Water sorption isotherms of different sodium alginates : thermodynamic evaluation and influence of mannuronate-guluronate copolymers

Water desorption isotherms of three alginates with different structural features were determined at 25, 37, and 50°C. The Halsey model was selected to fit the equilibrium water sorption data. Differential and integral enthalpy and entropy were estimated for tested alginates. Optimal storage conditions of tested alginates (moisture content from 0.15 to 0.20 kg water/kg dry solid and relative humidity from 35% to 50%) were determined from the maximum and minimum integral enthalpy and entropy values, respectively. A model was proposed to estimate the water sorption isotherms of al-ginates based on the alginate monomers (mannuronate, M, and guluronate, G) at low water activity (<0.4). M fraction was mainly responsible for the hygroscopicity of algi-nates. Alginates with similar G fraction showed different hygroscopic features by the presence of more homopolymeric G blocks that could form helical structures at low moisture content, decreasing the water affinityAuthors acknowledge the financial support of the Spanish Ministry of Science and Innovation (Project RTI2018-095919-B-C2) and the European Regional Development Fund (FEDER) and Xunta de Galicia (Consolidation Project ED431B 2019/01)S

Determination of thermal transitions of gluten-free chestnut flour doughs enriched with brown seaweed powders and antioxidant properties of baked cookies

A protocol for determining the characteristic temperatures of thermomechanical transitions on gluten-free flour doughs is proposed. This protocol is based on the mathematical analysis of experimental curve of storage modulus (G0 ) vs temperature obtained by means of Dynamic Mechanical Thermal Analysis (DMTA) technique. Doughs at constant consistency of chestnut flour with different levels (3, 6 and 9% flour basis, f.b.) of brown seaweed (Bifurcaria bifurcata, Fucus vesiculosus and Ascophyllum nodosum) powders addition, 2% f.b. of guar gum and 1.8% f.b. of salt with different water absorption were used to test the proposed protocol. The ranges of temperatures corresponding to starch gelatinization (59–97 C), amylopectin crystallites melting (82–101 C), reversible dissociation of lipid-amylose complexes (107–128 C) and amylose melting (133–171 C) showed a strong dependence with water absorption of samples. Doughs with the same water absorption submitted to starch gelatinization during mixing were also analysed to corroborate the protocol suitability. Total polyphenols content and radical scavenging activity of extracts from chestnut flour-seaweed powder blends and seaweed-enriched chestnut cookies baked at 180 C were determined. Extraction assisted with ultrasounds was carried out employing acetone-water (70:30 v/v) solution as solvent during 4 min with a liquid/solid ratio of 30 w/w. Seaweed powder addition had a positive effect on antioxidant properties of doughs before baking. However, the seaweed powder addition effect on baked products (cookies) is not clear due to antioxidant activity is overlapped by Maillard's products generated during bakingThis work was supported by the Ministry of Economy and competitiveness of Spain and European Regional Development Fund (ERDF) of European Union by the research project (CTQ 2013–43616/P)S

Influence of Oxidation and Dialysis of Phlorotannins on Bioactivity and Composition of Ultrasound-Assisted Extracts from Ascophyllum nodosum

The isolation and chemical characterization of phlorotannins has gained special attention in recent years due to their specific health-promoting benefits. Flow-cell ultrasound-assisted extraction (90 W/cm2 of sonication power, 2 min of retention time and 20 g solvent/g algae of liquid–solid ratio) was carried out by using double-distilled water (WE) and acetone:water mixture (AWE) as extraction solvents. The AWE showed a higher total polyphenols content (TPC), carbohydrates (CHOs) and antioxidant activities than WE. However, when the WE was purified by using Amberlite XAD16 column, the purified WE (PWE) showed similar a TPC, decreased CHOs and increased antioxidant activity compared to WE. The oxidation of the PWE extract was evaluated under natural, forced and severe oxidation condition for 120 h. Only severe oxidation conditions were able to significantly reduce TPC and antioxidant activities. PWE was dialyzed (20, 10, 3.5 and 2 kDa). The main bioactive fraction of phlorotannins was obtained from 10 to 20 kDa. CHOs were distributed in fractions below 20 kDa. MALDI-TOF analysis was performed for PWE, PD20 and PD2 extracts to analyze the degree of polymerization of phlorotannins, which ranged from 4 to 17 phloroglucinol units/molecule. Fragmentation patterns allowed the proximate identification of several phlorotannins in Ascophyllum nodosum extractsThis work was supported by the Ministry of Science and Innovation of Spain and European Regional Development Fund (ERDF) of European Union by the research project (RTI2018–095919–B–C2R) and Xunta de Galicia, Spain (Consolidation Project ED431B 2019/01).S

