Isabel Revilla - Academia.edu (original) (raw)
Papers by Isabel Revilla
Sensors, 2015
The potential of near infrared spectroscopy (NIR) with remote reflectance fiber-optic probes for ... more The potential of near infrared spectroscopy (NIR) with remote reflectance fiber-optic probes for determining the mineral composition of propolis was evaluated. This technology allows direct measurements without prior sample treatment. Ninety one samples of propolis were collected in Chile (Bio-Bio region) and Spain (Castilla-León and Galicia regions). The minerals measured were aluminum, calcium, iron, potassium, magnesium, phosphorus, and some potentially toxic trace elements such as zinc, chromium, nickel, copper and lead. The modified partial least squares (MPLS) regression method was used to develop the NIR calibration model. The determination coefficient (R²) and root mean square error of prediction (RMSEP) obtained for aluminum (0.79, 53), calcium (0.83, 94), iron (0.69, 134) potassium (0.95, 117), magnesium (0.70, 99), phosphorus (0.94, 24) zinc (0.87, 10) chromium (0.48, 0.6) nickel (0.52, 0.7) copper (0.64, 0.9) and lead (0.70, 2) in ppm. The results demonstrated that the capacity for prediction can be considered good for wide ranges of potassium, phosphorus and zinc concentrations, and acceptable for aluminum, calcium, magnesium, iron and lead. This indicated that the NIR method is comparable to chemical methods. The method is of interest in the rapid prediction of potentially toxic elements in propolis before consumption.
Processing and Impact on Active Components in Food, 2015
40 l. dorsi muscles from the left half carcass of suckling lambs raised under both organic and co... more 40 l. dorsi muscles from the left half carcass of suckling lambs raised under both organic and conventional systems were evaluated by a sixteen-member trained panel, following QDA methodology. After developing a common vocabulary for the evaluation of characteristics, 30 meat descriptors in raw and grilled meat were selected. Additionally, overall appreciation was evaluated by 140 consumers in a home-use test. The results obtained show that the appearance of the organic meat was more fibrous, darker, and with a lower aroma intensity than the conventional counterpart, but with no differences in homogeneity or juiciness. In grilled meat, the organic samples had less subcutaneous fat, less fatness, a less fibrous texture and less aroma intensity, but also less juiciness. Regarding overall appreciation, the consumers gave higher scores to the organically produced samples.
Food Chemistry, Feb 1, 2003
ABSTRACT The present work studies the effects of the addition of several commercial pectolytic en... more ABSTRACT The present work studies the effects of the addition of several commercial pectolytic enzyme products on the phenolic composition of red wine. Low-molecular-weight phenols and flavan-3-ol derivatives were studied. The results revealed that the addition of enzymes produced an overall increase in the extraction of these compounds. However, in the case of flavan-3-ol derivatives, extraction was increased only when sufficient time was allowed for maceration. Study of the evolution of the contents of these compounds over time suggested that, in general, wines that initially contain higher amounts of phenolic compounds are able to maintain higher levels of these compounds during storage.
Food Chemistry, Nov 30, 1998
Red grapes of the Tinto fino (Vitis vinifera) variety were treated with four different commercial... more Red grapes of the Tinto fino (Vitis vinifera) variety were treated with four different commercial preparations of pectolytic enzymes, and methanol production during fermentation of the grapes was studied. Pectin content of the grapes and in the final wine were also quantified, to study the relation between methanol release and the extent of pectin degradation by the enzymes. The results showed that the enzymatic treatments enhanced the methanol content from day one of fermentation for three of the four enzymes, and from day three for all of them. Every enzymatic treatment produced higher methanol levels than the control in the final wine. During storage the methanol levels remained more or less constant. 0
Czech Journal of Food Sciences
Czech Journal of Food Sciences
Journal of capillary electrophoresis and microchip technology, 2005
The primary proteolysis of ewe's cheeses made from milk with different somatic cell counts (5... more The primary proteolysis of ewe's cheeses made from milk with different somatic cell counts (5CC) included three groups of study: cheeses made with milk with less than 500,000 somatic cells (SC); with milk containing 1 x 10(6) to 1.5 x 10(6) SC, the normal range for ewe's milk; and with milk containing more than 3.106 SC. These were examined by capillary eledrophoresis. Intact caseins as alpha(s1)-CN (I, II, and III), alpha(s2)-CN, and beta-CN (beta, beta1, and beta2) were identified. Some peptides resulting from casein proteolysis as gamma-CN and l-alpha(s1)-CN were also identified. The study reveals that proteolysis increased with ripening time and the extent of casein degradation depended on the content in SC, showing that residual intact casein, both alpha(s1)-CN and beta-CN, decreased as the SCC of milk increased because of their higher proteolytic enzyme levels. The proteolysis pattern indicated that several enzymes were implicated in increased proteolysis in high SCC c...
