Going through the wine fining: Intimate dialogue between organics and clays

Abstract

Wine chemistry inspires and challenges with its complexity and intriguing composition. In this context, the composites based on the use of a model protein, a polyphenol of interest and montmorillonite in a model hydroalcoholic solution have been studied. A set of experimental characterization techniques highlighted the interactions between the organic and the inorganic parts in the composite. The amount of the organic part was determined by ultraviolet-visible (UV-VIS) and thermal analysis. X-ray diffraction (XRD) and transmission electronic microscopy (TEM) informed about the stacking/exfoliation of the layers in the composites. Vibrational and nuclear magnetic resonance spectroscopies methods stressed on the formation of a complex between the protein and the polyphenol before adsorption on the clay mineral. The mobility/rigidity of the organic parts were determined by fluorescence time resolved spectroscopy. Changes in the secondary structure of the protein occured upon complexation with polyphenol on clay mineral due to strong interactions. Although not representating faithfully enological conditions, these results highlight the range and nature of mechanisms possibly involved in wine fining.

Oxide-Clay Mineral as Photoactive Material for Dye Discoloration

“…Clay minerals have attracted attention in recent years as functional materials owing to their special and different structures, high specific surface areas, and remarkable adsorption capacities [29,30]. They can be used as alternative materials for the immobilization of compounds with photocatalytic properties [31,32].…”

Metal-Modified Montmorillonite as Plasmonic Microstructure for Direct Protein Detection

“…The low enhancing efficiency of Al_MMT treated with Trp can be explained by the low absorption of Trp of MMT due to the counterbalance of either positive (-NH 2 ) and negative (-COOH) groups in the aminoacidic structure. On the contrary, different studies showed the prompt absorption of BSA at the surface or the edges of MMT by electrostatic and/or chemical interaction [42,43]. Noticeably, while the fluorescent signal measured for Trp was reproducible between different tests (small standard deviation) both in water and with Al_MMT (Figure 7A), the reproducibility between measurements was observed only in water in the case of BSA.…”

Through alizarin-hectorite pigments: Influence of organofunctionalization on fading

“…Aluminum, iron, magnesium and sometimes lithium occupy the octahedral sites, whereas silicon and, in part aluminum occupy tetrahedral sites. Various cations, but specially Na + and Ca 2+ , may occupy interlayer positions [27,28].…”