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.     

Low-fat mozzarella as influenced by microbial exopolysaccharides, preacidification, and whey protein concentrate

Low-fat Mozzarella cheeses containing 6% fat were made by preacidification of milk, preacidification combined with exopolysaccharide- (EPS-) producing starter, used independently or as a coculture with non-EPS starter, and preacidification combined with whey protein concentrate (WPC) and EPS. The impact of these treatments on moisture retention, changes in texture profile analysis, cheese melt, stretch, and on pizza bake performance were investigated over 45 d of storage at 4°C. Preacidified cheeses without EPS (control) had the lowest moisture content (53.75%). These cheeses were hardest and exhibited greatest springiness and chewiness. The meltability and stretchability of these cheeses increased most during the first 28 d of storage. The moisture content in cheeses increased to 55.08, 54.79, and 55.82% with EPS starter (containing 41.18 mg/g of EPS), coculturing (containing 28.61 mg/g of EPS), and WPC (containing 44.23 mg/g of EPS), respectively. Exopolysaccharide reduced hardness, springiness, and chewiness of low-fat cheeses made with preacidified milk in general and such cheeses exhibited an increase in cohesiveness and meltability. Although stretch distance was similar in all cheeses, those containing EPS were softer than the control. Cocultured cheeses exhibited the greatest meltability. Cheeses containing WPC were softest in general; however, hardness remained unchanged over 45 d. Cheeses made with WPC had the least increase in meltability over time. Incorporation of WPC did not reduce surface scorching or increase shred fusion of cheese shreds during pizza baking; however, there was an improvement in these properties between d 7 and 45. Coating of the cheese shreds with oil was necessary for adequate browning, melt, and flow characteristics in all cheese types.     

Preliminary observations on proteolysis in Manchego cheese made with a defined-strain starter culture and adjunct starter (Lactobacillus plantarum) or a commercial starter

Different authors have demonstrated the potential of adding lactobacilli as adjunct cultures to pasteurized milk used in cheese manufacture. The aim of this work was to observe the effect of the use of a defined-strain starter culture and the addition of an adjunct culture (Lactobacillus plantarum) to cheesemilk in order to determine their effect on the ripening of Manchego cheese. Manchego cheeses were manufactured using one of the following starter culture systems: a defined starter consisting of Lactococcus lactis ssp. lactis and Leuconostoc mesenteroides ssp. dextranicum; a defined starter, as described above, and Lb. plantarum, which were isolated from a good quality Manchego cheese made from raw milk, or a commercial starter comprised of two strains of Lc. lactis. The cheeses were sampled at 15, 45, 90 and 150 d of ripening. Principal component analysis of peak heights of reversed-phase HPLC chromatograms of 70% (v/v) ethanol-insoluble and -soluble fractions distributed the samples according to the starter used in their manufacture. Quantitative differences in several peptides were evident between the three cheeses. Cheeses made with the defined-strain starters received higher scores for the flavour quality and intensity and for overall impression than the cheeses made with the commercial starter.     

Characterization of aromatic properties of old-style cheese starters

Old-style cheese starters were evaluated to determine their ability to produce cheese aroma compounds. Detailed analyses of the aroma-producing potential of 13 old-style starter cultures were undertaken. The proteolytic profile of the starters was established by an accelerated ripening study using a model cheese slurry and compared with those of a commercial aromatic starter and commercial Cheddar cheeses. To evaluate the aromatic potential of the starter cultures, quantification of free amino acids liberated and volatile compounds after 15 d of ripening at 30°C as well as sensory analysis were carried out. Results showed that proteolysis patterns of all 13 starter cultures in the curd model were comparable to those of commercial Cheddar cheeses. All tested cultures demonstrated the ability to produce high amounts of amino acids recognized as precursors of aroma compounds. Several differences were observed between the starters and commercial Cheddar cheeses regarding some amino acids such as glutamate, leucine, phenylalanine, proline, and ornithine, reflecting the various enzymatic systems present in the starters. Starters Bt (control) and ULAAC-E exhibited various significant differences regarding their free amino acid profiles, as confirmed by sensory analysis. In addition, identification of volatile compounds confirmed the presence of several key molecules related to aroma, such as 3-methylbutanal and diacetyl. Besides the aroma-producing aspect, 2 starters (ULAAC-A and ULAAC-H) seem to possess an important ability to generate large amounts of γ-aminobutyric acid, which contributed up to 15% of the total amino acids present in the model curd after 15 d ripening. γ-Aminobutyric acid is an amine well-known for its antihypertensive and calming effects.     