Journal of Dairy Science, 2007
Bulk tank ewe milk from the Assaf, Castellana, and Churra breeds categorized into 3 somatic cell ... more Bulk tank ewe milk from the Assaf, Castellana, and Churra breeds categorized into 3 somatic cell count (SCC) groups (<500,000; 1,000,000 to 1,500,000; and >2,500,000 cells/mL) was used to investigate changes in chemical composition and capillary electrophoresis protein profiles. The results obtained indicated that breed affected fat, protein, and total solids levels, and differences were also observed for the following milk proteins: β-, β 1 -, β 2 -, and α s1 -III-casein, α-lactalbumin, and β-lactoglobulin. High SCC affected fat and protein contents and bacterial counts. The level of β 1 -, β 2 -, and α s1 -I-casein, and α-lactalbumin were significantly lower in milk with SCC scores >2,500,000 cells/mL. A preliminary study of the chemical, microbiological, and electrophoretic data was performed by cluster analysis and principal components analysis. Applying discriminant analysis, it was possible to group the milk samples according to breed and level of SCC, obtaining a prediction of 100 and 97% of the samples, respectively.
IEEE Revista Iberoamericana de Tecnologias del Aprendizaje, 2014
ABSTRACT This paper reports an experiment in the application of rubrics, as an assessment tool, i... more ABSTRACT This paper reports an experiment in the application of rubrics, as an assessment tool, in different degree courses in the fields of engineering and architecture. This paper involved five subjects, seven teachers, and a total of 170 students. We analyze the scores obtained by the students and the degree of satisfaction of both the students and teachers, based on questionnaires developed specifically for this purpose.
Meat Science, 2004
The effects of reducing fat level from 20% to 12% and 9%, substituting pork fat with olive oil an... more The effects of reducing fat level from 20% to 12% and 9%, substituting pork fat with olive oil and adding locust bean/xanthan gum (0.5% and 0.6%) on emulsion stability, jelly and fat separation, processing yield, cook loss, texture and sensory characteristics of frankfurters were investigated and compared with control samples. Addition of locust bean/xanthan gum produced a significant increase in hydration/binding properties, characterised by lower cook losses, increasing yield, better emulsion stability and lower jelly and fat separation. The substitution of pork fat by olive oil did not affect these parameters. Indeed, results showed that reducing fat levels together with increasing moisture and locust bean/xanthan gum addition do not affect the sensory or textural properties, but olive oil addition produces a decrease in hardness and an increase in adhesiveness, however the overall acceptability was not affected.
Meat Science, 2006
The aim of the present work was to determine and assess the parameters affecting the choice of ve... more The aim of the present work was to determine and assess the parameters affecting the choice of veal under the "Ternera de Aliste" quality appellation. The parameters affecting the choice proved to be colour, taste, odour, hardness and juiciness. Using these parameters, sensory evaluation, both analytical (with trained judges, QDA) and affective (with consumers, the home-use test) was carried out on four veal types, and the relative preferences for the samples assessed. Colour, hardness and losses due to cooking were also analysed instrumentally. The results revealed that the methodology is important for discriminating small differences between samples. The same trend was observed for the results of the panel of judges, consumers, and instrumental analyses regarding both hardness and juiciness. Regarding the determinant parameters in the choice of veal, in raw meat consumers prefer light colours but when expressing their general relative preferences for samples, juiciness, taste and hardness of the cooked meat had the greatest weight.
