Elena Saguer | University of Girona (original) (raw)
Papers by Elena Saguer
Food Hydrocolloids, 2009
Generalized 2D correlation spectroscopy (COS) has been applied to FTIR spectra of porcine plasma ... more Generalized 2D correlation spectroscopy (COS) has been applied to FTIR spectra of porcine plasma proteins to elucidate the sequence of events leading to pH-and/or thermal-induced protein unfolding and aggregation. Changes in the amide I 0 region of the infrared spectra (in the pH range between 7.5 and 4.5, at 0.5 pH intervals) at 30 C were especially evident as the pH approached the pI of serum albumin (4.8), with the globulin fraction in the plasma proteins undergoing denaturation prior to serum albumin. The effect of increasing temperature (from 30 to 90 C, in increments of 5 C) on the secondary structure of the plasma proteins at pHs in the range of 7.5-6.0 revealed that a decrease in alpha-helical structures is taken place previously to diminish native beta-sheets. So, the overall results of this study demonstrate that serum albumin and the globulin fraction differ in their sensitivity to pH and temperature.
Food Hydrocolloids
The aim of the present work is the in depth study of the protein aggregation mechanisms of whole ... more The aim of the present work is the in depth study of the protein aggregation mechanisms of whole porcine plasma and its fractions (serum, albumin and globulins) during heating using FTIR spectroscopy. Also, 2D correlation spectroscopy (2D COS) was used to establish the sequence of events during heat-induced gelation for all fractions. The results indicate that serum albumin quickly aggregates from 70 C through non-native intramolecular b-sheets while globulins show lower susceptibility to protein aggregation.
Food Hydrocolloids, 2008
FTIR spectroscopic and texture analysis studies were undertaken to elucidate the molecular basis ... more FTIR spectroscopic and texture analysis studies were undertaken to elucidate the molecular basis of structure-functionality relationships of porcine plasma proteins in solution and the gel state at varying pH. At room temperature, porcine plasma proteins aggregated as a function of decreasing pH. A parallel decrease in the intensity of amide I 0 bands at 1652 cm À1 in the infrared spectra of the protein solution (assigned to a-helix, predominant in serum albumin) and 1688/1638 cm À1 (assigned to intramolecular antiparallel b-sheet, predominant in immunoglobulins) along with an increase in the band at 1644 cm À1 (assigned to unordered or random structure) was observed to take place with decreasing pH. Bands assigned to intermolecular antiparallel b-sheet structures (1683 and 1617 cm À1 ) were observed in infrared spectra of porcine plasma protein solutions heated to the point of gel formation. Texture and water holding capacity were also very sensitive to pH. The results indicate that the lower the remaining native secondary structure and the faster the heat-induced aggregation (observed by FTIR spectroscopy) with decreasing pH, the weaker and more exudative the gels. r
Food Hydrocolloids, 2009
Generalized 2D correlation spectroscopy (COS) has been applied to FTIR spectra of porcine plasma ... more Generalized 2D correlation spectroscopy (COS) has been applied to FTIR spectra of porcine plasma proteins to elucidate the sequence of events leading to pH-and/or thermal-induced protein unfolding and aggregation. Changes in the amide I 0 region of the infrared spectra (in the pH range between 7.5 and 4.5, at 0.5 pH intervals) at 30 C were especially evident as the pH approached the pI of serum albumin (4.8), with the globulin fraction in the plasma proteins undergoing denaturation prior to serum albumin. The effect of increasing temperature (from 30 to 90 C, in increments of 5 C) on the secondary structure of the plasma proteins at pHs in the range of 7.5-6.0 revealed that a decrease in alpha-helical structures is taken place previously to diminish native beta-sheets. So, the overall results of this study demonstrate that serum albumin and the globulin fraction differ in their sensitivity to pH and temperature.
Food Hydrocolloids
The aim of the present work is the in depth study of the protein aggregation mechanisms of whole ... more The aim of the present work is the in depth study of the protein aggregation mechanisms of whole porcine plasma and its fractions (serum, albumin and globulins) during heating using FTIR spectroscopy. Also, 2D correlation spectroscopy (2D COS) was used to establish the sequence of events during heat-induced gelation for all fractions. The results indicate that serum albumin quickly aggregates from 70 C through non-native intramolecular b-sheets while globulins show lower susceptibility to protein aggregation.