Impact of drying on the sodium alginate obtained after polyphenols ultrasound-assisted extraction from Ascophyllum nodosum seaweeds

Ultrasound-assisted extraction (UAE) of polyphenols from the brown seaweeds Ascophyllum nodosum leaves a solid phase where alginates can be extracted. This study characterizes alginates extracted after the UAE process, with and without an intermediate drying stage at different temperatures (50 and 90 °C) producing sequentially two bioactive compounds from a unique raw material. FT-IR and 1H NMR analyses showed the high purity of alginates with features in the range of commercial alginates. Drying at high temperature decreased average block length and viscosity average molecular weight (Mv) of alginate from 428 to 133 kg/mol. Steady-shear curves (shear-thinning behaviour) and viscoelasticity (liquid like character) features depended clearly on Mv. Solutions of alginates with high Mv were more viscous and the elastic character was more relevant. Cox-Merz rule was only accomplished within the semi-dilute regimes of alginate concentration. Tested process conditions allow the production of alginates with different propertiesS

Antioxidant and Antidiabetic Properties of Phlorotannins from Ascophyllum nodosum Seaweed Extracts

Seaweeds have gained considerable attention in recent years due to their potential health benefits and high contents of bioactive compounds. This review focuses on the exploration of seaweed’s health-promoting properties, with particular emphasis on phlorotannins, a class of bioactive compounds known for their antioxidant and antidiabetic properties. Various novel and ecofriendly extraction methods, including solid–liquid extraction, ultrasound-assisted extraction, and microwave-assisted extraction are examined for their effectiveness in isolating phlorotannins. The chemical structure and isolation of phlorotannins are discussed, along with methods for their characterization, such as spectrophotometry, nuclear magnetic resonance, Fourier transform infrared spectroscopy, and chromatography. Special attention is given to the antioxidant activity of phlorotannins. The inhibitory capacities of polyphenols, specifically phlorotannins from Ascophyllum nodosum against digestive enzymes, such as α-amylase and α-glucosidase, are explored. The results suggest that polyphenols from Ascophyllum nodosum seaweed hold significant potential as enzyme inhibitors, although the inhibitory activity may vary depending on the extraction conditions and the specific enzyme involved. In conclusion, seaweed exhibits great potential as a functional food ingredient for promoting health and preventing chronic diseases. Overall, this review aims to condense a comprehensive collection of high-yield, low-cost, and ecofriendly extraction methods for obtaining phlorotannins with remarkable antioxidant and antidiabetic capacities.This work was funded by the Ministry of Science and Innovation of Spain and European Regional Development Fund (ERDF) of European Union by the research project (RTI2018-095919-B-C2).S

Performance of Starch Gels on In Vitro Enzymatic Hydrolysis Assessed by Rheological Methodologies

Starch hydrolysis is attracting much attention due to its relationship to digestion and glucose release. The objective is to propose rapid and continuous analytical methods that allow measuring gels hydrolysis following apparent viscosity (μ). Three different starches (corn, wheat, and rice) are tested recording starch gelatinization followed by gels digestions (digestograms) using a rapid-visco analyzer (RVA) or a rheometer. Results are compared with those obtained by measuring glucose release along hydrolysis. A modified first-order kinetic model in the RVA (R2 > 0.99) and rheometer (R2 > 0.99) describes the gels digestograms. Wheat gel shows a higher hydrolysis rate (k), which indicates faster digestion followed by rice and corn gels. The proposed models allow rapid analysis of starch digestograms, allowing to discriminate among hydrolysis rate of different starches. These less time-consuming methods can be an option to continuously analyze starch gelatinization followed by enzymatic digestion.Generalitat Valenciana (Prometeo 2017/189) and Xunta de Galicia (Consolidation Project ED431B 2019/01).S

Osmotic dehydration of chestnut using static and dynamic media of salt, sucrose and glucose

