Characterization and improvement of rheological properties of sodium caseinate glycated with galactose, lactose and dextran

10 páginas, 7 figuras, 2 tablas.-- El pdf del artículo es la versión de autor.The aim of this work was to investigate the effect of non-enzymatic glycosylation with galactose, lactose, and 10 kDa dextran on the rheological properties of sodium caseinate. To promote the formation of covalent complexes, the reaction was done in solid state (aw = 0.67), pH 7.0 (0.1 M sodium phosphate buffer), and temperature set at 50 and 60 °C. The progress of Maillard reaction was indirectly traced by measuring the formation of the Amadori compound, through furosine (2-furoylmethyl-lysine) analysis, and brown polymers, and the resulting glycoconjugates were characterized by LC/ESI-MS and SEC. Results showed a higher reactivity of galactose than lactose and dextran to form the glycoconjugates, due to its smaller molecular weight. Glycation with galactose and lactose increased the viscosity of caseinate and also altered its flow characteristics from Newtonian to shear-thinning. Oscillatory testing showed a higher elastic modulus (G′) in glycoconjugates when compared to non-glycated caseinate, especially with galactose, where a gel-like behaviour was observed after long incubation times. Glycation with dextran did not produce substantial improvements in the rheological properties of caseinate, probably due to the limited extent of the reaction. Our results show that by controlling the rate and extent of the Maillard reaction is a technologically feasible operation to improve the viscosity and gelling properties of sodium caseinate-based ingredients.This work was supported by projects Consolider Ingenio 2010 FUN-C-FOOD CSD2007-00063 (Ministerio de Educación y Ciencia), ALIBIRD S-0505/AGR/000153 (Comunidad de Madrid) and Hatch project TEN00332 (University of Tennessee Institute of Agriculture). M. Corzo-Martínez thanks the CSIC for an I3P PhD-grant.Peer reviewe

Functionality of glycomacropeptide glycated with lactose and maltodextrin

The Maillard reaction (MR), under proper environmental conditions, has been used to improve protein functionality. In the present work, 2 high temperatures (50–80°C) and water activity (Aw; 0.45–0.67) were used to promote exogenous glycosylation of glycomacropeptide (GMP) while minimizing processing times (0, 8, 24, 48, and 96 h at 50°C; 0, 2, 4, 8, and 24 h at 80°C). Maltodextrin, a polysaccharide commonly used in the food industry as a functional ingredient, was used as a reducing sugar, and compared with lactose, a native milk sugar. The progression of MR was evaluated by tracking changes in molecular weight using SDS-PAGE, the formation of Amadori compounds, and browning. Aqueous glycosylated GMP solutions (5 to 20% wt/vol) were tested for solubility, rheological properties, and foam formation. As expected, MR progression was faster with Aw = 0.67 and 80°C. Glycosylated GMP powders showed no change in their solubility after MR. However, the apparent viscosity of the 20% wt/vol suspensions exhibited a slight increase when GMP was glycosylated with maltodextrin for 24 h at 80°C, and a 2-log increase when GMP was glycosylated with lactose, with a high browning development in both cases. The foam expansion index of the resuspended glycosylated powders was increased by between 25 and 66% compared with the nonglycosylated powders. Better foam stability (approximately 2 h) and no browning development were observed for GMP glycosylated with maltodextrin for 2 h at Aw = 0.67 and 80°C. The results show that GMP has undergone further glycosylation by means of controlled MR, which improves viscosity and foaming index without negatively affecting solubility. These preliminary studies provide a basis for the future creation of a new ingredient with GMP and reducing sugars

Peri-operative red blood cell transfusion in neonates and infants: NEonate and Children audiT of Anaesthesia pRactice IN Europe: A prospective European multicentre observational study

BACKGROUND: Little is known about current clinical practice concerning peri-operative red blood cell transfusion in neonates and small infants. Guidelines suggest transfusions based on haemoglobin thresholds ranging from 8.5 to 12 g dl-1, distinguishing between children from birth to day 7 (week 1), from day 8 to day 14 (week 2) or from day 15 (≥week 3) onwards. OBJECTIVE: To observe peri-operative red blood cell transfusion practice according to guidelines in relation to patient outcome. DESIGN: A multicentre observational study. SETTING: The NEonate-Children sTudy of Anaesthesia pRactice IN Europe (NECTARINE) trial recruited patients up to 60 weeks' postmenstrual age undergoing anaesthesia for surgical or diagnostic procedures from 165 centres in 31 European countries between March 2016 and January 2017. PATIENTS: The data included 5609 patients undergoing 6542 procedures. Inclusion criteria was a peri-operative red blood cell transfusion. MAIN OUTCOME MEASURES: The primary endpoint was the haemoglobin level triggering a transfusion for neonates in week 1, week 2 and week 3. Secondary endpoints were transfusion volumes, 'delta haemoglobin' (preprocedure - transfusion-triggering) and 30-day and 90-day morbidity and mortality. RESULTS: Peri-operative red blood cell transfusions were recorded during 447 procedures (6.9%). The median haemoglobin levels triggering a transfusion were 9.6 [IQR 8.7 to 10.9] g dl-1 for neonates in week 1, 9.6 [7.7 to 10.4] g dl-1 in week 2 and 8.0 [7.3 to 9.0] g dl-1 in week 3. The median transfusion volume was 17.1 [11.1 to 26.4] ml kg-1 with a median delta haemoglobin of 1.8 [0.0 to 3.6] g dl-1. Thirty-day morbidity was 47.8% with an overall mortality of 11.3%. CONCLUSIONS: Results indicate lower transfusion-triggering haemoglobin thresholds in clinical practice than suggested by current guidelines. The high morbidity and mortality of this NECTARINE sub-cohort calls for investigative action and evidence-based guidelines addressing peri-operative red blood cell transfusions strategies. TRIAL REGISTRATION: ClinicalTrials.gov, identifier: NCT02350348