Food Hydrocolloids, 2008
FTIR spectroscopic and texture analysis studies were undertaken to elucidate the molecular basis ... more FTIR spectroscopic and texture analysis studies were undertaken to elucidate the molecular basis of structure-functionality relationships of porcine plasma proteins in solution and the gel state at varying pH. At room temperature, porcine plasma proteins aggregated as a function of decreasing pH. A parallel decrease in the intensity of amide I 0 bands at 1652 cm À1 in the infrared spectra of the protein solution (assigned to a-helix, predominant in serum albumin) and 1688/1638 cm À1 (assigned to intramolecular antiparallel b-sheet, predominant in immunoglobulins) along with an increase in the band at 1644 cm À1 (assigned to unordered or random structure) was observed to take place with decreasing pH. Bands assigned to intermolecular antiparallel b-sheet structures (1683 and 1617 cm À1 ) were observed in infrared spectra of porcine plasma protein solutions heated to the point of gel formation. Texture and water holding capacity were also very sensitive to pH. The results indicate that the lower the remaining native secondary structure and the faster the heat-induced aggregation (observed by FTIR spectroscopy) with decreasing pH, the weaker and more exudative the gels. r
Food Chemistry, 2009
The objective of this work was to study the heat-induced gelling properties, at acid pH, of porci... more The objective of this work was to study the heat-induced gelling properties, at acid pH, of porcine plasma previously treated with microbial transglutaminase (MTGase) under high pressure (HP), when kept under refrigeration conditions for different times (setting time). The results indicated that, although the crosslinking activity of MTGase was enhanced under pressure, consequently, improving the thermal gel texture, the most significant effects, particularly on gel hardness, were obtained by keeping the treated plasma solutions under refrigeration for at least 2 h before gelation. On the whole, under such conditions, increases of approximately 60% of this textural parameter, calculated on the basis of the values corresponding to the heat-induced non-treated plasma gels at pH 5.5, were achieved. However, from the SDS-PAGE profiles, it can be suggested that mechanisms other than polymerisation by MTGase explain the beneficial effects of the treated plasma cold storage on gel texture. In contrast, the setting time had no effects on the water-holding capacity of heat-induced plasma gels at acid pH value, although this gel property was slightly enhanced by submitting porcine plasma solutions to the combined treatment (MTGase plus HP), with improvements being in accordance with the better-structured network of these heat-induced plasma gels.
High Hydrostatic Pressure as a Method to Reduce Microbial Contamination of Porcine Blood Plasma
Food Science and Technology International, 2001
The suitability of high hydrostatic pressure as an alternative method to produce porcine blood pl... more The suitability of high hydrostatic pressure as an alternative method to produce porcine blood plasma with a sufficient microbial stability without affecting its functional properties was evaluated. The effects of high pressure on plasma microorganisms were highly dependent on processing temperature. Treatments of 15 min at 450 MPa carried out at 5 'C led to reductions of about 90% in microbial counts and to 20-50% decreases in the growth ability of the survivors. At 25 'C and 40 'C, the efficiency was increased to reduction values of 99.82 and 99.97%, respectively. The lowering of the growth capacity was about 50% at 25 'C and up to 80% at 40 'C. The most efficient treatment (450 MPa, for 15 min at 40 'C) did not lead to appreciable negative effects on the functional properties of heat-induced gels from porcine blood plasma.
Food Hydrocolloids, 2007
The effects of the treatment of porcine plasma with microbial transglutaminase (MTGase) and cyste... more The effects of the treatment of porcine plasma with microbial transglutaminase (MTGase) and cysteine on its heat-induced gelation at pH 5.5 were studied. Four different conditions, besides the control samples, were considered in this work: cysteine addition; MTGase alone treatment; MTGase and cysteine simultaneously treatment; and MTGase treatment first, adding then cysteine just before the thermal gelation. Texture (hardness, springiness and cohesiveness) and water-holding capacity (WHC) were the measured gel properties. Scanning electron microscopy images were also taken in order to evaluate the effects on gel microstructure, and differential scanning calorimetry (DSC) and SDS-polyacrylamide gel electrophoresis analysis (SDS-PAGE) analyses were carried out to get information about the implied proteins in the cross-linking reactions. The results suggest that gel properties were differently affected due to of the applied treatment. All of them improved the texture of plasma gels with respect to the control samples; however, in the case of the combined treatments the order of addition of cysteine did not affect the obtained results and their effects seemed to be additive more than synergic. The MTGase treatment was the only one capable of improving WHC. Cysteine alone did not improve this parameter but, on the contrary, the improvements achieved with MTGase were lost when treating also with cysteine. From DSC and SDS-PAGE we postulate that at least fibrinogen and globulins would be proteins participating in the MTGase reaction. r
High Hydrostatic Pressure as a Method to Reduce Microbial Contamination of Porcine Blood Plasma
Food Science and Technology International, 2001
The suitability of high hydrostatic pressure as an alternative method to produce porcine blood pl... more The suitability of high hydrostatic pressure as an alternative method to produce porcine blood plasma with a sufficient microbial stability without affecting its functional properties was evaluated. The effects of high pressure on plasma microorganisms were highly dependent on processing temperature. Treatments of 15 min at 450 MPa carried out at 5 'C led to reductions of about 90% in microbial counts and to 20-50% decreases in the growth ability of the survivors. At 25 'C and 40 'C, the efficiency was increased to reduction values of 99.82 and 99.97%, respectively. The lowering of the growth capacity was about 50% at 25 'C and up to 80% at 40 'C. The most efficient treatment (450 MPa, for 15 min at 40 'C) did not lead to appreciable negative effects on the functional properties of heat-induced gels from porcine blood plasma.