EFFECT OF CALCIUM AND PHOSPHORUS, RESIDUAL LACTOSE AND SALT-TO-MOISTURE RATIO ON TEXTURAL PROPERTIES OF CHEDDAR CHEESE DURING RIPENING

The texture profile analysis (TPA) parameters and meltability of Cheddar cheeses with varying levels of calcium (Ca) and phosphorus (P) content, residual lactose content and salt‐to‐moisture (S/M) ratio were studied at 0, 1, 2, 4, 6 and 8 months of ripening. The TPA hardness had an inverse relationship with the meltability of Cheddar cheese and at any given ripening time, lower TPA hardness corresponded to higher meltability of Cheddar cheese. Higher Ca and P content (0.67% Ca and 0.53% P) in Cheddar cheese resulted in up to 22.8, 5.7, 14.6, 13.5 and 35.2% increase in hardness, springiness, cohesiveness, resilience and chewiness values, respectively, and up to 23.5 and 27.7% decrease in meltability and adhesiveness values during ripening compared to the Cheddar cheese prepared with lower Ca and P content (0.53% Ca and 0.39% P). Higher residual lactose content (1.4%) in Cheddar cheese resulted in up to 24.6, 8.8 and 20.0% increase in hardness, cohesiveness and chewiness values, respectively, and up to 12.7% decrease in meltability value in the Cheddar cheese during ripening compared to the lower lactose content (0.78%). High S/M ratio (6.4) resulted in up to 29.4, 30.3 and 29.4% increase in hardness, adhesiveness and chewiness values, respectively, and up to 7.3% decrease in meltability value in Cheddar cheese compared to low S/M ratio (4.8) during ripening.     

Influence of a defined-strain starter and Lactobacillus plantarum as adjunct culture on volatile compounds and sensory characteristics of Manchego cheese

Three batches of Manchego cheese were manufactured using one of the following starter culture systems: (1) a defined strain starter culture comprising Lactococcus lactis subsp. lactis and Leuconostoc mesenteroides subsp. dextranicum; (2) the above-defined strain starter culture and an adjunct culture (Lactobacillus plantarum), all these strains being isolated from high-quality Manchego cheeses and (3) a commercial starter consisting of two strains of Lactococcus lactis. Differences in volatile profile and the sensory characteristics of these cheeses were studied. After 4 months of ripening, the two batches of cheese made with the defined strain starter cultures obtained the highest scores for sensory attributes and for the overall impression. Additionally, Purge & Trap and SDE analysis showed a more complex volatile profile in these cheeses than in those made with the commercial starter. Extending the maturation time to 8 months for cheeses made with the defined starter cultures led to significant higher levels of free fatty acids and ethyl esters in those cheeses made without adjunct culture. However, panelists did not find significant differences among the sensory characteristics of the two cheeses.     

Application of exopolysaccharide-producing cultures in reduced-fat Cheddar cheese: texture and melting properties

Textural, melting, and sensory characteristics of reduced-fat Cheddar cheeses made with exopolysaccharide (EPS)-producing and nonproducing cultures were monitored during ripening. Hardness, gumminess, springiness, and chewiness significantly increased in the cheeses as fat content decreased. Cheese made with EPS-producing cultures was the least affected by fat reduction. No differences in hardness, springiness, and chewiness were found between young reduced fat cheese made with a ropy Lactococcus lactis ssp. cremoris [JFR1; the culture that produced reduced-fat cheese with moisture in the nonfat substance (MNFS) similar to that in its full-fat counterpart] and its full-fat counterpart. Whereas hardness of full-fat cheese and reduced-fat cheese made with JFR1 increased during ripening, a significant decrease in its value was observed in all other cheeses. After 6 mo of ripening, reduced fat cheeses made with all EPS-producing cultures maintained lower values of all texture profile analysis parameters than did those made with no EPS. Fat reduction decreased cheese meltability. However, no differences in meltability were found between the young full-fat cheese and the reduced-fat cheese made with the ropy culture JFR1. Both the aged full- and reduced-fat cheeses made with JFR1 had similar melting patterns. When heated, they both became soft and creamy without losing shape, whereas reduced-fat cheese made with no EPS ran and separated into greasy solids and liquid. No differences were detected by panelists between the textures of the full-fat cheese and reduced-fat cheese made with JFR1, both of which were less rubbery or firm, curdy, and crumbly than all other reduced-fat cheeses.     

