Prato Cheese Research Articles

Elaboração e Caracterização de Queijo Tipo Prato com Leite de Ovelha e de Vaca

The objective of this work was the preparation and characterization of Prato type cheeseof sheep's milk and cow's milk. The physicochemical analyzes were: titratable acidity, protein, lactose, fat, moisture, ash and the yield, microbiological analyzes contemplated Salmonella spp., coagulase positive Staphylococcus and Coliforms at 35°C, performed during the ripening. There were significant differences in the content of acidity, lactose, ash, protein and moisture at the level of 95% confidence over time of ripening cheese from sheep milk and cow milk. The variation behavior of the mean values of physicochemicalcomposition was quite similar between the cheeses. Comparing the results of physicochemical analyzes of Prato cheese from and cow's milk, the cheese with sheep's milk had higher concentrations of protein and ash content and lower fat content at 60 days of storage. As regards to yield, for Prato cheese of

Can lutein replace annatto in the manufacture of Prato cheese?

Abstract Prato cheese is a Brazilian yellow-orange cheese traditionally colored with annatto. However, the aim of this study was to replace annatto with lutein, a natural yellow food pigment with potent antioxidant properties. Accordingly, we evaluated the maintenance of antioxidant activity of two concentrations of lutein (16 and 32 mg L−1) in Prato cheese throughout 60 days of ripening, as well as changes in color, pH, texture and ripening profiles, and sensory acceptance of lutein containing Prato cheese. We observed that lutein added to milk was transferred to the curd and antioxidant activity was maintained throughout ripening for both lutein concentrations. The cheese containing the higher concentration of lutein was slightly redder in color than the others; however, the main color changes were due to the ripening. In addition, Prato cheeses containing both lutein concentrations demonstrated similar sensory acceptance compared to cheese containing annatto. Ripening indexes (extension and depth), pH, and texture profile parameters were not affected (p ≥ 0.05) by addition of lutein. Therefore, Prato cheese was found to be a good matrix carrier for lutein, maintaining the antioxidant activity of the colorant. Furthermore, lutein can replace annatto without affecting the properties and acceptance of Prato cheese.

Prato cheese as suitable carrier for Lactobacillus acidophilus La5 and Bifidobacterium Bb12

To assess Prato cheese as suitable carrier for probiotic bacteria, four cheeses were produced. Control cheese contained only starter culture, whereas the others contained starter culture and the probiotic cultures Lactobacillus acidophilus La5 and Bifidobacterium Bb12 either separately or in combination. Bacterial viability, physicochemical composition, proteolysis, and texture profile were assessed over 60 days of storage. The addition of microorganisms together or separately did not affect the characteristics of Prato cheese. On storage, the cheeses showed increased proteolysis, lower firmness, and the probiotic cheeses presented counts higher than 106 cfu g−1. The viability of probiotics during in vitro gastrointestinal simulation, including the effect of the cheese matrix, was also assessed. The probiotic bacteria showed resistance to loss of viability during in vitro gastrointestinal simulation.

English

The influence of storage temperature (6, 12 and 18°C) on texture parameters of Prato cheese were evaluated during 22 days of ripening. A reduction of firmness, gumminess and elasticity was observed; however, cohesiveness and adhesiveness increased. With the increasing temperature, firmness and gumminess reduced, whereas the elasticity, cohesiveness and adhesiveness did not change. It can be concluded that storage temperature influences the texture profile of Prato cheese which present differences in the evaluated parameters during 22 days of ripening.   Key words: Cheese ripening, hard cheese, colour, texture profile analysis.

Effectiveness of different methodologies for the selective enumeration of Lactobacillus acidophilus La5 from yoghurt and Prato cheese

Prior to the selective enumeration of probiotic microorganisms in fermented dairy products, a preliminary evaluation of different culture media and incubation conditions is required to choose a suitable culture medium. The objective of this study was to evaluate the effectiveness of different methodologies for the selective enumeration of Lactobacillus acidophilus in probiotic yoghurt and Prato cheese. For selective enumeration of L. acidophilus, four methods were investigated under anaerobic conditions, as follows: MRS agar containing bile solution; MRS agar containing clindamycin solution; and MRS agar containing sorbitol solution, each one incubated at 37 °C for 72 h, and MRS agar containing sorbitol incubated at 45 °C for 72 h. These methodologies were used for enumeration of both the pure cultures and the microorganisms from probiotic yoghurt and Prato cheese. The results showed that the best selective medium for enumeration of L. acidophilus from yoghurt was MRS agar containing bile incubated at 37 °C for 72 h under anaerobic conditions. For enumeration of this probiotics from Prato cheese, MRS agar containing sorbitol incubated at 45 °C for 72 h under anaerobic conditions was proven to be the best selective medium.

