Lourdes Sanchez

University of Zaragoza | UNIZAR · Area de Tecnología de los Alimentos

Milk is a source of proteins with high nutritional value and relevant biological activities. Bioactive milk proteins, like lactoferrin, are important for newborn development and can also be used as ingredients in functional products to improve health. Lactoferrin is essential in infant’s diet, since protects against infections and promotes immune s...

The effect of thermal and ultrasound treatments on denaturation and allergenicity of Pru p 3, the major peach allergenic protein, was determined. The degree of denaturation of Pru p 3 was estimated by sandwich ELISA using specific rabbit IgG, that was previously developed. Validation of ELISA test showed high sensitivity and specificity, and accept...

Clostridium tyrobutyricum is described as the main causative agent of late blowing defect in cheese. Currently, there are no fast methods to detect this microorganism in raw milk, which would allow determining the use of milk for fresh or cured cheese. The technique commonly used is the Most Probable Number, which is laborious and non-specific. In...

Las frutas rosáceas son las responsables del 60% de las alergias a frutas y entre ellas destaca la manzana. Las proteínas de la familia LTP (Lipid Transfer Proteins) a la que pertenece la Mal d 3 de la manzana (Malus domestica), son las más alergénicas de las frutas. El objetivo de este trabajo ha sido estudiar el efecto de la variedad de manzana (...

Milk is a source of bioactive proteins with defensive properties, of great value for protecting the newborn. The activity of bovine milk lactoferrin (LF) was investigated as an antibacterial agent in the internalisation of the emergent pathogen Cronobacter sakazakii into Caco-2/TC7 cells, a model of human intestinal epithelium. The effect of LF on...

Soy allergens detection is challenging when they are in trace amounts in foods, especially when foods are subjected to heat treatment, after which the target allergen maybe modified. Two ELISA formats, sandwich and indirect competitive, were developed using rabbit polyclonal antibodies against heat-denatured glycinin as the target protein. Sandwich...

Almond (Prunus dulcis) represents a potential allergenic hazard that should be included in Allergen Control Plans. In this study, sandwich ELISA and lateral flow immunoassay (LFIA), using amandin (Pru du 6) as the target protein, were developed to detect almond in processed food, and validated according to international guides. ELISA could detect 2...

A new coronavirus known as SARS-CoV-2 emerged in Wuhan in 2019, and spread rapidly to the rest of the world causing the pandemic disease named coronavirus disease of 2019 (COVID-19). Little information is known about the impact this virus can cause upon domestic and stray animals. The potential impact of SARS-CoV-2 has become of great interest in c...

The presence of undeclared soy proteins in food can cause severe reactions in soy allergic individuals. The extraction of target proteins from processed foods is a crucial step in allergen detection by immunoassays, as only successfully extracted target proteins can be detected by the specific antibodies. The effectiveness was studied of different...

The effect of high pressure (HP) and pulsed electric field (PEF) treatments combined or not with heat on denaturation and allergenicity of Pru p 3, the major allergenic protein of peach, was studied. Denaturation of Pru p 3, determined by ELISA using rabbit IgG, occurred when the protein was treated at 500 and 600 MPa at 20 °C and at 400 MPa at 50...

The interest in the applications of high-pressure processing (HPP) on milk and dairy products has increased in the last decades, with the main objective of being an alternative method to pasteurization. HPP produces changes in the structure of casein and whey proteins that allow obtaining products with new characteristics and functions. Apart from...

Clostridium tyrobutyricum is the major agent that causes the blowing defect in cheese due to the germination of its dormant spores during the ripening stage. As a result, many of the affected cheeses show cavities and cracks, which cause the product loss in most cases. Nowadays, there is not a fast method capable of detecting milk contaminated with...

Bovine lactoferrin (bLF) is an iron-binding glycoprotein used in functional and therapeutic products due to its biological properties, the most important being its antimicrobial activity. In this study, hydrolysates of bovine lactoferrin (bLFH) obtained with pepsin, chymosin and microbial rennet were assayed against Cronobacter sakazakii (104 CFU/m...

Two ELISA formats (sandwich and indirect competitive) were developed to quantify β-conglycinin, a major soy allergen. Their performance was evaluated using three model foods incurred with soy proteins. The sandwich format detects the addition of 0.005% and 0.05% soy proteins in pasteurized sausages and baked bread. However, the competitive format d...

