Optimal Conditions for Effective Use of Acid Urease in Wine

Assessment of Urea Degradation Rate in Model Wine Solutions by Acid Urease fromLactobacillus fermentum

“…Validation Tests Using Real Wines. To further check the short-cut method developed here, the time course of the urea degradation tests performed on a few real wines by Kodama (25) and Trioli and Ough (23) was characterized in terms of the half-life time (t 1/2 ), that is, the time needed to reduce the initial urea concentration by a factor of 2.…”

“…Because the enzyme preparation specific costs are of the order of 1 euro/g, the enzymatic processing costs per each liter of product treated may be uneconomical, especially if the process time is required to be <7 days. To avoid kidney stones and other diseases, urease can be quite easily inactivated by resorting to pasteurization (16) and clarification in the case of sake production or removed via bentonite adsorption and filtration in the case of table wine production (25). This clearly shows that the enzyme is applicable to the elimination of urea in fermented beverages with minimal modification of the conventional processes.…”

“…Despite this method having been industrialized and used for urea removal from sake by many companies in Japan, its extension to wines is restricted yet. The quite numerous experimental trials currently available refer to a limited number of wine types (11,(18)(19)(20)(21)(23)(24)(25)(26)(27). However, their main results do not appear to be usable for a safe extrapolation of the urease activity in any wine of given characteristics as a function of the enzyme concentration.…”

Assessing the Potential Content of Ethyl Carbamate in White, Red, and Rosé Wines as a Key Factor for Pursuing Urea Degradation by Purified Acid Urease

“…Obviously, the activity of acid urease is not only inhibited by total phenolics, but also by other wine components, such as malic and lactic acids, pH, SO 2 , and ethanolic degree (Trioli and Ough ; Famuyiwa and Ough ; Kodama ; Fidaleo and others ). The dependence of the specific activity π A (= r A0 / E 0 ) for a killed cell‐based acid urease preparation on the aforementioned parameters was previously expressed by means of a 2nd‐order canonical regression (Fidaleo and others ).…”

“…10 and plotted in Figure . Such a model was also able to fit previous data collected by Fujinawa and others (), Kodama (), Kodama and Yotsuzuka (), and Esti and others (). Thus, in agreement with Jiao and others (), it can be recognized as a milestone in the utilization of acid urease.…”