QUANTIFICAÇÃO E PORCENTAGEM DE RECUPERAÇÃO DE LUTEÍNA ADICIONADA NA FABRICAÇÃO DE QUEIJO PRATO ESFÉRICO

The manufacturing of spherical Prato cheese with lutein, a yellow dye, with beneficial health attributes, can be an alternative for the prevention of age-related diseases such as macular degeneration and cataracts. The aim of this study was to manufacture the cheese using milk enriched with lutein in 2 different concentrations and to study its partition between whey and cheese during manufacture. The percentage retention of lutein in cheese for both the highest concentration of lutein used (treatment 32 mg/L), and for the lowest concentration (16 mg/L) was approximately 30%, demonstrating that most of lutein added to milk is lost in the whey during the cheese manufacturing. To reach the minimum daily serving of 6mg of lutein in a cheese slice, ie, the minimum amount necessary to prevent macular degeneration, it is necessary that consumers ingest about 100 grams of cheese treatment 32 mg/L or 185g of cheese treatment 16 mg/L. Future research should be conducted in order to increase the percentage of retention of l utein in cheese.

Pulsed-Field Gel Electrophoresis characterization of Listeria monocytogenes isolates from cheese manufacturing plants in São Paulo, Brazil

This study aimed to evaluate the occurrence of Listeria monocytogenes in cheese and in the environment of three small-scale dairy plants (A, B, C) located in the Northern region state of São Paulo, Brazil, and to characterize the isolates using conventional serotyping and PFGE. A total of 393 samples were collected and analyzed from October 2008 to September 2009. From these, 136 came from dairy plant A, where only L. seeligeri was isolated. In dairy plant B, 136 samples were analyzed, and L. innocua, L. seeligeri and L. welshimeri were isolated together with L. monocytogenes. In dairy plant C, 121 samples were analyzed, and L. monocytogenes and L. innocua were isolated. Cheese from dairy plants B and C were contaminated with Listeria spp, with L. innocua being found in Minas frescal cheese from both dairy plants, and L. innocua and L. monocytogenes in Prato cheese from dairy plant C. A total of 85L. monocytogenes isolates were classified in 3 serotypes: 1/2b, 1/2c, and 4b, with predominance of serotype 4b in both dairy plants. The 85 isolates found in the dairy plants were characterized by genomic macrorestriction using ApaI and AscI with Pulsed Field Gel Electrophoresis (PFGE). Macrorestriction yielded 30 different pulsotypes. The presence of indistinguishable profiles repeatedly isolated during a 12-month period indicated the persistence of L. monocytogenes in dairy plants B and C, which were more than 100km away from each other. Brine used in dairy plant C contained more than one L. monocytogenes lineage. The routes of contamination were identified in plants B and C, and highlighted the importance of using molecular techniques and serotyping to track L. monocytogenes sources of contamination, distribution, and routes of contamination in dairy plants, and to develop improved control strategies for L. monocytogenes in dairy plants and dairy products.

Yield, changes in proteolysis, and sensory quality of Prato cheese produced with different coagulants

The objective of this research was to compare the effect of 2 fungal proteases, one that is already commercially established as a milk-clotting agent and another produced at the laboratory scale, on Prato cheese composition, protein and fat recovery, yield, and sensory characteristics. Cheeses were produced according to the traditional protocol, using protease from the fungus Thermomucor indicae-seudaticae N31 and commercial coagulant from Rhizomucor spp. as clotting agents. A 2×6 factorial design with 3 replications was performed: 2 levels of coagulants and 6 levels of storage time. After 5, 12, 19, 33, 43, and 53d of refrigerated storage (12°C), cheeses were monitored for proteolysis, firmness, and casein degradation by capillary electrophoresis. Sensory acceptance was evaluated after 29d of manufacturing. The different coagulants did not statistically affect Prato cheese composition, protein and fat recovery, and yield. Both cheeses presented good sensory acceptance. Proteolysis increased and firmness decreased for both cheeses during the storage time, as expected for Prato cheese. Caseins were well separated by capillary electrophoresis and the results showed, with good resolution, that the cheeses exhibited similar protein hydrolysis profile. Both cheeses presented good sensory acceptance. The gathered data showed that the protease from T. indicae-seudaticae N31 presented similar action compared with the commercial enzyme, indicating its efficiency as clotting agent for Prato cheese manufacture.

