Monitorization of hexanal as lipid oxidation indicator in a processed meat product packaged with poly(lactic acid)/clay nanocomposite films

One of the most detrimental processes in fatty foodstuffs is lipid oxidation, which occurs during production and storage, and influences food composition and safety. Through the analysis of volatile lipid oxidation products we can have an insight into the oxidation, and some volatiles, such as hexanal, which can be markers of undergoing oxidation processes. Hexanal is formed when fatty acids are oxidized and is one of many well-documented aromatic components that contributes to flavour and aroma in common food products containing fatty acids. During the last decade, the interest in polymer layered silicate (PLS) nanocomposites has rapidly increased due to their potential for enhancing physical, chemical, and mechanical properties of conventional materials. Polymer nanocomposites are represented by a polymeric matrix reinforced with nanoscale fillers, among them the most common silicate clays are represented by montmorillonite (MMT), which is naturally occurring and readily available in large quantities. The presence of MMT can lead to materials which generally exhibit great property enhancements, mainly due to its intercalation or exfoliation into the polymer chains. In this work natural MMT Cloisite Na+ was incorporated in PLA. The PLA/Cloisite® Na+ films were prepared through a two-step process. In the first step, PLA pellets were fed into a corotating laboratory twin-screw extruder at 170 °C and 50 rpm for 2 min. Subsequently, Cloisite® Na+ powder (5%, w/w) were added and mixed. After extrusion, the melted matter was then pressed with a P300P hot press at 170 °C and 100 bar to obtain the PLA/Cloisite® Na+ films. Salami slices were packaged with PLA-OMMT film and with a control film (PLA). After different storage times (0, 15, 30, 60 and 90 days), salami slices were analysed regarding their hexanal content. The hexanal derivatization was performed in a solution of 2,4-dinitrophenylhydrazine in sulfuric acid during 4 h in the dark, and the hexanal extraction was performed with n-hexane and evaporation till dryness. The residue was dissolved in methanol, filtered and analysed. The quantification of hexanal was performed by Ultra High Performance Liquid Chromatography coupled with Diode Array Detector at 365 nm, with a Pre-column AcquityTM UPLC® BEH C18 (2.1 x 5 mm, 1.7 μm particle size) and a column AcquityTM UPLC® BEH C18 (2.1 × 50 mm, 1.7 μm particle size), the mobile-phase was acetonitrile-water (75:25, v/v). The amount of hexanal in packaged salami decreased in the first 60 days of storage. In this period of time the hexanal content of the salami packaged with the PLA/Cloisite® Na+ films was lower than the salami packaged with control film, except after 15 days of storage, where there was no difference between two films. After 90 days of storage, the amount of hexanal in the samples increased, although it was higher in the samples packaged with control film (94.7 ± 6.02 μg/100g salami) than salami packaged with PLA/Cloisite® Na+ films (65.1 ± 6.12 μg/100g salami). The presence of MMT in the polymer film can reduce the lipid oxidation of processed meat products, extending their shelf life. Further studies to evaluate differences between PLA and the nanocomposite (PLA-5%Cloisite®Na+) in what regards to the mechanical and barrier properties are in progress.This work was supported by the research project “Labelling and tracking of nanoclay from food packaging nanocomposites: a food safety issue – NanoPack4Food” (2014DAN1019) under the Cooperative Programme of the Agreement on Scientific Cooperation between National Research Council of Italy (CNR) and Foundation for Science and Technology of Portugal (FCT)N/

Resistant Hypertension in Nondialysis Chronic Kidney Disease

Resistant hypertension (RH) is defined as blood pressure (BP) that remains above the target of less than 140/90 mmHg in the general population and 130/80 mmHg in people with diabetes mellitus or chronic kidney disease (CKD) in spite of the use of at least three full-dose antihypertensive drugs including a diuretic or as BP that reaches the target by means of four or more drugs. In CKD, RH is a common condition due to a combination of factors including sodium retention, increased activity of the renin-angiotensin system, and enhanced activity of the sympathetic nervous system. Before defining the hypertensive patient as resistant it is mandatory to exclude the so-called “pseudoresistance.” This condition, which refers to the apparent failure to reach BP target in spite of an appropriate antihypertensive treatment, is mainly caused by white coat hypertension that is prevalent (30%) in CKD patients. Recently we have demonstrated that “true” RH represents an independent risk factor for renal and cardiovascular outcomes in CKD patients

Functional Role of Natriuretic Peptides in Risk Assessment and Prognosis of Patients with Mitral Regurgitation

The management of mitral valve regurgitation (MR), a common valve disease, represents a challenge in clinical practice, since the indication for either surgical or percutaneous valve replacement or repair are guided by symptoms and by echocardiographic parameters which are not always feasible. In this complex scenario, the use of natriuretic peptide (NP) levels would serve as an additive diagnostic and prognostic tool. These biomarkers contribute to monitoring the progression of the valve disease, even before the development of hemodynamic consequences in a preclinical stage of myocardial damage. They may contribute to more accurate risk stratification by identifying patients who are more likely to experience death from cardiovascular causes, heart failure, and cardiac hospitalizations, thus requiring surgical management rather than a conservative approach. This article provides a comprehensive overview of the available evidence on the role of NPs in the management, risk evaluation, and prognostic assessment of patients with MR both before and after surgical or percutaneous valve repair. Despite largely positive evidence, a series of controversial findings exist on this relevant topic. Recent clinical trials failed to assess the role of NPs following the interventional procedure. Future larger studies are required to enable the introduction of NP levels into the guidelines for the management of MR