Porcine plasma as polyphosphate and caseinate replacer in frankfurters
Meat Science
The aim was to replace polyphosphate and caseinate by porcine blood plasma as functional ingredie... more The aim was to replace polyphosphate and caseinate by porcine blood plasma as functional ingredients in frankfurters. Three trials, each consisting of one control, formulated with caseinate and tripolyphosphate, and one test, formulated with plasma, were carried out in a pilot plant. The frankfurters with plasma were compared to their respective controls by determining the composition, water holding capacity, cooking losses, internal colour, texture, microstructure, sensorial characteristics, and overall acceptance. No significant differences were found in proximate analysis, WHC, and cooking losses. Texture was not affected by the replacement, according to both sensorial and instrumental measurements. Nevertheless, the panellists detected the presence of animal taste and odour in plasma-containing sausages. Despite this, their overall acceptance was scored as 6.3 in a 10 maximum scale, so plasma could be considered as an interesting alternative to produce healthier and cheaper frankfurters.
Colour Stabilization of Spray-Dried Porcine Red Blood Cells Using Nicotinic Acid and Nicotinamide
Food Science and Technology International, 2003
... Poultry Science 68: 12181225. Ahn DU and Maurer AJ (1990a). Poultry meat color: kinds of hem... more ... Poultry Science 68: 12181225. Ahn DU and Maurer AJ (1990a). Poultry meat color: kinds of heme pigments and concentrations of the ligands. Poultry Science 69: 157165. Ahn DU and Maurer AJ (1990b). Poultry meat colour: heme-complex-forming ligands and color of ...
Microstructure–function relationships of heat-induced gels of porcine haemoglobin
Food Hydrocolloids, 2009
The purpose of this work was to use image analysis to study the microstructural properties of hae... more The purpose of this work was to use image analysis to study the microstructural properties of haemoglobin gels, with structural changes induced by pH conditions, and their correlations with physical properties such as texture and water holding capacity (WHC). Two types of networks showing great differences in the dimensions of the gel structure were obtained as influenced by pH. At pH<5.5 there was a shift from an aggregated to a fine-stranded gel type. Fractal dimension values revealed that more complex structures corresponded to softest and non-exudative gels. Lacunarity and pore size, which were used to study the pore distribution within the network, confirmed that softest gels with high WHC showed large number of small cavities. Finally, correlations between textural attributes, i.e. springiness and adhesiveness, and spatial variability, referred quantitatively to the degree of compactness, were also established.
Meat Science, 2008
The effects of treating porcine plasma with microbial tranglutaminase (MTGase) under high hydrost... more The effects of treating porcine plasma with microbial tranglutaminase (MTGase) under high hydrostatic pressure (HHP) were studied as a means of improving its gel-forming properties when subsequently heated at pH 5.5, near the pH of meats. Plasma containing varying levels of commercial MTGase was pressurized (400 MPa, room temperature, pH 7) for different times, and adjusted to pH 5.5 prior to heating to induce gelation. MTGase-treatment under HHP led to greater enhancement of heat-induced plasma gel properties as compared to control samples. The greatest improvements were achieved by pressurising plasma with 43.3 U MTGase/g protein for 30 min, thereby achieving recoveries of 49% and 63% in fracture force (gel strength) and fracture distance (gel deformability) of the subsequently heat-induced gels, respectively, relative to gel properties obtained by heating untreated plasma at physiological conditions (pH 7.5).
Journal of Food Science, 2006
The properties of gels obtained from porcine blood plasma were studied under different pH conditi... more The properties of gels obtained from porcine blood plasma were studied under different pH conditions. Gels from liquid and spray-dried plasma were prepared and analyzed for water holding capacity (WHC), texture, and microstructure at pH 7.4, 6, 5.5 and 4.5. The denaturation extent of proteins was also determined by differential scanning calorimetry (DSC). All properties studied were dependent on pH. The WHC and consistency of gels decreased when pH decreased. These results correlated with microstructural changes observed by SEM. Spray drying affected the consistency of gels. The penetration force of the gel from dehydrated plasma was always lower than that prepared from liquid plasma where the pH was the same, but neither the WHC nor the micro-structure of gels were affected.
