Electrically conductive bioplastics based on chitosan,polyvinyl alcohol,polyvinyl pyrrolidone,and plant extract nanoparticles for detecting Rhizopus stolonifer on tomato fruit

This work aimed to manufacture bioplastics with mechanical and electrical properties for monitoring the Rhizopus stolonifer growth in tomato fruit packaging. Bioplastics were based on chitosan/polyvinyl alcohol (Ch/PVA), chitosan/polyvinyl pyrrolidone (Ch/PVP), and nanoparticles (NPs) of plant extracts at 10% and 30% of concentrations. Bioplastics were exposed to tomato inoculated with R. stolonifer for 6 d at 25°C. Water vapor permeability (WVP), mechanical properties, FTIR, UV–vis, morphology, electrical resistance of bioplastics, and the NPs size were assessed. In bioplastics added with plant extracts, 1.5 times more WVP than in the control group (18–35 gs⁻¹m⁻¹Pa⁻¹) were quantified. Ch/PVA bioplastic showed 51% more tensile strength, 44% more elongation at break, and 40% more Young's modulus than Ch/PVP, regardless of the plant extract. The electrical resistance in Ch/PVA bioplastics with 30% mushroom extract and 10% radish allowed the differentiation between inoculated (10⁹–10¹⁰ Ω) and non-inoculated tomatoes (10¹⁰–10¹¹ Ω). The FTIR assay confirmed the presence of each compound used in the bioplastic, and UV–vis confirmed phenols at 300 nm. The NPs measured less than 50 nm. Only Ch/PVA with 30% mushroom and 10% radish can be useful to monitor fungi in tomatoes based on their electrical behavior.     

Health-promoting properties of oleocanthal and oleacein: Two secoiridoids from extra-virgin olive oil

Abstract

Extra virgin olive oil (EVOO) polyphenols, including the secoiridoids oleocanthal (OLC) and oleacein (OLE), are attracting attention because of their beneficial effects on health. Data on OLC and OLE bioavailability are scarce, as most research on EVOO polyphenols has concentrated on hydroxytyrosol, tyrosol, and oleuropein. Consequently, relevant goals for future research are the elucidation of OLC and OLE bioavailability and finding evidence for their beneficial effects through pre-clinical and clinical studies. The aim of this review is to shed light on OLC and OLE, focusing on their precursors in the olive fruit and the impact of agronomic and processing factors on their presence in EVOO. Also discussed are their bioavailability and absorption, and finally, their bioactivity and health-promoting properties.     

Extra virgin olive oil: A comprehensive review of efforts to ensure its authenticity,traceability, and safety

The growing demand for extra virgin olive oil (EVOO), appreciated for its unique organoleptic properties and health benefits, has led to various fraudulent practices to maximize profits, including dilution with lower value edible oils. The adulterated oils would be of poor nutritional quality, more readily oxidized, and may contain unhealthy substances formed during processing. Nevertheless, the range of available techniques to detect fraud in EVOO production has been growing. Reliable markers of EVOO adulteration include fatty acids and minor components such as sterols, tocopherols, triterpene alcohols, phenolic compounds, phospholipids, volatile compounds, and pigments. Additionally, increasing consumer interest in high-quality EVOO has led to the development of robust scientific methods for its traceability. This review focuses on (i) the usefulness of certain compounds as markers of EVOO adulteration; (ii) the potential health risks of consuming adulterated EVOO; and (iii) reliable methods for the geographical traceability of olive oil. In conclusion, fraudulent production practices need to be detected to preserve the beneficial health effects of EVOO and to avoid the potential risks associated with ingesting substandard oil. In this work, as EVOO certification and regulatory framework limitations have already been extensively reviewed, we focus our attention on biomarkers that guarantee both the authenticity and traceability of oil, and consequently its health properties. When it is unavailable to obtain a high-resolution mass spectrometry full fingerprint, stigmastadienes and the sterolic profile are proposed as reliable markers.     

NMR spectroscopy: a powerful tool for the analysis of polyphenols in extra virgin olive oil

Extra virgin olive oil (EVOO), a key component of the Mediterranean diet, has aroused interest in recent years due to its health properties. Nuclear magnetic resonance (NMR) spectroscopy is an appropriate tool for the accurate quantification of minor compounds in complex food matrices, such as polyphenols in olive oil. Flavonoids, lignans, secoiridoids and phenolic acids and alcohols in EVOO have been identified and quantified by NMR. This review provides an overview of the major developments in the structural elucidation of polyphenol compounds in EVOO. © 2019 Society of Chemical Industry