Meat Science, 2006
The effect of breed, sex and ageing time on carcass, meat and eating quality were examined in 32 ... more The effect of breed, sex and ageing time on carcass, meat and eating quality were examined in 32 calves of the "Ternera de Aliste" Spanish Quality Label. Swiss Brown×Alistano-Sanabresa heifers were mated with Charolais or Limousin bulls in order to study the effect of breed. Bull and heifer calves were slaughtered when they were 6-7 months old. Samples of the M. longissimus dorsi were aged for 3, 5 or 7 days and chemical and sensory analyses were done. The results showed no differences due to sex but Charolais sires produced meat which was more tender, juicier and had more odour intensity with a darker colour than meat of the Limousin sired animals. Ageing influenced both sensory and instrumental hardness, colour and odour intensity. After seven days of maturation the meat from such young animals achieved a high quality.
Journal of Wine Research, 2001
Page 1. Journal of Wine Research, 2001, Vol. 12, No. 3, pp. 183197 Evolution During the Storage ... more Page 1. Journal of Wine Research, 2001, Vol. 12, No. 3, pp. 183197 Evolution During the Storage of Red Wines Treated with Pectolytic Enzymes: New Anthocyanin Pigment Formation ISABEL REVILLA and MA LUISA GONZA´ LEZ-SANJOSE´ ...
Journal of Dairy Research, 2009
The aim of the present work was to perform a physico-chemical, descriptive quantitative and consu... more The aim of the present work was to perform a physico-chemical, descriptive quantitative and consumer-preference analysis of hard ewes'-milk cheeses that had been matured for one year and to determine the correlations between the variables studied. The cheeses were elaborated with milk from three breeds of sheep (Castellana, Churra and Assaf) with different somatic cell counts (lower than 500,000 cells ml-1; between 1,000,000 and 1,500,000 cells ml-1, and more than 2,500,000 cells ml-1). The results show that the cheeses elaborated with milk with high SCC had lower values of dry extract and fat and high values of pH and fat acidity and were described as pungent, granulose and less creamy. Regarding the effect of breed, the cheeses made with milk from the Churra breed had lower values for fat and those made with Assaf breed milk were significantly more rancid. The study of correlations showed that creaminess was positively correlated with the dry extract and total fat content and negatively correlated with ash and fat acidity, indeed grainy texture and pungency had the opposite sign in their correlation with these latter variables. The yellow colour was positively correlated with ash and negatively with protein. Finally, the consumer preferences reveals that the less accepted cheeses showed the higher values for rancidness and pungency and they were less likely to accept the cheeses made with Assaf breed milk.
Journal of Dairy Research, 2007
Journal of Dairy Research, 2009
Bulk tank ewe's milks from Assaf, Castellana and Churra breeds categorized within three d... more Bulk tank ewe's milks from Assaf, Castellana and Churra breeds categorized within three different Somatic Cell Count (SCC) groups (LSCC: <500,000; MSCC: 1,000,000 to 1,500,000; and HSCC: 2,500,000 to 3,000,000 cells ml-1) were used to investigate changes in capillary electrophoresis protein profiles and cheese-making properties. The results do not reveal a significant effect of SCC on total casein contents, because the sum of beta-caseins decreased as SCC increased; no statistically significant differences were observed for the sum of alpha-caseins, and the values of kappa-casein were higher in the HSCC milk. However, the soluble proteins other than alpha-lactalbumin and beta-lactoglobulin increased with SCC. Regarding the effect of breed, the Assaf breed had the lowest contents of kappa-CN, alpha s1-I-CN, alpha s1-II-CN 1-CN, alpha s1-III-CN, beta1-CN and beta2-CN. The protein profile was significantly correlated with curd textural properties. alpha s1-I-CN was the most influential variant because it was positively correlated with a large number of textural parameters. Cheese yield was positively correlated with all casein variants except alpha s1-III-CN, showing that the milk from local breeds were more suitable for cheese-making due to their higher contents of all the casein variants. Regarding curd texture properties LSCC milk curds showed more cohesiveness, associated with its lower content of alpha s1-III-CN and Castellana milk curds showed the highest values for firmness owing to their higher content of alpha s1-I-CN.