Lwt - Food Science and Technology, 2007
The purpose of this work was to use image analysis to study the microstructural properties of hae... more The purpose of this work was to use image analysis to study the microstructural properties of haemoglobin gels, with structural changes induced by pH conditions, and their correlations with physical properties such as texture and water holding capacity (WHC). Two types of networks showing great differences in the dimensions of the gel structure were obtained as influenced by pH. At pH < 5.5 there was a shift from an aggregated to a fine-stranded gel type. Fractal dimension values revealed that more complex structures corresponded to softest and non-exudative gels. Lacunarity and pore size, which were used to study the pore distribution within the network, confirmed that softest gels with high WHC showed large number of small cavities. Finally, correlations between textural attributes, i.e. springiness and adhesiveness, and spatial variability, referred quantitatively to the degree of compactness, were also established.
Meat Science, 2008
The effects of high hydrostatic pressure (HHP) processing, at 400 MPa for 15 min at 20°C, on the ... more The effects of high hydrostatic pressure (HHP) processing, at 400 MPa for 15 min at 20°C, on the microbiological and functional characteristics of the red blood cell (RBC) fraction obtained from porcine blood, previously preserved by means of lactic acid bacteria (LAB) was studied. Biopreservation was achieved by incubation of inulin-enriched blood inoculated with a LAB strain (Enterococcus raffinosus PS99) for 72 h at 5°C. Results showed that incubation of blood with added E. raffinosus followed by HHP treatment reduced the levels of contaminant coliforms, proteolytic, hemolytic bacteria, and Pseudomonas spp. on RCB. Color parameters, protein solubility, foaming and emulsifying properties, as well as texture and water holding capacity of heat-induced gels from RBC were not seriously damaged by the combined treatments. This is a new approach to process and preserve animal blood fractions for the development of functional and/or nutritional food ingredients with added value.
Fish (Rainbow Trout) Blood and Its Fractions as Food Ingredients
Journal of Aquatic Food Product Technology, 2006
Plasma and red cell fraction (RCF) from rainbow trout blood were studied as possible food ingredi... more Plasma and red cell fraction (RCF) from rainbow trout blood were studied as possible food ingredients. The plasma proteins had a high solubility at both neutral and acid pH, although slightly lower at acid pH. RCF solubility was also negatively affected at acid pH, and, in all cases, the values were lower than plasma. At pH 7.5, heat-induced gels from plasma proteins showed good textural properties, especially with respect to springiness. These proteins had a relatively low thermal stability as indicated by DSC. On the other hand, foaming and emulsifying properties appeared to be lower for RCF proteins than for those from plasma.
Improvement of gelling properties of porcine blood plasma using microbial transglutaminase
Food Chemistry, 2007
The effect of microbial transglutaminase (MTGase) on the texture and water-holding capacity (WHC)... more The effect of microbial transglutaminase (MTGase) on the texture and water-holding capacity (WHC) of heat-induced gels prepared from porcine blood plasma at pH 5.5 was investigated. Different concentrations of commercial MTGase were added to plasma and incubated for several times under specific conditions of temperature and pH. From the results obtained, it can be postulated that enzymatic treatment enhances textural
Food Chemistry, 2004
The aims of this study were to evaluate the functional properties of a spray-dried porcine red bl... more The aims of this study were to evaluate the functional properties of a spray-dried porcine red blood cell fraction (RBC), and the effects of the prior application of high hydrostatic pressure (HHP) on RBC protein functionality (solubility, foaming capacity, foam stability, water-holding capacity and texture properties of heat-induced gels) as well as on its microbiological quality and colour. The application of HHP (400 MPa, 15 min, 20°C) and later dehydration allowed a dried product to be obtained with a reduction in the mesophilic bacterial counts of 3.2 logarithmic units. The colours of the pressurized and non-pressurized spray-dried RBC were the same, which indicated that both samples presented the same susceptibility to the hem group oxidation provoked by dehydration. The application of HHP increased the denaturant effects of spray-drying on hemoglobin (Hb), especially at pH 7 (isoelectric point; pI) since, after both processes, a decrease in protein solubility at neutral pH was observed. Spray-dried RBC had a maximum foaming capacity at the pI of Hb. The application of HHP decreased the foaming capacity but did not negatively affect the foam stability. Thermal treatment of RBC solutions led to hard and consistent gels at pH 7 whereas, at acid pH, less consistent, more adhesive and more elastic pastes were formed. The latter had higher water-holding capacities than gels at pH 7, in which, the water was retained by capillarity. Neither springiness and adhesiveness nor water-holding capacities of heat-induced gels or pastes were affected by the application of the HHP treatment to the fresh RBC.
