J.L. Rodríguez-Otero

• PhD
• Research Director at University of Santiago de Compostela

The use of flours as a material for biopolymer-based film preparation has gained interest due to the fact that they are a natural mixture of compatible macromolecules and due to their low cost. Chickpea flour shows a promising composition for the development of edible films. The aim of this study was to characterize and evaluate the properties of c...

In this study, we report on the evolution of phospholipid contents and their distribution in cheese and whey, during the production of fresh cheese. We found that the phospholipid content in the total mass of whey and fresh cheese together was greater than the content of phospholipids in the starting milk used to make them. This increase was probab...

We report the evolution of phosphatidylethanolamine (PE), phosphatidylinositol (PI), phosphatidylcholine (PC), phosphatidylserine (PS), and sphingomyelin (SM) contents during the production of quark cheese from buttermilk by successive ultrafiltration concentration, enrichment with cream, concurrent homogenization and pasteurization, fermentative c...

The international standard method for the determination of trypsin inhibitor activity (TIA) in soya products, ISO 14902, was compared with the American Association of Cereal Chemists' standard AACC 22-40.01 as modified by Hamerstrand in 1981 (AACC-based method), using soybean meals as matrices. TIA, expressed as milligram of inhibited trypsin per g...

The objective of this study was to compare the phospholipid content of conventional milk with that of organic milk and milk rich in conjugated linoleic acid (CLA). The membrane enclosing the fat globules of milk is composed, in part, of phospholipids, which have properties of interest for the development of so-called functional foods and technologi...

Obtaining a high milk quality is dependent on what happens during its production at dairy farms. The hazard analysis and critical control points (HACCP) methodology has been developed and implemented on dairy cattle farms. This system focuses on the influence that milking equipment and cooling tank have on the milk quality. The hazards related to t...

Bacteria from genera Listeria, Campylobacter and Arcobacter are potentially zoonotic pathogens for humans and they may be detected in dairy cattle farms. In this study the presence of these bacteria was considered in dairy cattle farms in Galicia (northwest of Spain). In the first part of the study, bulk tank milk samples were collected to determin...

The ATP bioluminescence method was used to evaluate the cleanliness of milking equipment surfaces (teat cup rubbers, teat dip containers, milk receivers, and pipeline joints) in dairy farms in Galicia (northwest Spain) with parlour, pipeline tie-stall or bucket tie-stall milking systems. The cleanest surfaces were teat cup rubbers. The use of non-c...

This cross-sectional study determined the prevalence of Listeria spp. in bulk-tank milk on dairy farms in the region of Galicia in northwest Spain. The aim was to identify management practices associated with the presence of Listeria spp. and possible effects on milk hygienic quality. A total of 98 farms was randomly selected on the basis of an exp...

A total of 311 samples of 10 mL for liquids and 400-cm2 for surfaces were analyzed in a cheese plant in Galicia (Spain) within a period of 10 months (Feb.-Nov. 1996). Forty-six samples were positive for Listeria spp., 36 of which corresponded to L. innocua, 8 to L. monocytogenes and 2 to L. welshimeri. Twenty percent of raw milk samples were Lister...

A total of 54 rabbits 50, 70 and 90 days old, were taken from farms in Galicia (NW Spain); 18 rabbits of each age were sampled. The minerals in the muscle meat from the back legs of the rabbits were analysed, and the following average concentrations were found: ash 1.21/100g, potassium 388mg/100g; phosphorus 237mg/100g; sodium 60mg/100g; magnesium...

The presence of moisture, starch, protein, and fat was determined in common beans (Phaseolus vulgaris L.) by near infrared (NIR) spectroscopy without any previous sample pretreatment except grinding. A set of 96 samples was used to calibrate the instrument by modified partial least-squares regression. The following statistical results were achieved...

Total nitrogen, soluble nitrogen (SN), nonprotein nitrogen (NPN), and acid-detergent insoluble nitrogen (ADIN) were analyzed in grass silage by near-infrared (NIR) spectroscopy. A set of 144 samples was used to calibrate the instrument by modified partial least-squares regression, and the following statistical results were achieved: standard error...