Journal of Dairy Research, 2011
Bulk tank ewe's milks with low (<500,000 ml(-1)), medium (1,000,000-1,500,000 ml(-... more Bulk tank ewe's milks with low (<500,000 ml(-1)), medium (1,000,000-1,500,000 ml(-1)) and high (>2,500,000 ml(-1)) somatic cell counts (SCC) from three breeds were used to manufacture hard ewes'-milk cheese. Physico-chemical analysis and capillary electrophoresis of fresh cheeses and cheeses that had been ripened for 1, 2, 3 and 6 months were carried out. The results showed that high SCC levels in milk affected the moisture content of only freshly made cheeses and the pH, fat content and fat acidity of ripened cheeses. Regarding proteolysis, the levels of all β-CNs in freshly made cheeses were significantly lower as the SCC values increased and the Castellana breed was the most affected by SCC levels because a significant decrease in all α-CNs was also observed as SCC levels rose. Analysis of the casein profile by principal component analysis (PCA) revealed that there were no clear differences according the SCC up to the third month. However in the third and sixth months cheeses with low levels of SC were closely grouped and characterised by the highest levels of intact caseins. Regarding the effect of breed, the results point to a more intense proteolytic activity in the Assaf breed, whose more matured cheeses showed the highest content of casein proteolytic fragments.
Journal of Chromatography A, 1999
The different options MS detection are investigated in order to achieve the best conditions for d... more The different options MS detection are investigated in order to achieve the best conditions for detection and identification of anthocyanins by LC–MS. A method for separation of these compounds that enables the main molecules in wines to be identified by direct analysis, without any previous preparation, is proposed. The anthocyanin composition of different red grape skin extracts and commercial monovarietal
Journal of Chromatography A, 1999
Different options of liquid chromatography-mass spectrometry were used to establish the most suit... more Different options of liquid chromatography-mass spectrometry were used to establish the most suitable ion source and conditions to analyse or detect some low-molecular mass phenols, flavan-3-ols, and apply such conditions to a complex sample (wine). Data presented in this work confirm the great utility of atmospheric pressure-ionisation electrospray mass spectrometry coupled to HPLC for analysis of phenolic compounds, under negative mode in the case of low-molecular mass phenols, and under both positive and negative modes in flavan-3-ol compounds. A fragmentor voltage of 60 V could be the most suitable for analysing the compounds under study.
Sensors, 2015
The potential of near infrared spectroscopy (NIR) with remote reflectance fiber-optic probes for ... more The potential of near infrared spectroscopy (NIR) with remote reflectance fiber-optic probes for determining the mineral composition of propolis was evaluated. This technology allows direct measurements without prior sample treatment. Ninety one samples of propolis were collected in Chile (Bio-Bio region) and Spain (Castilla-León and Galicia regions). The minerals measured were aluminum, calcium, iron, potassium, magnesium, phosphorus, and some potentially toxic trace elements such as zinc, chromium, nickel, copper and lead. The modified partial least squares (MPLS) regression method was used to develop the NIR calibration model. The determination coefficient (R²) and root mean square error of prediction (RMSEP) obtained for aluminum (0.79, 53), calcium (0.83, 94), iron (0.69, 134) potassium (0.95, 117), magnesium (0.70, 99), phosphorus (0.94, 24) zinc (0.87, 10) chromium (0.48, 0.6) nickel (0.52, 0.7) copper (0.64, 0.9) and lead (0.70, 2) in ppm. The results demonstrated that the capacity for prediction can be considered good for wide ranges of potassium, phosphorus and zinc concentrations, and acceptable for aluminum, calcium, magnesium, iron and lead. This indicated that the NIR method is comparable to chemical methods. The method is of interest in the rapid prediction of potentially toxic elements in propolis before consumption.
Processing and Impact on Active Components in Food, 2015
40 l. dorsi muscles from the left half carcass of suckling lambs raised under both organic and co... more 40 l. dorsi muscles from the left half carcass of suckling lambs raised under both organic and conventional systems were evaluated by a sixteen-member trained panel, following QDA methodology. After developing a common vocabulary for the evaluation of characteristics, 30 meat descriptors in raw and grilled meat were selected. Additionally, overall appreciation was evaluated by 140 consumers in a home-use test. The results obtained show that the appearance of the organic meat was more fibrous, darker, and with a lower aroma intensity than the conventional counterpart, but with no differences in homogeneity or juiciness. In grilled meat, the organic samples had less subcutaneous fat, less fatness, a less fibrous texture and less aroma intensity, but also less juiciness. Regarding overall appreciation, the consumers gave higher scores to the organically produced samples.
