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M Nunez - One of the best experts on this subject based on the ideXlab platform.
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casein degradation and peptide formation in cheeses made with micrococcus sp Inia 528 milk cultures and high enzymatic activity curds
Milchwissenschaft-milk Science International, 2008Co-Authors: Pilar Morales, Pilar Gaya, M NunezAbstract:The effect of milk inoculation with cultures of Micrococcus sp. Inia 528 and of the addition of high enzymatic activity (HEA) curds prepared with this strain on casein hydrolysis and formation of peptides during cheese ripening was investigated by capillary electrophoresis and reversed-phase HPLC. Milk inoculation at 2% with Micrococcus sp. Inia 528 cultures and addition of HEA curds at 10 or 20% enhanced significantly the degradation of all casein fractions, in particular of β-casein. Also, milk inoculation at 2% with Micrococcus sp. Inia 528 cultures and addition of HEA curds at 10 or 20% increased significantly the formation of both hydrophilic and hydrophobic peptides. However, the addition of HEA curds at 20% resulted in levels of hydrophobic peptides high enough to cause bitter flavour defect. Milk inoculation with Micrococcus sp. Inia 528 cultures at 2% and addition of HEA curds at 10% accelerated cheese proteolysis during ripening without risk of bitterness.
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volatile compounds and aroma of hispanico cheese manufactured using lacticin 481 producing lactococcus lactis subsp lactis Inia 639 as an adjunct culture
International Dairy Journal, 2007Co-Authors: Sonia Garde, Marta Avila, Margarita Medina, Estrella Fernandezgarcia, M NunezAbstract:Abstract Lacticin 481-producing Lactococcus lactis subsp. lactis Inia 639 (BP), bacteriocin-nonproducing L. lactis subsp. lactis Inia 437 (BNP), or a combination of both strains were used as mesophilic cultures for Hispanico cheese manufacture. A Lactobacillus helveticus (LH) culture of high aminopeptidase activity, sensitive to lacticin 481, was used as thermophilic culture. Three batches (BP+LH, BNP+LH, and BNP+BP+LH cheeses) were made in duplicate experiments. Ethanol, 1-propanol, and three ethyl esters reached their highest levels in BP+LH cheese, whereas acetic acid, five ketones, and two alkanes were at their maximum levels in BNP+LH cheese. Higher levels of acetaldehyde and three branched chain aldehydes were found in BNP+BP+LH cheese than in the other two cheeses. Aroma quality and aroma intensity scores were higher for BP+LH and BNP+BP+LH cheeses than for BNP+LH cheese.
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proteolysis of hispanico cheese manufactured using lacticin 481 producing lactococcus lactis ssp lactis Inia 639
Journal of Dairy Science, 2006Co-Authors: Sonia Garde, Marta Avila, Pilar Gaya, Margarita Medina, M NunezAbstract:Hispanico cheese was manufactured using lacticin 481-producing Lactococcus lactis ssp. lactis Inia 639, bacteriocin-nonproducing L. lactis ssp. lactis Inia 437, or a combination of both strains, as starter cultures. Lactobacillus helveticus LH 92, a culture of high amino-peptidase activity sensitive to lacticin 481, was added to all vats. Milk inoculation with the bacteriocin producer promoted early lysis of Lb. helveticus cells in cheese. Cell-free aminopeptidase activity in cheese made with the 3 lactic cultures was 1.8 times the level reached in cheese made only with L. lactis strain Inia 437 and Lb. helveticus, after 15 d of ripening. Proteolysis (as estimated by the o-phthaldialdehyde method) in cheese made with the 3 lactic cultures was twice as high, and the level of total free amino acids 2.4 times the level found in cheese made only with L. lactis strain Inia 437 and Lb. helveticus, after 25 d of ripening. Hydrophobic and hydrophilic peptides and their ratio were at the lowest levels in cheese made with the 3 lactic cultures, which received the lowest scores for bitterness and the highest scores for taste quality.