Fourteen batches of Tetilla, a short-ripening cows-milk cheese produced in Galicia (NW Spain), were prepared from pasteurized milk inoculated with autochthonous cultures isolated from Tetilla raw milk cheeses. Two batches were made with an acid-aromatic starter containing Lactococcus lactis subsp. lactis and Lactococcus lactis subsp. lactis var. di...

Resumen Resumo The fungal contamination in 10 farm-level cheesemaking units from Arzúa (A Coruña, Spain) throughout a year was studied. The greatest number of different genera were found in the air and, although in lesser amounts, in the cheese. The isolation frequency for the most representative genera in cheese were Rhizopus (26,8%), Cladosporium...

NIR transflectance spectroscopy was used to determine polarimetric parameters (direct polarization, polarization after inversion, specific rotation in dry matter, and polarization due to nonmonosaccharides) and sucrose in honey. In total, 156 honey samples were collected during 1992 (45 samples), 1995 (56 samples), and 1996 (55 samples). Samples we...

The fungal contamination in 10 farm-level cheesemaking units from Arzúa (A Coruña, Spain) throughout a year was studied. The greatest number of different genera were found in the air and, although in lesser amounts, in the cheese. The isolation frequency for the most representative genera in cheese were Rhizopus (26,8%), Cladosporium sp. (22,5%), G...

The microbiological, chemical and biochemical characteristics of Tetilla raw cow's-milk cheese produced in Galicia (NW Spain) were studied. The identification of the main microbial groups of technological interest was carried out. Mean log mesophilic counts, lactic acid bacteria on M17, citrate-utilizing bacteria and enterococci in 24 cheese sample...

Moisture, solids-non-fat and fat were analysed in butter by near infrared (NIR) spectroscopy without any previous sample treatment. A set of 102 samples was used to calibrate the instrument by modified partial least-squares regression. The following statistical results were achieved: standard error of calibration (SEC)=0.192 and square correlation...

NIR transflectance spectroscopy was used to analyze fructose, glucose, and moisture in honey. A total of 161 honey samples were collected during 1992 (46), 1995 (58), and 1996 (57). Samples were analyzed by instrumental, enzymatic (fructose and glucose), and refractometric (moisture) methods. Initially, different calibrations were performed for eac...

The Direct Epifluorescent Filter Technique (DEFT) and the reference method of counting total bacterial colonies on Petri dishes were compared. IDF Standards 128 (1985) and 161A (1995) were applied. A total of 496 samples of milk were analyzed. Colony forming units per microL milk were transformed to decimal logarithmic units: log (cfu/microL). The...

Seven batches of Arzúa-Ulloa, a short-ripened soft cow's milk cheese produced in Galicia (NW Spain), were prepared from pasteurized milk. Two control batches of cheese (CB) were made with an acid-aromatic starter containing Lactococcus lactis subsp. lactis and Lactococcus lactis subsp. lactis var. diacetylactis, isolated from raw-milk Arzúa-Ulloa c...

Ten batches of Cebreiro, a fresh or short-ripened acid-curd cheese, produced in the Galician mountains (NW Spain) were prepared from pasteurized milk inoculated with microorganisms isolated from raw-milk cheese. Two control batches were made with a Lactococcus lactis subsp. lactis starter; 8 batches were made with the lactococcal starter plus one o...

The Meatspec (Foss Electric, Hillerød, Denmark) is a near infrared spectrophotometer designed for analysing meat and meat products. The purpose of this study is to evaluate the application of this equipment to analyse major components in cheese; therefore, the instrument was calibrated with cheese samples analysed by the reference methods. Standard...

Near-infrared spectroscopy analysis of foodstuffs is a relatively recent technique. Its principal advantage is speed of analysis, and it does not require sample pretreatment either. In this paper we review its application to powder dairy products, liquid milk, cheese, butter, and fermented milk products, mainly from the analysis of the major compon...