Food Chemistry, Feb 1, 2003
ABSTRACT The present work studies the effects of the addition of several commercial pectolytic en... more ABSTRACT The present work studies the effects of the addition of several commercial pectolytic enzyme products on the phenolic composition of red wine. Low-molecular-weight phenols and flavan-3-ol derivatives were studied. The results revealed that the addition of enzymes produced an overall increase in the extraction of these compounds. However, in the case of flavan-3-ol derivatives, extraction was increased only when sufficient time was allowed for maceration. Study of the evolution of the contents of these compounds over time suggested that, in general, wines that initially contain higher amounts of phenolic compounds are able to maintain higher levels of these compounds during storage.
Food Chemistry, Nov 30, 1998
Red grapes of the Tinto fino (Vitis vinifera) variety were treated with four different commercial... more Red grapes of the Tinto fino (Vitis vinifera) variety were treated with four different commercial preparations of pectolytic enzymes, and methanol production during fermentation of the grapes was studied. Pectin content of the grapes and in the final wine were also quantified, to study the relation between methanol release and the extent of pectin degradation by the enzymes. The results showed that the enzymatic treatments enhanced the methanol content from day one of fermentation for three of the four enzymes, and from day three for all of them. Every enzymatic treatment produced higher methanol levels than the control in the final wine. During storage the methanol levels remained more or less constant. 0
Czech Journal of Food Sciences
Czech Journal of Food Sciences
Journal of capillary electrophoresis and microchip technology, 2005
The primary proteolysis of ewe's cheeses made from milk with different somatic cell counts (5... more The primary proteolysis of ewe's cheeses made from milk with different somatic cell counts (5CC) included three groups of study: cheeses made with milk with less than 500,000 somatic cells (SC); with milk containing 1 x 10(6) to 1.5 x 10(6) SC, the normal range for ewe's milk; and with milk containing more than 3.106 SC. These were examined by capillary eledrophoresis. Intact caseins as alpha(s1)-CN (I, II, and III), alpha(s2)-CN, and beta-CN (beta, beta1, and beta2) were identified. Some peptides resulting from casein proteolysis as gamma-CN and l-alpha(s1)-CN were also identified. The study reveals that proteolysis increased with ripening time and the extent of casein degradation depended on the content in SC, showing that residual intact casein, both alpha(s1)-CN and beta-CN, decreased as the SCC of milk increased because of their higher proteolytic enzyme levels. The proteolysis pattern indicated that several enzymes were implicated in increased proteolysis in high SCC c...
Journal of Dairy Science, 2007
Bulk tank ewe milk from the Assaf, Castellana, and Churra breeds categorized into 3 somatic cell ... more Bulk tank ewe milk from the Assaf, Castellana, and Churra breeds categorized into 3 somatic cell count (SCC) groups (<500,000; 1,000,000 to 1,500,000; and >2,500,000 cells/mL) was used to investigate changes in chemical composition and capillary electrophoresis protein profiles. The results obtained indicated that breed affected fat, protein, and total solids levels, and differences were also observed for the following milk proteins: β-, β 1 -, β 2 -, and α s1 -III-casein, α-lactalbumin, and β-lactoglobulin. High SCC affected fat and protein contents and bacterial counts. The level of β 1 -, β 2 -, and α s1 -I-casein, and α-lactalbumin were significantly lower in milk with SCC scores >2,500,000 cells/mL. A preliminary study of the chemical, microbiological, and electrophoretic data was performed by cluster analysis and principal components analysis. Applying discriminant analysis, it was possible to group the milk samples according to breed and level of SCC, obtaining a prediction of 100 and 97% of the samples, respectively.
IEEE Revista Iberoamericana de Tecnologias del Aprendizaje, 2014
ABSTRACT This paper reports an experiment in the application of rubrics, as an assessment tool, i... more ABSTRACT This paper reports an experiment in the application of rubrics, as an assessment tool, in different degree courses in the fields of engineering and architecture. This paper involved five subjects, seven teachers, and a total of 170 students. We analyze the scores obtained by the students and the degree of satisfaction of both the students and teachers, based on questionnaires developed specifically for this purpose.
