Browsing by Author "Martins, Jorge Manuel"

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    Grape Canes (Vitis vinifera L.) Applications on Packaging and Particleboard Industry: New Bioadhesive Based on Grape Extracts and Citric Acid
    (2022) Santos, Jorge; Pereira, Joao; Escobar-Avello, Danilo; Ferreira, Irene; Vieira, Carlos; Magalhaes, Fernao D.; Martins, Jorge Manuel; Carvalho, Luisa H.
    The main by-product generated in the wine industry are the grape canes, derived from the pruning process. In order to increase the valorisation possibilities of this highly polyphenolic lignocellulosic material, this work focuses on its applicability in the materials industry. As a first step, we demonstrate the viability of using grape cane particles as raw material for particleboard production, combined with a melamine formaldehyde urea (MFU) binder. In addition, looking for the application of these particleboards in the food packaging industry, particleboards based on grape canes were also produced using a new bioadhesive, obtained from the grape cane extract and citric acid. The self-condensation reaction of the grape cane extracts, and the curing reaction with citric acid, were studied by FTIR-ATR and ABES showing the feasibility of this new bioadhesive formulation. Looking for a zero-waste process, the effect of the type of raw material (fresh grape cane, solid by-product of the extraction) and of the extract used on the properties of particleboard were also studied. Citric acid was demonstrated to be a good crosslinking agent for grape cane extract. This work shows that it is possible to produce a new lignocellulosic product based only on grape cane particles using a binder based on grape cane extracts and citric acid. The implemented methodology allowed producing particleboards with applicability in the food-packaging industry, minimizing the waste generated in the process.
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    High-value compounds obtained from grape canes (Vitis vinifera L.) by steam pressure alkali extraction
    (2022) Santos, Jorge; Escobar-Avello, Danilo; Magalhaes, Pedro; Martins, Jorge Manuel; Gonzalez-alvarez, Julia; Carvalho, Luisa Hora de
    The main by-product generated by the wine industry is the grape canes derived from the pruning process. The aim of the current work was the valorisation of this highly poly phenolic lignocellulosic material, by alkali extraction methodology avoiding alcoholic solvents use. In lignocellulosic by-products valorisation, it is important to take into account the variability of the raw material. In the case of vine pruning this may be due to the different varieties used, the geographical area, the climate, or the processing. It is, however, important to develop a global strategy for valorisation, from a biorefinery and circular economy point of view. In this work, the grape canes were characterised, before and after the extraction process, by Fourier transform infrared spectroscopy - attenuated total reflectance (FTIR-ATR) spectroscopy. Changes in cellulose crystallinity, hemicellulose content and structural conformation of proteins, due to the alkali thermal extraction process were identified and evaluated. For the first time, a steam pressure alkali extraction method was used on this material. The products were characterised by FTIR-ATR and Matrix Assisted Laser Desorption Ionisation-Time of Flight (MALDI-TOF) mass spectrometry. The presence of high-value compounds such as stilbene oligomers and condensed tannins was demonstrated in the extracts. The work shows the viability of the steam pressure alkali extraction, a simple and environmentally friendly method, for grape cane valorisation. (c) 2022 Institution of Chemical Engineers. Published by Elsevier Ltd. All rights reserved.