Milk by-products such as whey and caseinate are widely used as ingredients or processing aids in food industry. However, since they could cause allergic reactions they are included in Allergen Control Plans. β-Lactoglobulin is the major whey protein and caseins are main proteins in milk. Selection of a unique target to analyze the presence of milk...

The aim of this work has been to determine the levels of lactoferrin and IgG in ovine milk during the two first months of lactation and to compare with some milk quality parameters. Milk samples were collected from ewes of an Assaf flock. The levels of lactoferrin were determined by radial immunodiffusion. For this purpose, lactoferrin was isolated...

Whey and buttermilk have shown a certain degree of neutralizing activity against rotavirus, which are still a serious public health problem worldwide. High hydrostatic pressure (HHP) can be an alternative to thermal treatment for preservation of dairy products, providing acceptable safety and shelf life with minimal effects on their quality. The ma...

Rotaviral gastroenteritis causes a high rate of infant mortality and severe healthcare implications worldwide. Several studies have pointed out that human milk and dairy fractions, such as whey and buttermilk, possess antirotaviral activity. This activity has been mainly associated with glycoproteins, among them lactoferrin (LF). Thermal treatments...

Indirect competitive and sandwich ELISA formats were developed to determine glycinin and applied to detect soy in model and commercial processed food. Antiserum to glycinin was used in the competitive format and specific purified antibodies in the sandwich format. Results obtained showed that the sandwich format could detect as low levels as 0.005%...

The viral gastroenteritis mediated by rotavirus remains a major health problem, causing significant infant morbidity and mortality, and health care costs worldwide. Diverse studies have indicated that some milk-derived fractions exhibit antirotaviral activity, associated to proteins such as immunoglobulins, lactoferrin, mucins, and lactadherin. Nev...

Lactoferrin (LF) is a multifunctional protein that exerts important activities in the neonate through its presence in milk, and also in other external mucosas, acting as a defense protein of innate immunity. The addition of bovine LF to infant formula and also to other functional products and cosmetics has increased during the last decades. Consequ...

Lactadherin is a peripheral glycoprotein of the milk fat globule membrane with several attributed biological activities. In this study, we developed an indirect competitive ELISA to determine lactadherin concentration by using a rabbit polyclonal antiserum. The ELISA was applied to quantify lactadherin in several dairy by-products. Of the products...

Rotaviral gastroenteritis is associated with significant morbidity in developed countries and high rate of infant mortality in developing countries. Diverse studies have demonstrated that a wide range of milk-derived fractions exhibit antirotaviral activity. The present study shows the antirotaviral activity of some bovine and ovine dairy by-produc...

Lactoferrin and lysozyme are 2 glycoproteins with great antimicrobial activity, being part of the nonspecific defensive system of human milk, though their use in commercial products is difficult because human milk is a limited source. Therefore, many investigations have been carried out to produce those proteins in biological systems, such as bacte...

Cronobacter sakazakii is a foodborne pathogen that has been associated with severe infections mainly in neonates. The binding of this bacterium to host cell surfaces represents the first step in the pathogenesis of disease. An ELISA-based assay has been developed using a polyclonal antiserum against C. sakazakii to determine its adhesion to Caco-2...

Human milk from donor mothers is processed in human milk banks using low-temperature long-time pasteurization to ensure microbial safety. However, this treatment can degrade relevant bioactive components. High-pressure processing of food is a nonthermal treatment that exerts an antimicrobial effect maintaining the nutritional quality of foods. In t...

Lactoferrin is a protein with important biological functions that can be obtained from milk and by-products derived from the dairy industry, such as whey. Although bovine lactoferrin has been extensively studied, ovine lactoferrin is not quite as well known. In the present study, the effect of several heat treatments in 3 different media, over a te...

The effect of high pressure and heat treatment of human milk on denaturation of lactoferrin was studied. The degree of protein denaturation was estimated using a sandwich enzyme-linked immunosorbent assay. Kinetic parameters for pressure-induced denaturation of lactoferrin were determined over the pressure range 300–650 MPa at 20 °C. Treatment at 3...

La lactoferrina es una proteína presente en la leche, a la cual se le confieren importantes propiedades como lo son participar en el transporte de hierro, actividades inmunológicas y antimicrobianas. El creciente interés comercial por utilizar las propiedades benéficas de la lactoferrina en diferentes tipos de alimentos, entre ellos las leches infa...