Meat Science, 2004
The effects of reducing fat level from 20% to 12% and 9%, substituting pork fat with olive oil an... more The effects of reducing fat level from 20% to 12% and 9%, substituting pork fat with olive oil and adding locust bean/xanthan gum (0.5% and 0.6%) on emulsion stability, jelly and fat separation, processing yield, cook loss, texture and sensory characteristics of frankfurters were investigated and compared with control samples. Addition of locust bean/xanthan gum produced a significant increase in hydration/binding properties, characterised by lower cook losses, increasing yield, better emulsion stability and lower jelly and fat separation. The substitution of pork fat by olive oil did not affect these parameters. Indeed, results showed that reducing fat levels together with increasing moisture and locust bean/xanthan gum addition do not affect the sensory or textural properties, but olive oil addition produces a decrease in hardness and an increase in adhesiveness, however the overall acceptability was not affected.
Meat Science, 2006
The aim of the present work was to determine and assess the parameters affecting the choice of ve... more The aim of the present work was to determine and assess the parameters affecting the choice of veal under the "Ternera de Aliste" quality appellation. The parameters affecting the choice proved to be colour, taste, odour, hardness and juiciness. Using these parameters, sensory evaluation, both analytical (with trained judges, QDA) and affective (with consumers, the home-use test) was carried out on four veal types, and the relative preferences for the samples assessed. Colour, hardness and losses due to cooking were also analysed instrumentally. The results revealed that the methodology is important for discriminating small differences between samples. The same trend was observed for the results of the panel of judges, consumers, and instrumental analyses regarding both hardness and juiciness. Regarding the determinant parameters in the choice of veal, in raw meat consumers prefer light colours but when expressing their general relative preferences for samples, juiciness, taste and hardness of the cooked meat had the greatest weight.
Meat Science, 2006
The effect of breed, sex and ageing time on carcass, meat and eating quality were examined in 32 ... more The effect of breed, sex and ageing time on carcass, meat and eating quality were examined in 32 calves of the "Ternera de Aliste" Spanish Quality Label. Swiss Brown×Alistano-Sanabresa heifers were mated with Charolais or Limousin bulls in order to study the effect of breed. Bull and heifer calves were slaughtered when they were 6-7 months old. Samples of the M. longissimus dorsi were aged for 3, 5 or 7 days and chemical and sensory analyses were done. The results showed no differences due to sex but Charolais sires produced meat which was more tender, juicier and had more odour intensity with a darker colour than meat of the Limousin sired animals. Ageing influenced both sensory and instrumental hardness, colour and odour intensity. After seven days of maturation the meat from such young animals achieved a high quality.
Journal of Wine Research, 2001
Page 1. Journal of Wine Research, 2001, Vol. 12, No. 3, pp. 183197 Evolution During the Storage ... more Page 1. Journal of Wine Research, 2001, Vol. 12, No. 3, pp. 183197 Evolution During the Storage of Red Wines Treated with Pectolytic Enzymes: New Anthocyanin Pigment Formation ISABEL REVILLA and MA LUISA GONZA´ LEZ-SANJOSE´ ...
Journal of Dairy Research, 2009
The aim of the present work was to perform a physico-chemical, descriptive quantitative and consu... more The aim of the present work was to perform a physico-chemical, descriptive quantitative and consumer-preference analysis of hard ewes'-milk cheeses that had been matured for one year and to determine the correlations between the variables studied. The cheeses were elaborated with milk from three breeds of sheep (Castellana, Churra and Assaf) with different somatic cell counts (lower than 500,000 cells ml-1; between 1,000,000 and 1,500,000 cells ml-1, and more than 2,500,000 cells ml-1). The results show that the cheeses elaborated with milk with high SCC had lower values of dry extract and fat and high values of pH and fat acidity and were described as pungent, granulose and less creamy. Regarding the effect of breed, the cheeses made with milk from the Churra breed had lower values for fat and those made with Assaf breed milk were significantly more rancid. The study of correlations showed that creaminess was positively correlated with the dry extract and total fat content and negatively correlated with ash and fat acidity, indeed grainy texture and pungency had the opposite sign in their correlation with these latter variables. The yellow colour was positively correlated with ash and negatively with protein. Finally, the consumer preferences reveals that the less accepted cheeses showed the higher values for rancidness and pungency and they were less likely to accept the cheeses made with Assaf breed milk.
