Evaluation of Plant-Based Byproducts as Green Fining Agents for Precision Winemaking

Abstract

Consumers are increasingly looking for foods, including wine, that are free of animal-derived proteins. This study seeks to evaluate patatin, a new, plant-based and allergen-free fining agent, by comparing it with the fining agents polyvinipolypyrrolidone, bovine serum albumin, and methylcellulose. Specifically, its effects on the phenolic profile of enological tannins were analyzed with four spectrophotometric assays: OD 280 nm, Folin–Ciocâlteu, Adams–Harbertson, and methylcellulose. In addition, changes in the polyphenol composition of Sangiovese red wine were determined by UV-Vis spectrophotometry and HPLC with adsorption trials, and the solid–liquid interaction in a wine solution was modeled by both Langmuir and Freundlich equations. Our findings highlight the occurrence of systematic proportional error between the selected spectrophotometric assays. As a result, direct comparisons of protein precipitation assays can be made only among results obtained with the same spectrophotometric method. However, it is clear that patatin has an impact on the phenolic profile of Sangiovese red wine: it removes simple phenolics (gallic acid, (+)-catechin, (–)-epicatechin, epicatechin gallate, syringic acid, fertaric acid, coutaric acid, and rutin) as well as both oligomeric and polymeric tannins to different extents. In concentrations of less than 1 g/L, the patatin isotherm showed a linear relation between the equilibrium concentration and the quantity absorbed, obeying the Freundlich model reasonably well (KF 1.46; 1/n 1.07; R2 0.996 with 1/n > 1). Thus, the adsorption process is strongly dependent on the fining dosage.

Potentialities of the Extraction Technologies and Use of Bioactive Compounds from Winery by-Products: A Review from a Circular Bioeconomy Perspective

“…This mixture, known as PVPP-white wine extract, is obtained through selective adsorption and contains a high concentration of phenolic compounds, making up roughly 80% of its dry mass. Among these compounds, phenolic acids, such as caftaric acid, and proanthocyanidins, such as catechin oligomers, are the most dominant [150][151][152]. This blend of phenolics exhibited impressive antioxidant activity by effectively scavenging superoxide anion radicals and maintaining lipid peroxidation in biological membranes.…”