Influence of the addition of natural antioxidant from mate leaves (Ilex paraguariensis St. Hill) on the chemical, microbiological and sensory characteristics of different formulations of Prato cheese.

The objective of this work is to evaluate the effects of the addition of dried extract from mate leaves and mesophilic cultures (Lactococcus lactis ssp. lactis and cremoris) on the chemical, microbiological and sensory characteristics of Prato cheese. The Prato cheese presented high moisture contents (49 to 53%) and mean pH values of 5.15 for all tested formulations. The addition of mate leaves extract in the product did not influence the growth of the microbial cultures. During the maturation time, all formulations with the addition of adjunct cultures and mate leaves extract presented lower levels of lipid and protein oxidation compared to the control, proving the antioxidant effect of mate extract. The formulation of Prato cheese added of 0.1wt.% of extract presented acceptability of about 80% after 30days of maturation. The sensory evaluation showed that only the formulation added by adjunct culture and 0.2wt.% of mate extract presented lower values for the attributes global acceptance, texture and flavor, compared to the control. The formulations added of mate leaves extract presented residual bitter flavor after 45days of storage.

Transference of lutein during cheese making, color stability, and sensory acceptance of prato cheese

The consumption of lutein is associated with the prevention and reduction of age-related macular degeneration. Its incorporation into Prato cheese as a yellowish food coloring is a valid alternative to increase the daily intake of this compound. However, part of the lutein added may be lost in the whey during the cheese making, or it can be degraded by light during storage, resulting in color changes reducing the sensory acceptance of the cheese. The objectives of this study were to determine the transference of the lutein (dye), added to the milk, in the whey, and cheese, to evaluate the effect of the lutein addition, light exposure, and storage time on the cheese color, and to verify the sensory acceptance of Prato cheese with addition of lutein. The lutein recovery of cheese was 95.25%. Color saturation (chrome) increased during storage time resulting in a cheese with more intense color, but there were no changes in the hue of the cheese. Adjusting the amount of lutein added to Prato cheese may lead to greater acceptance. The high recovery of lutein in the cheese and the fact that the hue remained unchanged during storage under light showed that the incorporation of lutein into Prato cheese is feasible from a technical point of view.

Evaluation of perception and consumer preferences in connection with Prato cheese

Foi conduzida uma pesquisa de mercado, por meio de entrevistas com consumidores da cidade de Lavras, sul de Minas Gerais, em diferentes locais de comercializacao de queijos Prato, com objetivo de avaliar a percepcao e preferencia dos consumidores em relacao a queijos Pratos produzidos por laticinios do sul de Minas Gerais. Foi verificado que o queijo Prato e aceito pelos consumidores devido a qualidade sensorial e pelo fato de que os consumidores encontram este produto com facilidade. O tipo de queijo Prato preferido pelos consumidores e o queijo Prato minilanche, a maioria o adquire embalado e o consomem no lanche. A maioria das pessoas entrevistadas afirmou que as embalagens/rotulos de queijo Prato sao otimas ou boas, sendo que o tamanho, praticidade e conveniencia, sao os principais pontos positivos das embalagens. Entretanto, as embalagens/rotulos de queijo Prato precisam ser analisadas, mantendo as caracteristicas que sao consideradas pontos positivos e adequando-as para a eliminacao dos pontos negativos, uma vez que foi verificado que 29% dos consumidores acham que as embalagens sao pessimas ou regulares, podendo influenciar de maneira negativa na compra do produto. Conclui-se em geral que o queijo Prato apresenta boa aceitacao. Os queijos produzidos na regiao do Sul de Minas Gerais no mercado de Lavras, MG, apresentam boa competitividade no mercado em relacao a sua qualidade e aceitacao sensorial. Entretanto existem pontos negativos que podem ser melhorados para aumento da competitividade e afirmacao das mesmas no mercado, como por exemplo, suas embalagens.

