Use of potassium polyaspartate for stabilization of potassium bitartrate in wines: influence on colloidal stability and interactions with other additives and enological practices

Abstract

The research was aimed at verifying the efficacy of potassium polyaspartate (KPA), added at bottling, for prevention of the precipitation of potassium bitartrate (KHT). The stability of KHT was determined with the mini‐contact test and the cold test. The effect of KPA on the colloidal stability of white and red wines was also studied. Turbidity, color, and total anthocyanins and flavonoids (red wines only) were monitored. In the first experiment, the stabilizing effect of KPA added at bottling, with or without Arabic gum, tannins, and filtration (0.45 µm cut‐off), was studied in comparison with metatartaric acid (MTA). KPA proved to have good stabilizing efficacy for prevention of KHT precipitation and maintained its effect in all trials after 1 year of bottle aging. On the contrary, all the trials with MTA became unstable after 6 months. Moreover, KPA did not modify wine turbidity and color. The filtration (0.45 µm cut‐off) did not reduce its stabilizing efficacy. In the second experiment, the effect of KPA added to a white and a red wine, respectively clarified with casein and gelatin or vegetal protein and/or bentonite, was studied. KPA did not cause any increase in turbidity or appreciable changes in the color of the white wines of the different trials. A preliminary treatment with bentonite can prevent the possible formation of haze in red wines after the addition of KPA. Practical Application KPA prevented the precipitation of KHT in unstable white and red wines. The stabilizing effect persisted after 1 year of bottle aging. The oenologist does not need to adopt special prescriptions when using KPA in combination with Arabic gum or tannins in prebottling operations. A treatment with bentonite prevented the appearance of turbidity in red wines after the addition of KPA.

Evaluating Alternatives to Cold Stabilization in Wineries: The Use of Carboxymethyl Cellulose, Potassium Polyaspartate, Electrodialysis and Ion Exchange Resins

“…Several studies have shown that CMC, even without the aid of GA, can be a KHT crystallization inhibitor suitable for red wines [ 19 , 20 , 37 , 38 ]; however, the efficiency of this additive for tartaric stabilization depends on the chemical composition of the wine as well as doses [ 39 ], and our results showed how in 2016 the wines treated with CMC+GA remained stable after one year in the bottle but the same result was not observed in 2017, even though the tartaric acid, Ca and K concentration ( Table 1 and Table 2 ) were lower in this wine. The inhibitory effect of KPA+GA remained after one year in the wine and similar results were observed by Canuti et al [ 40 ] with KPA and Bosso et al [ 36 ] working with KPA combined with GA.…”

“…Several studies have shown that CMC, even without the aid of GA, can be a KHT crystallization inhibitor suitable for red wines [19,20,37,38]; however, the efficiency of this additive for tartaric stabilization depends on the chemical composition of the wine as well as doses [39], and our results showed how in 2016 the wines treated with CMC+GA remained stable after one year in the bottle but the same result was not observed in 2017, even though the tartaric acid, Ca and K concentration (Tables 1 and 2) were lower in this wine. The inhibitory effect of KPA+GA remained after one year in the wine and similar results were observed by Canuti et al [40] with KPA and Bosso et al [36] working with KPA combined with GA. All treatments stabilized the wine, especially the cold treatment, and the wine maintained its stability after a year in the bottle. When looking at the two subtractive methods, the one that led to the most stable wine was ED, although after a year, the wine treated with IER showed the lowest values in the stability test (highest stability).…”

“…In the 2017 wines and after 12 months in the bottle, the observed variations in tannin content between the different wines were lower, the KPA+GA-treated wine being the only wine that significantly differed from the results of the control wine, with a lower concentration of tannin, as also observed in Table 4, although in this case, the values were not significantly different from the control wine. Contrary to these results, Bosso et al [36] reported an increase in the flavonoid compounds after 12 months, when KPA+GA was used to treat the red wine. The mean degree of polymerization was quite similar for all the wines, only slightly higher in the CMC+GA-treated wine.…”

“…Looking at the two additive methods, the one that best stabilized the wine was potassium polyaspartate; it was also the only one that maintained the wine stable after a year of storage in the bottle. Bosso et al [36] also found that KPA was a very good tartaric stabilizer for both red and white wines. Wines treated with carboxymethyl cellulose lost stability twelve months after treatment.…”

Stabilization of wines with polymers and new bio-based carbon materials

“…The purpose of stabilization is to ensure the clarity of the wine during aging and storage. Stabilization is carried out by removal (adsorption) of polyphenolic, protein and crystalline compounds with gluing agents, as well as filtration using membranes [1][2][3][4]. Traditionally, these are bentonite of various modifications, fish glue, albumin, chitosan (and others) and polymer compounds -PVP, PAA, and POE in combinations required for a specific stabilization method [5].…”