Physicochemical,rheological and sensory properties of Egyptian Kariesh cheese containing wheat bran

The physicochemical, rheological and sensory properties during the storage of Kariesh cheeses made with 0.1, 0.2, 0.3, 0.4 or 0.5 g wheat bran/100 g milk were evaluated at 0, 7 and 15 days. The cheeses with 0.5 g wheat bran/100 g milk had a significantly (P < 0.01) higher yield and moisture content, and lower pH and protein content than the control. No significant differences (P > 0.01) in salt and ash contents were observed among the cheeses studied. Texture profile analysis showed that the rheological characteristics decreased significantly in cheeses made with wheat bran. These results suggested that wheat bran (up to 0.4%) can be used to produce a fibre fortified Kariesh cheese.     

Ripening of extra-hard cheese made with mesophilic DL-starter

Extra hard cheese is commonly made with thermophilic starters using high temperatures to stimulate expulsion of whey. In this work, microflora, proteolysis and volatiles were investigated in an extra-hard cheese made with mesophilic DL-starter, produced using challenging cooking temperatures for the starter bacteria over several hours. Cheese from six commercially produced vats was investigated over 56 weeks. The number of starter bacteria decreased after three weeks of ripening. Casein breakdown was characterised by chymosin and plasmin activity on α_s1- and β-caseins, respectively. Peptide profiles showed accumulation of Lactococcus derived peptides from α_s1-CN f1–23, and the peptide β-CN 29–93 as a result of joint plasmin and chymosin activity and absence of highly proteolytic thermophilic Lactobacillus, commonly present in extra-hard cheese. The composition of amino acids depended mainly on starter during the first 26 weeks of ripening. The content of volatiles depended both on ripening time and the starter used.     

Ripening changes of Kashkaval cheese made from cow's milk

Kashkaval cheese was made from cow's milk and examined for the changes in its microstructure and chemical composition during ripening.The percentages of fat, protein, soluble nitrogen, non-protein nitrogen, amino acid nitrogen and the total free fatty and amino acids increased during ripening.The presence of glutamic acid, leucine, phenylalanine, valine and tyrosine at high concentration, and of butyric, caproic, caprylic and capric acids may contribute to the formation of Kashkaval cheese flavour. The small concentrations of acetic and propionic acids preclude any contribution to Kashkaval flavour.In young cheese, casein aggregates lose their spherical shape due to the scalding and kneading processes and they form a fibrous network including cavities.During ripening, dissociation and fusion processes occur in protein fibres to form a more homogeneous structure and interaction between layers of casein sheets increases to give a more compact structure.     

Ripening changes in Ras cheese prepared from ultrafiltered milk

Summary The changes in the proteins and fats of Ras cheese prepared from ultrafiltered milk (UF) were followed during ripening. The soluble protein fraction was made up of whey protein which resisted hydrolysis during ripening. The insoluble protein fraction of fresh cheese was made up mainly of-casein,-casein ands₁-I, indicating pronounced proteolysis during the salting step. Further ripening was accompanied with decrease ins₁-I and increase in-casein. The free fatty acids (FFA) of UF Ras cheese increased with advanced ripening. The pattern of FFA in Ras cheese was similar to that of bovine milk triacylglycerols.

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Veränderungen in der Zusammensetzung von Ras-Käse aus ultrafiltrierter Milch während der Reifung

Zusammenfassung Es wurden die Veränderungen der Proteine und der Fettfraktionen von Ras-Käse aus ultrafiltrierter Milch während der Reifung studiert. Die lösliche Proteinfraktion bestand aus Molkeproteinen, die der Hydrolyse während der Reifung widerstand. Die unlösliche Proteinfraktion des frischen Käses bestand aus-Casein,-Casein unds₁-I, was auf starke Proteolyse während des Einsalzens hinweist. In der nachfolgenden Reifung wurde eine Abnahme dess₁-Caseins und eine Zunahme der-Caseine beobachtet. Die freien Fettsäuren des Ras-Käses nahmen während der Reifung zu. Das Muster der freien Fettsäuren des Ras-Käses und das der Milchtriglyceride sind ähnlich.

     

Ripening of cheddar cheese with added attenuated adjunct cultures of lactobacilli

We made Milled curd Cheddar cheese with Lactococcus starter and an adjunct culture of Lactobacillus helveticus I or Lactobacillus casei T subjected to different attenuation treatments: freeze shocking (FS), heat shocking (HS), or spray drying (SD). Proteolysis during cheese ripening (0 to 6 mo), measured by urea-PAGE and water-soluble nitrogen, indicated only minor differences between control and most adjunct-treated cheeses. However, there were significant differences in the effect of Lactobacillus adjuncts on the level of free amino nitrogen in cheese. Cheeses made with FS or HS Lb. helveticus adjunct exhibited significantly greatest rates of free amino group formation. Lipolysis as measured by total free fatty acids was consistently highest in adjunct-treated cheeses, and FS Lb. casei-treated cheeses showed the highest rate of free fatty acid formation followed by FS Lb. helveticus treated cheeses. Mean flavor and aroma scores were significantly higher for cheeses made with Lb. helveticus strain. Freeze-shocked Lb. helveticus-treated cheeses obtained the highest flavor and aroma scores. Sensory evaluation indicated that most of the adjunct-treated cheeses promoted better texture and body quality.     