Food Hydrocolloids, 2009
Generalized 2D correlation spectroscopy (COS) has been applied to FTIR spectra of porcine plasma ... more Generalized 2D correlation spectroscopy (COS) has been applied to FTIR spectra of porcine plasma proteins to elucidate the sequence of events leading to pH-and/or thermal-induced protein unfolding and aggregation. Changes in the amide I 0 region of the infrared spectra (in the pH range between 7.5 and 4.5, at 0.5 pH intervals) at 30 C were especially evident as the pH approached the pI of serum albumin (4.8), with the globulin fraction in the plasma proteins undergoing denaturation prior to serum albumin. The effect of increasing temperature (from 30 to 90 C, in increments of 5 C) on the secondary structure of the plasma proteins at pHs in the range of 7.5-6.0 revealed that a decrease in alpha-helical structures is taken place previously to diminish native beta-sheets. So, the overall results of this study demonstrate that serum albumin and the globulin fraction differ in their sensitivity to pH and temperature.
Food Hydrocolloids
The aim of the present work is the in depth study of the protein aggregation mechanisms of whole ... more The aim of the present work is the in depth study of the protein aggregation mechanisms of whole porcine plasma and its fractions (serum, albumin and globulins) during heating using FTIR spectroscopy. Also, 2D correlation spectroscopy (2D COS) was used to establish the sequence of events during heat-induced gelation for all fractions. The results indicate that serum albumin quickly aggregates from 70 C through non-native intramolecular b-sheets while globulins show lower susceptibility to protein aggregation.
Food Hydrocolloids, 2008
FTIR spectroscopic and texture analysis studies were undertaken to elucidate the molecular basis ... more FTIR spectroscopic and texture analysis studies were undertaken to elucidate the molecular basis of structure-functionality relationships of porcine plasma proteins in solution and the gel state at varying pH. At room temperature, porcine plasma proteins aggregated as a function of decreasing pH. A parallel decrease in the intensity of amide I 0 bands at 1652 cm À1 in the infrared spectra of the protein solution (assigned to a-helix, predominant in serum albumin) and 1688/1638 cm À1 (assigned to intramolecular antiparallel b-sheet, predominant in immunoglobulins) along with an increase in the band at 1644 cm À1 (assigned to unordered or random structure) was observed to take place with decreasing pH. Bands assigned to intermolecular antiparallel b-sheet structures (1683 and 1617 cm À1 ) were observed in infrared spectra of porcine plasma protein solutions heated to the point of gel formation. Texture and water holding capacity were also very sensitive to pH. The results indicate that the lower the remaining native secondary structure and the faster the heat-induced aggregation (observed by FTIR spectroscopy) with decreasing pH, the weaker and more exudative the gels. r
Food Hydrocolloids, 2009
Generalized 2D correlation spectroscopy (COS) has been applied to FTIR spectra of porcine plasma ... more Generalized 2D correlation spectroscopy (COS) has been applied to FTIR spectra of porcine plasma proteins to elucidate the sequence of events leading to pH-and/or thermal-induced protein unfolding and aggregation. Changes in the amide I 0 region of the infrared spectra (in the pH range between 7.5 and 4.5, at 0.5 pH intervals) at 30 C were especially evident as the pH approached the pI of serum albumin (4.8), with the globulin fraction in the plasma proteins undergoing denaturation prior to serum albumin. The effect of increasing temperature (from 30 to 90 C, in increments of 5 C) on the secondary structure of the plasma proteins at pHs in the range of 7.5-6.0 revealed that a decrease in alpha-helical structures is taken place previously to diminish native beta-sheets. So, the overall results of this study demonstrate that serum albumin and the globulin fraction differ in their sensitivity to pH and temperature.
Food Hydrocolloids
The aim of the present work is the in depth study of the protein aggregation mechanisms of whole ... more The aim of the present work is the in depth study of the protein aggregation mechanisms of whole porcine plasma and its fractions (serum, albumin and globulins) during heating using FTIR spectroscopy. Also, 2D correlation spectroscopy (2D COS) was used to establish the sequence of events during heat-induced gelation for all fractions. The results indicate that serum albumin quickly aggregates from 70 C through non-native intramolecular b-sheets while globulins show lower susceptibility to protein aggregation.