Choline and Choline Metabolite Patterns and Associations in Blood and Milk during Lactation in Dairy Cows

Milk and dairy products are an important source of choline, a nutrient essential for human health. Infant formula derived from bovine milk contains a number of metabolic forms of choline, all contribute to the growth and development of the newborn. At present, little is known about the factors that influence the concentrations of choline metabolites in milk. The objectives of this study were to characterize and then evaluate associations for choline and its metabolites in blood and milk through the first 37 weeks of lactation in the dairy cow. Milk and blood samples from twelve Holstein cows were collected in early, mid and late lactation and analyzed for acetylcholine, free choline, betaine, glycerophosphocholine, lysophosphatidylcholine, phosphatidylcholine, phosphocholine and sphingomyelin using hydrophilic interaction liquid chromatography-tandem mass spectrometry, and quantified using stable isotope-labeled internal standards. Total choline concentration in plasma, which was almost entirely phosphatidylcholine, increased 10-times from early to late lactation (1305 to 13,535 µmol/L). In milk, phosphocholine was the main metabolite in early lactation (492 µmol/L), which is a similar concentration to that found in human milk, however, phosphocholine concentration decreased exponentially through lactation to 43 µmol/L in late lactation. In contrast, phosphatidylcholine was the main metabolite in mid and late lactation (188 µmol/L and 659 µmol/L, respectively), with the increase through lactation positively correlated with phosphatidylcholine in plasma (R2 = 0.78). Unlike previously reported with human milk we found no correlation between plasma free choline concentration and milk choline metabolites. The changes in pattern of phosphocholine and phosphatidylcholine in milk through lactation observed in the bovine suggests that it is possible to manufacture infant formula that more closely matches these metabolites profile in human milk

Fatty acid profile and CLA isomers content of cow, ewe and goat milks processed by high pressure homogenization

High pressure homogenization (HPH) is a novel technology that promotes fat globule size reduction and microbial inactivation, but little research exists on the fate of milk fat lipids. This work studied the effect of HPH (0-350 MPa) of raw cow, goat and ewe milks on the fatty acid total content and profile to elucidate whether this technology has a major impact on the lipid fraction of milk and especially on CLA isomers. Fatty acids in processed milks were determined by GC-FID and CLA isomers by Ag+-HPLC. Our results indicate that the total amount of fat extracted from the milk samples decreased as the homogenization pressure increased, whereas no significant differences were found in the fatty acid composition, especially in the PUFA and CLA isomers profile of raw milk treated by HPH process up to 350 MPa. Industrial relevance: The absent of significant modifications of the fatty acids content and CLA isomers profile in milk by using high-pressure homogenization is relevant in the development of nonthermal technologies able to pasteurize/sterilize foods, without the organoleptic, functional, and chemical alterations associated to thermal processing. © 2008 Elsevier Ltd. All rights reserved.This is a collaborative study under a CYTED project 105PI0274 and was carried out with funds from the Comunidad Autónoma de Madrid (Project S-0505/AGR-0153) and the University of Tennessee Agricultural Experimental Station (Project UTIA-TEN00332).Peer Reviewe

Effect of glycation on sodium caseinate-stabilized emulsions obtained by ultrasound

5 páginas, 3 figuras, 4 tablas.This work explores the potential of high-intensity ultrasound to produce fine-dispersion, long-time-stable, oil-in-water emulsions prepared with native and glycated bovine sodium caseinate (SC). Regardless the ultrasound amplitude and time assayed, the sonicated emulsions of native SC at 0.5 mg/mL had much higher emulsifying activity indexes compared with those emulsions formed by Ultra-Turrax (IKA Werke GmbH & Co., Staufen, Germany) homogenization. Nevertheless, the native SC emulsions were very unstable despite the optimization of parameters such as protein concentration, amplitude of ultrasound wave, and sonication time by using a Box-Behnken design. Early glycation of SC with either galactose, lactose, or 10 kDa dextran substantially improved both emulsifying activity and the stability, whereas at advanced stages of glycation, SC emulsions showed notably reduced emulsifying properties, likely because extensive glycation of SC promoted its polymerization mainly through covalent cross-linking, as was demonstrated by particle size measurements. The increase in particle diameter of glycoconjugates likely affected the diffusion of SC from bulk to the oil–water interface and slowed the reorientation process of the protein at the interface. These findings show that the combined effect of early-stage glycation of SC and high-intensity ultrasound as an emergent technique to form emulsions has the potential to provide improved emulsions that could be used in several food applications.This work was supported by Consolider Ingenio 2010 Programme FUN-C-FOOD CSD2007-00063 and project AGL2007-63462/ALI (Ministerio de Educación y Ciencia) and ALIBIRD S2009/AGR-1469 (Comunidad de Madrid).Peer reviewe