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free amino acids in cheeses made with micrococcus sp Inia 528 milk cultures and high enzymatic activity curds
Milchwissenschaft-milk Science International, 2006Co-Authors: Pilar Morales, Pilar Gaya, M NunezAbstract:The effect of milk inoculation with cultures of Micrococcus sp. Inia 528 and of the addition of high enzymatic activity (HEA) curds prepared with this strain on the formation of free amino acids (FAA) during cheese ripening was investigated by reversed-phase high performance liquid chromatography. Milk inoculation with Micrococcus sp. Inia 528 cultures achieved the highest increases in levels of total FAA with respect to control cheese (34.0%, 62.9%, and 62.8%) on days 1,7 and 14, respectively. HEA curds added at 10% increased levels of total FAA by 20.2%, 29.5% and 28.2% on days 1, 7 and 14, and HEA curds added at 20% by 22.4%, 28.3% and 43.5%, respectively. The highest mean increases of individual FAA in 14-day-old cheeses achieved by Micrococcus sp. Inia 528 cultures or curds were those of Met, lie, His and Tyr. Counts of Micrococcus sp. Inia 528 in cheese were positively correlated with levels of Asp, Glu, His, Pro, Val, Met, lie and Leu, and negatively with levels of Arg.
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influence of a bacteriocin producing lactic culture on the volatile compounds odour and aroma of hispanico cheese
International Dairy Journal, 2005Co-Authors: Sonia Garde, Marta Avila, Margarita Medina, M NunezAbstract:Abstract The effect of milk inoculation with a bacteriocin-producing lactic culture on Hispanico cheese volatile compounds, odour and aroma was investigated in duplicate experiments, each consisting of two 50-L vats. Milk for experimental cheese was inoculated with 0.5% Lactococcus lactis subsp. lactis Inia 415, a bacteriocin-producing (Bac + ) strain harbouring the structural genes of nisin Z and lacticin 481, 0.5% L. lactis subsp. lactis Inia 415-2, a Bac − mutant, and 2% TA052, a commercial Streptococcus thermophilus culture. Lactic cultures for control cheese were 1% L. lactis subsp. lactis Inia 415-2 and 2% TA052. Milk inoculation with bacteriocin-producing culture enhanced the formation of hexanal, 2-methyl-1-propanol, 3-methyl-1-butanol, acetone, 2-pentanone, 2-hexanone and 2-heptanone, but decreased the formation of acetaldehyde, ethanol, 3-methyl-3-buten-1-ol, 3-methyl-2-buten-1-ol, ethyl acetate, ethyl butanoate, ethyl hexanoate, 2-butanone, 2,3-butanedione, 2,3-pentanedione and 3-hydroxy-2-butanone. Experimental cheese received higher scores than control cheese for the odour descriptor “clean cheese” and for the aroma descriptor “sheepy”, but quality and intensity of odour and aroma were not significantly influenced by milk inoculation with the bacteriocin-producing culture.
Sonia Garde - One of the best experts on this subject based on the ideXlab platform.
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industrial scale application of lactobacillus reuteri coupled with glycerol as a biopreservation system for inhibiting clostridium tyrobutyricum in semi hard ewe milk cheese
Food Microbiology, 2017Co-Authors: Marta Avila, David Delgado, Natalia Gomeztorres, Pilar Gaya, Sonia GardeAbstract:The suitability of the biopreservation system formed by reuterin-producing L. reuteri Inia P572 and glycerol (required for reuterin production) to prevent late blowing defect (LBD) was evaluated in industrial sized semi-hard ewe milk cheese contaminated with Clostridium tyrobutyricum Inia 68, a wild strain isolated from a LBD cheese. For this purpose, six batches of cheese were made (three with and three without clostridial spores): control cheeses with lactococci starter, cheeses with L. reuteri as adjunct, and cheeses with L. reuteri and 30 mM glycerol. Spores of C. tyrobutyricum Inia 68 germinated during pressing of cheese curd, causing butyric acid fermentation in cheese after 30 d of ripening. The addition of L. reuteri, without glycerol, enhanced the symptoms and the formation of volatile compounds associated with LBD. When glycerol was added to cheese milk contaminated with C. tyrobutyricum, L. reuteri was able to produce reuterin in cheese resulting in cheeses with a uniform cheese matrix and a volatile profile similar to cheese made with L. reuteri and glycerol (without spores). Accordingly, L. reuteri Inia P572 coupled with glycerol seems a novel biopreservation system to inhibit Clostridium growth and prevent LBD by means of in situ reuterin production.