Assessment of proteolysis and sensory characteristics of prato cheese with adjunct culture

A influência de culturas adjuntas sobre as características químicas e sensoriais, e sobre a proteólise do queijo Prato foi avaliada. Os queijos foram fabricados com cultura starter comercial e cepas de Lactobacillus (Lactobacillus plantarum ou Lactobacillus helveticus) como culturas adjuntas. Os queijos controle não foram adicionados de cultura adjunta. A composição química foi analisada no dia 5 após a fabricação e a proteólise nos dias 5, 25, 45 e 65 de maturação. A aceitação sensorial foi avaliada em 60 dias. Um delineamento de parcelas subdivididas foi utilizado e o experimento completo foi realizado em triplicata. Os resultados foram avaliados pela análise de variância e teste de Tukey no nível de 5% de probabilidade. Os queijos não apresentaram diferenças significativas em relação à composição química. Um aumento significativo na proteólise ocorreu durante o período de maturação para os queijos com cultura adjunta, quando comparado aos queijos sem adição desse tipo de cultura. Os queijos com Lactobacillus helveticus apresentaram médias das notas mais altas para os atributos sabor, textura e intenção de compra em comparação aos demais tratamentos. A utilização de Lactobacillus como cultura adjunta indica que a proteólise do queijo prato pode ser acelerada a fim de reduzir o seu tempo de maturação.

Identity and quality standard of colonial and prato cheese, sold in Medianeira City

The present study relate the hygienic and sanitary quality of Colonial and Prato cheeses, commercialized in supermarkets and free markets of Medianeira-PR. Microbiological ( Salmonella sp., total and thermo-tolerant coliforms and Staphylococci coagulase-positive), physical-chemical (determination of fat, moisture and fat content on dry extract) and microscopic analyses were conducted in eight samples of Colonial cheese and eight samples of Prato cheese in two separate batches. According to the results, 50% of Colonial cheese samples were in disagreement with the current legislation for thermotolerant coliforms and 12.5% of samples showed Staphylococci coagulase-positive above the standards. Samples of Prato cheese showed heterogeneity among them and were in disagreement with the standard of identity. Colonial cheese presented a large amount of dirtiness, probabily due to the characteristics of the raw material and inadequate processing.

Use of a new milk-clotting protease from Thermomucor indicae-seudaticae N31 as coagulant and changes during ripening of Prato cheese

Prato cheeses were manufactured using coagulant from Thermomucor indicae-seudaticae N31 or a commercial coagulant. Cheeses were characterised using the following analysis: yield; fat; acidity; moisture; ash; salt; pH; total nitrogen; total protein; NS-pH 4.6/NT*100; NS-TCA 12%/NT*100; casein electrophoresis; and RP-HPLC. The results were statistically analysed and revealed that the proteolytic indices were not significantly different throughout the 60days of ripening of cheeses made with either coagulant. Even though there were some quantitative differences in the peptide profile of cheeses, the enzyme from T. indicae-seudaticae N31 was used in the production of good quality Prato cheese without having to change the established technological parameters of the process.

Método da espectroscopia no infravermelho para análise dos soros de queijos de minas padrão e prato

An electronic equipment based on the infrared spectroscopy was evaluated to measure the whey composition in Minas padrao and prato cheeses. The results for fat, protein, and total solids using infrared instrument based on filters and using standard methods were compared. There were differences between the values obtained from both analytical methods, and since compounds formed during heating of the analyzed whey may have interfered with infrared spectrum readings, a linear transformation of the data was done. After this statistical adjustment, results for Minas padrao cheese were equivalent in both infrared and standard methods. For prato cheese whey, the difference was significant, even after the adjustment.

Incidence of Listeria monocytogenes in cheese manufacturing plants from the northeast region of São Paulo, Brazil.

The incidence of Listeria monocytogenes in three cheese manufacturing plants from the northeastern region of São Paulo, Brazil, was evaluated from October 2008 to September 2009. L. monocytogenes was found in samples from two plants, at percentages of 13.3% (n = 128) and 9.6% (n = 114). Samples of raw and pasteurized milk, water, and Minas Frescal cheese were negative for L. monocytogenes, although the pathogen was isolated from the surface of Prato cheese and in brine from one of the plants evaluated. L. monocytogenes was also isolated from different sites of the facilities, mainly in non-food contact surfaces such as drains, floors, and platforms. Serotype 4b was the most predominant in the plants studied. The results of this study indicate the need for control strategies to prevent the dispersion of L. monocytogenes in the environment of cheese manufacturing plants.