Se estudió la deshidratación osmótica de la castaña en disoluciones acuosas de sal (17, 22, 26,5 % p/p), sacarosa (40, 50, 60 % p/p) y glucosa (40, 50, 56,5 % p/p) a diferentes grados de agitación (0, 40, 110 rpm) y tiempos (1, 2, 4, 8 h) a 20 ºC. En las disoluciones de glucosa se estudió el efecto de la temperatura (50 ºC). Se determinaron los parámetros cinéticos de ganancia de sólidos, pérdida de agua, reducción de peso y relación pérdida de agua-ganancia de sólidos. Al aumentar la agitación, aumentó la ganancia de sólidos, la pérdida de agua y disminuyó la relación entre ambos, especialmente cuando las disoluciones tuvieron elevada viscosidad. Las cinéticas de los contenidos de humedad y de sólidos se modelizaron mediante la ecuación de Hawkes y Flink para tiempos cortos. Se determinaron los coeficientes de transferencia para el agua y el soluto osmótico y los coeficientes de difusividad mediante la ley de Fick.Chestnut fruits were submitted to osmotic dehydration in sodium chloride (17, 22, 26.5 % w/w), sucrose (40, 50, 60 % w/w) and glucose (40, 50, 56.5 % w/w) solutions at different stirring rates (0, 40, 110 rpm) and periods of time (1, 2, 4, 8 h) at 20 ºC. The effect of temperature (50 ºC) was studied in the case of samples dehydrated with glucose solutions. Several parameters for each dehydration process such as solids gain, water loss, and its corresponding ratio and weight reduction, were determined. High stirring rates increased solids gain and decreased water loss and its ratio, especially in the case of solutions of high viscosity. Moisture and solids gain contents were modelled by Hawkes and Flink equation for short times and water and osmotic solute transfer coefficients were calculated. The corresponding effective coefficients of diffusion were also evaluated by means of Fick’s law.Los autores agradecen a la Xunta de Galicia (España) y a FEDER el apoyo parcial con el proyecto PGIDIT04TAL265004PRS

Clonal chromosomal mosaicism and loss of chromosome Y in elderly men increase vulnerability for SARS-CoV-2

The pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2, COVID-19) had an estimated overall case fatality ratio of 1.38% (pre-vaccination), being 53% higher in males and increasing exponentially with age. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, we found 133 cases (1.42%) with detectable clonal mosaicism for chromosome alterations (mCA) and 226 males (5.08%) with acquired loss of chromosome Y (LOY). Individuals with clonal mosaic events (mCA and/or LOY) showed a 54% increase in the risk of COVID-19 lethality. LOY is associated with transcriptomic biomarkers of immune dysfunction, pro-coagulation activity and cardiovascular risk. Interferon-induced genes involved in the initial immune response to SARS-CoV-2 are also down-regulated in LOY. Thus, mCA and LOY underlie at least part of the sex-biased severity and mortality of COVID-19 in aging patients. Given its potential therapeutic and prognostic relevance, evaluation of clonal mosaicism should be implemented as biomarker of COVID-19 severity in elderly people. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, individuals with clonal mosaic events (clonal mosaicism for chromosome alterations and/or loss of chromosome Y) showed an increased risk of COVID-19 lethality

Heterogeneous contributions of change in population distribution of body mass index to change in obesity and underweight NCD Risk Factor Collaboration (NCD-RisC)

From 1985 to 2016, the prevalence of underweight decreased, and that of obesity and severe obesity increased, in most regions, with significant variation in the magnitude of these changes across regions. We investigated how much change in mean body mass index (BMI) explains changes in the prevalence of underweight, obesity, and severe obesity in different regions using data from 2896 population-based studies with 187 million participants. Changes in the prevalence of underweight and total obesity, and to a lesser extent severe obesity, are largely driven by shifts in the distribution of BMI, with smaller contributions from changes in the shape of the distribution. In East and Southeast Asia and sub-Saharan Africa, the underweight tail of the BMI distribution was left behind as the distribution shifted. There is a need for policies that address all forms of malnutrition by making healthy foods accessible and affordable, while restricting unhealthy foods through fiscal and regulatory restrictions

Polyphenols extraction kinetics from Ascophyllum nodosum seaweed employing water and saltwater: effect of ultrasound sonication

Saltwater (S), with the same ionic strength of seawater, was employed as solvent to extract polyphenols from seaweeds. Aqueous extracts were chemically characterized by means of total polyphenols (TPC), carbohydrates (CHOS) and uronic acids (UA) content and antioxidant capacities (DPPH, ABTS and FRAP). S-extracts showed lower TPC than those obtained with distilled water (D) using two different extraction methods, conventional solid-liquid extraction (SLE) and ultrasound-assisted extraction (UAE). The antioxidant capacities of both non-sonicated extracts did not show significant (p < 0.05) differences. SLE kinetics employing both solvents (D and S) were successfully modelled by Peleg's model, and equilibria were achieved after 15 min. Long-time UAE (15 min) increased phytochemical content in both D- and S-extracts with respect to SLE. Extracts showed three main (A, B, and C) regions from RP-HPLC profiles with different peak areas and shapes. Normalized regions areas from RP-HPLC were related to antioxidant activities by linear regressions and showed that B-region was the main responsible of phytochemical features of the extracts. SLE with saltwater promoted the leaching of other compounds (mainly proteins) that formed intermolecular complexes. These interactions were notoriously diminished with UAE. At these conditions, saltwater can be employed as eco-friendly solvent according to the green chemistry principlesS