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Effect of reuterin-producing Lactobacillus reuteri coupled with glycerol on the volatile fraction, odour and aroma of semi-hard ewe milk cheese
International Journal of Food Microbiology, 2016Co-Authors: Natalia Gómez-torres, David Delgado, Marta Avila, Sonia GardeAbstract:The effect of the biopreservation system formed by Lactobacillus reuteri Inia P572, a reuterin-producing strain, and glycerol (required for reuterin production), on the volatile fraction, aroma and odour of industrial sized semi-hard ewe milk cheese (Castellano type) was investigated over a 3-month ripening period. The volatile compounds were extracted and analyzed by SPME-GC-MS and cheese odour and aroma profiles were studied by descriptive sensory analysis. Control cheese was made only with a mesophilic starter and experimental cheeses with L. reuteri were made with and without glycerol. The addition of L. reuteri Inia P572 to milk enhanced the formation of six volatile compounds. Despite the changes in the volatile compounds profile, the use of L. reuteri Inia P572 did not noticeably affect the sensory characteristics of cheese. On the other hand, the addition of L. reuteri Inia P572 coupled with 30 mM glycerol enhanced the formation of twelve volatile compounds, but decreased the formation of five ones. The use of the biopreservation system did not affect overall odour and aroma quality of cheese although it resulted in a significant decrease of the odour intensity scores. In addition, this cheese received significant higher scores for "cheesy" aroma and significant lower scores for the aroma attributes "milky", "caramel" and "yogurt-like". The first two axes of a principal component analysis (PCA) performed for selected volatile compounds and sensory characteristics, accounting for 75% of the variability between cheeses, separated cheeses made with L. reuteri Inia P572 and glycerol from the rest of cheeses, and also differentiated control cheese from cheeses made with L. reuteri Inia P572 from day 60 onward. Our results showed that the reuterin-producing L. reuteri Inia P572 strain, when coupled with glycerol, may be a suitable biopreservation system to use in cheese without affecting odour and aroma quality.
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impact of clostridium spp on cheese characteristics microbiology color formation of volatile compounds and off flavors
Food Control, 2015Co-Authors: Natalia Gomeztorres, Sonia Garde, Angela Peiroten, Marta AvilaAbstract:Abstract The impact of autochthonous and type-strains of Clostridium tyrobutyricum, Clostridium butyricum, Clostridium beijerinckii and Clostridium sporogenes on spoilage (late blowing defect, LBD), physico-chemical characteristics and volatile profile of cheese has been investigated. Five semi-hard cheeses were produced from ewe milk inoculated with 104 spores/mL of five Clostridium strains and ripened for 60 d. One cheese without clostridial spores served as control. C. tyrobutyricum CECT 4011 and Inia 68 resulted potent cheese spoilers, and caused the appearance of the earliest and greatest symptoms of LBD, affecting cheese pH and color, and leading to accumulation of volatile compounds like butyric, propionic and pentanoic acids and some aldehydes, alcohols and esters associated with cheese rancid and pungent off-odors. Cheeses contaminated with C. beijerinckii Inia 63 and C. sporogenes Inia 71 showed milder and late LBD symptoms, and a volatile profile characterized by higher levels of 2-butanone, 2,3-butanedione and 2-butanol than the rest of cheeses. Despite cheese inoculated with C. butyricum CECT 361 presented a slight blown-pack at the end of ripening, it showed physico-chemical characteristics and a volatile profile similar to control cheese. The first two axes of a principal component analysis (PCA) performed for the 21 significant volatile compounds out of 38, accounting for 91% of the variability between cheeses, separated cheeses made with C. tyrobutyricum CECT 4011 and Inia 68, with severe LBD symptoms, from the rest of cheeses, and also differentiated control cheese and cheese made with C. butyricum CECT 361, from cheeses with milder LBD symptoms made with C. beijerinckii Inia 63 and C. sporogenes Inia 71.
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volatile compounds and aroma of hispanico cheese manufactured using lacticin 481 producing lactococcus lactis subsp lactis Inia 639 as an adjunct culture
International Dairy Journal, 2007Co-Authors: Sonia Garde, Marta Avila, Margarita Medina, Estrella Fernandezgarcia, M NunezAbstract:Abstract Lacticin 481-producing Lactococcus lactis subsp. lactis Inia 639 (BP), bacteriocin-nonproducing L. lactis subsp. lactis Inia 437 (BNP), or a combination of both strains were used as mesophilic cultures for Hispanico cheese manufacture. A Lactobacillus helveticus (LH) culture of high aminopeptidase activity, sensitive to lacticin 481, was used as thermophilic culture. Three batches (BP+LH, BNP+LH, and BNP+BP+LH cheeses) were made in duplicate experiments. Ethanol, 1-propanol, and three ethyl esters reached their highest levels in BP+LH cheese, whereas acetic acid, five ketones, and two alkanes were at their maximum levels in BNP+LH cheese. Higher levels of acetaldehyde and three branched chain aldehydes were found in BNP+BP+LH cheese than in the other two cheeses. Aroma quality and aroma intensity scores were higher for BP+LH and BNP+BP+LH cheeses than for BNP+LH cheese.
