Polyphasic identification of Penicillium spp. isolated from Spanish semi-hard ripened cheeses

P. 409-444Fifteen samples of semi-hard ripened cheeses, both spoiled (10) and unspoiled (5), and obtained from cheese factories located in Northwest of Spain, were analysed by a dilution plating technique and direct sampling. A total of 32 isolates were identified at species level by a polyphasic approach (phenotypic characterization, partial extrolite analysis and molecular identification). Most isolates (65.6%) belonged to the species P. commune; other species found were P. solitum, P. chrysogenum, P. nordicum, P. expansum and P. cvjetkovicii. All of the P. commune isolates were able to produce cyclopiazonic acid, while the P. nordicum and the P. expansum isolates were producers of ochratoxin A and patulin respectively. Despite this, the role of P. commune as beneficial fungi in cheese ripening should be investigated. Molecular identification based on BenA sequence analysis was able to identify the majority of isolates. The three mycotoxins investigated can be considered key for identification. The polyphasic approach seems to be a very valuable tool for identification of isolates of this complex genusS

A comparative study on physicochemical and sensorial properties of butter made from yogurt and cream

In this study, some physicochemical and sensorial properties of butter made from yogurt and cream in Malatya (Turkey) were investigated. Twenty-five butter samples (11 yogurt and 14 cream origin) provided from markets were analyzed to determine the effects of raw materials, yogurt and cream, on above-mentioned properties. Analyses were performed according to the methods of International Dairy Federation (IDF) and Turkish Standard Institute (TSE). Butter samples have high level of moisture, curd and salt contents. Consequently, fat contents were found under the regulation for the table butter, as mean values. Similarly, the peroxide value (PV) for both types of butter was of a high level. Other characteristics of the butter samples showed some similarity. No significant correlation was found between yogurt and cream butter in terms of refractive index, iodine value, and Reichert-Meissl, Polenske and saponification numbers. However, differences between acid degree (free fatty acids) and titration acidity values were found to be statistically significant (p <0.05). Also, expert panel evaluation of the butter samples indicated that butters made from both raw materials were not different in all sensorial properties. It could be concluded that no major qualitative and quantitative differences between butters produced by 2 raw materials, yogurt and cream, were observed

Effect of single strains of Lactococci on manufacture and chemical quality of fresh Beyaz peynir, Turkish white-brined cheese

Beyaz peynir, Turkish white-brined cheese, was produced with six different strains of Lactococcus and ripened at 6–8 °C. Two of these were Lc. lactis subsp. lactis UC317 and NCDO763, while four of them were Lc. lactis subsp. cremoris SK11, HP, Wg2 and AM2. To determine their performance in manufacture of Beyaz cheesemaking, the activity of six different strains of Lactococcus were monitored during cheese production by determining the curd acidity. Also, their proteolytic and lipolytic activities were tested by determining nitrogen fractions and free fatty acid contents, respectively, after 3 days of ripening. These cheeses made with each strain of Lactococcus did not differ significantly in pH decline during cheesemaking. The gross compositions of the fresh cheeses were found to be similar; however, the cheeses made with HP and Wg2 had the lowest and highest levels of salt-in-moisture content, respectively. Water-soluble nitrogen, 12% trichloroacetic acid soluble nitrogen, total free amino acid and total free fatty acid contents were significantly influenced by using different strains of lactococci in manufacture of Beyaz peynir. All strains, except for Wg2 and AM2, gave a satisfactory result in chemical quality of the cheese; however, some differences were observed

Influence of brine immersion and vacuum packaging on the chemistry, biochemistry, and microstructure of Mihalic cheese made using sheep’s milk during ripening

Due to practical and hygienic uses in storage and marketing, cheese maker preference for the use of vacuum packaging instead of the brining method has increased significantly in recent years. The objective of the paper was to study and compare the chemistry, biochemistry, and microstructure of Mihalic cheeses ripened in vacuum packaging or under brine over 360 days. Proteolysis in Mihalic cheese was quite low (e.g., pH 4.6 soluble nitrogen was lower than 15%, as a percentage of the total nitrogen, and as1-casein was slower in comparison to other brined cheeses) due to its high salt-in-moisture and low moisture contents. Urea-PAGE patterns of the pH 4.6 insoluble fractions of the cheeses showed different degradation patterns of as1-casein in cheeses of different ages. However, β-casein was relatively resistant to hydrolysis. Packaging the cheese in polyethylene bags significantly increased the levels of pH 4.6 soluble nitrogen, 12% trichloroacetic acid-soluble nitrogen, and free amino acids compared to the cheeses ripened in brine. The total concentrations of free amino acids (FAA) in cheeses increased after 120 days of ripening, and Glu, Val, Leu, Lys, and Phe were the most abundant FAA in the cheeses. Higher levels of these AAs were found in the cheeses ripened in polyethylene bags. The peptide profiles by reversed-phase high-performance liquid chromatography of 70% (v/v) ethanolsoluble and ethanol-insoluble fractions of the pH 4.6 soluble fraction of the cheeses revealed that slight differences were found in the levels of some peptides between cheeses. Majority of the volatile compounds were present at higher concentrations in vacuum-packaged cheeses than in those ripened in brines. The images obtained by scanning electron microscopy of the cheeses ripened in polyethylene bags were clearly different (the protein matrix was more compact) from those of brine-ripened cheeses. The cheese ripened in vacuum packaging was completely different in terms of chemical composition, proteolysis, volatile composition, and microstructure. It was concluded that the vacuum packaging may be useful to maintain the chemical and biochemical qualities of Mihalic cheese, and it is also an easy practice during ripening