EQUILIBRIUM BETWEEN THE PROTEIN MATRIX AND THE SERUM PHASE OF PRATO CHEESE

Prato is a Brazilian cheese produced from a washed, semicooked curd obtained by enzyme coagulation, which is brine-salted and ripened for at least 25 days. This study evaluated Prato cheese and its expressible serum during the initial stages of ripening. The experiment was done in triplicate and the results were analyzed by analysis of variance and linear regression. There were an increase of water-holding capacity and a decrease of expressible serum, tending to zero during the five first ripening days. The total protein increased twice as fast as the pH 4.6-soluble protein in the expressible serum. The electrophoresis showed progressive migration of β-CN, αs1-CN, αs1-I-CN and γ-CN from the cheese matrix to the serum phase, and αs1-CN hydrolysis in cheese matrix. The observed changes suggest that besides proteolysis, the increase of the water-binding capacity of protein matrix should improve the sliceability and meltability of Prato cheese at the initial stages of ripening. PRACTICAL APPLICATIONS The Brazilian legislation requires at least 25 days for the Prato cheese developing its functional properties. However, the major changes in the cheese water-holding capacity profile seem to occur during the five first days of ripening, showing that this period may be the main one improving the cheese functionality as a result of the protein matrix hydration. Thus, the ripening required by law could be shortened, reducing the total cost of the Prato cheese manufacture.

Multicomponent diffusion during Prato cheese ripening: mathematical modeling using the finite element method

The partial replacement of NaCl by KCl is a promising alternative to produce a cheese with lower sodium content since KCl does not change the final quality of the cheese product. In order to assure proper salt proportions, mathematical models are employed to control the product process and simulate the multicomponent diffusion during the reduced salt cheese ripening period. The generalized Fick's Second Law is widely accepted as the primary mass transfer model within solid foods. The Finite Element Method (FEM) was used to solve the system of differential equations formed. Therefore, a NaCl and KCl multicomponent diffusion was simulated using a 20% (w/w) static brine with 70% NaCl and 30% KCl during Prato cheese (a Brazilian semi-hard cheese) salting and ripening. The theoretical results were compared with experimental data, and indicated that the deviation was 4.43% for NaCl and 4.72% for KCl validating the proposed model for the production of good quality, reduced-sodium cheeses.

Microbial and Sensory Changes Throughout the Ripening of Prato Cheese Made from Milk with Different Levels of Somatic Cells

The objective of this research was to evaluate the effects of 2 levels of raw milk somatic cell count (SCC) on the composition of Prato cheese and on the microbiological and sensory changes of Prato cheese throughout ripening. Two groups of dairy cows were selected to obtain low-SCC (<200,000 cells/mL) and high-SCC (>700,000 cells/mL) milks, which were used to manufacture 2 vats of cheese. The pasteurized milk was evaluated according to the pH, total solids, fat, total protein, lactose, standard plate count, coliforms at 45°C, and Salmonella spp. The cheese composition was evaluated 2 d after manufacture. Lactic acid bacteria, psychrotrophic bacteria, and yeast and mold counts were carried out after 3, 9, 16, 32, and 51 d of storage. Salmonella spp., Listeria monocytogenes, and coagulase-positive Staphylococcus counts were carried out after 3, 32, and 51 d of storage. A 2×5 factorial design with 4 replications was performed. Sensory evaluation of the cheeses from low- and high-SCC milks was carried out for overall acceptance by using a 9-point hedonic scale after 8, 22, 35, 50, and 63 d of storage. The somatic cell levels used did not affect the total protein and salt:moisture contents of the cheeses. The pH and moisture content were higher and the clotting time was longer for cheeses from high-SCC milk. Both cheeses presented the absence of Salmonella spp. and L. monocytogenes, and the coagulase-positive Staphylococcus count was below 1×102 cfu/g throughout the storage time. The lactic acid bacteria count decreased significantly during the storage time for the cheeses from both low- and high-SCC milks, but at a faster rate for the cheese from high-SCC milk. Cheeses from high-SCC milk presented lower psychrotrophic bacteria counts and higher yeast and mold counts than cheeses from low-SCC milk. Cheeses from low-SCC milk showed better overall acceptance by the consumers. The lower overall acceptance of the cheeses from high-SCC milk may be associated with texture and flavor defects, probably caused by the higher proteolysis of these cheeses.

Efeito da adição de probióticos sobre as características de queijo prato com reduzido teor de gordura fabricado com fibras e lactato de potássio

Pasteurized milk with 1.3% fat was used in the preparation of prato cheese, with the addition of the probiotic microorganism Lactobacillus rhamnosus, fibers, and partial substitution of sodium chloride by a 60% potassium lactate solution. The aim of this work was to follow the development of lactic bacteria and the evolution of pH, lactose content and acidity during storage for 90 days, at 6 °C, since not much information about the addition of such a probiotic in prato cheese is available. Cheese was prepared by the conventional method, followed by vacuum packing and storage. Analyses were carried out immediately after preparation and after 15, 30, 45, 60, 75 and 90 days of storage. The cheese formulated with the probiotic culture presented higher counts of lactic bacteria, higher pH and lactose content, but lower acidity than the cheese prepared without the probiotic.