The fat, protein and total solids in fermented milks were determined by near infrared transflectance spectroscopy. A set of 104 samples from different types of fermented milks: whole, skimmed, natural (without added flavours) and flavoured were used to calibrate the instrument by Modified Partial Least Square Regression (MPLS) and Multiple Linear R...

A total of 302 lactic acid bacteria (LAB) isolates were obtained from samples taken at various stages during manufacture and ripening of Arzu´a cheese (a traditional raw cows' milk cheese from northwest Spain). Of the 302 isolates, 121 were identified as Lactococcus lactis subsp. lactis, 49 as Lactobacillus casei, six as Lb. plantarum, 49 as Leucon...

Thirty samples of Cebreiro, a fresh or short-time-ripened raw cow's-milk cheese produced in Northwest Spain, were analyzed for the presence of aerobic mesophilic bacteria, (AMC) lactic acid bacteria (LAB), enterococci and Micrococcaceae. Mean AMC and LAB counts exceeding 10(9)/g were higher than those reported for other fresh or short-time-ripened...

Ten batches of Arzúa, a soft cow's-milk cheese produced in northwest Spain, were prepared from pasteurized milk. Two (control) batches (CB) were made with a commercial starter containingLactococcus lactis subspecieslactis andcremoris. Another eight batches (MB) were made with the commercial starter plus one of eightMicrococcus spp. strains previous...

Fat, protein, and total solids in fermented milk were determined by near-infrared reflectance spectroscopy (NIRS). A set of 107 samples from diverse types of fermented milk (whole, skimmed, with added flavors, and without added flavors) were used to calibrate the instrument by modified partial least-square regression. Global calibration, using all...

The presence of Listeria spp. in chicken drumsticks, wings, breasts, and livers taken from a poultry processing plant was investigated. The poultry pieces found to be most contaminated were drumstick meat and skin, with 96% of samples shown to contain Listeria spp. Drumsticks contained the highest number of Listeria spp., with counts in many cases...

Four hundred ten strains of Penicillium and 120 strains of Aspergillus isolated from air, surfaces, and cheese, in 10 farm-level cheesemaking farm units from Arzúa (La Coruña, Spain) were classified. The mycotoxin production using the APA medium and thin-layer chromatography was proved. With respect to the production of aflatoxins, 19% from Aspergi...

Near-infrared reflectance (NIR) spectroscopy was used to analyze fat, protein, and total solids in cheese without any sample treatment. A set of 92 samples of cow's milk cheese was used for instrument calibration by principal components analysis and modified partial least-square regression. The following statistical values were obtained: standard e...

Silicon, phosphorus, sulphur, chlorine and ash contents were determined in samples of 24 Spanish commercial honeys. Mean contents (mg/kg of honey) were 3.2 for silicon, 78 for phosphorus, 45 for sulphur and 262 for chlorine. The values for phosphorus and chlorine are high with respect to honeys from other regions. Mean ash content was 0.19%. In all...

152 enterococcal isolates and 88 micrococcal isolates obtained from secondary microflora of Arzúa raw cows'-milk cheese at various stages of ripening were characterized. The most frequent Enterococcus specie was E. faecalis. The most frequent Micrococcus specie was M. varians, followed by M. luteus and M. lylae; 27 micrococcal isolates could not be...

Silicon, phosphorus, sulphur, chlorine and ash contents were determined in samples of 24 Spanish commercial honeys. Mean contents (mg/kg of honey) were 3.2 for silicon, 78 for phosphorus, 45 for sulphur and 262 for chlorine. The values for phosphorus and chlorine are high with respect to honeys from other regions. Mean ash content was 0.19%. In all...

Sodium, potassium, calcium, magnesium, copper, iron, manganese, phosphorus (phosphate), chlorine (chloride), silicon (silica), sulphur (sulphate), and ash contents of 91 samples of raw honey from Galicia (NW Spain) were determined. The mean ash content was 0.408%. Potassium was the most abundant of the elements determined, with an average content o...

