Antimicrobial activity of different nanocellulose films embedded with thyme, cinnamon, and oregano essential oils for active packaging application on raspberries

The study focuses on the antimicrobial activity of nanocellulose films (NFC) embedded with thyme, cinnamon, and oregano essential oils for active packaging application. The activity against model pathogenic bacteria was first tested to obtain each oil's minimum inhibitory concentration (MIC). The tests showed that the surface area of the films and the quantity of essential oil strongly influenced the antimicrobial effect. Then, the different active packaging systems were tested directly on packed raspberries to study their actual commercial packaging conditions. Through 12 days of storage at 1 & DEG;C, it was observed that thyme and oregano essential oils were more effective in maintaining the firmness and reducing the weight loss of the fruits compared to cinnamon essential oil or the control; no significant effect was observed on the other quality parameters that were considered. The essential oils independently proved effective in preventing fungal growth. However, the combined impact of thyme+oregano (NAP_TO) demonstrated the best performance.COST ACTION 19124 CIRCULA-BILITYinfo:eu-repo/semantics/publishedVersio

Atmospheric plasma assisted PLA/microfibrillated cellulose (MFC) multilayer biocomposite for sustainable barrier application

Fully bio-based and biodegradable materials, such as polylactic acid (PLA) and microfibrillated cellulose (MFC), are considered in order to produce a completely renewable packaging solution for oxygen barrier applications, even at medium-high relative humidity (R.H.). Thin layers of MFC were coated on different PLA substrates by activating film surface with an atmospheric plasma treatment, leading to the fabrication of robust and transparent multilayer composite films, which were then characterized by different experimental techniques. UV transmission measurements confirmed the transparency of multilayer films (60% of UV transmission rate), while SEM micrographs showed the presence of a continuous, dense and defect free layer of MFC on PLA surface. Concerning the mechanical behavior of the samples, tensile tests revealed that the multilayer films significantly improved the stress at break value of neat PLA. Moreover, the oxygen barrier properties of the multilayer films were improved more than one order of magnitude compared to neat PLA film at 35\ua0\ub0C and 0% R.H. and the permeability values were maintained up to 60% R.H. The obtained materials therefore showed interesting properties for their possible use in barrier packaging applications as fully biodegradable solution, coupling two primarily incompatible matrices in a multilayer film with no need of any solvent or chemical

FTIR-ATR Study of Water Distribution in a Short-Side-Chain PFSI Membrane

Fourier transform infrared\u2013attenuated total reflectance (FTIR-ATR) spectroscopy was used to study in detail water vapor sorption in a short-side-chain perfluorosulfonic acid ionomer membrane suitable for use as electrolyte in proton exchange membranes fuel cells. The analysis of the membrane IR spectra, at different values of relative humidity (0.00\u20130.50) and at 35 \ub0C, allows to identify four types of water molecules, characterized by decreasing strength of interaction with the polymer sulfonate groups. The actual concentration of the different water species inside the membrane was determined by calibrating the IR absorbance data with independent measurements of total water vapor uptake. The sorption of the different populations of water can be represented by Langmuir isotherms: the first population is directly attached to sulfonate sites, while the others form subsequent layers, adsorbed one onto the other in a shell-like structure. To describe the overall sorption behavior of the different populations, four adjustable parameters are required, which are consistent with literature data, thus supporting the validity of the physical model considered