Manufacture of low-fat Cheddar cheese by exopolysaccharide-producing Lactobacillus plantarum JLK0142 and its functional properties

This study aimed to evaluate the effect of exopolysaccharide (EPS)-producing Lactobacillus plantarum JLK0142 on the ripening characteristics and in vitro health-promoting benefits of low-fat Cheddar cheese. Three batches of cheese were made by employing a non-EPS–producing cheese starter (control), in combination with Lb. plantarum JLK0142 as an adjunct and the purified EPS as an ingredient. Lactobacillus plantarum JLK0142 survived well in cheese, with counts of 7.99 log cfu/g after 90 d of ripening. All experimental cheeses (with adjunct culture or EPS ingredient) had higher moisture, proteolysis, and sensory scores, and lower hardness and cohesiveness compared with the control cheese. Water-soluble extracts from the experimental cheeses outperformed that of the control in scavenging 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS), and hydroxyl radicals, and inhibiting α-amylase, angiotensin-converting enzyme, and HT-29 tumor cell growth. Therefore, incorporation of the EPS-producing culture of Lb. plantarum JLK0142 is promising for improvement of low-fat cheese quality and bioactivities.     

Proteolysis on Reggianito Argentino cheeses manufactured with natural whey cultures and selected strains of Lactobacillus helveticus

Reggianito Argentino cheese is traditionally manufactured with whey starter cultures that provide typical and intense flavor but can cause poor quality standardization. In this study, the influence of natural and selected starters on Reggianito Argentino cheese proteolysis was investigated. Cheeses were manufactured with three strains of Lactobacillus helveticus (SF133, SF138 and SF209) cultured individually in sterile whey and used as single or mixed starters. Control cheeses were made with natural whey starter culture. Cheeses were analyzed to determine gross composition, as well as total thermophilic lactic flora. Proteolysis was assessed by N fractions, electrophoresis and liquid chromatography. Gross composition of the cheeses did not significantly differ, while viable starter cell counts were lower for cheeses made with strain SF209 alone or combined with other strains. Soluble N at pH 4.6 was the same for cheeses made with natural or selected starters, but soluble N in 12% trichloroacetic acid and 2.5% phosphotungstic acid was significantly higher in cheeses made with starters containing strain SF209. Nitrogen fractions results indicated that natural whey starter cultures could be replaced by several starters composed of the selected strains without significant changes to proteolysis patterns. Starter cultures prepared only with SF209 or with the three selected L. helveticus strains produced cheese products with significantly more proteolysis than control cheeses. Chromatographic profiles analyzed by principal components showed that three main peaks on chromatograms, presumptively identified as Tyr, Phe, and Trp, explained most of variability. Principal component scores indicated that cheese samples were grouped by ripening time, which was confirmed by linear discriminant analysis. On the contrary, samples did not cluster by Lactobacillus strain or type of starter.     

Effect of wild strains used as starter cultures and adjunct cultures on the volatile compounds of the Pecorino Siciliano cheese

The effect of six wild strains on the volatile profile of the PS cheese was investigated and compared to that generated from industrial starters generally used to produce PS cheese. All cheeses were subjected to microbiological, physicochemical, and volatile compounds analyses. The DGGE of the 16S rDNA analysis was also applied. The volatile compounds generated during ripening were studied through the SPME and the GC-MS methods. No difference was detected between the experimental and control cheeses throughout chemical and microbiological analyses, while the DGGE results showed the presence of Streptococcus thermophilus in all cheeses, and the dominance of Enterococcus durans, Lactobacillus rhamnosus, and Lactobacillus casei in most of the experimental cheeses. Moreover, the presence of Lactococcus lactis species as in the control and in the experimental P2 and P4 cheeses was also revealed. The SPME results showed more pronounced volatile compounds in the experimental cheese samples than in the control ones.     

