Influence of Homofermentative Lactobacilli on Physicochemical and Sensory Properties of Cheddar Cheese

Cheddar cheeses were produced under pilot plant conditions using a commercial Streptococcus culture amended with one of 10 homofermentative Lactobacillus strains. During the ripening period, pH, acidity, salt, moisture, fat, texture, fissure formation, gas development and sensory status were evaluated. Lactobacillus treated cheese did not differ much from the control in pH and acidity but acidity increased substantially after draining and cheddaring. Lactobacillus numbers increased at all stages as compared with the uninoculated control. High quality Cheddar cheese was produced by L. casei-subsp-casei (119-10/62) and L. casei-subsp-pseudoplantarum (137-10/62) from 7 to 12 vats aged for 2 months at 15°C and for a further 10 months at 7°C or 15°C. Fissure formation was observed in cheese made with L. casei-subsp-rhamnosus, one of the four cultures of L. casei-subsp-casei (LH13) and two of the three strains of L. casei-subsp-pseudoplantarum (83-4-12/62 and L3E). Certain Lactobacillus strains produced cheese with slight flavor defects. Other strains, in particular L. casei-subsp-rhamnosus, contributed to high acidity (72 - 0.89° domic) and low pH (5.2) at salting.     

Heat-Shocked Lactobacilli for Acceleration of Cheddar Cheese Ripening

The aim of this study was to establish adequate conditions for heat-shocking cells of lactobacilli, to sufficiently suppress lactic acid production without damaging the proteolytic enzyme system important for cheese maturation. Three temperatures, 65, 67 and 70°C were tested, for 22 sec. The best combination for maximum retardation of lactic acid production and minimum damage to the proteolytic system was obtained by treating cells at 67°C for 22 sec. Following such treatment, lactic acid production was retarded by 24 hr, while the proteolytic enzyme system remained scarcely unchanged.     

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.     

Accelerated Maturation of Cheddar Cheese: Influence of Added Lactobacilli and Commercial Protease on Composition and Texture

The addition of live and heat-shocked Lactobacillus casei-casei L2A and Neutrase© was tested for its ability to accelerate the maturation of Cheddar cheese. An evaluation of physicochemical and rheological properties showed that cheese pH was decreased by bacterial and enzymatic additives, while fracturability and cohesiveness were influenced principally by Neutrase. The integrated process recommended is composed of three parts: first, the addition of live L. casei-casei L2A to control the undesirable microflora, second, heat-shocked cells of the same species at a concentration of 1.0%, and third, Neutrase at a concentration not higher than 1.0 × 10^-5 AU/g of cheese. This process led to a good-quality sharp Cheddar cheese with 60% increase in flavor intensity compared to control cheese.     

Effect of Added Lactobacilli on Composition and Texture of Cheddar Cheese During Accelerated Maturation

The evolution of cheese composition and texture was studied in maturing Cheddar cheese supplemented with live cells and cell homogenates of Lactobacillus casei-casei L2A in order to accelerate maturation. The pH was significantly modified by the lactic acid of the bacterial additives. The Theological properties showed the same general pattern of evolution in experimental as in control cheeses. The process we developed has led to a good-quality matured cheese with 40% increase in flavor intensity compared to control cheeses.     

Impact of Autolytic and Proteolytic Lactobacilli and Nisin-Producing Culture on Proteolysis and Sensory Characteristics in Cheddar Cheese

ABSTRACT: Cheddar cheeses were made using a nisin-tolerant starter culture with either Lactobacillus delbrueckii subsp. bulgaricus UL12 (autolytic strain), Lactobacillus casei subsp. casei L2A (proteolytic strain), Lactococcus lactis subsp. lactis biovar. diacetylactis UL719 (nisin producer), or of Lb. bulgaricus UL12 and Lc. diacetylactis UL719. Lb. bulgaricus UL12 produced more trichloroacetic acid-soluble nitrogen than did Lb. casei L2A, which produced more phosphotungstic acid-soluble nitrogen than did Lc. diacetylactis UL719. High-performance liquid chromatography analyses showed that either lactobacilli or Lc. diacetylactis UL719 increased the hydrophilic and hydrophobic peptide contents. Cheeses containing both Lb. bulgaricus UL12 and Lc. diacetylactis UL719 had the most intense old Cheddar cheese flavor after 6 mo of ripening.     