Purpose The prevalence of HCV infection has increased during recent years and the incidence reach 3% of the world's population, and in some countries like Egypt, may around 20%. The developments of effective and preventive agents are critical to control the current public health burden imposed by HCV infection. Lactoferrin in general and camel lact...

The effect of high-pressure treatment (400, 500 and 650 MPa) on the structure and activity of bovine lactoferrin in different iron-saturation forms has been studied by several techniques. The structural changes produced in lactoferrin by high-pressure were analysed by differential scanning calorimetry and fluorescence spectroscopy, and the immunore...

The effect of heat treatment on denaturation of Ara h1 protein, a major allergen from peanut, was studied using several techniques. Previously, Ara h1 protein was isolated from raw peanut using ammonium sulphate precipitation and chromatograpic techniques. Antibodies against Ara h1 protein were obtained in rabbits, conjugated with horseradish perox...

To extend the study of the camel milk proteins which have antiviral activity against HCV, camel naïve polyclonal IgGs, α-lactalbumin were purified from camel milk and their anti-HCV effect was examined using PBMCs and Huh7.5 cell-lines. They were compared with the activity of human polyclonal IgGs and camel lactoferrin and casein. Three types of ex...

Kinetic parameters for pressure-induced denaturation of immunoglobulin G (IgG) in skim milk, rennet whey and phosphate buffer were determined over the pressure range 450–700 MPa at 20 °C. Denaturation of IgG was estimated by the loss of reactivity with their specific antibodies using radial immunodifussion. Values of residual immunoreactive IgG aft...

The effect of high-pressure treatment on denaturation of β-lactoglobulin and α-lactalbumin in skimmed milk, whey, and phosphate buffer was studied over a pressure range of 450–700 MPa at 20 °C. The degree of protein denaturation was measured by the loss of reactivity with their specific antibodies using radial immunodiffusion. The denaturation of β...

Nowadays, the reference method for the detection of Clostridium tyrobutyricum in milk is the most-probable-number method, a very time-consuming and non-specific method. In this work, the suitability of the use of superparamagnetic beads coated with specific antibodies and peptides for bioseparation and concentration of spores of C. tyrobutyricum ha...

It is over 60years since the discovery and isolation of the serum ferroxidase ceruloplasmin. In that time much basic information about the protein has been elucidated including its catalytic and kinetic properties as an enzyme, expression, sequence and structure. The importance of its biological role is indicated in genetic diseases such as acerulo...

Heat denaturation of recombinant human lactoferrin (rhLf) from rice with 3 different iron-saturation degrees, holo rhLf (iron-saturated), AsIs rhLf (60% iron saturation), and apo rhLf (iron-depleted), was studied. The 3 forms of rhLf were subjected to heat treatment, and the kinetic and thermodynamic parameters of the denaturation process were dete...

Lactoferrin and lactoperoxidase are whey proteins with biological properties that may provide health benefits to consumers. These properties are vulnerable to potentially denaturing conditions during processing. High-pressure treatment is an appealing alternative to the traditional heat processing of foods because it exerts an antimicrobial effect...

High pressure was applied to recombinant human lactoferrin obtained from rice (rhLF) and its effect was evaluated on the structure and activity of the protein. Treatments of 400, 500, and 650 MPa for 15 min (20 °C), were applied to rhLF at 2 mg/mL in three iron-saturation forms. The structural characteristics of the treated proteins were analyzed b...

Thermal denaturation of recombinant human lysozyme from rice has been studied by differential scanning calorimetry at acidic (4.2), neutral (7.2) and basic (9.2) pH levels at various heating rates, and it has been compared with thermal denaturation of human lysozyme isolated from milk at the same pH levels at a heating rate of 10 °C/min. Data obtai...

α-Lactalbumin (α-LA) is a whey protein that has been extensively studied for its folding properties and its ability to bind several cations. An interesting property of α-LA is its ability to interact with fatty acids, although this interaction requires the previous unfolding of the protein by removing the Ca(2+) bound. The main function of α-LA is...

The effect of high pressure (HP) treatment on bovine whey proteins has been studied and compared to the effect of thermal treatment. The concentration of β-lactoglobulin, α-lactalbumin, lactoferrin and IgG was determined by immunochemical techniques. The enzymatic activity of lactoperoxidase was determined by a spectrophotometric technique. Skimmed...

Lysozyme is an enzyme with antibacterial activity often used as food preservative and as active ingredient in pharmaceutical preparations. Lysozyme is quantitatively important in human milk and has been proposed to be used in special products to improve infant health. The production of recombinant human lysozyme (rhLz) in rice is very valuable for...