Acceleration of cheese ripening at elevated temperature. An estimation of the optimal ripening time of a traditional Argentinean hard cheese

The effect of elevated ripening temperature on physicochemical, biochemical and sensory characteristics in Reggianito Argentino cheese was evaluated to determine the optimal time for cheese ripening at 18 °C that ensures typical cheese characteristics. Cheeses ripened at 12 or 18 °C and 85% relative humidity were analysed at 2, 4 and 6 months. Seventy-eight variables (as determined by urea-PAGE, RP-HPLC of the water-soluble at pH 4.6 fraction, free amino acids, free fatty acids and sensory analysis) were considered for the principal component analysis. The statistical analysis allowed determination of the optimal time for ripening Reggianito Argentino cheese at 18 °C, which was ranged between 2 and 3 months. In conclusion, the results obtained were not only useful in characterising the ripening of an Argentinean hard cheese, but also in evaluating the effect of an increase of ripening temperature on the main physicochemical, biochemical and sensory changes of Reggianito Argentino cheese.     

Ripening of Cheddar cheese made from blends of raw and pasteurised milk

Cheddar cheeses were made from pasteurised milk (P), raw milk (R) or pasteurised milk to which 10 (PR10), 5 (PR5) or 1 (PR1) % of raw milk had been added. Non-starter lactic acid bacteria (NSLAB) were not detectable in P cheese in the first month of ripening, at which stage PR1, PR5, PR10 and R cheeses had 10⁴, 10⁵, 10⁶ and 10⁷ cfu NSLAB g⁻¹, respectively. After ripening for 4 months, the number of NSLAB was 1–2 log cycles lower in P cheese than in all other cheeses. Urea–polyacrylamide gel electrophoretograms of water-soluble and insoluble fractions of cheeses and reverse-phase HPLC chromatograms of 70% (v/v) ethanol-soluble as well as -insoluble fractions of WSF were essentially similar in all cheeses. The concentration of amino acids were pro rata the number of NSLAB and were the highest in R cheese and the lowest in P cheese throughout ripening. Free fatty acids and most of the fatty acid esters in 4-month old cheeses were higher in PR1, PR5, PR10 and R cheeses than in P cheese. Commercial graders awarded the highest flavour scores to 4-month-old PR1 cheeses and the lowest to P or R cheese. An expert panel of sensory assessors awarded increasingly higher scores for fruity/sweet and pungent aroma as the level of raw milk increased. The trend for aroma intensity and perceived maturity was R>PR10>PP5>PR1>P. The NSLAB from raw milk appeared to influence the ripening and quality of Cheddar cheese.     

Ripening of cheese made from full concentrated milk retentate with and without peptidase addition

The aim of this study was to determine ripening of cheese made from full concentrated (FC) milk retentate with and without peptidase addition. No free amino acids (FAAs) were found in FC cheese at the end of ripening. However, added peptidase increased FAA formation. Protein and peptide profile analysis showed that FAA and small peptides increased during ripening and therefore some secondary proteolysis occurred. Added peptidase increased D‐lactic acid formation during ripening of cheeses. This kind of changes in lactose fermentation should be considered during developing the making cheese with different enzyme addition.     

Ripening changes of Ras cheese made from recombined milk as affected by certain additives

An attempt has been made to accelerate the ripening of Ras cheese made from recombined milk (RM). RM cheese was made from curd with either a mixture of Fromase 100 (fungal rennet) and Kapalase L (an animal lipase) at concentrations of 0·025 and 0·05% or a slurry of fully ripened cheese at concentrations of 1 and 2%. These treatments enhanced flavour development, body characteristics, formation of soluble nitrogen compounds and free fatty acids. The proteinase/lipase mixture was the most effective. A rancid flavour and bitter taste were developed in 3–4-month-old RM cheese made with the higher concentration enzyme mixture.     

Optimal conditions for the production of exopolysaccharide by Pediococcus acidilactici and impact of the bacterium,its EPS and dextran on the quality of Kariesh cheese

The effect of some growth conditions on the production of exopolysaccharide (EPS) by Pediococcus acidilactici was studied. Furthermore, the impact of utilisation of the isolated EPS, dextran and P. acidilactici on some properties of Kariesh cheese was investigated. The maximum EPS production by P. acidilactici was obtained after 10 h of incubation at 37°C in MRS medium with an initial pH of 7. Kariesh cheese manufactured with dextran or P. acidilactici exhibited the highest (P ≤ 0.05) moisture content and the lowest hardness values. Protein, fat, ash, total bacterial and yeast and mould counts were not significantly affected by the applied treatments. However, the body and texture of Kariesh cheese were significantly improved.     