The agar dilution method was used to determine the activities of gentamicin, erythromycin, streptomycin, chloramphenicol, ampicillin, sulfamethazine, cephalothin, penicillin G, and tetracycline against 73 strains belonging to the genus Listeria (L. innocua, L. seeligeri, and L. monocytogenes). All strains were isolated from raw milk, cheese, the da...

Changes during production and ripening in the microbial flora of 11 batches of Arzúa, a soft cheese made from raw cow's milk, were investigated. The following microbial groups were counted on the surface and interior of the cheese: total viable count (TVC), lactic acid bacteria (LAB), halotolerant flora, enterococci, proteolytic enterococci, staphy...

Cebrero cheese is traditionally manufactured from raw cow's milk in the Cebrero mountains of Galicia (NW Spain). We report determinations of pH and aw, and counts of total aerobic bacteria, psychrotrophs, Enterobacteriaceae, Escherichia coli, coagulase-positive Staphylococcus aureus, Listeria, molds and yeasts, in 49 samples. E. coli count exceeded...

Sodium, potassium, calcium, magnesium, copper, iron and manganese contents, total ash content and total cationic milliequivalents in 21 samples of Spanish commercial honeys were determined after calcination of the samples and dissolution of the ash obtained in 0.1 N hydrochloric acid. Sodium and potassium concentrations were determined by atomic em...

Addn. of urea to milk increased the apparent protein content detd. by the Kjeldahl procedure but not by IR spectrometry. A com. enzyme kit (Boehringer) specific for urea can be used to complement the Kjeldahl anal.

Sodium, potassium, calcium, magnesium, copper, iron and manganese contents, total ash content and total cationic milliequivalents in 21 samples of Spanish commercial honeys were determined after calcination of the samples and dissolution of the ash obtained in 0.1 N hydrochloric acid. Sodium and potassium concentrations were determined by atomic em...

RESUMEN Se ha desarrollado un método de valoración de la cafeína contenida en cafés verdes y de tueste natural por espectrofotometría ultravioleta (UV). El método supone la clarificación de las muestras con óxido de magnesio ligero y posterior extracción y purificación con minicolum-nas Sep Pak C18. El método propuesto es sencillo, rápido y preciso...

Las muestras son tratados por óxido de Mg. La extracción y la purificación son efectuadas en cartucho Sep Pak. El porcentaje de recuperación es de 100%. Los resultados obtenidos concuerdan con los del micrométodo Bailey-Andrew (AOAC). La técnica presentada es simple, precisa y fiable

Se han separado las distintas fracciones proteicas de la miel mediante electroforesis en gel de poli~crilamida (según el método de AcROYD, 1968), habiéndose obtenido hasta 23 fracciones distintas. Al aplicar el programa BMDP7M de análisis discriminante a las movilidades relativas de las distintas fracciones proteicas de mieles naturales de Galicia...

SE LLEVA A CABO EL ESTUDIO DE DISTINTOS ELEMENTOS MINERALES: NA, K, CA, MG, CU, FE, SI, MN, CL Y S, ASI COMO EL CONTENIDO EN CENIZAS Y LA DETERMINACION DE LOS MILIEQUIVALENTES CATIONICOS TOTALES. SE HACE ASIMISMO UN ESTUDIO DE LA SEPARACION DE LAS DISTINTAS FRACCIONES PROTEICAS, MEDIANTE ELECTROFORESIS EN GEL DE POLIACRILAMIDA. TAMBIEN SE HACE LA C...

PALABRAS CLAVE: Miliequivalentes catiónicos, leche, leche en polvo. Espectro fotometría de emisión atómica. · RESUMEN: P. Paseiro, J. Simal, J. L. Rodríguez Otero y Ma Isabel Estévez. -1983- Miliequivalentes catiónicos en leches y leches en polvo.- Trabajos Compostelanos Biol. 10: 5-14 (1983) Se estudian los cationes, mediante espectrofotometría de...