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Characteristics of Manchego cheese manufactured from raw ewes' milk inoculated with a bacteriocin-producing adjunct culture
Milchwissenschaft-milk Science International, 2007Co-Authors: Marta Avila, Sonia Garde, Margarita Medina, Nunez Monica SarriaAbstract:The effect of Lactococcus lactis subsp. lactis Inia 415, a nisin Z and lacticin 481 producer, on the characteristics of raw milk Manchego cheese has been studied. Experimental cheese was made from milk inoculated with the bacteriocin producer, and control cheese from milk without it. Bacteriocin-nonproducing mutant L. lactis subsp. lactis Inia 415-2 and a bacteriocin-sensitive Streptococcus thermophilus culture were added to both vats. Cheeses were ripened at 12°C and 85% RH for 90 days. Lysis of S. thermophilus was not enhanced by the bacteriocin, and aminopeptidase activity was lower in experimental cheese than in control cheese. Proteolysis values (estimated by the o-phthaldialdehyde method) of experimental and control cheeses did not differ, and textural characteristics (fracturability, elasticity and hardness) were not influenced either by the bacteriocin producer. Odour, aroma and taste of experimental cheese received higher quality and intensity scores than those of control cheese on day 30, but differences gradually disappeared afterwards.
Marta Avila - One of the best experts on this subject based on the ideXlab platform.
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industrial scale application of lactobacillus reuteri coupled with glycerol as a biopreservation system for inhibiting clostridium tyrobutyricum in semi hard ewe milk cheese
Food Microbiology, 2017Co-Authors: Marta Avila, David Delgado, Natalia Gomeztorres, Pilar Gaya, Sonia GardeAbstract:The suitability of the biopreservation system formed by reuterin-producing L. reuteri Inia P572 and glycerol (required for reuterin production) to prevent late blowing defect (LBD) was evaluated in industrial sized semi-hard ewe milk cheese contaminated with Clostridium tyrobutyricum Inia 68, a wild strain isolated from a LBD cheese. For this purpose, six batches of cheese were made (three with and three without clostridial spores): control cheeses with lactococci starter, cheeses with L. reuteri as adjunct, and cheeses with L. reuteri and 30 mM glycerol. Spores of C. tyrobutyricum Inia 68 germinated during pressing of cheese curd, causing butyric acid fermentation in cheese after 30 d of ripening. The addition of L. reuteri, without glycerol, enhanced the symptoms and the formation of volatile compounds associated with LBD. When glycerol was added to cheese milk contaminated with C. tyrobutyricum, L. reuteri was able to produce reuterin in cheese resulting in cheeses with a uniform cheese matrix and a volatile profile similar to cheese made with L. reuteri and glycerol (without spores). Accordingly, L. reuteri Inia P572 coupled with glycerol seems a novel biopreservation system to inhibit Clostridium growth and prevent LBD by means of in situ reuterin production.
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Effect of reuterin-producing Lactobacillus reuteri coupled with glycerol on the volatile fraction, odour and aroma of semi-hard ewe milk cheese
International Journal of Food Microbiology, 2016Co-Authors: Natalia Gómez-torres, David Delgado, Marta Avila, Sonia GardeAbstract:The effect of the biopreservation system formed by Lactobacillus reuteri Inia P572, a reuterin-producing strain, and glycerol (required for reuterin production), on the volatile fraction, aroma and odour of industrial sized semi-hard ewe milk cheese (Castellano type) was investigated over a 3-month ripening period. The volatile compounds were extracted and analyzed by SPME-GC-MS and cheese odour and aroma profiles were studied by descriptive sensory analysis. Control cheese was made only with a mesophilic starter and experimental cheeses with L. reuteri were made with and without glycerol. The addition of L. reuteri Inia P572 to milk enhanced the formation of six volatile compounds. Despite the changes in the volatile compounds profile, the use of L. reuteri Inia P572 did not noticeably affect the sensory characteristics of cheese. On the other hand, the addition of L. reuteri Inia P572 coupled with 30 mM glycerol enhanced the formation of twelve volatile compounds, but decreased the formation of five ones. The use of the biopreservation system did not affect overall odour and aroma quality of cheese although it resulted in a significant decrease of the odour intensity scores. In addition, this cheese received significant higher scores for "cheesy" aroma and significant lower scores for the aroma attributes "milky", "caramel" and "yogurt-like". The first two axes of a principal component analysis (PCA) performed for selected volatile compounds and sensory characteristics, accounting for 75% of the variability between cheeses, separated cheeses made with L. reuteri Inia P572 and glycerol from the rest of cheeses, and also differentiated control cheese from cheeses made with L. reuteri Inia P572 from day 60 onward. Our results showed that the reuterin-producing L. reuteri Inia P572 strain, when coupled with glycerol, may be a suitable biopreservation system to use in cheese without affecting odour and aroma quality.