Lactoferrin, the main iron-binding protein of milk, has biological activities that are essential for the newborn and are beneficial for adults. Given this beneficial effect, there is broad interest in exogenous sources of lactoferrin in human nutrition. Consequently, several transgenic approaches to produce lactoferrin have been achieved. However,...

The aim of this work was to study the effect of milk supplementation with lactoferrin of different iron saturation on the manufacturing and characteristics of yogurt. Bovine lactoferrin was added at concentrations of 0.5, 1, and 2 mg/mL in the holo (iron saturated) and apo (without iron) forms. Some physicochemical properties, such as pH, concentra...

The effect of different heat treatments on the antimicrobial activity of bovine lactoferrin against Escherichia coli O157:H7, Salmonella enteritidis and Listeria monocytogenes has been studied. We have observed that the heat treatments lower than 85°C for 10 min did not affect the antibacterial activity of the protein. Hydrolysates of bovine lactof...

The aim of this work was to study the in vitro digestion of Cry1A(b) protein by pepsin. To perform this work, a protein fraction purified from transgenic maize by immunoadsorption was employed. The undigested fraction showed several bands of molecular weight ranging between 14 and 70 kDa when assayed by SDS-PAGE. These bands were identified as corr...

The possibility of using recombinant human lactoferrin from rice (rhLF) makes it necessary to study its differences from the protein of milk. In this work, the binding of different iron-saturated forms of rhLF to Caco-2 cells was studied. Iron-saturated rhLF bound in higher proportion than the apo-form, but, the data obtained for specific binding w...

The effect of pulsed electric field (PEF) processing on denaturation of bovine whey proteins has been studied. Protein concentration was determined by radial immunodiffusion and lactoperoxidase activity by a spectrophotometric technique. For the five proteins studied (beta-lactoglobulin, alpha-lactalbumin, lactoperoxidase, IgG and lactoferrin), no...

Clostridium tyrobutyricum is the main agent responsible for "late blowing" in cheese, which causes severe economic losses. Nowadays, the reference method for its detection is the Most-Probable-Number (MPN); however, it is time consuming and non-specific. Thus, in order to check milk contamination with spores of C. tyrobutyricum, a more specific and...

Milk proteins have many functional properties, making them valuable food ingredients. However, they are a frequent cause of food allergy, especially in children. The aim of the present work was to develop and evaluate two immunoassays (indirect competitive and double antibody sandwich formats) for the detection of undeclared milk proteins in foods....

The antibacterial activity of recombinant human lactoferrin from rice (rhLF) compared with that of human milk lactoferrin (hLF) was evaluated against Escherichia coli O157:H7, Salmonella Enteritidis and Listeria monocytogenes. The hydrolysates of rhLF and hLF were found to be more active than native proteins against E. coli O157:H7, and their activ...

The present work investigates the feasibility of using flow cytometry (FCM) combined with fluorescent-labelled specific polyclonal antibodies for the detection and presumptive identification of Clostridium tyrobutyricum spores in bovine milk. Two fluorescent molecules (fluorescein isothiocyanate and Alexa Fluor 488) were conjugated to antispores po...

The activity of human milk on cell growth has been evaluated on two cell lines, MDCK and Caco-2. The proportion of human milk samples that reduced by half the growth of MDCK cells was of 36%. This inhibitory activity was associated with casein and not the whey fraction. Great variability was found in the degree of inhibitory activity depending on t...

Immunoassays are used to screen for the presence of genetically modified organisms in raw materials. However, processing may condition the usefulness of immunoassays to analyse genetically modified foods because it leads to protein denaturation that affects recognition by antibodies. We studied the effect of processing on the detection of Cry1A(b)...

The antibacterial activity of human lactoferrin from milk (hLF), recombinant human lactoferrin from Aspergillus awamori (rhLF) and their hydrolysates obtained with pepsin was investigated against Escherichia coli O157:H7, Salmonella Enteritidis and Listeria monocytogenes. The minimum inhibitory concentrations (MIC) and the minimum bactericidal conc...

Enzyme-linked immunosorbent assay (ELISA) kits (indirect competitive and sandwich formats) to determine either β-lactoglobulin or ovomucoid were evaluated in model foods. A cut-off value was established for each kit to consider food samples as positive for milk or egg addition. Sausage and bread were positive at lower percentages of added milk usin...