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Papers by Laura Tuminello

Research paper thumbnail of Interaction of Brine Concentration, Brine Temperature, and Presalting on Salt Penetration in Ragusano Cheese

Journal of Dairy Science, 2006

Research paper thumbnail of Tina wooden vat biofilm: A safe and highly efficient lactic acid bacteria delivering system in PDO Ragusano cheese making

International Journal of Food Microbiology, 2009

In the Sicilian PDO Ragusano cheese making, raw milk is placed in a wooden vat called a Tina. As ... more In the Sicilian PDO Ragusano cheese making, raw milk is placed in a wooden vat called a Tina. As no starter is added, lactic acid is produced by milk flora and flora released from the Tina biofilm. The aim of this work was to assess the safety and efficiency of this natural inoculation system. From 15 Tinas' biofilms, bacteria total counts varied from 10 3 to 10 6 CFU/cm 2 , with the predominance of thermophilic lactic acid bacteria. Low counts of yeasts and moulds were found in a few Tinas. Salmonella, Listeria monocytogenes, Escherichia coli O157:H7 were totally absent, as assessed by conventional plating and the Bax detection system after enrichment, highlighting the safety of the system. From four Tinas out of the 15, micropieces of wood were observed by confocal and scanning electron microscopy. The biofilm entrapped in a matrix covered almost entirely the surface of the wood. Polysaccharides were detected in the four Tinas. In three of the latter, cocci were predominant in the ecosystem whereas in the other one, cocci, bacilli, yeasts and moulds were observed. Fifty litres of microfiltrated milk (b 10 CFU/mL) were poured in the four Tinas for 10 min of contact. Enumeration of lactic acid bacteria, yeasts and enterococci were performed in the milk after contact. Depending on the Tina, from 5•10 4 to 10 6 CFU/mL of Streptococcus thermophilus were released into the milk, and from 10 4 to 10 5 CFU/mL of thermophilic lactobacilli. Spontaneous acidification after contact confirmed the high efficiency of biofilm lactic acid bacteria delivery.

Research paper thumbnail of Differences in volatiles, and chemical, microbial and sensory characteristics between artisanal and industrial Piacentinu Ennese cheeses

International Dairy Journal, 2005

Research paper thumbnail of Quantitative analysis of cheese microstructure using SEM imagery

Communications to SIMAI Congress, Jan 10, 2007

Structural properties of cheese highly influence its chemical, mechanical and nutritive propertie... more Structural properties of cheese highly influence its chemical, mechanical and nutritive properties. The analysis and quantification of relevant features in food imagery is the basis of modern food, and in particular cheese, microscopy. Processing Scanning Electron Microscopy (SEM) images is a powerful tool to estimate microstructural cheese features.

Research paper thumbnail of Proteolysis and Microstructure of Piacentinu Ennese Cheese Made Using Different Farm Technologies

Journal of Dairy Science, 2006

The aim of this study was to provide the biochemical and structural characterization of Piacentin... more The aim of this study was to provide the biochemical and structural characterization of Piacentinu Ennese cheese and to evaluate the impact of different farm technologies on cheese proteolysis and microstructure. Fifteen cheeses were manufactured according to traditional technology, i.e., from raw milk and farmhouse rennet in the absence of starter culture. Pasteurized milk, commercial rennet, and starter were used for production of 20 nontraditional cheeses. Proteolysis in Piacentinu Ennese cheese was monitored during a 2-to 10-mo ripening time. Low rates of overall proteolysis were observed in cheese, as percentages of total N soluble at pH 4.6 and in 12% trichloroacetic acid were about 11.40 and 8.10%, respectively, after 10 mo of age. Patterns of primary proteolysis by urea-PAGE showed that α s-caseins were degraded to a larger extent than were βcaseins, although a considerable amount of both caseins was still intact after 10 mo. Reversed phase-HPLC analysis of the cheese peptide fractions showed a slow decrease in the levels of hydrophobic peptides coupled to increasing levels of hydrophilic compounds as the cheese aged. The structural characteristics of Piacentinu Ennese cheese were evaluated by scanning electron microscopy after 2, 4, and 6 mo of age. The micrographs showed a sponge-like structural network with a well-distributed system of empty spaces, originally occupied by whey and fat. The microstructure changed during cheese ripening to become more compact with cavities of smaller size. Farm technology significantly affected cheese proteolysis and microstructure. Nontraditional cheeses had higher levels of pH 4.6-soluble N and showed a larger hydrolysis of α s-casein fractions by urea-PAGE analysis than did traditional cheeses.

