 32 min for UFHT, UFLT, UFLTL, and control milks, respectively. Storage moduli of gels at cutting were lower for the UFHT and UFLT samples compared with UFLTL or control. Yield stress values of gels from the UF-fortified milks were higher than those of control milks, and decreasing the renneting temperature reduced the yield stress values. Increasing the cutting time for the gels made from the UF-fortified milks resulted in an increase in yield stress values. Yield strain values were significantly lower in gels made from control or UFLTL milks compared with gels made from UFHT or UFLT milks. Cheese composition did not differ except for fat content, which was lower in the control compared with the UF-fortified cheeses. No residual lactose or galactose remained in the cheeses after 2 mo of ripening. Fat recoveries were similar in control, UFHT, and UFLTL but lower in UFLT cheeses. Significantly higher N recoveries were obtained in the UF-fortified cheeses compared with control cheese. Because of higher fat and CN contents, cheese yield was significantly higher in UF-fortified cheeses (∼11.0 to 11.2%) compared with control cheese (∼8.5%). A significant reduction was observed in volume of whey produced from cheese made from UF-fortified milk and in these wheys, the protein was a higher proportion of the solids. During ripening, the pH values and 12% trichloroacetic acid-soluble N levels were similar for all cheeses. No differences were observed in the sensory properties of the cheeses. The use of UF retentates improved cheese yield with no significant effect on ripening or sensory quality. The faster coagulation and gel firming can be decreased by altering the renneting conditions.     

Casein breakdown during ripening of Idiazabal cheese: influence of starter and rennet type

The objective of this work was to determine the effect of starter and rennet type on casein breakdown during Idiazabal cheese ripening. Four batches of cheeses were manufactured with two rennets, commercial calf rennet and artisanal lamb rennet, and the use of natural flora or a commercial starter. Electrophoretic analysis of cheese samples showed six bands identified as α_s1‐, α_s2 + β‐, α_s1‐I‐, γ₁‐, β‐I‐ and para‐κ‐casein. As expected, the casein breakdown during cheese ripening was considerably affected by rennet type and the use of a commercial starter. The artisanal lamb rennet produced a higher hydrolysis of casein fractions than the commercial calf rennet, probably owing to its high percentage of chymosin (around 78%). The effect of addition of starter on proteolysis was dependent on the casein fractions generated by artisanal lamb rennet or commercial calf rennet. © 2000 Society of Chemical Industry     

Improvement of sensory quality of lowfat kefalograviera-type cheese by using commercial special starter cultures

Two commercially available special starter culture systems, Alp DIP and a mixture of Alp DIP D and Joghurt V1, were compared with one commercial regular starter culture, CH-1, for their effects on the compositional, sensory and textural characteristics of lowfat (9.5%) high moisture (49.6%) Kefalograviera-type cheese during aging. A full-fat control Kefalograviera cheese (30.8% fat, 37.8% moisture) was also made with the regular starter culture. The results indicated that the type of starter did not affect the composition (moisture, fat, protein, salt and pH) of the lowfat cheese. Sensory analysis showed that the lowfat cheeses made with the special cultures received greater body and texture scores and significantly higher flavor scores than the lowfat control cheese after aging for 90 and 180 d. Moreover, the former cheeses received body and texture and flavor scores not significantly different from those of the full-fat cheese. Texture profile analysis by Instron showed that there were no significant differences in the textural characteristics (force and compression to fracture, cohesiveness, springiness, gumminess and chewiness) between lowfat cheeses made with the special cultures and that made with the regular starter, except for hardness which was significantly lower in the former cheeses.     

凝乳酶对超滤浓缩乳生产Quark干酪的影响

采用每100g超滤乳中添加0、50、100、150、200、250μL六个水平的凝乳酶,研究了不同的凝乳酶添加量对Quark干酪组成、凝乳硬度、贮藏期产品感官品质和干酪中水溶性氮含量的影响。结果表明,当凝乳酶的添加量从0μL/100g增大到250μL/100g时,产品的水分含量上升了1·49%,粗产率和校正产率分别上升了1·42%和0·99%,固形物的回收率下降了3·5%,凝乳硬度从16·83g增大到40·84g,但干酪的苦味和水溶性氮含量,随着贮存期的延长和凝乳酶用量的增加而增大。