Use of Wheat Gluten as Clarifying Agent of Musts and White Wines

Abstract

The bovine spongiform encephalopathy crisis has led some winemakers to question gelatin as a fining agent and to reject the use of animal proteins. Gluten was evaluated as a substitute for gelatin by comparing gluten treatments to other fining agents currently used (casein, association gelatin-tannin, fish glue, bentonite). The turbidity of a Chardonnay must treated by gluten (20 and 40 g/hL) was approximately 70% less than that of the control. A gluten with high hydrolysis of prolamins gave poor flocculation. Better results were obtained with partially hydrolyzed and deamidated wheat proteins and vital gluten. Gluten at 20 g/hL and the mixed tannin-gelatin at 5 g/hL had similar clarifications. Must treated with bentonites at 60 g/hL had 50 to 60% lower turbidity than untreated must. Compared with gluten only, deamidated gluten associated with tannin had poor clarifying efficiency. Fining of Chardonnay wine showed efficient clarification with gluten at 20 and 40 g/hL depending upon the gluten type. Wine fining with gluten was similar to fining with tannin-gelatin and more efficient than bentonite treatment. However, lower turbidities were obtained with fish glue at 1 g/hL and casein at 5 g/hL. The volume of lees generated by fining with gluten ranged between 0.2 and 0.4% (v/v), similar to the values obtained with casein, fish glue, and tannin-gelatin and much lower than the value obtained with bentonites.