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impact of clostridium spp on cheese characteristics microbiology color formation of volatile compounds and off flavors
Food Control, 2015Co-Authors: Natalia Gomeztorres, Sonia Garde, Angela Peiroten, Marta AvilaAbstract:Abstract The impact of autochthonous and type-strains of Clostridium tyrobutyricum, Clostridium butyricum, Clostridium beijerinckii and Clostridium sporogenes on spoilage (late blowing defect, LBD), physico-chemical characteristics and volatile profile of cheese has been investigated. Five semi-hard cheeses were produced from ewe milk inoculated with 104 spores/mL of five Clostridium strains and ripened for 60 d. One cheese without clostridial spores served as control. C. tyrobutyricum CECT 4011 and Inia 68 resulted potent cheese spoilers, and caused the appearance of the earliest and greatest symptoms of LBD, affecting cheese pH and color, and leading to accumulation of volatile compounds like butyric, propionic and pentanoic acids and some aldehydes, alcohols and esters associated with cheese rancid and pungent off-odors. Cheeses contaminated with C. beijerinckii Inia 63 and C. sporogenes Inia 71 showed milder and late LBD symptoms, and a volatile profile characterized by higher levels of 2-butanone, 2,3-butanedione and 2-butanol than the rest of cheeses. Despite cheese inoculated with C. butyricum CECT 361 presented a slight blown-pack at the end of ripening, it showed physico-chemical characteristics and a volatile profile similar to control cheese. The first two axes of a principal component analysis (PCA) performed for the 21 significant volatile compounds out of 38, accounting for 91% of the variability between cheeses, separated cheeses made with C. tyrobutyricum CECT 4011 and Inia 68, with severe LBD symptoms, from the rest of cheeses, and also differentiated control cheese and cheese made with C. butyricum CECT 361, from cheeses with milder LBD symptoms made with C. beijerinckii Inia 63 and C. sporogenes Inia 71.
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volatile compounds and aroma of hispanico cheese manufactured using lacticin 481 producing lactococcus lactis subsp lactis Inia 639 as an adjunct culture
International Dairy Journal, 2007Co-Authors: Sonia Garde, Marta Avila, Margarita Medina, Estrella Fernandezgarcia, M NunezAbstract:Abstract Lacticin 481-producing Lactococcus lactis subsp. lactis Inia 639 (BP), bacteriocin-nonproducing L. lactis subsp. lactis Inia 437 (BNP), or a combination of both strains were used as mesophilic cultures for Hispanico cheese manufacture. A Lactobacillus helveticus (LH) culture of high aminopeptidase activity, sensitive to lacticin 481, was used as thermophilic culture. Three batches (BP+LH, BNP+LH, and BNP+BP+LH cheeses) were made in duplicate experiments. Ethanol, 1-propanol, and three ethyl esters reached their highest levels in BP+LH cheese, whereas acetic acid, five ketones, and two alkanes were at their maximum levels in BNP+LH cheese. Higher levels of acetaldehyde and three branched chain aldehydes were found in BNP+BP+LH cheese than in the other two cheeses. Aroma quality and aroma intensity scores were higher for BP+LH and BNP+BP+LH cheeses than for BNP+LH cheese.