Improving the textural properties of Egyptian kariesh cheese by addition of hydrocolloids

In this study, the effect of addition of hydrocolloids (commercial pectin, citrus pectin or carboxymethylcellulose) to Egyptian Kariesh cheese at 0.2, 0.4 and 0.6% (w/w) on chemical composition, yield, rheological and sensory characteristics was investigated. The results revealed that the addition of hydrocolloids increased moisture content and yield values of Kariesh cheeses compared with control. Protein, salt and ash content decreased with increasing hydrocolloids levels. Rheological characteristics (hardness, adhesiveness, springiness, cohesiveness, gumminess, chewiness, resilience) were significantly lower in cheeses made with hydrocolloids. Kariesh cheese made with 0.4% w/w commercial pectin and 0.6% w/w carboxymethylcellulose recorded the highest scores for sensory attributes.     

Volatile composition and improvement of the aroma of industrial Manchego cheese by using Lactobacillus paracasei subsp. paracasei as adjunct and other autochthonous strains as starters

The use of several autochthonous strains of lactic acid bacteria, including Lactobacillus paracasei subsp. paracasei as adjunct of the starter in the manufacture of Manchego cheese, was evaluated in an attempt to improve the aroma of the industrial Manchego cheese. Volatile composition and odour characteristics were evaluated and compared to those in Manchego cheese manufactured with a commercial starter (CS) culture and with raw milk cheese manufactured without starter. Manchego cheeses manufactured with two autochthonous strains of Lactococcus lactis subsp. lactis displayed a similar volatile profile and odour characteristics to the cheese made with the CS. The use of the strain Lactobacillus paracasei subsp. paracasei CECT 7882 as adjunct of the Lactococcus strains produced cheeses with higher amounts of some free fatty acids and alcohols, acetoin, lactones, phenylacetaldehyde, 2-phenylethanol and linalool, and higher scores of the odour intensity, odour quality, and ewe’s milk odour than the CS cheeses. It resulted in an intensification and improvement of industrial Manchego cheese aroma.     

Influence of starter and nonstarter on the formation of biogenic amine in goat cheese during ripening

Two commercial starters were investigated for their potential ability to decarboxylate amino acids during goat cheese ripening. Two batches of goat cheese were produced with identical pasteurized milk but different starter cultures. One of them contained Lactococcus lactis subsp. lactis and Lactococcus lactis subsp. cremoris and the other Lactococcus lactis subsp. lactis. The amine contents, microbial counts, proteolysis-related parameters, pH, total solids and salt content were studied in raw materials and cheeses. In raw materials, polyamines were the prevailing amines, whereas the main amines in cheeses were putrescine, tryptamine and, in particular, tyramine (94.59 mg/kg). Aerobic mesophilic microorganisms and Lactococcus counts increased throughout ripening, while Enterobacteriaceae were no longer detectable in cheese after 30 days of ripening. Amine concentration rose during cheese ripening in both batches. Moreover, the decarboxylase activity of microorganisms isolated from samples during cheese ripening was assayed and discussed.     

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。     

Physicochemical,textural and sensory properties of white soft cheese made from buffalo and cow milk mixtures

The physicochemical, textural and sensory properties of white soft cheeses made from three different buffalo and cow milk mixtures (100:0, 70:30 and 30:70) during 3‐month storage were studied. The increase in buffalo milk concentration resulted in increasing total cheese yield, dry matter (DM) and fat retention and fat in DM content. However, it caused reductions in moisture content, salt intake, hardness, chewiness, elasticity, sensory hardness and sensory cohesiveness of the samples. The percentage of water‐soluble nitrogen to total nitrogen increased during storage resulting in decreased fracturability, hardness (textural and sensory), cohesiveness (textural and sensory), springiness, chewiness and elasticity. The panellists evaluated the white soft cheese made with buffalo milk as the most acceptable.     