Correction: High piezo-resistive performances of anisotropic composites realized by embedding rGO-based chitosan aerogels into open cell polyurethane foams

Correction for 'High piezo-resistive performances of anisotropic composites realized by embedding rGO-based chitosan aerogels into open cell polyurethane foams' by Tianliang Zhai et al., Nanoscale, 2019, 11, 8835–8844

Atrial natriuretic peptide stimulates autophagy/mitophagy and improves mitochondrial function in chronic heart failure

Mitochondrial dysfunction, causing increased reactive oxygen species (ROS) production, is a molecular feature of heart failure (HF). A defective antioxidant response and mitophagic flux were reported in circulating leucocytes of patients with chronic HF and reduced ejection fraction (HFrEF). Atrial natriuretic peptide (ANP) exerts many cardiac beneficial effects, including the ability to protect cardiomyocytes by promoting autophagy. We tested the impact of ANP on autophagy/mitophagy, altered mitochondrial structure and function and increased oxidative stress in HFrEF patients by both ex vivo and in vivo approaches. The ex vivo study included thirteen HFrEF patients whose peripheral blood mononuclear cells (PBMCs) were isolated and treated with αANP (10-11 M) for 4 h. The in vivo study included six HFrEF patients who received sacubitril/valsartan for two months. PBMCs were characterized before and after treatment. Both approaches analyzed mitochondrial structure and functionality. We found that levels of αANP increased upon sacubitril/valsartan, whereas levels of NT-proBNP decreased. Both the ex vivo direct exposure to αANP and the higher αANP level upon in vivo treatment with sacubitril/valsartan caused: (i) improvement of mitochondrial membrane potential; (ii) stimulation of the autophagic process; (iii) significant reduction of mitochondrial mass-index of mitophagy stimulation-and upregulation of mitophagy-related genes; (iv) reduction of mitochondrial damage with increased inner mitochondrial membrane (IMM)/outer mitochondrial membrane (OMM) index and reduced ROS generation. Herein we demonstrate that αANP stimulates both autophagy and mitophagy responses, counteracts mitochondrial dysfunction, and damages ultimately reducing mitochondrial oxidative stress generation in PBMCs from chronic HF patients. These properties were confirmed upon sacubitril/valsartan administration, a pivotal drug in HFrEF treatment

Preparation, Characterization and Effectiveness to Delay Lipid Oxidation in Almonds and Beef Meat

Funding Information: This study was carried out under the VIPACFood project, funded by ARIMNet2 (Coordination of Agricultural Research in the Mediterranean; 2014–2017), an ERA-NET Action financed by the European Union under the Seventh Framework Programme, and by the Programa de Cooperación Interreg V-A España–Portugal (POCTEP) 2014–2020 (project 0377_IBERPHENOL_6_E). Cássia H. Barbosa is grateful for her research grant in the frame of the VIPACFood project (ARIMNET2/0003/2016) and the Foundation for Science and Technology (FCT), Portugal, for the Ph.D. grant 2021.08154.BD. This research was also funded by PT national funds (FCT/MCTES, Fundação para a Ciência e Tecnologia and Ministério da Ciência, Tecnologia e Ensino Superior) through grants UIDB/50006/2020 and UIDB/00211/2020. L. Barbosa-Pereira is grateful to the Spanish Ministry of Science, Innovation and Universities for her “Juan de la Cierva-Incorporación” grant (Agreement No. IJCI-2017-31665). Publisher Copyright: © 2023 by the authors.Low-density polyethylene-based packaging with 4% lemon extract (LDPE/4LE) and two polylactic-based (PLA) packaging materials with 4% and 6% lemon extract (PLA/PEG/4LE and PLA/6LE) were produced. O2 and water permeability tests were performed, the total and individual phenolic compounds content were measured, and the films’ antioxidant activities were determined. The films’ ability to delay lipid oxidation was tested in two model foods: almonds, packaged with LDPE/4LE, PLA/4LE and PLA/6LE for a maximum period of 60 days at 40 °C (accelerated assay); and beef meat, packaged with the PLA/6LE for a maximum period of 11 days at 4 °C. The LE improved the WVP in all of the active films by 33%, 20% and 60% for the LDPE/4LE, PLA/4LE and PLA/6LE films, respectively. At the end of 10 days, the migration of phenolic compounds through the PLA films was measured to be 142.27 and 114.9 μg/dm2 for the PLA/4LE and PLA/6LE films, respectively, and was significantly higher than phenolic compounds migration measured for the LDPE/4LE (15.97 μg/dm2). Naringenin, apigenin, ferulic acid, eriocitrin, hesperidin and 4-hydroxybenzoic acid were the main identified compounds in the PLA, but only 4-hydroxybenzoic acid, naringenin and p-coumaric acid were identified in the LDPE films. Regarding the films’ ability to delay lipid oxidation, LDPE/4LE presented the best results, showing a capacity to delay lipid oxidation in almonds for 30 days. When applied to raw beef meat, the PLA/6LE packaging was able to significantly inhibit lipid oxidation for 6 days, and successfully inhibited total microorganisms’ growth until the 8th day of storage.publishersversionpublishe