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Characteristics of Manchego cheese manufactured from raw ewes' milk inoculated with a bacteriocin-producing adjunct culture
Milchwissenschaft-milk Science International, 2007Co-Authors: Marta Avila, Sonia Garde, Margarita Medina, Nunez Monica SarriaAbstract:The effect of Lactococcus lactis subsp. lactis Inia 415, a nisin Z and lacticin 481 producer, on the characteristics of raw milk Manchego cheese has been studied. Experimental cheese was made from milk inoculated with the bacteriocin producer, and control cheese from milk without it. Bacteriocin-nonproducing mutant L. lactis subsp. lactis Inia 415-2 and a bacteriocin-sensitive Streptococcus thermophilus culture were added to both vats. Cheeses were ripened at 12°C and 85% RH for 90 days. Lysis of S. thermophilus was not enhanced by the bacteriocin, and aminopeptidase activity was lower in experimental cheese than in control cheese. Proteolysis values (estimated by the o-phthaldialdehyde method) of experimental and control cheeses did not differ, and textural characteristics (fracturability, elasticity and hardness) were not influenced either by the bacteriocin producer. Odour, aroma and taste of experimental cheese received higher quality and intensity scores than those of control cheese on day 30, but differences gradually disappeared afterwards.
Margarita Medina - One of the best experts on this subject based on the ideXlab platform.
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volatile compounds and aroma of hispanico cheese manufactured using lacticin 481 producing lactococcus lactis subsp lactis Inia 639 as an adjunct culture
International Dairy Journal, 2007Co-Authors: Sonia Garde, Marta Avila, Margarita Medina, Estrella Fernandezgarcia, M NunezAbstract:Abstract Lacticin 481-producing Lactococcus lactis subsp. lactis Inia 639 (BP), bacteriocin-nonproducing L. lactis subsp. lactis Inia 437 (BNP), or a combination of both strains were used as mesophilic cultures for Hispanico cheese manufacture. A Lactobacillus helveticus (LH) culture of high aminopeptidase activity, sensitive to lacticin 481, was used as thermophilic culture. Three batches (BP+LH, BNP+LH, and BNP+BP+LH cheeses) were made in duplicate experiments. Ethanol, 1-propanol, and three ethyl esters reached their highest levels in BP+LH cheese, whereas acetic acid, five ketones, and two alkanes were at their maximum levels in BNP+LH cheese. Higher levels of acetaldehyde and three branched chain aldehydes were found in BNP+BP+LH cheese than in the other two cheeses. Aroma quality and aroma intensity scores were higher for BP+LH and BNP+BP+LH cheeses than for BNP+LH cheese.
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Characteristics of Manchego cheese manufactured from raw ewes' milk inoculated with a bacteriocin-producing adjunct culture
Milchwissenschaft-milk Science International, 2007Co-Authors: Marta Avila, Sonia Garde, Margarita Medina, Nunez Monica SarriaAbstract:The effect of Lactococcus lactis subsp. lactis Inia 415, a nisin Z and lacticin 481 producer, on the characteristics of raw milk Manchego cheese has been studied. Experimental cheese was made from milk inoculated with the bacteriocin producer, and control cheese from milk without it. Bacteriocin-nonproducing mutant L. lactis subsp. lactis Inia 415-2 and a bacteriocin-sensitive Streptococcus thermophilus culture were added to both vats. Cheeses were ripened at 12°C and 85% RH for 90 days. Lysis of S. thermophilus was not enhanced by the bacteriocin, and aminopeptidase activity was lower in experimental cheese than in control cheese. Proteolysis values (estimated by the o-phthaldialdehyde method) of experimental and control cheeses did not differ, and textural characteristics (fracturability, elasticity and hardness) were not influenced either by the bacteriocin producer. Odour, aroma and taste of experimental cheese received higher quality and intensity scores than those of control cheese on day 30, but differences gradually disappeared afterwards.
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proteolysis of hispanico cheese manufactured using lacticin 481 producing lactococcus lactis ssp lactis Inia 639
Journal of Dairy Science, 2006Co-Authors: Sonia Garde, Marta Avila, Pilar Gaya, Margarita Medina, M NunezAbstract:Hispanico cheese was manufactured using lacticin 481-producing Lactococcus lactis ssp. lactis Inia 639, bacteriocin-nonproducing L. lactis ssp. lactis Inia 437, or a combination of both strains, as starter cultures. Lactobacillus helveticus LH 92, a culture of high amino-peptidase activity sensitive to lacticin 481, was added to all vats. Milk inoculation with the bacteriocin producer promoted early lysis of Lb. helveticus cells in cheese. Cell-free aminopeptidase activity in cheese made with the 3 lactic cultures was 1.8 times the level reached in cheese made only with L. lactis strain Inia 437 and Lb. helveticus, after 15 d of ripening. Proteolysis (as estimated by the o-phthaldialdehyde method) in cheese made with the 3 lactic cultures was twice as high, and the level of total free amino acids 2.4 times the level found in cheese made only with L. lactis strain Inia 437 and Lb. helveticus, after 25 d of ripening. Hydrophobic and hydrophilic peptides and their ratio were at the lowest levels in cheese made with the 3 lactic cultures, which received the lowest scores for bitterness and the highest scores for taste quality.