Short communication: Effects of milk fat depression induced by a dietary supplement containing trans-10, cis-12 conjugated linoleic acid on properties of semi-hard goat cheese

Dietary supplements of conjugated linoleic acid (CLA) containing trans-10, cis-12 CLA reduce milk fat synthesis in lactating goats. This study investigated effects of milk fat depression induced by dietary CLA supplements on the properties of semi-hard goat cheese. Thirty Alpine does were randomly assigned to 1 of 3 groups and fed diets with lipid-encapsulated CLA that provided trans-10, cis-12 CLA at 0 (control), 3 (CLA-1), and 6 g/d (CLA-2). The experiment was a 3 × 3 Latin square design. Periods were 2 wk in length, each separated by 2-wk periods without CLA supplements. Bulk milk was collected on d 3 and 13 of each of 3 periods for cheese manufacture. The largest decrease (23.2%) in milk fat content, induced by the high dosage (6 g/d per doe) of trans-10, cis-12 CLA supplementation at d 13 of treatment, resulted in decreases of cheese yield and moisture of 10.2 and 10.0%, respectively. Although CLA supplementation increased the hardness, springiness, and chewiness, and decreased the cohesiveness and adhesiveness of cheeses, no obvious defects were detected and no significant differences were found in sensory scores among cheeses. In conclusion, milk fat depression induced by a dietary CLA supplement containing trans-10, cis-12 CLA resulted in changes of fat-to-protein ratio in cheese milk and consequently affected properties of semi-hard goat cheese.     

Applicability of bacteriocin‐producing Lactobacillus plantarum,Enterococcus faecium and Lactococcus lactis ssp. lactis as adjunct starter in Minas Frescal cheesemaking

The antimicrobial and technological characteristics of three bacteriocinogenic cultures used as adjunct starters in Minas Frescal cheese were investigated. The cheeses were manufactured with 1% commercial lactic starter and 0.5%Lactococcus lactis ssp. lactis ATCC 11454, Lactobacillus plantarum ALC 01 or Enterococcus faecium FAIR‐E 198. The cheeses were then artificially inoculated with Listeria monocytogenes Scott A, Staphylococcus aureus ATCC 27154 and Bacillus cereus K1‐B041 and stored for 21 days at 8°C. The results show that there was no significant difference in the counts of L. monocytogenes and S. aureus between the cheeses made with added bacteriocinogenic cultures and the control cheese. On the other hand, B. cereus exhibited susceptibility to Lb. plantarum ALC 01 and E. faecium FAIR‐E 198 from the seventh day of storage. However, these cultures increased the proteolysis of the Minas Frescal cheese.     

热激处理菌种对奶酪品质的影响

为研究热激处理（63 ℃、20 min）发酵剂菌种（唾液链球菌嗜热亚种和保加利亚乳杆菌德氏亚种混合菌种）对奶酪成熟过程中品质特性的影响,对两种不同菌种所制作奶酪基本组成及成熟过程中的质构、感官、蛋白降解、风味物质等指标进行了测定。结果表明,热激处理菌种对奶酪基本组成影响不大,但热激处理菌种有利于奶酪成熟过程中蛋白质的降解,进而使奶酪的硬度和咀嚼性显著降低,也促使奶酪在成熟120 d时形成了更多的醛类、酮类、酯类等主要挥发性风味物质,同时奶酪的风味和组织状态的感官评价也较好。     

大叶麻竹笋腌制过程中质地的变化

应用质构仪质地多面分析(TPA)试验方法,研究了大叶麻竹笋在不同食盐浓度腌制条件下及腌制过程中的质地变化。研究结果表明:大叶麻竹笋腌制过程中的硬度、咀嚼性、内聚性、弹性与回复性呈下降趋势,腌制食盐浓度越低,上述5个质地参数的数值降低的越多;黏着性呈上升趋势,腌制食盐浓度越低,其数值增加的越多。大叶麻竹笋TPA测试各质地参数间的相关性分析表明,硬度、咀嚼性、内聚性、弹性和回复性可用于更好地评价腌制大叶麻竹笋质地的变化。