Journal of Dairy Research, 2007
Journal of Dairy Research, 2009
Bulk tank ewe's milks from Assaf, Castellana and Churra breeds categorized within three d... more Bulk tank ewe's milks from Assaf, Castellana and Churra breeds categorized within three different Somatic Cell Count (SCC) groups (LSCC: <500,000; MSCC: 1,000,000 to 1,500,000; and HSCC: 2,500,000 to 3,000,000 cells ml-1) were used to investigate changes in capillary electrophoresis protein profiles and cheese-making properties. The results do not reveal a significant effect of SCC on total casein contents, because the sum of beta-caseins decreased as SCC increased; no statistically significant differences were observed for the sum of alpha-caseins, and the values of kappa-casein were higher in the HSCC milk. However, the soluble proteins other than alpha-lactalbumin and beta-lactoglobulin increased with SCC. Regarding the effect of breed, the Assaf breed had the lowest contents of kappa-CN, alpha s1-I-CN, alpha s1-II-CN 1-CN, alpha s1-III-CN, beta1-CN and beta2-CN. The protein profile was significantly correlated with curd textural properties. alpha s1-I-CN was the most influential variant because it was positively correlated with a large number of textural parameters. Cheese yield was positively correlated with all casein variants except alpha s1-III-CN, showing that the milk from local breeds were more suitable for cheese-making due to their higher contents of all the casein variants. Regarding curd texture properties LSCC milk curds showed more cohesiveness, associated with its lower content of alpha s1-III-CN and Castellana milk curds showed the highest values for firmness owing to their higher content of alpha s1-I-CN.
Journal of Dairy Research, 2011
Bulk tank ewe's milks with low (<500,000 ml(-1)), medium (1,000,000-1,500,000 ml(-... more Bulk tank ewe's milks with low (<500,000 ml(-1)), medium (1,000,000-1,500,000 ml(-1)) and high (>2,500,000 ml(-1)) somatic cell counts (SCC) from three breeds were used to manufacture hard ewes'-milk cheese. Physico-chemical analysis and capillary electrophoresis of fresh cheeses and cheeses that had been ripened for 1, 2, 3 and 6 months were carried out. The results showed that high SCC levels in milk affected the moisture content of only freshly made cheeses and the pH, fat content and fat acidity of ripened cheeses. Regarding proteolysis, the levels of all β-CNs in freshly made cheeses were significantly lower as the SCC values increased and the Castellana breed was the most affected by SCC levels because a significant decrease in all α-CNs was also observed as SCC levels rose. Analysis of the casein profile by principal component analysis (PCA) revealed that there were no clear differences according the SCC up to the third month. However in the third and sixth months cheeses with low levels of SC were closely grouped and characterised by the highest levels of intact caseins. Regarding the effect of breed, the results point to a more intense proteolytic activity in the Assaf breed, whose more matured cheeses showed the highest content of casein proteolytic fragments.
Journal of Chromatography A, 1999
The different options MS detection are investigated in order to achieve the best conditions for d... more The different options MS detection are investigated in order to achieve the best conditions for detection and identification of anthocyanins by LC–MS. A method for separation of these compounds that enables the main molecules in wines to be identified by direct analysis, without any previous preparation, is proposed. The anthocyanin composition of different red grape skin extracts and commercial monovarietal
Journal of Chromatography A, 1999
Different options of liquid chromatography-mass spectrometry were used to establish the most suit... more Different options of liquid chromatography-mass spectrometry were used to establish the most suitable ion source and conditions to analyse or detect some low-molecular mass phenols, flavan-3-ols, and apply such conditions to a complex sample (wine). Data presented in this work confirm the great utility of atmospheric pressure-ionisation electrospray mass spectrometry coupled to HPLC for analysis of phenolic compounds, under negative mode in the case of low-molecular mass phenols, and under both positive and negative modes in flavan-3-ol compounds. A fragmentor voltage of 60 V could be the most suitable for analysing the compounds under study.