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influence of a bacteriocin producing lactic culture on the volatile compounds odour and aroma of hispanico cheese
International Dairy Journal, 2005Co-Authors: Sonia Garde, Marta Avila, Margarita Medina, M NunezAbstract:Abstract The effect of milk inoculation with a bacteriocin-producing lactic culture on Hispanico cheese volatile compounds, odour and aroma was investigated in duplicate experiments, each consisting of two 50-L vats. Milk for experimental cheese was inoculated with 0.5% Lactococcus lactis subsp. lactis Inia 415, a bacteriocin-producing (Bac + ) strain harbouring the structural genes of nisin Z and lacticin 481, 0.5% L. lactis subsp. lactis Inia 415-2, a Bac − mutant, and 2% TA052, a commercial Streptococcus thermophilus culture. Lactic cultures for control cheese were 1% L. lactis subsp. lactis Inia 415-2 and 2% TA052. Milk inoculation with bacteriocin-producing culture enhanced the formation of hexanal, 2-methyl-1-propanol, 3-methyl-1-butanol, acetone, 2-pentanone, 2-hexanone and 2-heptanone, but decreased the formation of acetaldehyde, ethanol, 3-methyl-3-buten-1-ol, 3-methyl-2-buten-1-ol, ethyl acetate, ethyl butanoate, ethyl hexanoate, 2-butanone, 2,3-butanedione, 2,3-pentanedione and 3-hydroxy-2-butanone. Experimental cheese received higher scores than control cheese for the odour descriptor “clean cheese” and for the aroma descriptor “sheepy”, but quality and intensity of odour and aroma were not significantly influenced by milk inoculation with the bacteriocin-producing culture.
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fast induction of nisin resistance in streptococcus thermophilus Inia 463 during growth in milk
International Journal of Food Microbiology, 2004Co-Authors: Sonia Garde, Marta Avila, Margarita Medina, M NunezAbstract:Streptococcus thermophilus Inia 463 became nisin-resistant after exposure in skim milk to subminimal inhibitory concentrations of nisin (1–3 IU/ml) for less than 2 h. Addition of 20 IU/ml caused a 4 log unit decrease in S. thermophilus counts of a culture not exposed previously to nisin, whereas no decrease was observed in the culture exposed to nisin for 2 h. Transfer of immunity genes as responsible for nisin resistance was discarded. The presence of extracellular or intracellular specific nisin-degrading enzymes was not detected in the nisin-resistant variant of S. thermophilus Inia 463. Nisin resistance was caused by the induction of a resistance mechanism. Transmission electron microscopy (TEM) revealed that the nisinresistant variant of S. thermophilus Inia 463 had a thickened cell wall compared to the wild strain. Resistance to nisin was lost after one transfer (4 h growth) in nisin-free skim milk. D 2004 Elsevier B.V. All rights reserved.
Pilar Gaya - One of the best experts on this subject based on the ideXlab platform.
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industrial scale application of lactobacillus reuteri coupled with glycerol as a biopreservation system for inhibiting clostridium tyrobutyricum in semi hard ewe milk cheese
Food Microbiology, 2017Co-Authors: Marta Avila, David Delgado, Natalia Gomeztorres, Pilar Gaya, Sonia GardeAbstract:The suitability of the biopreservation system formed by reuterin-producing L. reuteri Inia P572 and glycerol (required for reuterin production) to prevent late blowing defect (LBD) was evaluated in industrial sized semi-hard ewe milk cheese contaminated with Clostridium tyrobutyricum Inia 68, a wild strain isolated from a LBD cheese. For this purpose, six batches of cheese were made (three with and three without clostridial spores): control cheeses with lactococci starter, cheeses with L. reuteri as adjunct, and cheeses with L. reuteri and 30 mM glycerol. Spores of C. tyrobutyricum Inia 68 germinated during pressing of cheese curd, causing butyric acid fermentation in cheese after 30 d of ripening. The addition of L. reuteri, without glycerol, enhanced the symptoms and the formation of volatile compounds associated with LBD. When glycerol was added to cheese milk contaminated with C. tyrobutyricum, L. reuteri was able to produce reuterin in cheese resulting in cheeses with a uniform cheese matrix and a volatile profile similar to cheese made with L. reuteri and glycerol (without spores). Accordingly, L. reuteri Inia P572 coupled with glycerol seems a novel biopreservation system to inhibit Clostridium growth and prevent LBD by means of in situ reuterin production.