Enhanced foaming and emulsifying properties of high-pressure-jet-processed skim milk

The effect of high pressure jet (HPJ) processing on foaming and emulsifying properties of skim milk was studied. Viscosity of milk significantly increased at HPJ processing pressures ≥300 MPa and particle size distribution became bimodal for milk processed at 400 or 500 MPa. Cryo-electron microscopy of milk processed at 400 or 500 MPa showed formation of non-uniform aggregates of proteins, which were distinctly larger than intact casein micelles. HPJ processing markedly increased the foam expansion index of milk. In addition, significant increases in foam volume stability index and emulsion activity index were observed for milk following HPJ processing at ≥300 MPa. It is suggested that the structural modifications occurring in the micelles due to HPJ processing are primarily responsible for the observed changes in interfacial properties. The ability to modify key functional properties of milk by HPJ processing opens opportunities for milk-based novel ingredient manufacturing.This work was supported by the USDA National Institute of Food and Agriculture Federal Appropriations under Project PEN04565 and Accession number 1002916.Peer reviewe

Effect of dynamic high-pressure treatment on the interfacial and foaming properties of soy protein isolate-hydroxypropylmethylcelluloses systems

The objective of the work was to study the effect of dynamic high-pressure homogenization (HPH) on the interfacial and foaming properties of soy protein isolate (SP) and surface-active polysaccharides (E4M and E15) with different molecular weight. SP was dispersed with water (2% w/v) together with the polysaccharides (0.3% w/v) and subjected to high-pressure from 0 to 300 MPa, in 100 MPa intervals. After treatment, foam overrun by whipping method, viscosity, particle size distribution and surface pressure at 48 s of drop formation time, of systems were measured. The effect of HPH of these systems on foam overrun was not directly relation with the effect on the surface pressure at short adsorption time. The viscosity decrease may be explained some of the foaming results together with interfacial performance at longer adsorption time than 48 s which depend on the system and level of pressure applied. According to the polysaccharide used in this work, interactions between SP and polysaccharides apparently favour the foam overrun on untreated mixed systems; this effect was promoted using HPH particularly in the case of E15 at 300 MPa. The effect of SP–E4M was less pronounced from the one observed for E15. Thus, the molecular weight of polysaccharides is a very important factor of interaction with soy protein isolate under these conditions of high-pressure homogenization.Fil: Martínez, Karina Dafne. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Industrias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Ganesan, Vykundeshwari. University Of Tennessee; Estados UnidosFil: Pilosof, Ana Maria Renata. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Industrias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Harte, Federico M.. University Of Tennessee; Estados Unido

Solvent-Free Lipase-Catalyzed Synthesis of Technical-Grade Sugar Esters and Evaluation of Their Physicochemical and Bioactive Properties

Technical-grade oleic acid esters of sucrose and fructose were prepared using solvent-free biocatalysis at 65 °C, without any downstream purification applied, and their physicochemical and bioactivity-related properties were evaluated and compared to a commercially available sucrose laurate emulsifier. To increase the conversion of sucrose and fructose oleate, prepared previously using solvent-free lipase-catalyzed esterification catalyzed by Rhizomucor miehei lipase (81% and 83% ester, respectively), the enzymatic reaction conditions was continued using CaSO4 to control the reactor’s air headspace and a lipase (from Candida antarctica B) with a hydrophobic immobilization matrix to provide an ultralow water activity, and high-pressure homogenation, to form metastable suspensions of 2.0–3.3 micron sized saccharide particles in liquid-phase reaction media. These measures led to increased ester content of 89% and 96% for reactions involving sucrose and fructose, respectively. The monoester content among the esters decreased from 90% to <70% due to differences in regioselectivity between the lipases. The resultant technical-grade sucrose and fructose lowered the surface tension to <30 mN/m, and possessed excellent emulsification capability and stability over 36 h using hexadecane and dodecane as oils, comparable to that of sucrose laurate and Tween® 80). The technical-grade sugar esters, particularly fructose oleate, more effectively inhibited gram-positive foodborne pathogens (Lactobacillus plantarum, Pediococcus pentosaceus and Bacillus subtilis). Furthermore, all three sugar esters displayed antitumor activity, particularly the two sucrose esters. This study demonstrates the importance of controlling the biocatalysts’ water activity to achieve high conversion, the impact of a lipase’s regioselectivity in dictating product distribution, and the use of solvent-free biocatalysis to important biobased surfactants useful in foods, cosmetics, personal care products, and medicine