Research paper thumbnail of Interaction of Brine Concentration, Brine Temperature, and Presalting on Salt Penetration in Ragusano Cheese

Journal of Dairy Science, 2006

Research paper thumbnail of Tina wooden vat biofilm: A safe and highly efficient lactic acid bacteria delivering system in PDO Ragusano cheese making

International Journal of Food Microbiology, 2009

In the Sicilian PDO Ragusano cheese making, raw milk is placed in a wooden vat called a Tina. As ... more In the Sicilian PDO Ragusano cheese making, raw milk is placed in a wooden vat called a Tina. As no starter is added, lactic acid is produced by milk flora and flora released from the Tina biofilm. The aim of this work was to assess the safety and efficiency of this natural inoculation system. From 15 Tinas' biofilms, bacteria total counts varied from 10 3 to 10 6 CFU/cm 2 , with the predominance of thermophilic lactic acid bacteria. Low counts of yeasts and moulds were found in a few Tinas. Salmonella, Listeria monocytogenes, Escherichia coli O157:H7 were totally absent, as assessed by conventional plating and the Bax detection system after enrichment, highlighting the safety of the system. From four Tinas out of the 15, micropieces of wood were observed by confocal and scanning electron microscopy. The biofilm entrapped in a matrix covered almost entirely the surface of the wood. Polysaccharides were detected in the four Tinas. In three of the latter, cocci were predominant in the ecosystem whereas in the other one, cocci, bacilli, yeasts and moulds were observed. Fifty litres of microfiltrated milk (b 10 CFU/mL) were poured in the four Tinas for 10 min of contact. Enumeration of lactic acid bacteria, yeasts and enterococci were performed in the milk after contact. Depending on the Tina, from 5•10 4 to 10 6 CFU/mL of Streptococcus thermophilus were released into the milk, and from 10 4 to 10 5 CFU/mL of thermophilic lactobacilli. Spontaneous acidification after contact confirmed the high efficiency of biofilm lactic acid bacteria delivery.

Research paper thumbnail of Differences in volatiles, and chemical, microbial and sensory characteristics between artisanal and industrial Piacentinu Ennese cheeses

International Dairy Journal, 2005

Research paper thumbnail of Quantitative analysis of cheese microstructure using SEM imagery

Communications to SIMAI Congress, Jan 10, 2007

Structural properties of cheese highly influence its chemical, mechanical and nutritive propertie... more Structural properties of cheese highly influence its chemical, mechanical and nutritive properties. The analysis and quantification of relevant features in food imagery is the basis of modern food, and in particular cheese, microscopy. Processing Scanning Electron Microscopy (SEM) images is a powerful tool to estimate microstructural cheese features.

Research paper thumbnail of Proteolysis and Microstructure of Piacentinu Ennese Cheese Made Using Different Farm Technologies

Journal of Dairy Science, 2006

The aim of this study was to provide the biochemical and structural characterization of Piacentin... more The aim of this study was to provide the biochemical and structural characterization of Piacentinu Ennese cheese and to evaluate the impact of different farm technologies on cheese proteolysis and microstructure. Fifteen cheeses were manufactured according to traditional technology, i.e., from raw milk and farmhouse rennet in the absence of starter culture. Pasteurized milk, commercial rennet, and starter were used for production of 20 nontraditional cheeses. Proteolysis in Piacentinu Ennese cheese was monitored during a 2-to 10-mo ripening time. Low rates of overall proteolysis were observed in cheese, as percentages of total N soluble at pH 4.6 and in 12% trichloroacetic acid were about 11.40 and 8.10%, respectively, after 10 mo of age. Patterns of primary proteolysis by urea-PAGE showed that α s-caseins were degraded to a larger extent than were βcaseins, although a considerable amount of both caseins was still intact after 10 mo. Reversed phase-HPLC analysis of the cheese peptide fractions showed a slow decrease in the levels of hydrophobic peptides coupled to increasing levels of hydrophilic compounds as the cheese aged. The structural characteristics of Piacentinu Ennese cheese were evaluated by scanning electron microscopy after 2, 4, and 6 mo of age. The micrographs showed a sponge-like structural network with a well-distributed system of empty spaces, originally occupied by whey and fat. The microstructure changed during cheese ripening to become more compact with cavities of smaller size. Farm technology significantly affected cheese proteolysis and microstructure. Nontraditional cheeses had higher levels of pH 4.6-soluble N and showed a larger hydrolysis of α s-casein fractions by urea-PAGE analysis than did traditional cheeses.