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casein degradation and peptide formation in cheeses made with micrococcus sp Inia 528 milk cultures and high enzymatic activity curds
Milchwissenschaft-milk Science International, 2008Co-Authors: Pilar Morales, Pilar Gaya, M NunezAbstract:The effect of milk inoculation with cultures of Micrococcus sp. Inia 528 and of the addition of high enzymatic activity (HEA) curds prepared with this strain on casein hydrolysis and formation of peptides during cheese ripening was investigated by capillary electrophoresis and reversed-phase HPLC. Milk inoculation at 2% with Micrococcus sp. Inia 528 cultures and addition of HEA curds at 10 or 20% enhanced significantly the degradation of all casein fractions, in particular of β-casein. Also, milk inoculation at 2% with Micrococcus sp. Inia 528 cultures and addition of HEA curds at 10 or 20% increased significantly the formation of both hydrophilic and hydrophobic peptides. However, the addition of HEA curds at 20% resulted in levels of hydrophobic peptides high enough to cause bitter flavour defect. Milk inoculation with Micrococcus sp. Inia 528 cultures at 2% and addition of HEA curds at 10% accelerated cheese proteolysis during ripening without risk of bitterness.
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proteolysis of hispanico cheese manufactured using lacticin 481 producing lactococcus lactis ssp lactis Inia 639
Journal of Dairy Science, 2006Co-Authors: Sonia Garde, Marta Avila, Pilar Gaya, Margarita Medina, M NunezAbstract:Hispanico cheese was manufactured using lacticin 481-producing Lactococcus lactis ssp. lactis Inia 639, bacteriocin-nonproducing L. lactis ssp. lactis Inia 437, or a combination of both strains, as starter cultures. Lactobacillus helveticus LH 92, a culture of high amino-peptidase activity sensitive to lacticin 481, was added to all vats. Milk inoculation with the bacteriocin producer promoted early lysis of Lb. helveticus cells in cheese. Cell-free aminopeptidase activity in cheese made with the 3 lactic cultures was 1.8 times the level reached in cheese made only with L. lactis strain Inia 437 and Lb. helveticus, after 15 d of ripening. Proteolysis (as estimated by the o-phthaldialdehyde method) in cheese made with the 3 lactic cultures was twice as high, and the level of total free amino acids 2.4 times the level found in cheese made only with L. lactis strain Inia 437 and Lb. helveticus, after 25 d of ripening. Hydrophobic and hydrophilic peptides and their ratio were at the lowest levels in cheese made with the 3 lactic cultures, which received the lowest scores for bitterness and the highest scores for taste quality.
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free amino acids in cheeses made with micrococcus sp Inia 528 milk cultures and high enzymatic activity curds
Milchwissenschaft-milk Science International, 2006Co-Authors: Pilar Morales, Pilar Gaya, M NunezAbstract:The effect of milk inoculation with cultures of Micrococcus sp. Inia 528 and of the addition of high enzymatic activity (HEA) curds prepared with this strain on the formation of free amino acids (FAA) during cheese ripening was investigated by reversed-phase high performance liquid chromatography. Milk inoculation with Micrococcus sp. Inia 528 cultures achieved the highest increases in levels of total FAA with respect to control cheese (34.0%, 62.9%, and 62.8%) on days 1,7 and 14, respectively. HEA curds added at 10% increased levels of total FAA by 20.2%, 29.5% and 28.2% on days 1, 7 and 14, and HEA curds added at 20% by 22.4%, 28.3% and 43.5%, respectively. The highest mean increases of individual FAA in 14-day-old cheeses achieved by Micrococcus sp. Inia 528 cultures or curds were those of Met, lie, His and Tyr. Counts of Micrococcus sp. Inia 528 in cheese were positively correlated with levels of Asp, Glu, His, Pro, Val, Met, lie and Leu, and negatively with levels of Arg.