Evolution of Free Amino Acids during the Ripening of Cheddar Cheese Containing Added Lactobacilli Strains

Cheddar cheese was produced with different lactobacilli strains added to accelerate ripening. The concentration of proteolytic products was determined as free amino acids in the water-soluble fraction at two, four, seven and nine months of aging and at two different maturation temperatures (6°C, 15°C). All amino acids increased during ripening and were higher in the Lactobacillus- added cheeses than in the control cheese, and higher in cheeses ripened at 15°C than at 6°C. Glutamic acid, leucine, phenylalanine, valine and lysine were generally in higher proportion in all cheeses. The cheeses with added L. casei-casei L2A were classified as having a “strong Cheddar cheese” flavor after only seven months of ripening at 6°C.     

Probiotic Cheddar Cheese: Influence of Ripening Temperatures on Proteolysis and Sensory Characteristics of Cheddar Cheeses

ABSTRACT:  Bifidobacterium longum 1941, B. animalis subsp. lactis LAFTI^® B94, Lactobacillus casei 279, Lb. casei LAFTI L26, Lb. acidophilus 4962, or Lb. acidophilus LAFTI L10 were used as an adjunct in the production of Cheddar cheeses, which were ripened at 4 and 8 °C for 24 wk. Effects of ripening temperatures and probiotic adjuncts on proteolysis and sensory evaluation of the cheeses were examined. Higher ripening temperature increased the level of proteolysis in the cheeses. Product of proteolysis and organic acids released during ripening were shown to be important for the flavor of Cheddar cheeses. There were positive and significant correlations between the levels of soluble nitrogen, lactic, acetic, and butyric acids, percentage hydrolysis of α_s1-CN and β-CN to the scores of cheddary flavor ( P < 0.05). Scores for sour-acid and vinegary flavors were higher in cheeses with the addition of Bifidobacterium sp. or Lb. casei 279 ripened at 8 °C. The scores were positively and significantly correlated to the level of lactic, acetic, and free amino acids in the cheeses ( P < 0.05). The results show that both 4 and 8 °C have potential for use in the ripening of probiotic Cheddar cheeses.     

Milk Plasmin Activity Influence on Cheddar Cheese Quality during Ripening

Up to six-fold increase in plasmin activity in milk did not significantly (p<0.05) affect the composition (moisture, protein, NaCl) of cheese, although a slight increase in moisture and decrease in protein content of the cheese was noted. Proteolysis in cheese increased with plasmin activity, resulting in improved flavor and overall quality of the cheese after 3 and 6 months ripening. Consistently, increasing the plasmin activity in milk about three-fold resulted in cheese of superior sensory quality.     

不同发酵剂对切达干酪成熟期间品质的影响

应用乳酸乳球菌乳酸亚种LA、乳酸乳球菌乳脂亚种LC以及不同比例混合菌(LA∶LC=1∶1,LA∶LC=1∶2,LA∶LC=2∶1)制作切达干酪,研究这5种发酵剂在干酪成熟过程中对其质构、感官、风味物质形成及蛋白水解程度等方面的影响。结果表明:3种不同比例组合菌株发酵剂的蛋白水解能力适中,生产出的干酪口味清淡,其中按1∶1接种制作的干酪具有良好的成熟度、质地和风味,具有一定的商业应用价值,可将其用于切达干酪的生产。     

Time and Temperature Influence on Chemical Aging Indicators for a Commercial Cheddar Cheese

Cooling freshly formed Cheddar cheese requires close control for uniform and consistent flavor. Cheese in 18–kg blocks collected after pressing, at 30–35°C was used. Samples were cooled rapidly to 12 25°C as small pieces individually vacuum-wrapped at a local production site. The extent of proteolysis, total acidity, pH, lactose and organic acids was quantified after storage at these temperatures. Theoretical and empirical equations describing the influence of time and temperature on these chemical indicators were developed through nonlinear statistical methods. The kinetic expressions were applied to generate recommendations for the cooling rate and subsequent aging temperature of Cheddar cheese blocks.     

Effect of Lactobacilli on the Properties of Swiss Cheese

Two Lactobacillus strains produced by mutagenesis of Lactobacillus bulgaricus AR2 were selected on the basis of the flavor generated after their growth in milk or whey permeate, and these strains were tested for acid development and proteolysis in milk cultures. Although differences in the flavor generated by the mutants and their parent strain could not be verified by a formal panel, there were significant differences between the mutants and their parent strain in proteolysis and acid development. Strain AR2, its two mutants, and two other lactobacilli that differed from them in flavor, proteolysis, and acid development were used to make Swiss cheese on a small scale. Significant differences were found in the flavor, proteolysis, and texture of the cheeses made with different strains of lactobacilli.     

