Use of ultrafiltration and proteolytic enzymes as alternative approaches for protein stabilisation of white wine

Abstract

Background and Aims: Precipitation of unstable proteins present in white wine after bottling can cause cloudiness, which is generally considered commercially unacceptable. Winemakers therefore use bentonite to remove protein prior to bottling, however, this can result in losses of wine volume and/or sensory quality. As such, there is interest in alternate strategies for protein stabilisation. This study evaluated the potential for ultrafiltration (UF), in combination with heat and proteolytic enzymes, to remove haze-forming proteins and stabilise white wine. Methods and Results: Heat-unstable white wines were fractionated using UF membranes with nominal 10 or 20 kDa molecular mass cutoff specifications, to first assess protein removal. Fractionation of wines with the 10 kDa membrane generated heat-stable permeate and protein-rich retentate. Pilot and semi-commercial scale trials were therefore conducted with 10 kDa molecular mass cutoff membranes and conditions optimised for heat and enzyme treatment of retentate. Heating retentate at 62 C for 10 min (with or without enzyme addition) achieved significant protein removal (30-96%, depending on the protein concentration of wine). Recombination of treated retentate with permeate gave wine that was almost heatstable, such that a substantially reduced amount of bentonite (~50-60%) was required to achieve full heat stabilisation. Conclusions: Ultrafiltration can fractionate white wine, enabling targeted heat and enzyme treatment of a protein-rich fraction of wine, thereby mitigating the impacts of traditional stabilisation treatments on wine aroma and flavour. Significance of the Study: This is the first study to evaluate the combined use of UF, heat and proteolytic enzyme treatments as an alternative approach to protein stabilisation of white wine.

The Effect of Dicarboxymethyl Cellulose on the Prevention of Protein Haze Formation on White Wine

“…Therefore, DCMC promoted wine stabilization as verified by heat stability test. Contrarily to other methods described in the literature, DCMC can be used in very low doses and without heating the samples [3,8].…”

“…Therefore, DCMC promoted wine stabilization as verified by heat stability test. Contrarily to other methods described in the literature, DCMC can be used in very low doses and without heating the samples [3,8]. To understand the impact of the protein concentration in the wine stability, total protein was quantified in both control and fined wines.…”

“…These drawbacks drive the search for new wine protein removal methods and materials. Several techniques and materials have been studied as alternatives to bentonite fining [3,[6][7][8][9].…”

Advances in White Wine Protein Stabilization Technologies

“…The table includes the operating conditions, range of protein reduction (%), and time of application for each technology. AF 2-3 g/L 67-95% [24][25][26] Physical-enzymaticmixed treatments High power ultrasound AF 30%/10 min; 60-90%/5-10 min n/a [27] Heat + enzymes BF 75 • C for 1 min + 15 mg/L of enzymes 1 81-84% [5] AF 75 • C for 2 min + 2 mL/L of enzymes 2 80-90% for CHI [28] Ultrafiltration AF 80% permeate/20% retentate, 10 kDa membrane n/a [29] Ultrafiltration + heat + enzymes AF 62 • C for 10 min + 30 mg/L of enzymes 1 30-96% [29] Immobilized enzyme supported on chitosan AF Continuous PBR 3 : 0.3-15 mL/min flow and 106-260 g/L 4-68% 61-63% [30,31] Adsorption-based treatments Magnetic nanoparticles coated with acrylic acid AF 10 W by 10 min (plasma deposition) and 13.3-25 g/L for 10 min >90% [32][33][34] Zeolites AF 4-8 g/L of zeolites for 1-3 h >90% [35,36] Roasted grape seeds powder BF 5-15 g/L for 1 h 37-85% [37,38] AF 25-32 g/L for 1 h 90-98% [37] Zirconium DF 25 g/L pellet in metallic cage for 3 days ~90% [39] AF Batch: 25 g/L for 72-192 h >70% [22] Continuous: 175-300 BV 4 (~5.7-3.3 g/L) for 30 min of residence time ~42% [40] Closed-loop operation: pellet packed (6.5 L), 300 L/h flow rate for 8-139 h ~54-60% [41,42] 1 Enzyme type: Proctase, prepared containing aspergillopesin I and II. 2 Enzyme type: Two proteases in aspergillopepsin-containing liquid preparations obtained from Aspergillus niger.…”

DCMC as a Promising Alternative to Bentonite in White Wine Stabilization. Impact on Protein Stability and Wine Aromatic Fraction

“…Therefore, there is a significant focus on developing alternative economical practices to replace bentonite to stabilize wines. Some of these state-of-the-art practices include the use of magnetic nanoparticles [ 7 ], free [ 8 ] and immobilized proteases [ 9 ], chitosan [ 10 ] or chitin-rich yeasts [ 6 ], zirconia [ 11 ] or low-swelling adsorbing clays [ 12 ], together with techniques such as ultrafiltration [ 13 ] or flash pasteurization [ 14 ].…”