Food Hydrocolloids, 2008
FTIR spectroscopic and texture analysis studies were undertaken to elucidate the molecular basis ... more FTIR spectroscopic and texture analysis studies were undertaken to elucidate the molecular basis of structure-functionality relationships of porcine plasma proteins in solution and the gel state at varying pH. At room temperature, porcine plasma proteins aggregated as a function of decreasing pH. A parallel decrease in the intensity of amide I 0 bands at 1652 cm À1 in the infrared spectra of the protein solution (assigned to a-helix, predominant in serum albumin) and 1688/1638 cm À1 (assigned to intramolecular antiparallel b-sheet, predominant in immunoglobulins) along with an increase in the band at 1644 cm À1 (assigned to unordered or random structure) was observed to take place with decreasing pH. Bands assigned to intermolecular antiparallel b-sheet structures (1683 and 1617 cm À1 ) were observed in infrared spectra of porcine plasma protein solutions heated to the point of gel formation. Texture and water holding capacity were also very sensitive to pH. The results indicate that the lower the remaining native secondary structure and the faster the heat-induced aggregation (observed by FTIR spectroscopy) with decreasing pH, the weaker and more exudative the gels. r
Food Chemistry, 2009
The objective of this work was to study the heat-induced gelling properties, at acid pH, of porci... more The objective of this work was to study the heat-induced gelling properties, at acid pH, of porcine plasma previously treated with microbial transglutaminase (MTGase) under high pressure (HP), when kept under refrigeration conditions for different times (setting time). The results indicated that, although the crosslinking activity of MTGase was enhanced under pressure, consequently, improving the thermal gel texture, the most significant effects, particularly on gel hardness, were obtained by keeping the treated plasma solutions under refrigeration for at least 2 h before gelation. On the whole, under such conditions, increases of approximately 60% of this textural parameter, calculated on the basis of the values corresponding to the heat-induced non-treated plasma gels at pH 5.5, were achieved. However, from the SDS-PAGE profiles, it can be suggested that mechanisms other than polymerisation by MTGase explain the beneficial effects of the treated plasma cold storage on gel texture. In contrast, the setting time had no effects on the water-holding capacity of heat-induced plasma gels at acid pH value, although this gel property was slightly enhanced by submitting porcine plasma solutions to the combined treatment (MTGase plus HP), with improvements being in accordance with the better-structured network of these heat-induced plasma gels.
High Hydrostatic Pressure as a Method to Reduce Microbial Contamination of Porcine Blood Plasma
Food Science and Technology International, 2001
The suitability of high hydrostatic pressure as an alternative method to produce porcine blood pl... more The suitability of high hydrostatic pressure as an alternative method to produce porcine blood plasma with a sufficient microbial stability without affecting its functional properties was evaluated. The effects of high pressure on plasma microorganisms were highly dependent on processing temperature. Treatments of 15 min at 450 MPa carried out at 5 'C led to reductions of about 90% in microbial counts and to 20-50% decreases in the growth ability of the survivors. At 25 'C and 40 'C, the efficiency was increased to reduction values of 99.82 and 99.97%, respectively. The lowering of the growth capacity was about 50% at 25 'C and up to 80% at 40 'C. The most efficient treatment (450 MPa, for 15 min at 40 'C) did not lead to appreciable negative effects on the functional properties of heat-induced gels from porcine blood plasma.
Food Hydrocolloids, 2007
The effects of the treatment of porcine plasma with microbial transglutaminase (MTGase) and cyste... more The effects of the treatment of porcine plasma with microbial transglutaminase (MTGase) and cysteine on its heat-induced gelation at pH 5.5 were studied. Four different conditions, besides the control samples, were considered in this work: cysteine addition; MTGase alone treatment; MTGase and cysteine simultaneously treatment; and MTGase treatment first, adding then cysteine just before the thermal gelation. Texture (hardness, springiness and cohesiveness) and water-holding capacity (WHC) were the measured gel properties. Scanning electron microscopy images were also taken in order to evaluate the effects on gel microstructure, and differential scanning calorimetry (DSC) and SDS-polyacrylamide gel electrophoresis analysis (SDS-PAGE) analyses were carried out to get information about the implied proteins in the cross-linking reactions. The results suggest that gel properties were differently affected due to of the applied treatment. All of them improved the texture of plasma gels with respect to the control samples; however, in the case of the combined treatments the order of addition of cysteine did not affect the obtained results and their effects seemed to be additive more than synergic. The MTGase treatment was the only one capable of improving WHC. Cysteine alone did not improve this parameter but, on the contrary, the improvements achieved with MTGase were lost when treating also with cysteine. From DSC and SDS-PAGE we postulate that at least fibrinogen and globulins would be proteins participating in the MTGase reaction. r
High Hydrostatic Pressure as a Method to Reduce Microbial Contamination of Porcine Blood Plasma
Food Science and Technology International, 2001
The suitability of high hydrostatic pressure as an alternative method to produce porcine blood pl... more The suitability of high hydrostatic pressure as an alternative method to produce porcine blood plasma with a sufficient microbial stability without affecting its functional properties was evaluated. The effects of high pressure on plasma microorganisms were highly dependent on processing temperature. Treatments of 15 min at 450 MPa carried out at 5 'C led to reductions of about 90% in microbial counts and to 20-50% decreases in the growth ability of the survivors. At 25 'C and 40 'C, the efficiency was increased to reduction values of 99.82 and 99.97%, respectively. The lowering of the growth capacity was about 50% at 25 'C and up to 80% at 40 'C. The most efficient treatment (450 MPa, for 15 min at 40 'C) did not lead to appreciable negative effects on the functional properties of heat-induced gels from porcine blood plasma.