Fromages de Turquie : 3. Variétés aux herbes et aux épices

Ripened cheese varieties containing herbs are traditional in Turkey and have been manufactured for more than 200 years in the east and southeast of the country. They are manufactured from raw milk, semi-hard in texture and salty in taste and have the aroma of garlic or thyme due to added herbs. Twenty-five types of herb, including Allium, Thymus, Silene and Ferula species which are most popular, are used individually or as appropriate mixtures. The most popular of these cheeses is Otlu which is produced mainly in the Van province of Turkey in small dairies and villages, but now is produced in other cities of the eastern region of Turkey and its popularity increases continuously throughout Turkey. The manufacturing technology, chemical, biochemical and microbiological status of Otlu cheese and the most common herbs used in its manufacture are reviewed. The possible effect of herbs used on the biochemical and microbiological characteristics of the cheeses are discussed also. In addition, some varieties of Otlu cheese and cheeses flavoured with spices (chilli pepper, black pepper, cinnamon, allspice, mint, thyme, cumin, etc.), including Carra, Surk and related cheeses, are discussed briefly.Les variétés de fromages contenant des herbes sont traditionnelles en Turquie et sont produites depuis plus de 200 ans dans l'est et le sud-est du pays. Elles sont produites à partir de lait cru, ont une texture semi-dure et un goût salé et des arômes d'ail ou de thym apportés par les herbes ajoutées. Vingt-cinq sortes d'herbes, incluant les espèces Allium, Thymus, Silene et Ferula qui sont les plus populaires, sont utilisées individuellement ou en mélange. Le plus populaire de ces fromages est l'Otlu qui est produit principalement dans la province de Van en Turquie dans des petites laiteries et des villages, mais actuellement aussi dans d'autres villes de la région Est de la Turquie et sa popularité grandit continuellement dans tout le pays. La technologie de fabrication, le statut chimique, biochimique et microbiologique du fromage Otlu et les herbes les plus courantes utilisées dans sa fabrication sont présentés dans cette revue. L'effet possible des herbes utilisées sur les caractéristiques biochimiques et microbiologiques des fromages est aussi discuté. De plus, quelques variétés d'Otlu et de fromages aromatisés avec des épices (piment, poivre noir, cannelle, poivre de la Jamaïque, menthe, thym, cumin, etc.) incluant les fromages Carra, Surk et apparentés sont brièvement présentées

Physical, chemical and flavour quality of non-fat yogurt as affected by a beta-glucan hydrocolloidal composite during storage

WOS: 000257275700011In this study, a possible use of beta-glucan hydrocolloidal composite as a fat replacer in the manufacture of non-fat yogurts was investigated. The yogurts with added beta-glucan composite were compared with non-fat yogurt without addition of beta-glucan composite and the samples were analysed for physical, chemical and sensory attributes after 1, 7 or 15 d of storage. Fat and protein contents of the experimental yogurts were identical, while ash content differed. Addition of beta-glucan composite did not show a significant change of pH, titratable acidity, acetaldehyde, volatile fatty acids and tyrosine contents at any storage time. Titratable acidity and tyrosine content increased significantly throughout storage. Gel firmness and water-holding capacity in the yogurts were not influenced by addition of beta-glucan composite, but these variables decreased with storage time. Addition of beta-glucan composite and storage time caused a decrease in whey separation. Viscosity values in the yogurts increased by addition of beta-glucan composite and storage time. Sensory results indicated a preference for control yogurts; however, use of low levels of beta-glucan composite in the production of non-fat yogurt gave satisfactory sensory scores. Yogurts containing 0.25% or 0.50% beta-glucan hydrocolloidal composite were acceptable by expert panels and had scores similar to the control yogurt. (C) 2007 Elsevier Ltd. All rights reserved

Effect of milk pasteurization and curd scalding temperature on proteolysis in Malatya, a Halloumi-type cheese

The effect of pasteurization of cheese milk and cooking temperature of the curd on proteolysis of Malatya cheese was examined during ripening. The cheeses that were characterized by the scalding of curd in hot whey were manufactured from raw or pasteurized milk and the curds were scalded in hot whey at 60, 70, 80 or 90 °C. Differences in the levels of pH 4.6-soluble nitrogen between cheeses were significant (P < 0.05) after 30 days of ripening. Urea-polyacrylamide gel electrophoresis of the pH 4.6-insoluble fractions showed that both αs1- and β-caseins were not extensively degraded, especially after 30 days of ripening, but β-casein was less degraded than αs1-casein. Analysis of peptide profiles of the pH 4.6-soluble fractions by RP-HPLC showed significant differences in the concentrations of some peptides between the cheeses. Principal component analysis distinguished the cheeses made from raw or pasteurized milk based on their peptide profiles. The results suggest that the pasteurization of cheese milk had a greater effect on peptide profiles of cheese than scalding temperature of the curd