Ripening of Camembert-type cheese made from caprine milk using calf rennet or kid rennet as coagulant

Camembert-type cheese was made from caprine milk using either calf rennet or kid 'Grandine' rennet as coagulant. The pH of all cheeses increased throughout ripening and levels of pH 4.6-soluble nitrogen increased from 8.1 to 18.2% of total nitrogen (TN) and from 6.9 to 20% TN for the cheeses made using calf rennet and kid rennet, respectively. Degradation of β-casein, measured by urea–polyacrylamide gel electrophoresis, and total and free amino acids were greater in the cheese made using kid rennet. Production of peptides, analysed by high performance liquid chromatography (HPLC), was slightly more extensive in the Camembert-type cheese made using calf rennet as coagulant. In general, a higher degree of proteolysis was found in Camembert-type cheese made from caprine milk using kid rennet than in cheese made using calf rennet as coagulant.     

应用电子鼻区分不同成熟期的契达干酪

将电子鼻用于对契达干酪的检测,旨在寻求一种快速有效的方法以实现对契达干酪成熟期的判定。用电子鼻检测9个不同成熟期的契达干酪样本的气味。结果表明,电子鼻可以准确地区分契达干酪的成熟期,所建模型能够准确识别契达干酪的成熟期。     

Pyroglutamic acid in cheese: presence, origin, and correlation with ripening time of Grana Padano cheese

Pyroglutamic acid is present in many cheese varieties and particularly in high amounts (0.5 g/100 g of cheese) in extensively ripened Italian cheeses (Grana Padano and Parmigiano Reggiano) that are produced with thermophilic lactic acid bacteria as starters. The mechanism of pyroglutamic acid formation in cheese seems to be mostly enzymatic, as demonstrated by the presence of only L-pyroglutamic acid enantiomer. Thermophilic lactobacilli are involved in pyroglutamic acid production, as suggested by the low pyroglutamic acid content found in Bagos, a ripened Italian mountain cheese produced without addition of starter. Because milk pasteurization did not influence the pyroglutamic acid content in the ripened Grana Padano cheese, the formation of pyroglutamic acid mainly depends on the whey starter microflora rather than that of raw milk. Pyroglutamic acid concentration is linearly correlated (R2 = 0.94) with the age of Grana Padano cheese.     

棉及其混纺筒子纱一次准确染色

筒子纱一次准确染色的工艺设计是一项多因素综合性工作。分析了前处理和染色工艺设计、染色设备的选用和染色工艺条件试验,对棉及其混纺筒子纱一次准确染色提出了工艺设计方面的要求。     

Ripening of traditional Örgü cheese manufactured with raw or pasteurized milk: Composition and biochemical properties

The changes in composition and some biochemical properties of Örgü cheeses made from raw (RMC) and pasteurized (PMC) cow milk were investigated during a 90-day ripening period. The average contents of total solids (TS), protein, water soluble nitrogen (WSN), trichloro-acetic acid soluble nitrogen (TCA-SN) and acid degree value (ADV) were lower, while salt and salt in TS were found to be statistically higher in PMC than RMC (P < 0.05). In addition, in both RMC and PMC, the TS and protein contents were decreased as compared to an increase in salt, salt in TS, WSN and TCA-SN contents, and ADV, during ripening (P < 0.05). The evaluation of WSN, TCA-SN and ADV shows that these two experimental Örgü cheese types undergo little proteolysis and lipolysis. On the other hand, acidity development was observed to be high in both before curdling and in cheese made from raw milk during ripening.     

A fast micromethod for the estimation of nisin activity in a soft cheese

The British Standard protocol currently used to determine the nisin concentration in cheese requires the manipulation of a 40 g sample involves two critical points, pH adjustment and heating/cooling. In this work, we developed a fast micromethod that permits the manipulation of 0.2 g cheese, substitutes the use of 0.02N HCl by 50 mM citric acid and facilitates the handling of many samples in reduced time, and with increased efficiency/yield. This change keeps the pH stable at ~3.4, enough to sidestep the pH adjustment, and nisin antimicrobial activity was stable at boiling temperatures.     

Immunological estimation of bovine casein in sheep cheese products (author's transl)

Casein fraction of cow's milk and sheep's milk are very similar in their immunological behavior. Therefore, in the presence of sheep's milk, precipitation reaction with commercially obtained serum are not specific. Results from comparative immunoelectrophoresis according to Grabar and Williams also are equivocal, for heat and other denaturing factors caused shifts in the pattern of just the small group of differing elecrophoretic bonds present among many identical bonds. Qualitative identification of large amounts of cow's milk added to sheep's milk or of bovine casein to sheep cheese or similar products are possible in principle by two dimensional immunoelectrophoresis or so called crossed immunoelectrophoresis as described by Clarke and Freeman, but this estimation takes a lot of time and is not suitable for analysis of a series of samples. Sufficient sensitivity for certain and semiquantitative statements about the content of cows' milk casein in products from sheep's milk are obtained by the technique of radial double diffusion by Ouchterlony in Agarose gels only by the saturation of commercial anti-bovine-casein-serum by means of a suitable protein-standardized sheep's milk extract and its subsequent work-up and lyophilisation to yield a stable serum.