Porcine plasma as polyphosphate and caseinate replacer in frankfurters
Meat Science
The aim was to replace polyphosphate and caseinate by porcine blood plasma as functional ingredie... more The aim was to replace polyphosphate and caseinate by porcine blood plasma as functional ingredients in frankfurters. Three trials, each consisting of one control, formulated with caseinate and tripolyphosphate, and one test, formulated with plasma, were carried out in a pilot plant. The frankfurters with plasma were compared to their respective controls by determining the composition, water holding capacity, cooking losses, internal colour, texture, microstructure, sensorial characteristics, and overall acceptance. No significant differences were found in proximate analysis, WHC, and cooking losses. Texture was not affected by the replacement, according to both sensorial and instrumental measurements. Nevertheless, the panellists detected the presence of animal taste and odour in plasma-containing sausages. Despite this, their overall acceptance was scored as 6.3 in a 10 maximum scale, so plasma could be considered as an interesting alternative to produce healthier and cheaper frankfurters.
Colour Stabilization of Spray-Dried Porcine Red Blood Cells Using Nicotinic Acid and Nicotinamide
Food Science and Technology International, 2003
... Poultry Science 68: 12181225. Ahn DU and Maurer AJ (1990a). Poultry meat color: kinds of hem... more ... Poultry Science 68: 12181225. Ahn DU and Maurer AJ (1990a). Poultry meat color: kinds of heme pigments and concentrations of the ligands. Poultry Science 69: 157165. Ahn DU and Maurer AJ (1990b). Poultry meat colour: heme-complex-forming ligands and color of ...
Microstructure–function relationships of heat-induced gels of porcine haemoglobin
Food Hydrocolloids, 2009
The purpose of this work was to use image analysis to study the microstructural properties of hae... more The purpose of this work was to use image analysis to study the microstructural properties of haemoglobin gels, with structural changes induced by pH conditions, and their correlations with physical properties such as texture and water holding capacity (WHC). Two types of networks showing great differences in the dimensions of the gel structure were obtained as influenced by pH. At pH<5.5 there was a shift from an aggregated to a fine-stranded gel type. Fractal dimension values revealed that more complex structures corresponded to softest and non-exudative gels. Lacunarity and pore size, which were used to study the pore distribution within the network, confirmed that softest gels with high WHC showed large number of small cavities. Finally, correlations between textural attributes, i.e. springiness and adhesiveness, and spatial variability, referred quantitatively to the degree of compactness, were also established.
Meat Science, 2008
The effects of treating porcine plasma with microbial tranglutaminase (MTGase) under high hydrost... more The effects of treating porcine plasma with microbial tranglutaminase (MTGase) under high hydrostatic pressure (HHP) were studied as a means of improving its gel-forming properties when subsequently heated at pH 5.5, near the pH of meats. Plasma containing varying levels of commercial MTGase was pressurized (400 MPa, room temperature, pH 7) for different times, and adjusted to pH 5.5 prior to heating to induce gelation. MTGase-treatment under HHP led to greater enhancement of heat-induced plasma gel properties as compared to control samples. The greatest improvements were achieved by pressurising plasma with 43.3 U MTGase/g protein for 30 min, thereby achieving recoveries of 49% and 63% in fracture force (gel strength) and fracture distance (gel deformability) of the subsequently heat-induced gels, respectively, relative to gel properties obtained by heating untreated plasma at physiological conditions (pH 7.5).
Journal of Food Science, 2006
The properties of gels obtained from porcine blood plasma were studied under different pH conditi... more The properties of gels obtained from porcine blood plasma were studied under different pH conditions. Gels from liquid and spray-dried plasma were prepared and analyzed for water holding capacity (WHC), texture, and microstructure at pH 7.4, 6, 5.5 and 4.5. The denaturation extent of proteins was also determined by differential scanning calorimetry (DSC). All properties studied were dependent on pH. The WHC and consistency of gels decreased when pH decreased. These results correlated with microstructural changes observed by SEM. Spray drying affected the consistency of gels. The penetration force of the gel from dehydrated plasma was always lower than that prepared from liquid plasma where the pH was the same, but neither the WHC nor the micro-structure of gels were affected.