Protein Quality of Cheddar Cheese Compared with Casein and Fabricated Cheese in the Rat

The protein quality of freeze-dried cheddar cheese, spray-dried cheddar cheese, freeze-dried fabricated cheddar cheese (with casein as the main protein source), and sodium caseinate was evaluated in rats using the protein efficiency ratio (PER) assay (AOAC procedures) in two feeding experiments with casein as the control. Biological evaluation of the products showed that PER values for freeze-dried cheddar cheese were significantly higher than casein (3.7 vs 2.5). Freeze-dried cheddar also had a PER value significantly higher than spray-dried cheddar cheese (3.7 vs 3.0). Freeze-dried fabricated cheddar cheese and sodium caseinate had PER values not significantly different from the casein control.     

不同体细胞数原料乳对契达干酪成熟过程中蛋白水解的影响

为探讨原料乳中体细胞数(SCC)对契达干酪成熟过程中蛋白质水解的影响,选择SCC分别是5.6×104(LSCC)、48.8×104(MSCC)、476.1(HSCC)×104 个/mL的原料乳制作契达(cheddar)干酪,得到LSCC、MSCC、HSCC组干酪,并对各组干酪成熟过程中蛋白质水解的各项指标进行了测定.结果显示3组干酪成熟过程中蛋白的水解产物不同,LSCC组干酪品质更好.     

益生酵母菌对切达干酪风味的影响

从传统发酵乳制品中筛选得到两株益生酵母菌PC1和PC2,用于制备切达干酪。对干酪不同成熟阶段理化指标进行检测,并采用顶空固相微萃取及气质联用技术对挥发性风味成分进行鉴定及判别分析。结果表明,不同成熟阶段干酪各项理化指标发生明显变化,与对照组相比,添加PC1和PC2菌株干酪的蛋白质含量、pH值和风味化合物均有明显差异,变化明显的挥发性化合物主要有3-甲基-1-丁醇、苯乙醇、乙酸乙酯、2-戊基呋喃、乙烯基甲醚和3-甲基-1-戊醇。PC1和PC2菌株对切达干酪风味改善有积极影响,可作为干酪加工的辅助发酵剂,并且酵母菌PC2优于酵母菌PC1。     

契达干酪浆中使用热激瑞士乳杆菌的研究

在食品加工中添加酶解干酪比添加天然干酪更加营养、经济、有效。为了改善酶解干酪的风味,研究经优化热激(67℃/20s,68℃/15s,69℃/10s)条件处理与未处理的瑞士乳杆菌对干酪浆蛋白水解的影响。研究结果表明,经过5d成熟时间,蛋白水解产生肽段的数量增加,疏水性肽对亲水性肽的比率降低。感官评价结果显示,在适当条件下热激组的干酪浆滋气味显著增加,酸味降低,硬度减小。     

Use of Recombinant Chymosin in the Manufacture of Cheddar and Colby Cheese

Recombinant chymosin purified from E. coli K12 (Genencor Inc.) was examined for its suitability to manufacture Cheddar cheese. Commercial calf rennet or recombinant chymosin with and without Bacillus subtilis cellular homogenate was used to determine if enzyme sources affected Cheddar cheese quality or yield. Cheese was evaluated at 3 and 6 mo of age. Purified enzyme was mixed with cellular extracts from B. subtilis at approximately one and four times the protein concentration in the initial homogenates. Cellular materials did not affect clot times, cheese quality, or inhibit cheese acid development. No differences were noted between the yields of Colby cheese manufactured with calf rennet and recombinant chymosin. Initial Cheddar cheese manufactured with recombinant chymosin were excessively bitter, typical of cheese retaining excessive amounts of proteases. Dilution of purified prochymosin preparations increased total enzymic activity 2.7 times. Evidently, the purified recombinant preparations contained some oligomers that became active after being incorporated into the cheese mass, causing bitter flavors to develop during aging. Diluted enzyme preparations were used successfully in the manufacture of Cheddar cheese.     

Culture Effect on Ripening Characteristics and Rheological Behavior of Cheddar Cheese

Six defined strains of bacteriophage-insensitive Streptococcus cremoris, grown in whey-based starter media, were used over a period of 10 months to produce more than 2 million kg of Cheddar cheese on continuous cheesemaking equipment. Flavor development in this cheese was less than that in cheese made with conventional bulk starter. Proteolysis in the trichloracetic acid (TCA) soluble cheese fraction was less in cheese manufactured using S. cremoris compared to conventional bulk starter. Rheological properties were studied and the force-compression curves related to the age, composition and pH of the cheese. Pattern recognition techniques were used to analyze the multivariate data. The texture was affected by the mechanical process, moisture content and yield point of the cheese. Casein proteolysis, age, culture type and firmness were the most discriminating variables affecting maturity.