Lwt - Food Science and Technology, 2007
The purpose of this work was to use image analysis to study the microstructural properties of hae... more The purpose of this work was to use image analysis to study the microstructural properties of haemoglobin gels, with structural changes induced by pH conditions, and their correlations with physical properties such as texture and water holding capacity (WHC). Two types of networks showing great differences in the dimensions of the gel structure were obtained as influenced by pH. At pH < 5.5 there was a shift from an aggregated to a fine-stranded gel type. Fractal dimension values revealed that more complex structures corresponded to softest and non-exudative gels. Lacunarity and pore size, which were used to study the pore distribution within the network, confirmed that softest gels with high WHC showed large number of small cavities. Finally, correlations between textural attributes, i.e. springiness and adhesiveness, and spatial variability, referred quantitatively to the degree of compactness, were also established.
Meat Science, 2008
The effects of high hydrostatic pressure (HHP) processing, at 400 MPa for 15 min at 20°C, on the ... more The effects of high hydrostatic pressure (HHP) processing, at 400 MPa for 15 min at 20°C, on the microbiological and functional characteristics of the red blood cell (RBC) fraction obtained from porcine blood, previously preserved by means of lactic acid bacteria (LAB) was studied. Biopreservation was achieved by incubation of inulin-enriched blood inoculated with a LAB strain (Enterococcus raffinosus PS99) for 72 h at 5°C. Results showed that incubation of blood with added E. raffinosus followed by HHP treatment reduced the levels of contaminant coliforms, proteolytic, hemolytic bacteria, and Pseudomonas spp. on RCB. Color parameters, protein solubility, foaming and emulsifying properties, as well as texture and water holding capacity of heat-induced gels from RBC were not seriously damaged by the combined treatments. This is a new approach to process and preserve animal blood fractions for the development of functional and/or nutritional food ingredients with added value.
Fish (Rainbow Trout) Blood and Its Fractions as Food Ingredients
Journal of Aquatic Food Product Technology, 2006
Plasma and red cell fraction (RCF) from rainbow trout blood were studied as possible food ingredi... more Plasma and red cell fraction (RCF) from rainbow trout blood were studied as possible food ingredients. The plasma proteins had a high solubility at both neutral and acid pH, although slightly lower at acid pH. RCF solubility was also negatively affected at acid pH, and, in all cases, the values were lower than plasma. At pH 7.5, heat-induced gels from plasma proteins showed good textural properties, especially with respect to springiness. These proteins had a relatively low thermal stability as indicated by DSC. On the other hand, foaming and emulsifying properties appeared to be lower for RCF proteins than for those from plasma.
Improvement of gelling properties of porcine blood plasma using microbial transglutaminase
Food Chemistry, 2007
The effect of microbial transglutaminase (MTGase) on the texture and water-holding capacity (WHC)... more The effect of microbial transglutaminase (MTGase) on the texture and water-holding capacity (WHC) of heat-induced gels prepared from porcine blood plasma at pH 5.5 was investigated. Different concentrations of commercial MTGase were added to plasma and incubated for several times under specific conditions of temperature and pH. From the results obtained, it can be postulated that enzymatic treatment enhances textural
Food Chemistry, 2004
The aims of this study were to evaluate the functional properties of a spray-dried porcine red bl... more The aims of this study were to evaluate the functional properties of a spray-dried porcine red blood cell fraction (RBC), and the effects of the prior application of high hydrostatic pressure (HHP) on RBC protein functionality (solubility, foaming capacity, foam stability, water-holding capacity and texture properties of heat-induced gels) as well as on its microbiological quality and colour. The application of HHP (400 MPa, 15 min, 20°C) and later dehydration allowed a dried product to be obtained with a reduction in the mesophilic bacterial counts of 3.2 logarithmic units. The colours of the pressurized and non-pressurized spray-dried RBC were the same, which indicated that both samples presented the same susceptibility to the hem group oxidation provoked by dehydration. The application of HHP increased the denaturant effects of spray-drying on hemoglobin (Hb), especially at pH 7 (isoelectric point; pI) since, after both processes, a decrease in protein solubility at neutral pH was observed. Spray-dried RBC had a maximum foaming capacity at the pI of Hb. The application of HHP decreased the foaming capacity but did not negatively affect the foam stability. Thermal treatment of RBC solutions led to hard and consistent gels at pH 7 whereas, at acid pH, less consistent, more adhesive and more elastic pastes were formed. The latter had higher water-holding capacities than gels at pH 7, in which, the water was retained by capillarity. Neither springiness and adhesiveness nor water-holding capacities of heat-induced gels or pastes were affected by the application of the HHP treatment to the fresh RBC.